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WO2020209014A1 - Light emitting element and method of manufacturing light emitting element - Google Patents

Light emitting element and method of manufacturing light emitting element Download PDF

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Publication number
WO2020209014A1
WO2020209014A1 PCT/JP2020/011575 JP2020011575W WO2020209014A1 WO 2020209014 A1 WO2020209014 A1 WO 2020209014A1 JP 2020011575 W JP2020011575 W JP 2020011575W WO 2020209014 A1 WO2020209014 A1 WO 2020209014A1
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light emitting
layer
active layer
type
atoms
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PCT/JP2020/011575
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French (fr)
Japanese (ja)
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石崎　順也
山田　雅人
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信越半導体株式会社
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
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    • H01L21/02387—Group 13/15 materials
    • H01L21/02395—Arsenides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/40—AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02439—Materials
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02439—Materials
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    • H01L21/02463—Arsenides
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02494—Structure
    • H01L21/02496—Layer structure
    • H01L21/02505—Layer structure consisting of more than two layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02538—Group 13/15 materials
    • H01L21/02543—Phosphides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/0257—Doping during depositing
    • H01L21/02573—Conductivity type
    • H01L21/02576—N-type
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    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/0257—Doping during depositing
    • H01L21/02573—Conductivity type
    • H01L21/02579—P-type
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    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/0262—Reduction or decomposition of gaseous compounds, e.g. CVD
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/81—Bodies
    • H10H20/822—Materials of the light-emitting regions
    • H10H20/824—Materials of the light-emitting regions comprising only Group III-V materials, e.g. GaP

Definitions

  • the present invention relates to a method for manufacturing a light emitting element and a light emitting element, and particularly to a method for manufacturing a light emitting element and a light emitting element having good luminance characteristics with respect to an environmental temperature and suppressing deterioration of life characteristics.
  • the AlGaInP-based material has the largest direct transition energy gap in the III-V compound semiconductor mixed crystal excluding nitrides, and is attracting attention as a material for visible light emitting devices in the 550 to 650 nm band (green to red region). ing.
  • An AlGaInP-based light emitting element having an active layer made of AlGaInP having such a large direct transition type energy gap can emit light with higher brightness than those using an indirect transition type material such as GaP or GaAsP ().
  • Patent Document 1 discloses Patent Document 1.
  • FIG. 4 is a schematic cross-sectional view showing an example of a conventional AlGaInP-based light emitting device.
  • the light emitting device 310 is formed on a GaAs starting substrate 300 with a GaAs buffer layer having a thickness of 0.1 to 1.0 ⁇ m, for example, an AlInP etch stop layer 302 having a thickness of 1.0 ⁇ m, for example, an N-type AlGaInP clad layer having a thickness of 1.0 ⁇ m.
  • the GaAs buffer layer may not be particularly provided. In FIG. 4, the electrodes of the light emitting element and the like are omitted.
  • an N-type dopant for example, Si, S, Se, etc. are doped into the N-type clad layer 303.
  • As the P-type dopant Zn, Mg, Te and the like are doped into the P-type clad layer 305, the P-type buffer layer 306 and the P-type current propagation layer 307.
  • the N-type clad layer 303 is composed of an epitaxial layer having one or more compositions and a doping level
  • the P-type clad layer 305 is composed of an epitaxial layer having one or more layers and a doping level.
  • the active layer 304 is composed of a bulk-type active layer having a uniform composition or a multi-bonded active layer in which a luminescent recombination layer and a barrier layer having a bandgap composition larger than the composition of the luminescent recombination layer are multi-bonded.
  • the concentration of the dopant remaining in the active layer or diffused / electrophoresed during the life test is minimized in order to avoid deterioration of the life characteristics.
  • the lifetime characteristics can be improved by minimizing the dopant concentration in the active layer, the change in brightness with respect to the ambient temperature tends to be large.
  • it has been found that it is effective to add an excessive amount of dopant in the active layer in order to improve the luminance characteristics with respect to the ambient temperature.
  • the dopant excessively charged into the active layer improves the luminance characteristics, it becomes a source of dislocations and defects and significantly deteriorates the lifetime characteristics.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide a light emitting device having good luminance characteristics with respect to environmental temperature and suppressing deterioration of life characteristics, and a method for manufacturing the same.
  • the present invention is a light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
  • the active layer contains a P-type dopant whose concentration gradually decreases from the P-type clad layer side to the N-type clad layer side. 2.
  • the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 ⁇ 10 16 atoms / cm 3 or more.
  • a light emitting element having a concentration of 0 ⁇ 10 17 atoms / cm 3 or less.
  • the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 ⁇ 10 16 atoms / cm 3 or more. , The light output is improved and the brightness characteristic with respect to the ambient temperature is improved. Further, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 3.0 ⁇ 10 17 atoms / cm 3 or less, and in the active layer.
  • the concentration profile of the P-type dopant that gradually decreases from the P-type clad layer side to the N-type clad layer side can suppress deterioration of the life characteristics.
  • the light emitting unit can be made of an AlGaInP-based compound semiconductor.
  • the present invention can be particularly preferably used for a light emitting device in which the light emitting portion is made of an AlGaInP-based compound semiconductor.
  • the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer to the position of 2/3 of the thickness is 0. .3 ⁇ 10 16 atoms / cm 3 or more and 3.0 ⁇ 10 16 atoms / cm 3 or less.
  • the P-type dopant concentration is in the above-mentioned numerical range in the above-mentioned region as described above, the deterioration of the life characteristic can be suppressed more reliably.
  • the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the P-type clad layer to the N-type clad layer is 0.3 ⁇ 10. It can be 16 atoms / cm 3 or less.
  • the P-type dopant concentration is in the above-mentioned numerical range in the above-mentioned region as described above, the deterioration of the life characteristic can be suppressed more reliably.
  • the present invention is a method for manufacturing a light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
  • the concentration of the P-type dopant gradually decreases from the P-type clad layer side to the N-type clad layer side, and 3.
  • the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 ⁇ 10 16 atoms / cm 3 or more.
  • a method for manufacturing a light emitting device which comprises doping the P-type dopant so as to be 0 ⁇ 10 17 atoms / cm 3 or less.
  • the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 ⁇ 10 16 atoms / cm 3 or more. If manufactured in, the light output will be improved and the brightness characteristics with respect to the ambient temperature will be improved. Further, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is set to 3.0 ⁇ 10 17 atoms / cm 3 or less, and the activity is increased. By setting the concentration profile of the P-type dopant that gradually decreases from the P-type clad layer side to the N-type clad layer side in the layer, deterioration of the life characteristics can be suppressed.
  • the light emitting unit can be made of an AlGaInP-based compound semiconductor.
  • the present invention can be particularly preferably used for manufacturing a light emitting device in which the light emitting unit is made of an AlGaInP-based compound semiconductor.
  • the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 thickness of the active layer to the position of 2/3 thickness is 0.3. It can be doped so as to be ⁇ 10 16 atoms / cm 3 or more and 3.0 ⁇ 10 16 atoms / cm 3 or less.
  • the P-type dopant concentration is set within the above numerical range in the above region in this way, deterioration of the life characteristics can be suppressed more reliably.
  • the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the P-type clad layer to the N-type clad layer is 0.3 ⁇ 10 16 atoms /. It can be doped so as to be cm 3 or less.
  • the P-type dopant concentration is set within the above numerical range in the above region in this way, deterioration of the life characteristics can be suppressed even more reliably.
  • the active layer is doped with the P-type dopant. This can be done by gas doping while forming the active layer.
  • the active layer is doped with the P-type dopant.
  • the P-type clad layer doped with the P-type dopant is formed and then heat-treated to diffuse the P-type dopant doped in the P-type clad layer into the active layer. Can be done by.
  • each of the above regions can be easily doped with the above concentration profile.
  • the light emitting element and the method for manufacturing the light emitting element of the present invention it is assumed that the light output is improved, the brightness characteristic with respect to the ambient temperature is good, and the deterioration of the life characteristic is suppressed. Can be done.
  • the present inventors have found that at least in a light emitting element having a light emitting portion in which an N-type clad layer, an active layer and a P-type clad layer are formed in this order, the ambient temperature Since the major factor that changes the brightness characteristics is the behavior of carriers in the P-type carrier-rich region in the active layer region, the active layer region near the P-type clad layer, specifically, 1/3 of the total thickness of the active layer.
  • the region closer to the P-type clad layer is defined as the P-type active layer region, and the concentration of the P-type dopant in the P-type active layer region is 1.0 ⁇ 10 16 atoms / cm 3 or more and 3 ⁇ 10 17 atoms / cm.
  • the concentration profile gradually decreases from the P-type clad layer side to the N-type clad layer side toward the active layer during epitaxial growth.
  • the present invention is not limited thereto.
  • the light emitting device 110 of the first embodiment has a GaAs buffer layer having a thickness of 0.1 to 1.0 ⁇ m, for example, an AlInP etch stop layer 102 having a thickness of 1.0 ⁇ m, for example, a thickness on the GaAs starting substrate 100.
  • the InGaP buffer layer 106 has, for example, a P-type GaP current propagation layer 107 having a thickness of 5.0 ⁇ m, which propagates and diffuses the current applied to the device and has a function of extracting light.
  • the GaAs buffer layer may not be particularly provided. In FIG. 1, the electrodes of the light emitting element and the like are omitted.
  • one or more of Si, S, and Se as N-type dopants are doped into the N-type clad layer 103, and one or more of Zn, Mg, and Te as P-type dopants are the P-type clad layer 105 and The P-type buffer layer 106 and the P-type current propagation layer 107 are doped.
  • the N-type clad layer 103 is composed of one or more layers of epitaxial layers having a composition and a doping level
  • the P-type clad layer 105 is composed of an epitaxial layer having one or more layers and a doping level.
  • the active layer 104 is composed of a bulk type active layer having a uniform composition.
  • the active layer 104 is doped with a P-type dopant whose concentration gradually decreases from the P-type clad layer 105 toward the N-type clad layer 103, for example, in a gentle or stepwise manner (gradient doping).
  • grade doping a gentle or stepwise manner.
  • the following shows an example in which two types of Zn and Mg are doped as P-type dopants, but the present invention is not limited to this, and for example, only Zn can be doped, or three or more types can be doped.
  • the light emitting portion (N-type clad layer, active layer, P-type clad layer) is made of an AlGaInP-based compound semiconductor will be described, but the present invention is not limited thereto.
  • FIG. 2 shows an explanatory diagram of the average concentration of P-type dopant in the active layer.
  • the direction from the P-type clad layer 105 to the N-type clad layer 103 is defined as the depth direction of the active layer 104, and the interface between the active layer 104 and the P-type clad layer 105 is used as a reference for the depth position.
  • the concentration profile of the gradient dope is a region from the P-type clad layer 105 to the position of 1/3 of the depth (that is, a region from the P-type clad layer 105 to the position of 1/3 of the thickness of the active layer 104).
  • the average P-type dopant concentration in the above is 1.0 ⁇ 10 16 atoms / cm 3 or more and 3 ⁇ 10 17 atoms / cm 3 or less.
  • the average concentration of Zn is designed to be, for example, 5 ⁇ 10 16 atoms / cm 3
  • the average concentration of Mg is designed to be, for example, 1 ⁇ 10 16 atoms / cm 3 (total average concentration: 6). ⁇ 10 16 atoms / cm 3 ). If there is only one type of P-type dopant doped in the region up to the position of 1/3 of the depth, it is sufficient that the average concentration of the one type is within the above concentration range. If there are two or more types, the total value obtained by adding the average concentrations of each may be within the above concentration range.
  • the P-type dopant is gradient-doped and the average concentration of the region up to the depth of 1/3 is 3.0 ⁇ 10 17 atoms / cm 3 or less, deterioration of the lifetime characteristics can be suppressed. Is. Moreover, since the average density of the region up to the depth 1/3 position is 1.0 ⁇ 10 16 atoms / cm 3 or more, the light output can be improved and the luminance characteristic with respect to the ambient temperature can be improved. Can be done. As described above, when the concentration profile of the P-type dopant in the active layer 104 satisfies the above conditions, it is possible to achieve both improvement of luminance characteristics with respect to environmental temperature and suppression of deterioration of life characteristics, which could not be achieved by conventional products. Can be done.
  • An active layer consisting of x ⁇ 1,0.4 ⁇ y ⁇ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1,0.4 ⁇ y ⁇ 0.6) 1.0 ⁇ m thick P-type clad layer made of, Ga y in 1-y P (0.0 ⁇ y ⁇ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5 ⁇ m thick
  • a wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers). Further, electrodes were formed, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
  • the active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1, 0.4 ⁇ y ⁇ 0.6) layer having a uniform composition.
  • the active layer was doped with a P-type dopant so that the concentration gradually decreased from the P-type clad layer to the N-type clad layer.
  • a plurality of light emitting devices having different average concentrations in the region were manufactured.
  • an experiment was conducted on the relative light output ratio at 0 ° C. and 60 ° C. and the life characteristics. The results are shown in Table 1.
  • the relative light output As shown in Table 1, if the average concentration of the region from the P-type clad layer to the position of 1/3 of the depth is 1.0 ⁇ 10 16 atoms / cm 3 or more in the gradient-doped active layer, the relative light output It can be seen that the ratio is 0.86 or more, the ratio is closer to 1, and the change in output with respect to the ambient temperature can be reduced. Further, it can be seen that if the life characteristic is 3.0 ⁇ 10 17 atoms / cm 3 or less, the life characteristic can be 81% or more, and its deterioration can be suppressed.
  • a region from the P-type clad layer 105 to a depth of 1/3 to a depth of 2/3 (that is, from the P-type clad layer 105 to 1 / of the active layer 104).
  • the average P-type dopant concentration in the region from the position of 3 thickness to the position of 2/3 thickness) is 0.3 ⁇ 10 16 atoms / cm 3 or more and 3.0 ⁇ 10 16 atoms / cm 3 or less. Is preferable.
  • the average concentration of Zn is designed to be, for example, 2 ⁇ 10 16 atoms / cm 3
  • the average concentration of Mg is designed to be, for example, 0.5 ⁇ 10 16 atoms / cm 3 (total average concentration: 2.5 ⁇ ). 10 16 averages / cm 3 ).
  • concentration range as described above deterioration of life characteristics can be suppressed more reliably.
  • the average P-type dopant concentration (specifically, the total value of the average concentrations of Zn and Mg) of the region up to the mold clad layer 103 is 0.3 ⁇ 10 16 atoms / cm 3 .
  • the lower limit is not particularly limited, but may be, for example, 0 atoms / cm 3 or more. Within the concentration range as described above, deterioration of life characteristics can be suppressed even more reliably.
  • the light emitting element 210 of the second embodiment has a GaAs buffer layer having a thickness of 0.5 ⁇ m, for example, an AlInP etch stop layer 202 having a thickness of 1.0 ⁇ m, for example, a thickness of 1 on the GaAs starting substrate 200.
  • the layer 206 has, for example, a 5.0 ⁇ m P-type GaP current propagation layer 207 having a function of propagating and diffusing the current applied to the element and extracting light.
  • the GaAs buffer layer may not be particularly provided. In FIG. 3, the electrodes of the light emitting element and the like are omitted.
  • One or more of Si, S, and Se as N-type dopants are doped into the N-type clad layer 203, and one or more of Zn, Mg, and Te as P-type dopants are P-type clad layer 205 and P-type.
  • the buffer layer 206 and the P-type current propagation layer 207 are doped.
  • the N-type clad layer 203 is composed of one or more layers of epitaxial layers having a composition and a doping level
  • the P-type clad layer 205 is composed of an epitaxial layer having one or more layers and a doping level.
  • the active layer 204 is composed of a multi-bonded active layer in which a light-emitting recombination layer made of AlGaInP and a barrier layer having a bandgap composition larger than that of the light-emitting recombination layer are multi-bonded. ..
  • the barrier layer has a higher Al composition than the AlGaInP of the luminescent recombination layer.
  • the thickness of the barrier layer may be set to be thinner than the de Broglie wavelength at which the wave functions overlap, or may be set to a thicker thickness. For example, the thickness of the luminescent recombination layer is 8 nm, the thickness of the barrier layer is 8 nm, and a 30-pair active layer structure can be formed.
  • the active layer 204 is doped with a P-type dopant whose concentration gradually decreases from the P-type clad layer 205 to the N-type clad layer 203, for example, in a gentle or stepwise manner (gradient doping).
  • a P-type dopant whose concentration gradually decreases from the P-type clad layer 205 to the N-type clad layer 203, for example, in a gentle or stepwise manner (gradient doping).
  • the concentration profile of the gradient dope shows that the average P-type dopant concentration in the region from the P-type clad layer 205 to the position of 1/3 depth is 1.0 ⁇ 10 16 atoms / cm 3 or more and 3 ⁇ 10 17 atoms / cm 3 It is as follows. Specifically, as the P-type dopant, the average concentration of Zn is designed to be, for example, 5 ⁇ 10 16 atoms / cm 3 , and the average concentration of Mg is designed to be, for example, 1 ⁇ 10 16 atoms / cm 3 (total average concentration: 6). ⁇ 10 16 atoms / cm 3 ). If it is such a thing, it is possible to achieve both brightness characteristics with respect to good environmental temperature and good life characteristics.
  • the average P-type dopant concentration in the region from the P-type clad layer 205 at a depth of 1/3 to a depth of 2/3 is 0.3 ⁇ 10 16 atoms / cm 3 or more and 3.0 ⁇ 10 16 atoms. It is preferably 1 / cm 3 or less.
  • the average concentration of Zn is designed to be, for example, 2 ⁇ 10 16 atoms / cm 3
  • the average concentration of Mg is designed to be, for example, 0.5 ⁇ 10 16 atoms / cm 3 (total average concentration: 2.5 ⁇ ). 10 16 averages / cm 3 ).
  • the average P-type dopant concentration (specifically, the total value of the average concentrations of Zn and Mg) in the region on the side of the N-type clad layer 203 from the position 2/3 of the depth from the P-type clad layer 205 is 0. .3 ⁇ 10 16 atoms / cm 3 or less is preferable.
  • the lower limit is not particularly limited, but may be, for example, 0 atoms / cm 3 or more. If each of the above regions is within these concentration ranges, deterioration of life characteristics can be suppressed even more reliably.
  • first production method a gas doping method
  • second production method a heat treatment doping method
  • the doping method for the active layer is limited to these. It is not something that is done.
  • First manufacturing method First, an example in which the active layer is doped by gas doping will be described. A GaAs starting substrate 100 is prepared as a growth substrate, washed, and then placed in a MOVPE (MetalOrganic Vapor Phase Epitaxy) furnace.
  • MOVPE MetalOrganic Vapor Phase Epitaxy
  • the AlInP etch stop layer 102 On the GaAs starting substrate 100, the AlInP etch stop layer 102, the N-type AlGaInP clad layer 103, and the AlGaInP activity
  • the layer 104, the P-type AlGaInP clad layer 105, and the P-type InGaP buffer layer 106 are epitaxially grown.
  • the epitaxial growth of each of the above layers can be carried out by a known MOVPE method.
  • the raw material gas that is the source of each component of Al, Ga, In, and P is not limited to these, and for example, the following can be used.
  • -Al source gas trimethylaluminum (TMAl), triethylaluminum (TEAl), etc.
  • -Ga source gas trimethylgallium (TMGa), triethylgallium (TEGa), etc.
  • -In source gas trimethylindium (TMIn), triethylindium (TEIn), etc.
  • -P source gas trimethyl phosphorus (TMP), triethyl phosphorus (TEP), phosphine (PH3), etc.
  • the dopant is doped into each layer by gas doping.
  • Each layer such as the active layer can be gas-doped while epitaxially growing.
  • the dopant gas for example, the following can be used.
  • P-type dopant -Zn source Dimethylzinc (DMZn), diethylzinc (DEZn), etc.
  • -Mg source Biz (cyclopentadienyl) magnesium (Cp 2 Mg), etc.
  • -Te source Dimethyl telluride (DMTe), diethyl tellurium (DETe), etc.
  • N-type dopant) -Si source Silicon hydride such as monosilane.
  • -S source hydrogen sulfide (H 2 S), etc.
  • -Se source hydrogen selenide, etc.
  • the concentration profile of the gradient doping as shown in FIG. 2 is used for the P-type dopant in the active layer 104. That is, in the active layer 104, gradient doping is performed from the side of the P-type clad layer 105 to the side of the N-type clad layer 103 so that the concentration of the P-type dopant gradually decreases. Moreover, the average P-type dopant concentration in the region from the P-type clad layer 105 to the position of 1/3 of the depth is 1.0 ⁇ 10 16 atoms / cm 3 or more and 3.0 ⁇ 10 17 atoms / cm 3 or less. Dope to.
  • the flow rate of the dopant gas by controlling the flow rate of the dopant gas with a mass flow controller or the like, it is possible to easily perform gas doping with the above concentration profile. Due to the thermal effect during epitaxial growth, the concentration profile tends to be slightly shifted to the thermal equilibrium side from the intended concentration profile. Regarding this point, it is advisable to appropriately adjust the flow rate and the like in consideration of the deviation and perform gas doping to obtain the intended concentration profile. If the P-type dopant has such a concentration profile in the active layer, as described above, it is possible to achieve both improvement of the luminance characteristic with respect to the ambient temperature and suppression of deterioration of the lifetime characteristic.
  • the average P-type dopant concentration in the region from the P-type clad layer 105 at a depth of 1/3 to a depth of 2/3 is 0 in the active layer 104. It is preferable to dope so that the content is 3 ⁇ 10 16 atoms / cm 3 or more and 3.0 ⁇ 10 16 atoms / cm 3 or less. Furthermore, in the active layer 104, the average P-type dopant concentration in the region on the side of the N-type clad layer 103 from the position 2/3 of the depth from the P-type clad layer 105 is 0.3 ⁇ 10 16 atoms / cm 3 or less.
  • the lower limit is not particularly limited, but may be, for example, 0 atoms / cm 3 or more. When each of the above regions is within these concentration ranges, deterioration of life characteristics can be suppressed even more reliably.
  • the P-type GaP current propagation layer 107 is vapor-deposited by the HVPE method (Hydride Vapor Phase Epitaxy method).
  • HVPE method for example, by introducing hydrogen chloride onto the metal Ga while heating and holding the metal Ga at a predetermined temperature, GaCl is generated by the reaction of the following formula (1) to generate a carrier gas. It is supplied on the substrate together with the H 2 gas.
  • the growth temperature can be set to, for example, 640 ° C. or higher and 860 ° C. or lower.
  • P which is a Group V element
  • P supplies, for example, PH 3 on the substrate together with H 2 which is a carrier gas.
  • Zn can be supplied as a P-type dopant in the form of dimethylzinc (DMZn) to form the current propagation layer 107 by a reaction as shown in the following equation (2).
  • DMZn dimethylzinc
  • the buffer layer 106 is formed from the preparation of the starting substrate 100 in the same manner as in the first manufacturing method.
  • the active layer 104 is not doped during epitaxial growth.
  • the P-type cladding layer 105 is doped with the P-type dopant at a higher concentration than in the case of the first production method.
  • the P-type dopant concentration of the P-type clad layer 105 is such that, when Zn and Mg are P-type dopants, the Zn concentration is 1.0 ⁇ 10 16 to 3.0 ⁇ 10 18 atoms / cm. 3.
  • the concentration of Mg can be in the concentration range of 1.0 ⁇ 10 16 to 5.0 ⁇ 10 17 atoms / cm 3 . Within such a concentration range, the gradient dope concentration profile as shown in FIG. 2 can be more reliably obtained in the heat treatment step, which is the next step.
  • heat treatment is performed in a MOVPE furnace, for example, in a PH 3 atmosphere at 700 ° C. or higher for 3 hours or longer.
  • the heat treatment is performed at 700 ° C. (a temperature similar to that at the time of epitaxial growth) for 8 hours.
  • the concentration profile of the gradient dope as shown in FIG. 2 can be easily obtained.
  • the dopant is diffused from the P-type clad layer 105 into the active layer 104 according to the diffusion formula, and forms a concentration profile that gradually decreases toward the N-type clad layer 103.
  • the temperature and time of the heat treatment are not particularly limited, and can be appropriately determined so as to obtain a desired gradient dope concentration profile. Further, it is preferable to carry out in a PH 3 atmosphere as described above because desorption of P (phosphorus) from the surface of the epitaxial layer can be effectively avoided.
  • the current propagation layer 107 is formed by the HVPE method in the same manner as in the first manufacturing method.
  • the buffer layer 106 was formed and then heat-treated, but instead of being heat-treated at that timing, the current propagation layer 107 was formed and then heat-treated (in an HVPE furnace under a PH 3 atmosphere, at 700 ° C. or higher for 3 hours).
  • the concentration profile of the gradient dope can be formed in the active layer 104 by subjecting the active layer 104 at 700 ° C. for 8 hours).
  • Example 1 The light emitting device of the present invention was manufactured by the manufacturing method of the present invention as follows. (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ ) with a thickness of 1.0 ⁇ m by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction.
  • MOVPE organic metal vapor phase growth method
  • An etch stop layer consisting of 1,0.4 ⁇ y ⁇ 0.6), a 1.0 ⁇ m thick N-type clad layer, and a 0.9 ⁇ m thick (Al x Ga 1-x ) y In 1-y P (0 ⁇ ).
  • An active layer consisting of x ⁇ 1,0.4 ⁇ y ⁇ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1,0.4 ⁇ y ⁇ 0.6) 1.0 ⁇ m thick P-type clad layer made of, Ga y in 1-y P (0.0 ⁇ y ⁇ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5 ⁇ m thick
  • a wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).
  • the active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1, 0.4 ⁇ y ⁇ 0.6) layer having a uniform composition.
  • the active layer was doped with a P-type dopant (two types of Zn and Mg) so that the concentration gradually decreased from the P-type clad layer to the N-type clad layer.
  • a P-type dopant two types of Zn and Mg
  • the concentration profile is that the concentration of Zn as a P-type dopant is 5 ⁇ 10 16 atoms / cm 3 and the concentration of Mg as a P-type dopant is 1 ⁇ 10 16 atoms / cm 3 at the interface with the P-type clad layer. It was. Then, the Zn average concentration in the region from the P-type clad layer to the position of 0.3 ⁇ m in depth (1/3 of the total thickness of the active layer of 0.9 ⁇ m) is 2 ⁇ 10 16 atoms / cm 3 , and the Mg average concentration is 0. It was 5 ⁇ 10 16 atoms / cm 3 (total average concentration: 2.5 ⁇ 10 16 atoms / cm 3 ).
  • the average Zn concentration in the region from the position of 0.3 ⁇ m in depth to the position of 0.6 ⁇ m in depth (1/3 to 2/3 of the total thickness of 0.9 ⁇ m) is 0.5 ⁇ 10 16 atoms / cm 3
  • Mg average concentration was 0.2 ⁇ 10 16 atoms / cm 3 (total value of average concentration: 0.7 ⁇ 10 16 atoms / cm 3 ).
  • the total average concentration of each of Mg and Zn at the subsequent depths (from the position of 2/3 depth to the N-type clad layer) was 0.3 ⁇ 10 16 atoms / cm 3 or less. Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
  • Example 2 The light emitting device of the present invention was manufactured by the manufacturing method of the present invention as follows. (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ ) with a thickness of 1.0 ⁇ m by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ⁇ y ⁇ 0.6), an N-type clad layer with a thickness of 1.0 ⁇ m, and a (Al x Ga 1-x ) y In 1-y P (0 ⁇ ) with a thickness of 0.48 ⁇ m.
  • MOVPE organic metal vapor phase growth method
  • An active layer consisting of x ⁇ 1,0.4 ⁇ y ⁇ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1,0.4 ⁇ y ⁇ 0.6) 1.0 ⁇ m thick P-type clad layer made of, Ga y in 1-y P (0.0 ⁇ y ⁇ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5 ⁇ m thick
  • a wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).
  • the active layer consists of a luminescent recombination layer composed of a (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1, 0.4 ⁇ y ⁇ 0.6) layer having the first composition, and a second composition.
  • (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1,0.4 ⁇ y ⁇ 0.6) It is composed of multiple barrier type active layers in which barrier layers are alternately laminated. Will be done.
  • the Al ratio of the first composition was set to be smaller than the Al ratio of the second composition.
  • the active layer was doped with a P-type dopant (two types of Zn and Mg) so that the concentration gradually decreased from the P-type clad layer to the N-type clad layer.
  • a P-type dopant two types of Zn and Mg
  • DEZn and Cp 2 Mg were flowed and gas-doped.
  • the concentration profile is that the concentration of Zn as a P-type dopant is 5 ⁇ 10 16 atoms / cm 3 and the concentration of Mg as a P-type dopant is 1 ⁇ 10 16 atoms / cm 3 at the interface with the P-type clad layer. It was.
  • the average concentration of Zn in the region from the P-type clad layer to the position of 0.16 ⁇ m in depth (1/3 of the total thickness of the active layer of 0.48 ⁇ m) is 2 ⁇ 10 16 atoms / cm 3
  • the average concentration of Mg is 0. It was .5 ⁇ 10 16 atoms / cm 3 (total average concentration: 2.5 ⁇ 10 16 atoms / cm 3 ).
  • the average Zn concentration in the region from the position of 0.16 ⁇ m in depth to the position of 0.32 ⁇ m in depth (1/3 to 2/3 of the total thickness of 0.48 ⁇ m) is 0.5 ⁇ 10 16 atoms / cm 3
  • Mg average concentration was 0.2 ⁇ 10 16 atoms / cm 3 (total value of average concentration: 0.7 ⁇ 10 16 atoms / cm 3 ).
  • the total average concentration of each of Mg and Zn at the subsequent depths (from the position of 2/3 depth to the N-type clad layer) was 0.3 ⁇ 10 16 atoms / cm 3 or less. Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
  • a light emitting device was manufactured as follows. (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ ) with a thickness of 1.0 ⁇ m by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ⁇ y ⁇ 0.6), a 1.0 ⁇ m thick N-type clad layer, and a 0.9 ⁇ m thick (Al x Ga 1-x ) y In 1-y P (0 ⁇ ).
  • MOVPE organic metal vapor phase growth method
  • An active layer consisting of x ⁇ 1,0.4 ⁇ y ⁇ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1,0.4 ⁇ y ⁇ 0.6) 1.0 ⁇ m thick P-type clad layer made of, Ga y in 1-y P (0.0 ⁇ y ⁇ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5 ⁇ m thick
  • a wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).
  • the active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1,0.4 ⁇ y ⁇ 0.6) layer having a uniform composition, and is gas-doped (DEZn, Cp 2 Mg).
  • the total concentration of Mg and Zn in the active layer was set to 0.3 ⁇ 10 16 atoms / cm 3 or less. Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
  • a light emitting device was manufactured as follows. (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ ) with a thickness of 1.0 ⁇ m by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ⁇ y ⁇ 0.6), a 1.0 ⁇ m thick N-type clad layer, and a 0.9 ⁇ m thick (Al x Ga 1-x ) y In 1-y P (0 ⁇ ).
  • MOVPE organic metal vapor phase growth method
  • An active layer consisting of x ⁇ 1,0.4 ⁇ y ⁇ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1,0.4 ⁇ y ⁇ 0.6) 1.0 ⁇ m thick P-type clad layer made of, Ga y in 1-y P (0.0 ⁇ y ⁇ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5 ⁇ m thick
  • a wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).
  • the active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ⁇ x ⁇ 1,0.4 ⁇ y ⁇ 0.6) layer having a uniform composition, and is gas-doped (DEZn, Cp 2 Mg). (Use) made the Zn concentration of the active layer constant at 5 ⁇ 10 16 atoms / cm 3 and the Mg concentration at 1 ⁇ 10 16 atoms / cm 3 (total concentration: 6 ⁇ 10 16 atoms / cm 3 ). .. Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
  • Table 2 shows the light output ratio and the life characteristics of the light emitting elements of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 due to the difference in environmental temperature (0 ° C vs. 60 ° C).
  • the light output ratio due to the difference in environmental temperature was 0.86 or more, and the life characteristic was 87, both of which were good values.
  • Comparative Example 1 since there was almost no dopant in the active layer, the lifetime characteristics were good, but the light output ratio was 0.8 due to the difference in the environmental temperature, and the change in brightness due to the environmental temperature was large. Further, in Comparative Example 2, the light output ratio was good due to the difference in the environmental temperature, but the lifetime characteristic was 60%, which was deteriorated by keeping the dopant of the active layer constant without gradually reducing it.
  • each layer up to at least the P-type clad layer is formed, and then heat treatment is performed to diffuse the P-type dopant from the P-type clad layer to the active layer.
  • the present inventors have confirmed that a light emitting device having the same gradient doping concentration profile as No. 2 and having the same light output ratio and lifetime characteristics can be manufactured.
  • the present invention is not limited to the above embodiment.
  • the above embodiment is an example, and any one having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. It is included in the technical scope of the invention.

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Abstract

The present invention is a light emitting element having a light emitting part in which an N-type cladding layer, an active layer, and a P-type cladding layer are formed in this order, wherein the active layer includes a P-type dopant of which the concentration gradually decreases from the P-type cladding layer side to the N-type cladding layer side, and in the active layer, the average concentration of the P-type dopant in a region from the P-type cladding layer to a position corresponding to 1/3 of the thickness of the active layer is 1.0 × 1016 atoms/cm3 or more and 3.0 × 1017 atoms/cm3 or less. Accordingly, provided are: the light emitting element which has excellent luminance characteristics with respect to the environmental temperature and which suppresses the deterioration of life characteristics; and a method of manufacturing the same.

Description

発光素子および発光素子の製造方法Light emitting element and manufacturing method of light emitting element

　本発明は、発光素子および発光素子の製造方法に関し、特に環境温度に対する輝度特性が良好で、かつ、寿命特性の悪化が抑制された発光素子および発光素子の製造方法に関する。 The present invention relates to a method for manufacturing a light emitting element and a light emitting element, and particularly to a method for manufacturing a light emitting element and a light emitting element having good luminance characteristics with respect to an environmental temperature and suppressing deterioration of life characteristics.

　ＡｌＧａＩｎＰ系材料は、窒化物を除くＩＩＩ－Ｖ族化合物半導体混晶中で最大の直接遷移型エネルギーギャップを有し、５５０～６５０ｎｍ帯（緑色～赤色域）の可視光発光装置の材料として注目されている。このような大きな直接遷移型エネルギーギャップを持つＡｌＧａＩｎＰからなる活性層を有するＡｌＧａＩｎＰ系発光素子は、ＧａＰ、ＧａＡｓＰ等の間接遷移型の材料を用いたものと比べて高輝度の発光が可能である（例えば特許文献１）。 The AlGaInP-based material has the largest direct transition energy gap in the III-V compound semiconductor mixed crystal excluding nitrides, and is attracting attention as a material for visible light emitting devices in the 550 to 650 nm band (green to red region). ing. An AlGaInP-based light emitting element having an active layer made of AlGaInP having such a large direct transition type energy gap can emit light with higher brightness than those using an indirect transition type material such as GaP or GaAsP (). For example, Patent Document 1).

　図４は、従来のＡｌＧａＩｎＰ系発光素子の一例を示す概略断面図である。
　この発光素子３１０はＧａＡｓ出発基板３００上に厚さ０．１～１．０μｍのＧａＡｓバッファ層、例えば厚さ１．０μｍのＡｌＩｎＰエッチストップ層３０２、例えば厚さ１．０μｍのＮ型ＡｌＧａＩｎＰクラッド層３０３、例えば厚さ０．９μｍのＡｌＧａＩｎＰ活性層３０４、例えば厚さ１．０μｍのＰ型ＡｌＧａＩｎＰクラッド層３０５、電流伝播層との格子不整を緩和するＰ型ＩｎＧａＰ緩衝層３０６、素子に印加された電流を伝播かつ拡散し、光取り出しの機能を有する例えば厚さ５．０μｍのＰ型ＧａＰ電流伝播層３０７を有する。ＧａＡｓバッファ層は特になくてもよい。なお、図４においては発光素子の電極等は省略されている。 FIG. 4 is a schematic cross-sectional view showing an example of a conventional AlGaInP-based light emitting device.
The light emitting device 310 is formed on a GaAs starting substrate 300 with a GaAs buffer layer having a thickness of 0.1 to 1.0 μm, for example, an AlInP etch stop layer 302 having a thickness of 1.0 μm, for example, an N-type AlGaInP clad layer having a thickness of 1.0 μm. 303, for example, an AlGaInP active layer 304 with a thickness of 0.9 μm, for example, a P-type AlGaInP clad layer 305 with a thickness of 1.0 μm, a P-type InGaP buffer layer 306 for alleviating lattice irregularities with a current propagation layer, and applied to the device. It has, for example, a 5.0 μm-thick P-type GaP current propagation layer 307 that propagates and diffuses current and has a function of extracting light. The GaAs buffer layer may not be particularly provided. In FIG. 4, the electrodes of the light emitting element and the like are omitted.

　ここでＮ型ドーパントとして、例えばＳｉ、Ｓ、Ｓｅ等がＮ型クラッド層３０３にドーピングされる。またＰ型ドーパントとしては、Ｚｎ、Ｍｇ、Ｔｅ等がＰ型クラッド層３０５及びＰ型緩衝層３０６及びＰ型電流伝播層３０７にドーピングされる。 Here, as an N-type dopant, for example, Si, S, Se, etc. are doped into the N-type clad layer 303. As the P-type dopant, Zn, Mg, Te and the like are doped into the P-type clad layer 305, the P-type buffer layer 306 and the P-type current propagation layer 307.

　Ｎ型クラッド層３０３は、１層以上の組成及びドーピング水準のエピタキシャル層で構成され、Ｐ型クラッド層３０５は、１層以上の組成及びドーピング水準のエピタキシャル層で構成される。活性層３０４は均一組成のバルク型活性層、または、発光再結合層と該発光再結合層の組成よりも大きなバンドギャップ組成を有する障壁層とが多重接合した多重接合型活性層から成る。 The N-type clad layer 303 is composed of an epitaxial layer having one or more compositions and a doping level, and the P-type clad layer 305 is composed of an epitaxial layer having one or more layers and a doping level. The active layer 304 is composed of a bulk-type active layer having a uniform composition or a multi-bonded active layer in which a luminescent recombination layer and a barrier layer having a bandgap composition larger than the composition of the luminescent recombination layer are multi-bonded.

　ところで発光素子（例えばＡｌＧａＩｎＰ系発光素子）の発光部をエピタキシャル成長で形成する際に、寿命特性の悪化を回避するため、活性層中に残留、もしくは寿命試験中に拡散・泳動するドーパントの濃度を極小に設計する必要があった。しかし、活性層中のドーパント濃度を極小にすることで寿命特性は改善できるが、一方で、環境温度に対する輝度の変化は大きくなる傾向にあった。
　また、環境温度に対する輝度特性を改善するためには、活性層中にドーパントを過剰に入れることが効果的であることが分かっている。しかし、過剰に活性層中に投入されたドーパントは輝度特性を改善するものの、転位・欠陥発生源となり、寿命特性を著しく悪化させる。 By the way, when the light emitting portion of a light emitting device (for example, an AlGaInP type light emitting device) is formed by epitaxial growth, the concentration of the dopant remaining in the active layer or diffused / electrophoresed during the life test is minimized in order to avoid deterioration of the life characteristics. Had to be designed. However, although the lifetime characteristics can be improved by minimizing the dopant concentration in the active layer, the change in brightness with respect to the ambient temperature tends to be large.
Further, it has been found that it is effective to add an excessive amount of dopant in the active layer in order to improve the luminance characteristics with respect to the ambient temperature. However, although the dopant excessively charged into the active layer improves the luminance characteristics, it becomes a source of dislocations and defects and significantly deteriorates the lifetime characteristics.

　従って、環境温度に対する輝度特性が良好な発光素子は寿命特性が悪く、一方、寿命特性が良好な発光素子では環境温度に対する輝度特性が悪く、二つの特性が良好である発光素子の実現が望まれていた。 Therefore, it is desired to realize a light emitting device having a good luminance characteristic with respect to the ambient temperature, which has a poor lifetime characteristic, while a light emitting device having a good lifetime characteristic has a poor luminance characteristic with respect to the ambient temperature and has good two characteristics. Was there.

特開２００５－１５０６４５号公報Japanese Unexamined Patent Publication No. 2005-150645

　本発明は上記の課題に鑑みてなされたもので、環境温度に対する輝度特性が良好であり、かつ、寿命特性の悪化が抑制された発光素子およびその製造方法を提供することを目的とする。 The present invention has been made in view of the above problems, and an object of the present invention is to provide a light emitting device having good luminance characteristics with respect to environmental temperature and suppressing deterioration of life characteristics, and a method for manufacturing the same.

　上記目的を達成するために、本発明は、Ｎ型クラッド層と活性層とＰ型クラッド層がこの順序で形成された発光部を有する発光素子であって、
　前記活性層は、前記Ｐ型クラッド層側から前記Ｎ型クラッド層側へ濃度が漸減するＰ型ドーパントを含み、
　前記活性層において、前記Ｐ型クラッド層から前記活性層の１／３の厚さ分の位置までの領域の平均の前記Ｐ型ドーパントの濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１７ａｔｏｍｓ／ｃｍ３以下であることを特徴とする発光素子を提供する。 In order to achieve the above object, the present invention is a light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
The active layer contains a P-type dopant whose concentration gradually decreases from the P-type clad layer side to the N-type clad layer side.
2. In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. Provided is a light emitting element having a concentration of 0 × 10 17 atoms / cm 3 or less.

　このように活性層において、Ｐ型クラッド層から活性層の１／３の厚さ分の位置までの領域の平均のＰ型ドーパントの濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上であれば、光出力が向上するとともに環境温度に対する輝度特性が向上する。
　また、Ｐ型クラッド層から活性層の１／３の厚さ分の位置までの領域の平均のＰ型ドーパントの濃度が３．０×１０１７ａｔｏｍｓ／ｃｍ３以下であり、かつ、活性層においてＰ型クラッド層側からＮ型クラッド層側へ漸減するＰ型ドーパントの濃度プロファイルであることで、寿命特性の悪化を抑制することができる。 As described above, in the active layer, if the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. , The light output is improved and the brightness characteristic with respect to the ambient temperature is improved.
Further, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 3.0 × 10 17 atoms / cm 3 or less, and in the active layer. The concentration profile of the P-type dopant that gradually decreases from the P-type clad layer side to the N-type clad layer side can suppress deterioration of the life characteristics.

　また、前記発光部は、ＡｌＧａＩｎＰ系の化合物半導体からなるものとすることができる。 Further, the light emitting unit can be made of an AlGaInP-based compound semiconductor.

　本発明は、発光部がＡｌＧａＩｎＰ系の化合物半導体からなる発光素子に特に好適に用いることができる。 The present invention can be particularly preferably used for a light emitting device in which the light emitting portion is made of an AlGaInP-based compound semiconductor.

　また、前記活性層において、前記Ｐ型クラッド層から前記活性層の１／３の厚さ分の位置から２／３の厚さ分の位置までの領域の平均の前記Ｐ型ドーパントの濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１６ａｔｏｍｓ／ｃｍ３以下のものとすることができる。 Further, in the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer to the position of 2/3 of the thickness is 0. .3 × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less.

　このようにＰ型ドーパント濃度が上記領域で上記数値範囲のものであれば、より確実に寿命特性の悪化を抑制できる。 If the P-type dopant concentration is in the above-mentioned numerical range in the above-mentioned region as described above, the deterioration of the life characteristic can be suppressed more reliably.

　このとき、前記活性層において、前記Ｐ型クラッド層から前記活性層の２／３の厚さ分の位置からＮ型クラッド層までの領域の平均の前記Ｐ型ドーパントの濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以下のものとすることができる。 At this time, in the active layer, the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the P-type clad layer to the N-type clad layer is 0.3 × 10. It can be 16 atoms / cm 3 or less.

　このようにＰ型ドーパント濃度が上記領域で上記数値範囲のものであれば、より一層確実に寿命特性の悪化を抑制することができる。 If the P-type dopant concentration is in the above-mentioned numerical range in the above-mentioned region as described above, the deterioration of the life characteristic can be suppressed more reliably.

　また本発明は、Ｎ型クラッド層と活性層とＰ型クラッド層をこの順序で形成した発光部を有する発光素子の製造方法であって、
　前記活性層において、前記Ｐ型クラッド層側から前記Ｎ型クラッド層側へＰ型ドーパントの濃度が漸減し、かつ、
　前記活性層において、前記Ｐ型クラッド層から前記活性層の１／３の厚さ分の位置までの領域の平均の前記Ｐ型ドーパントの濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１７ａｔｏｍｓ／ｃｍ３以下となるように前記Ｐ型ドーパントをドープして製造することを特徴とする発光素子の製造方法を提供する。 The present invention is a method for manufacturing a light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
In the active layer, the concentration of the P-type dopant gradually decreases from the P-type clad layer side to the N-type clad layer side, and
3. In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. Provided is a method for manufacturing a light emitting device, which comprises doping the P-type dopant so as to be 0 × 10 17 atoms / cm 3 or less.

　このように活性層において、Ｐ型クラッド層から活性層の１／３の厚さ分の位置までの領域の平均のＰ型ドーパントの濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上となるように製造すれば、光出力が向上するとともに環境温度に対する輝度特性が向上する。
　また、Ｐ型クラッド層から活性層の１／３の厚さ分の位置までの領域の平均のＰ型ドーパントの濃度が３．０×１０１７ａｔｏｍｓ／ｃｍ３以下となるようにし、かつ、活性層においてＰ型クラッド層側からＮ型クラッド層側へ漸減するＰ型ドーパントの濃度プロファイルとすることで、寿命特性の悪化を抑制することができる。 In this way, in the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. If manufactured in, the light output will be improved and the brightness characteristics with respect to the ambient temperature will be improved.
Further, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is set to 3.0 × 10 17 atoms / cm 3 or less, and the activity is increased. By setting the concentration profile of the P-type dopant that gradually decreases from the P-type clad layer side to the N-type clad layer side in the layer, deterioration of the life characteristics can be suppressed.

　このとき、前記発光部を、ＡｌＧａＩｎＰ系の化合物半導体からなるものとすることができる。 At this time, the light emitting unit can be made of an AlGaInP-based compound semiconductor.

　本発明は、発光部がＡｌＧａＩｎＰ系の化合物半導体からなる発光素子を製造するのに特に好適に用いることができる。 The present invention can be particularly preferably used for manufacturing a light emitting device in which the light emitting unit is made of an AlGaInP-based compound semiconductor.

　また、前記活性層に前記Ｐ型ドーパントをドープするとき、
　前記活性層において、前記Ｐ型クラッド層から前記活性層の１／３の厚さ分の位置から２／３の厚さ分の位置までの領域の平均の前記Ｐ型ドーパントの濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１６ａｔｏｍｓ／ｃｍ３以下となるようにドープすることができる。 When the active layer is doped with the P-type dopant,
In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 thickness of the active layer to the position of 2/3 thickness is 0.3. It can be doped so as to be × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less.

　このようにＰ型ドーパント濃度を上記領域で上記数値範囲のものとすれば、より確実に寿命特性の悪化を抑制できる。 If the P-type dopant concentration is set within the above numerical range in the above region in this way, deterioration of the life characteristics can be suppressed more reliably.

　このとき、前記活性層に前記Ｐ型ドーパントをドープするとき、
　前記活性層において、前記Ｐ型クラッド層から前記活性層の２／３の厚さ分の位置からＮ型クラッド層までの領域の平均の前記Ｐ型ドーパントの濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以下となるようにドープすることができる。 At this time, when the active layer is doped with the P-type dopant,
In the active layer, the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the P-type clad layer to the N-type clad layer is 0.3 × 10 16 atoms /. It can be doped so as to be cm 3 or less.

　このようにＰ型ドーパント濃度を上記領域で上記数値範囲のものとすれば、より一層確実に寿命特性の悪化を抑制することができる。 If the P-type dopant concentration is set within the above numerical range in the above region in this way, deterioration of the life characteristics can be suppressed even more reliably.

　また、前記活性層への前記Ｐ型ドーパントのドープを、
　前記活性層を形成しつつガスドープにより行うことができる。
　または、前記活性層への前記Ｐ型ドーパントのドープを、
　前記活性層を形成した後、前記Ｐ型ドーパントをドープした前記Ｐ型クラッド層を形成してから熱処理を施して、前記Ｐ型クラッド層にドープした前記Ｐ型ドーパントを前記活性層に拡散させることにより行うことができる。 In addition, the active layer is doped with the P-type dopant.
This can be done by gas doping while forming the active layer.
Alternatively, the active layer is doped with the P-type dopant.
After forming the active layer, the P-type clad layer doped with the P-type dopant is formed and then heat-treated to diffuse the P-type dopant doped in the P-type clad layer into the active layer. Can be done by.

　このようにガスドープまたは熱処理によるドープによって、上記各領域に上記の濃度プロファイルで簡便にドープすることができる。 By doping by gas doping or heat treatment in this way, each of the above regions can be easily doped with the above concentration profile.

　以上のように、本発明の発光素子および発光素子の製造方法であれば、光出力が向上するとともに環境温度に対する輝度特性が良好であり、かつ、寿命特性の悪化が抑制されたものとすることができる。 As described above, according to the light emitting element and the method for manufacturing the light emitting element of the present invention, it is assumed that the light output is improved, the brightness characteristic with respect to the ambient temperature is good, and the deterioration of the life characteristic is suppressed. Can be done.

本発明の発光素子の一例を示す概略図である。It is the schematic which shows an example of the light emitting element of this invention. 活性層中の平均のＰ型ドーパントの濃度を示す説明図である。It is explanatory drawing which shows the average concentration of P-type dopant in an active layer. 本発明の発光素子の他の一例を示す概略図である。It is the schematic which shows another example of the light emitting element of this invention. 従来の発光素子の一例を示す概略図である。It is the schematic which shows an example of the conventional light emitting element.

　上述したように、寿命特性及び環境温度に対する輝度特性の両方が良好な発光素子（特にはＡｌＧａＩｎＰ系ＬＥＤ）の開発が望まれていた。本発明者らはこのような課題に対し、鋭意検討を重ねたところ、少なくともＮ型クラッド層と活性層とＰ型クラッド層がこの順序で形成された発光部を有する発光素子において、環境温度に対する輝度特性を変える大きな要因は活性層領域におけるＰ型キャリアリッチの領域でのキャリアの挙動であるため、Ｐ型クラッド層寄りの活性層領域、具体的には、活性層全厚の１／３の厚さで、Ｐ型クラッド層寄りの領域をＰ型活性層領域とし、該Ｐ型活性層領域のＰ型ドーパントの濃度を１．０×１０１６ａｔｏｍｓ／ｃｍ３以上３×１０１７ａｔｏｍｓ／ｃｍ３以下とすること、更に活性層中に過剰に拡散することを防止するため、エピタキシャル成長時に、Ｐ型クラッド層側からＮ型クラッド層側に向かって活性層中にかけて漸減する濃度プロファイルとなるように活性層中にＰ型のドーパント不純物をドーピングすることで、環境温度に対する輝度特性と寿命特性の両方の特性が良好な発光素子を製造できることが判り、更に検討を加えて本発明を完成した。 As described above, it has been desired to develop a light emitting element (particularly an AlGaInP LED) having good life characteristics and brightness characteristics with respect to the environmental temperature. As a result of diligent studies on such issues, the present inventors have found that at least in a light emitting element having a light emitting portion in which an N-type clad layer, an active layer and a P-type clad layer are formed in this order, the ambient temperature Since the major factor that changes the brightness characteristics is the behavior of carriers in the P-type carrier-rich region in the active layer region, the active layer region near the P-type clad layer, specifically, 1/3 of the total thickness of the active layer. In terms of thickness, the region closer to the P-type clad layer is defined as the P-type active layer region, and the concentration of the P-type dopant in the P-type active layer region is 1.0 × 10 16 atoms / cm 3 or more and 3 × 10 17 atoms / cm. In order to reduce the concentration to 3 or less and to prevent excessive diffusion into the active layer, the concentration profile gradually decreases from the P-type clad layer side to the N-type clad layer side toward the active layer during epitaxial growth. It has been found that by doping the active layer with a P-type dopant impurity, it is possible to produce a light emitting device having good characteristics of both brightness characteristics and lifetime characteristics with respect to environmental temperature, and further studies have been carried out to complete the present invention.

　以下、本発明について、実施形態について図を参照しながら更に詳細に説明するが、本発明はこれに限定されるものではない。
　（第一実施形態）
　本発明の発光素子の第一実施形態を図１に示す。図１に示すように第一実施形態の発光素子１１０はＧａＡｓ出発基板１００上に厚さ０．１～１．０μｍのＧａＡｓバッファ層、例えば厚さ１．０μｍのＡｌＩｎＰエッチストップ層１０２、例えば厚さ１．０μｍのＮ型ＡｌＧａＩｎＰクラッド層１０３、例えば厚さ０．９μｍのＡｌＧａＩｎＰ活性層１０４、例えば厚さ１．０μｍのＰ型ＡｌＧａＩｎＰクラッド層１０５、電流伝播層との格子不整を緩和するＰ型ＩｎＧａＰ緩衝層１０６、素子に印加された電流を伝播かつ拡散し、光取り出しの機能を有する例えば厚さ５．０μｍのＰ型ＧａＰ電流伝播層１０７を有する。
　ＧａＡｓバッファ層は特になくてもよい。なお、図１においては発光素子の電極等は省略されている。 Hereinafter, the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto.
(First Embodiment)
The first embodiment of the light emitting device of the present invention is shown in FIG. As shown in FIG. 1, the light emitting device 110 of the first embodiment has a GaAs buffer layer having a thickness of 0.1 to 1.0 μm, for example, an AlInP etch stop layer 102 having a thickness of 1.0 μm, for example, a thickness on the GaAs starting substrate 100. An N-type AlGaInP clad layer 103 having a thickness of 1.0 μm, for example, an AlGaInP active layer 104 having a thickness of 0.9 μm, for example, a P-type AlGaInP clad layer 105 having a thickness of 1.0 μm, and a P-type that alleviates lattice irregularities with a current propagation layer. The InGaP buffer layer 106 has, for example, a P-type GaP current propagation layer 107 having a thickness of 5.0 μm, which propagates and diffuses the current applied to the device and has a function of extracting light.
The GaAs buffer layer may not be particularly provided. In FIG. 1, the electrodes of the light emitting element and the like are omitted.

　ここでＮ型ドーパントとしてＳｉ、Ｓ、Ｓｅのうち、１種類以上がＮ型クラッド層１０３にドーピングされ、Ｐ型ドーパントとしてはＺｎ、Ｍｇ、Ｔｅのうち、１種類以上がＰ型クラッド層１０５及びＰ型緩衝層１０６及びにＰ型電流伝播層１０７にドーピングされる。 Here, one or more of Si, S, and Se as N-type dopants are doped into the N-type clad layer 103, and one or more of Zn, Mg, and Te as P-type dopants are the P-type clad layer 105 and The P-type buffer layer 106 and the P-type current propagation layer 107 are doped.

　Ｎ型クラッド層１０３は、１層以上の組成及びドーピング水準のエピタキシャル層で構成され、Ｐ型クラッド層１０５は、１層以上の組成及びドーピング水準のエピタキシャル層で構成される。 The N-type clad layer 103 is composed of one or more layers of epitaxial layers having a composition and a doping level, and the P-type clad layer 105 is composed of an epitaxial layer having one or more layers and a doping level.

　活性層１０４は均一組成のバルク型活性層から成る。
　活性層１０４にはＰ型クラッド層１０５からＮ型クラッド層１０３に向かって、例えばなだらかに又は階段状に、濃度が漸減するＰ型ドーパントがドープされている（傾斜ドープ）。以下にＰ型ドーパントとしてＺｎとＭｇの２種がドープされている例を示すが、本発明はこれに限定されず、例えばＺｎのみドープすることもできるし、３種以上ドープすることもできる。
　また、本発明が特に好適な例として、発光部（Ｎ型クラッド層、活性層、Ｐ型クラッド層）がＡｌＧａＩｎＰ系の化合物半導体からなるものを挙げて説明するが、これに限定されない。 The active layer 104 is composed of a bulk type active layer having a uniform composition.
The active layer 104 is doped with a P-type dopant whose concentration gradually decreases from the P-type clad layer 105 toward the N-type clad layer 103, for example, in a gentle or stepwise manner (gradient doping). The following shows an example in which two types of Zn and Mg are doped as P-type dopants, but the present invention is not limited to this, and for example, only Zn can be doped, or three or more types can be doped.
Further, as a particularly preferable example of the present invention, an example in which the light emitting portion (N-type clad layer, active layer, P-type clad layer) is made of an AlGaInP-based compound semiconductor will be described, but the present invention is not limited thereto.

　図２に活性層中の平均のＰ型ドーパントの濃度の説明図を示す。
　ここで、Ｐ型クラッド層１０５からＮ型クラッド層１０３へ向かう方向を活性層１０４の深さ方向と定義し、活性層１０４とＰ型クラッド層１０５との界面を深さ位置の基準とする。上記傾斜ドープの濃度プロファイルは、Ｐ型クラッド層１０５から深さ１／３の位置までの領域（すなわち、Ｐ型クラッド層１０５から活性層１０４の１／３の厚さ分の位置までの領域）の平均Ｐ型ドーパント濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上３×１０１７ａｔｏｍｓ／ｃｍ３以下となっている。具体的にはＰ型ドーパントとして、Ｚｎの平均濃度が例えば５×１０１６ａｔｏｍｓ／ｃｍ３、Ｍｇの平均濃度が例えば１×１０１６ａｔｏｍｓ／ｃｍ３に設計される（平均濃度の合計値：６×１０１６ａｔｏｍｓ／ｃｍ３）。
　なお、上記深さ１／３の位置までの領域において、ドープされているＰ型ドーパントの種類が１種であればその１種自体の平均濃度が上記濃度範囲に収まっていれば良く、また、２種以上であれば、各々の平均濃度を足した合計値が上記濃度範囲に収まっていれば良い。 FIG. 2 shows an explanatory diagram of the average concentration of P-type dopant in the active layer.
Here, the direction from the P-type clad layer 105 to the N-type clad layer 103 is defined as the depth direction of the active layer 104, and the interface between the active layer 104 and the P-type clad layer 105 is used as a reference for the depth position. The concentration profile of the gradient dope is a region from the P-type clad layer 105 to the position of 1/3 of the depth (that is, a region from the P-type clad layer 105 to the position of 1/3 of the thickness of the active layer 104). The average P-type dopant concentration in the above is 1.0 × 10 16 atoms / cm 3 or more and 3 × 10 17 atoms / cm 3 or less. Specifically, as the P-type dopant, the average concentration of Zn is designed to be, for example, 5 × 10 16 atoms / cm 3 , and the average concentration of Mg is designed to be, for example, 1 × 10 16 atoms / cm 3 (total average concentration: 6). × 10 16 atoms / cm 3 ).
If there is only one type of P-type dopant doped in the region up to the position of 1/3 of the depth, it is sufficient that the average concentration of the one type is within the above concentration range. If there are two or more types, the total value obtained by adding the average concentrations of each may be within the above concentration range.

　上記のようにＰ型ドーパントの傾斜ドープ、かつ、深さ１／３の位置までの領域の平均濃度が３．０×１０１７ａｔｏｍｓ／ｃｍ３以下であれば、寿命特性の悪化の抑制が可能である。しかも、深さ１／３の位置までの領域の平均濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上であるので、光出力を向上させることができるし、環境温度に対する輝度特性を向上させることができる。このように、活性層１０４においてＰ型ドーパントの濃度プロファイルが上記条件を満たしている場合、従来品では成し得なかった、環境温度に対する輝度特性の向上および寿命特性の悪化の抑制を両立することができる。 As described above, if the P-type dopant is gradient-doped and the average concentration of the region up to the depth of 1/3 is 3.0 × 10 17 atoms / cm 3 or less, deterioration of the lifetime characteristics can be suppressed. Is. Moreover, since the average density of the region up to the depth 1/3 position is 1.0 × 10 16 atoms / cm 3 or more, the light output can be improved and the luminance characteristic with respect to the ambient temperature can be improved. Can be done. As described above, when the concentration profile of the P-type dopant in the active layer 104 satisfies the above conditions, it is possible to achieve both improvement of luminance characteristics with respect to environmental temperature and suppression of deterioration of life characteristics, which could not be achieved by conventional products. Can be done.

　上記本発明の効果について調査した実験について以下に説明する。
（実験）
　［００１］方向に１５度傾斜したＧａＡｓ基板上に有機金属気相成長法（ＭＯＶＰＥ）法にて、１．０μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなるエッチストップ層、１．０μｍ厚のＮ型クラッド層、０．９μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる活性層、（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる１．０μｍ厚のＰ型クラッド層、ＧａｙＩｎ１－ｙＰ（０．０≦ｙ≦１．０）から成る中間組成層（緩衝層）、０．５μｍ以上の厚さを有するＧａＰ電流拡散層（電流伝播層）を順次積層した発光素子用ウェーハを形成した。さらに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。 The experiment investigated for the effect of the present invention will be described below.
(Experiment)
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), a 1.0 μm thick N-type clad layer, and a 0.9 μm thick (Al x Ga 1-x ) y In 1-y P (0 ≦). An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers). Further, electrodes were formed, dicing was performed, and wire bonding was performed to manufacture a light emitting device.

　なお、活性層は均一組成の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）層から成る。
　また活性層にはＰ型クラッド層からＮ型クラッド層へ向かって濃度が漸減するようにＰ型ドーパントをドープした。この際、活性層のＰ型クラッド層から深さ１／３の位置までの領域の平均濃度を変えることにより、該領域の平均濃度が異なる複数の発光素子を製造した。
　そして、各発光素子において、０℃と６０℃での相対光出力比、及び寿命特性について実験を行った。その結果を表１に示す。 The active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) layer having a uniform composition.
The active layer was doped with a P-type dopant so that the concentration gradually decreased from the P-type clad layer to the N-type clad layer. At this time, by changing the average concentration of the region from the P-type clad layer of the active layer to the position of 1/3 of the depth, a plurality of light emitting devices having different average concentrations in the region were manufactured.
Then, in each light emitting element, an experiment was conducted on the relative light output ratio at 0 ° C. and 60 ° C. and the life characteristics. The results are shown in Table 1.

Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001

　表１に示すように傾斜ドープした活性層において、Ｐ型クラッド層から深さ１／３の位置までの領域の平均濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上であれば、相対光出力比が０．８６以上であり、該比が１により一層近く、環境温度に対する出力の変化を少なくすることができることが判る。また、３．０×１０１７ａｔｏｍｓ／ｃｍ３以下であれば寿命特性を８１％以上とすることができ、その悪化を抑制できることが判る。
　これらの結果から、良好な環境温度に対する輝度特性および良好な寿命特性を両立するには、傾斜ドープの活性層の上記領域において１．０×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１７ａｔｏｍｓ／ｃｍ３以下の濃度範囲とする必要があることが分かる。 As shown in Table 1, if the average concentration of the region from the P-type clad layer to the position of 1/3 of the depth is 1.0 × 10 16 atoms / cm 3 or more in the gradient-doped active layer, the relative light output It can be seen that the ratio is 0.86 or more, the ratio is closer to 1, and the change in output with respect to the ambient temperature can be reduced. Further, it can be seen that if the life characteristic is 3.0 × 10 17 atoms / cm 3 or less, the life characteristic can be 81% or more, and its deterioration can be suppressed.
From these results, in order to achieve both brightness characteristics for good environmental temperature and good lifetime characteristics, 1.0 × 10 16 atoms / cm 3 or more and 3.0 × 10 17 atoms in the above region of the gradient-doped active layer. / cm 3 it can be seen that it is necessary to make the following concentration range.

　また、図１の第一実施形態において、更にＰ型クラッド層１０５から深さ１／３の位置から深さ２／３の位置の領域（すなわち、Ｐ型クラッド層１０５から活性層１０４の１／３の厚さ分の位置から２／３の厚さ分の位置までの領域）の平均Ｐ型ドーパント濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１６ａｔｏｍｓ／ｃｍ３以下であるものが好ましい。具体的にはＺｎの平均濃度が例えば２×１０１６ａｔｏｍｓ／ｃｍ３、Ｍｇの平均濃度が例えば０．５×１０１６ａｔｏｍｓ／ｃｍ３に設計される（平均濃度の合計値：２．５×１０１６ａｔｏｍｓ／ｃｍ３）。
　上記のような濃度範囲であれば、より確実に寿命特性の悪化を抑制できる。 Further, in the first embodiment of FIG. 1, a region from the P-type clad layer 105 to a depth of 1/3 to a depth of 2/3 (that is, from the P-type clad layer 105 to 1 / of the active layer 104). The average P-type dopant concentration in the region from the position of 3 thickness to the position of 2/3 thickness) is 0.3 × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less. Is preferable. Specifically, the average concentration of Zn is designed to be, for example, 2 × 10 16 atoms / cm 3 , and the average concentration of Mg is designed to be, for example, 0.5 × 10 16 atoms / cm 3 (total average concentration: 2.5 ×). 10 16 averages / cm 3 ).
Within the concentration range as described above, deterioration of life characteristics can be suppressed more reliably.

　また更に、Ｐ型クラッド層１０５から深さ２／３の位置からＮ型クラッド層１０３の側の領域（すなわち、Ｐ型クラッド層１０５から活性層１０４の２／３の厚さ分の位置からＮ型クラッド層１０３までの領域）の平均Ｐ型ドーパント濃度（具体的には、ＺｎとＭｇの平均濃度の合計値）が０．３×１０１６ａｔｏｍｓ／ｃｍ３以下のものであるものが好ましい。なお下限値は特に限定されないが、例えば０ａｔｏｍｓ／ｃｍ３以上とすることができる。
　上記のような濃度範囲であれば、より一層確実に寿命特性の悪化を抑制できる。 Furthermore, from the position of 2/3 of the depth from the P-type clad layer 105 to the region on the side of the N-type clad layer 103 (that is, from the position of 2/3 of the thickness of the P-type clad layer 105 to the active layer 104, N It is preferable that the average P-type dopant concentration (specifically, the total value of the average concentrations of Zn and Mg) of the region up to the mold clad layer 103 is 0.3 × 10 16 atoms / cm 3 . The lower limit is not particularly limited, but may be, for example, 0 atoms / cm 3 or more.
Within the concentration range as described above, deterioration of life characteristics can be suppressed even more reliably.

（第二実施形態）
　本発明の発光素子の第二実施形態を図３に示す。図３に示すように第二実施形態の発光素子２１０は、ＧａＡｓ出発基板２００上に例えば厚さ０．５μｍのＧａＡｓバッファ層、例えば厚さ１．０μｍのＡｌＩｎＰエッチストップ層２０２、例えば厚さ１．０μｍのＮ型ＡｌＧａＩｎＰクラッド層２０３、例えば厚さ０．４８μｍのＡｌＧａＩｎＰ活性層２０４、例えば厚さ１．０μｍのＰ型ＡｌＧａＩｎＰクラッド層２０５、電流伝播層との格子不整を緩和するＰ型ＩｎＧａＰ緩衝層２０６、素子に印加された電流を伝播かつ拡散し、光取り出しの機能を有する例えば厚さ５．０μｍＰ型ＧａＰ電流伝播層２０７を有する。
　ＧａＡｓバッファ層は特になくてもよい。なお、図３においては発光素子の電極等は省略されている。 (Second Embodiment)
A second embodiment of the light emitting device of the present invention is shown in FIG. As shown in FIG. 3, the light emitting element 210 of the second embodiment has a GaAs buffer layer having a thickness of 0.5 μm, for example, an AlInP etch stop layer 202 having a thickness of 1.0 μm, for example, a thickness of 1 on the GaAs starting substrate 200. 0.0 μm N-type AlGaInP clad layer 203, for example 0.48 μm thick AlGaInP active layer 204, for example 1.0 μm thick P-type AlGaInP clad layer 205, P-type InGaP buffer that alleviates lattice irregularities with the current propagation layer The layer 206 has, for example, a 5.0 μm P-type GaP current propagation layer 207 having a function of propagating and diffusing the current applied to the element and extracting light.
The GaAs buffer layer may not be particularly provided. In FIG. 3, the electrodes of the light emitting element and the like are omitted.

　Ｎ型ドーパントとしてＳｉ、Ｓ、Ｓｅのうち、１種類以上がＮ型クラッド層２０３にドーピングされ、Ｐ型ドーパントとしてはＺｎ、Ｍｇ、Ｔｅのうち、１種類以上がＰ型クラッド層２０５及びＰ型緩衝層２０６及びにＰ型電流伝播層２０７にドーピングされる。 One or more of Si, S, and Se as N-type dopants are doped into the N-type clad layer 203, and one or more of Zn, Mg, and Te as P-type dopants are P-type clad layer 205 and P-type. The buffer layer 206 and the P-type current propagation layer 207 are doped.

　Ｎ型クラッド層２０３は、１層以上の組成及びドーピング水準のエピタキシャル層で構成され、Ｐ型クラッド層２０５は、１層以上の組成及びドーピング水準のエピタキシャル層で構成される。 The N-type clad layer 203 is composed of one or more layers of epitaxial layers having a composition and a doping level, and the P-type clad layer 205 is composed of an epitaxial layer having one or more layers and a doping level.

　第二実施形態の発光素子２１０では、活性層２０４はＡｌＧａＩｎＰからなる発光再結合層と発光再結合層の組成よりも大きなバンドギャップ組成を有する障壁層とが多重接合した多重接合型活性層から成る。障壁層は発光再結合層のＡｌＧａＩｎＰより高いＡｌ組成を有する。また、障壁層の厚さは波動関数が重なるドブロイ波長より薄い厚さに設定しても良いし、厚い厚さに設定しても良い。例えば発光再結合層の厚さを８ｎｍ、障壁層の厚さを８ｎｍとし、３０ペアの活性層構造とすることができる。 In the light emitting device 210 of the second embodiment, the active layer 204 is composed of a multi-bonded active layer in which a light-emitting recombination layer made of AlGaInP and a barrier layer having a bandgap composition larger than that of the light-emitting recombination layer are multi-bonded. .. The barrier layer has a higher Al composition than the AlGaInP of the luminescent recombination layer. Further, the thickness of the barrier layer may be set to be thinner than the de Broglie wavelength at which the wave functions overlap, or may be set to a thicker thickness. For example, the thickness of the luminescent recombination layer is 8 nm, the thickness of the barrier layer is 8 nm, and a 30-pair active layer structure can be formed.

　活性層２０４にはＰ型クラッド層２０５からＮ型クラッド層２０３に向かって、例えばなだらかに又は階段状に、濃度が漸減するＰ型ドーパントがドープされている（傾斜ドープ）。以下にＰ型ドーパントとしてＺｎとＭｇの２種がドープされている例を示すが、第一実施形態と同様、これに限定されない。 The active layer 204 is doped with a P-type dopant whose concentration gradually decreases from the P-type clad layer 205 to the N-type clad layer 203, for example, in a gentle or stepwise manner (gradient doping). An example in which two types of Zn and Mg are doped as the P-type dopant is shown below, but the present invention is not limited to this as in the first embodiment.

　上記傾斜ドープの濃度プロファイルは、Ｐ型クラッド層２０５から深さ１／３の位置までの領域の平均Ｐ型ドーパント濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上３×１０１７ａｔｏｍｓ／ｃｍ３以下となっている。具体的にはＰ型ドーパントとして、Ｚｎの平均濃度が例えば５×１０１６ａｔｏｍｓ／ｃｍ３、Ｍｇの平均濃度が例えば１×１０１６ａｔｏｍｓ／ｃｍ３に設計される（平均濃度の合計値：６×１０１６ａｔｏｍｓ／ｃｍ３）。
　このようなものであれば、良好な環境温度に対する輝度特性および良好な寿命特性を両立可能である。 The concentration profile of the gradient dope shows that the average P-type dopant concentration in the region from the P-type clad layer 205 to the position of 1/3 depth is 1.0 × 10 16 atoms / cm 3 or more and 3 × 10 17 atoms / cm 3 It is as follows. Specifically, as the P-type dopant, the average concentration of Zn is designed to be, for example, 5 × 10 16 atoms / cm 3 , and the average concentration of Mg is designed to be, for example, 1 × 10 16 atoms / cm 3 (total average concentration: 6). × 10 16 atoms / cm 3 ).
If it is such a thing, it is possible to achieve both brightness characteristics with respect to good environmental temperature and good life characteristics.

　また、Ｐ型クラッド層２０５から深さ１／３の位置から深さ２／３の位置の領域の平均Ｐ型ドーパント濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１６ａｔｏｍｓ／ｃｍ３以下であるものが好ましい。具体的にはＺｎの平均濃度が例えば２×１０１６ａｔｏｍｓ／ｃｍ３、Ｍｇの平均濃度が例えば０．５×１０１６ａｔｏｍｓ／ｃｍ３に設計される（平均濃度の合計値：２．５×１０１６ａｔｏｍｓ／ｃｍ３）。
　また更に、Ｐ型クラッド層２０５から深さ２／３の位置からＮ型クラッド層２０３の側の領域の平均Ｐ型ドーパント濃度（具体的には、ＺｎとＭｇの平均濃度の合計値）が０．３×１０１６ａｔｏｍｓ／ｃｍ３以下のものであるものが好ましい。なお下限値は特に限定されないが、例えば０ａｔｏｍｓ／ｃｍ３以上とすることができる。
　上記の各領域がこれらの濃度範囲であれば、より一層確実に寿命特性の悪化を抑制できる。 In addition, the average P-type dopant concentration in the region from the P-type clad layer 205 at a depth of 1/3 to a depth of 2/3 is 0.3 × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms. It is preferably 1 / cm 3 or less. Specifically, the average concentration of Zn is designed to be, for example, 2 × 10 16 atoms / cm 3 , and the average concentration of Mg is designed to be, for example, 0.5 × 10 16 atoms / cm 3 (total average concentration: 2.5 ×). 10 16 averages / cm 3 ).
Furthermore, the average P-type dopant concentration (specifically, the total value of the average concentrations of Zn and Mg) in the region on the side of the N-type clad layer 203 from the position 2/3 of the depth from the P-type clad layer 205 is 0. .3 × 10 16 atoms / cm 3 or less is preferable. The lower limit is not particularly limited, but may be, for example, 0 atoms / cm 3 or more.
If each of the above regions is within these concentration ranges, deterioration of life characteristics can be suppressed even more reliably.

　次に、本発明の発光素子の製造方法について説明する。なお、ここでは例として図１の発光素子１１０を製造する場合について説明する。また、活性層へのドープ方法としてガスドープによる方法（第一の製造方法）と熱処理によるドープ方法（第二の製造方法）を例に挙げて説明するが、活性層へのドープ方法はこれらに限定されるものではない。
（第一の製造方法）
　まず、活性層へのドープをガスドープにより行う例について説明する。
　成長用基板としてＧａＡｓ出発基板１００を用意し、洗浄した後、ＭＯＶＰＥ（Ｍｅｔａｌ　Ｏｒｇａｎｉｃ　Ｖａｐｏｒ　Ｐｈａｓｅ　Ｅｐｉｔａｘｙ）炉に入れ、ＧａＡｓ出発基板１００上に、ＡｌＩｎＰエッチストップ層１０２、Ｎ型ＡｌＧａＩｎＰクラッド層１０３、ＡｌＧａＩｎＰ活性層１０４、Ｐ型ＡｌＧａＩｎＰクラッド層１０５、Ｐ型ＩｎＧａＰ緩衝層１０６をエピタキシャル成長させる。 Next, a method for manufacturing the light emitting device of the present invention will be described. Here, a case where the light emitting element 110 of FIG. 1 is manufactured will be described as an example. Further, as the doping method for the active layer, a gas doping method (first production method) and a heat treatment doping method (second production method) will be described as examples, but the doping method for the active layer is limited to these. It is not something that is done.
(First manufacturing method)
First, an example in which the active layer is doped by gas doping will be described.
A GaAs starting substrate 100 is prepared as a growth substrate, washed, and then placed in a MOVPE (MetalOrganic Vapor Phase Epitaxy) furnace. On the GaAs starting substrate 100, the AlInP etch stop layer 102, the N-type AlGaInP clad layer 103, and the AlGaInP activity The layer 104, the P-type AlGaInP clad layer 105, and the P-type InGaP buffer layer 106 are epitaxially grown.

　なお、上記各層のエピタキシャル成長は、公知のＭＯＶＰＥ法により行なうことができる。Ａｌ、Ｇａ、Ｉｎ、Ｐの各成分源となる原料ガスとしては、これらに限定されるわけではないが、例えば以下のようなものを使用できる。
・Ａｌ源ガス：トリメチルアルミニウム（ＴＭＡｌ）、トリエチルアルミニウム（ＴＥＡｌ）など。
・Ｇａ源ガス：トリメチルガリウム（ＴＭＧａ）、トリエチルガリウム（ＴＥＧａ）など。
・Ｉｎ源ガス：トリメチルインジウム（ＴＭＩｎ）、トリエチルインジウム（ＴＥＩｎ）など。
・Ｐ源ガス：トリメチルリン（ＴＭＰ）、トリエチルリン（ＴＥＰ）、ホスフィン（ＰＨ３）など。 The epitaxial growth of each of the above layers can be carried out by a known MOVPE method. The raw material gas that is the source of each component of Al, Ga, In, and P is not limited to these, and for example, the following can be used.
-Al source gas: trimethylaluminum (TMAl), triethylaluminum (TEAl), etc.
-Ga source gas: trimethylgallium (TMGa), triethylgallium (TEGa), etc.
-In source gas: trimethylindium (TMIn), triethylindium (TEIn), etc.
-P source gas: trimethyl phosphorus (TMP), triethyl phosphorus (TEP), phosphine (PH3), etc.

　また、各層へのドーパントのドープとしてはガスドープにより行うことができる。活性層などの各層をエピタキシャル成長しつつガスドープすることができる。ドーパントガスとしては、例えば以下のようなものを使用できる。
（Ｐ型ドーパント）
・Ｚｎ源：ジメチル亜鉛（ＤＭＺｎ）、ジエチル亜鉛（ＤＥＺｎ）など。
・Ｍｇ源：ビズ（シクロペンタジエニル）マグネシウム（Ｃｐ２Ｍｇ）など。
・Ｔｅ源：ジメチルテルル（ＤＭＴｅ）、ジエチルテルル（ＤＥＴｅ）など
（Ｎ型ドーパント）
・Ｓｉ源：モノシランなどのシリコン水素化物など。
・Ｓ源：硫化水素（Ｈ２Ｓ）など。
・Ｓｅ源：セレン化水素など。 Further, the dopant is doped into each layer by gas doping. Each layer such as the active layer can be gas-doped while epitaxially growing. As the dopant gas, for example, the following can be used.
(P-type dopant)
-Zn source: Dimethylzinc (DMZn), diethylzinc (DEZn), etc.
-Mg source: Biz (cyclopentadienyl) magnesium (Cp 2 Mg), etc.
-Te source: Dimethyl telluride (DMTe), diethyl tellurium (DETe), etc. (N-type dopant)
-Si source: Silicon hydride such as monosilane.
-S source: hydrogen sulfide (H 2 S), etc.
-Se source: hydrogen selenide, etc.

　なお、このガスドープの際、活性層１０４中のＰ型ドーパントに関して、図２に示すような傾斜ドープの濃度プロファイルとする。すなわち、活性層１０４において、Ｐ型クラッド層１０５の側からＮ型クラッド層１０３の側へＰ型ドーパントの濃度が漸減するように傾斜ドープする。かつ、Ｐ型クラッド層１０５から深さ１／３の位置までの領域の平均Ｐ型ドーパント濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１７ａｔｏｍｓ／ｃｍ３以下となるようにドープする。
　例えばマスフローコントローラー等によりドーパントガスの流量を制御することにより、簡便に、上記のような濃度プロファイルでガスドープすることが可能である。
　エピタキシャル成長中の熱効果により、多少、意図した濃度プロファイルよりも熱平衡側にずれた濃度プロファイルとなり易い。この点に関しては、そのずれを考慮した上で流量等を適宜調整してガスドープし、意図した濃度プロファイルとなるようにすると良い。
　そして、活性層においてＰ型ドーパントがこのような濃度プロファイルであれば、前述したように、環境温度に対する輝度特性の向上および寿命特性の悪化の抑制の両立を図ることができる。 At the time of this gas doping, the concentration profile of the gradient doping as shown in FIG. 2 is used for the P-type dopant in the active layer 104. That is, in the active layer 104, gradient doping is performed from the side of the P-type clad layer 105 to the side of the N-type clad layer 103 so that the concentration of the P-type dopant gradually decreases. Moreover, the average P-type dopant concentration in the region from the P-type clad layer 105 to the position of 1/3 of the depth is 1.0 × 10 16 atoms / cm 3 or more and 3.0 × 10 17 atoms / cm 3 or less. Dope to.
For example, by controlling the flow rate of the dopant gas with a mass flow controller or the like, it is possible to easily perform gas doping with the above concentration profile.
Due to the thermal effect during epitaxial growth, the concentration profile tends to be slightly shifted to the thermal equilibrium side from the intended concentration profile. Regarding this point, it is advisable to appropriately adjust the flow rate and the like in consideration of the deviation and perform gas doping to obtain the intended concentration profile.
If the P-type dopant has such a concentration profile in the active layer, as described above, it is possible to achieve both improvement of the luminance characteristic with respect to the ambient temperature and suppression of deterioration of the lifetime characteristic.

　また、活性層１０４にＰ型ドーパントをドープするとき、活性層１０４において、Ｐ型クラッド層１０５から深さ１／３の位置から深さ２／３の位置の領域の平均Ｐ型ドーパント濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１６ａｔｏｍｓ／ｃｍ３以下となるようにドープするのが好ましい。
　更には、活性層１０４において、Ｐ型クラッド層１０５から深さ２／３の位置からＮ型クラッド層１０３の側の領域の平均Ｐ型ドーパント濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以下となるようにドープするのが好ましい。なお下限値は特に限定されないが、例えば０ａｔｏｍｓ／ｃｍ３以上とすることができる。
　上記の各領域がこれらの濃度範囲であれば、より一層確実に寿命特性の悪化を抑制することができる。 Further, when the active layer 104 is doped with a P-type dopant, the average P-type dopant concentration in the region from the P-type clad layer 105 at a depth of 1/3 to a depth of 2/3 is 0 in the active layer 104. It is preferable to dope so that the content is 3 × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less.
Furthermore, in the active layer 104, the average P-type dopant concentration in the region on the side of the N-type clad layer 103 from the position 2/3 of the depth from the P-type clad layer 105 is 0.3 × 10 16 atoms / cm 3 or less. It is preferable to dope so as to be. The lower limit is not particularly limited, but may be, for example, 0 atoms / cm 3 or more.
When each of the above regions is within these concentration ranges, deterioration of life characteristics can be suppressed even more reliably.

　この後、Ｐ型ＧａＰ電流伝播層１０７をＨＶＰＥ法（ハイドライド気相成長法：Ｈｙｄｒｉｄｅ　Ｖａｐｏｒ　Ｐｈａｓｅ　Ｅｐｉｔａｘｙ法）で気相成長する。
　ＨＶＰＥ法は、具体的には、例えば金属Ｇａを所定の温度に加熱保持しながら、その金属Ｇａ上に塩化水素を導入することにより、下記（１）式の反応によりＧａＣｌを生成させ、キャリアガスであるＨ２ガスとともに基板上に供給する。
Ｇａ（液体）＋ＨＣｌ（気体）→ＧａＣｌ（気体）＋１／２Ｈ２（気体）…（１）
　成長温度は例えば６４０℃以上８６０℃以下に設定することができる。また、Ｖ族元素であるＰは、例えばＰＨ３をキャリアガスであるＨ２と共に基板上に供給する。さらに、Ｐ型ドーパントとして例えばＺｎを、ジメチル亜鉛（ＤＭＺｎ）の形で供給して、下記（２）式のような反応によって電流伝播層１０７を形成することができる。
ＧａＣｌ（気体）＋ＰＨ３（気体）
　→ＧａＰ（固体）＋ＨＣｌ（気体）＋Ｈ２（気体）…（２） After that, the P-type GaP current propagation layer 107 is vapor-deposited by the HVPE method (Hydride Vapor Phase Epitaxy method).
Specifically, in the HVPE method, for example, by introducing hydrogen chloride onto the metal Ga while heating and holding the metal Ga at a predetermined temperature, GaCl is generated by the reaction of the following formula (1) to generate a carrier gas. It is supplied on the substrate together with the H 2 gas.
Ga (liquid) + HCl (gas) → GaCl (gas) + 1 / 2H 2 (gas) ... (1)
The growth temperature can be set to, for example, 640 ° C. or higher and 860 ° C. or lower. Further, P, which is a Group V element, supplies, for example, PH 3 on the substrate together with H 2 which is a carrier gas. Further, for example, Zn can be supplied as a P-type dopant in the form of dimethylzinc (DMZn) to form the current propagation layer 107 by a reaction as shown in the following equation (2).
GaCl (gas) + PH 3 (gas)
→ GaP (solid) + HCl (gas) + H 2 (gas) ... (2)

（第二の製造方法：熱処理によるドープ）
　次に、活性層へのドープを熱処理により行う例について説明する。
　基本的に第一の製造方法と同様にして、出発基板１００の準備から緩衝層１０６の形成を行う。ただし、Ｐ型クラッド層１０５から活性層１０４へＰ型ドーパントを熱処理により拡散してドープすることを考慮して、活性層１０４のエピタキシャル成長時はノンドープとする。また、Ｐ型クラッド層１０５においては第一の製造方法の場合よりも高濃度でＰ型ドーパントをドープしておくと良い。 (Second manufacturing method: doping by heat treatment)
Next, an example in which the active layer is doped by heat treatment will be described.
Basically, the buffer layer 106 is formed from the preparation of the starting substrate 100 in the same manner as in the first manufacturing method. However, in consideration of diffusing and doping the P-type dopant from the P-type clad layer 105 to the active layer 104 by heat treatment, the active layer 104 is not doped during epitaxial growth. Further, it is preferable that the P-type cladding layer 105 is doped with the P-type dopant at a higher concentration than in the case of the first production method.

　より具体的には、Ｐ型クラッド層１０５のＰ型ドーパント濃度は、例えばＺｎ、ＭｇをＰ型ドーパントとした場合、Ｚｎの濃度を１．０×１０１６～３．０×１０１８ａｔｏｍｓ／ｃｍ３、Ｍｇの濃度を１．０×１０１６～５．０×１０１７ａｔｏｍｓ／ｃｍ３の濃度範囲とすることができる。このような濃度範囲であれば、より確実に、次の工程である熱処理工程で図２に示すような傾斜ドープの濃度プロファイルとすることができる。 More specifically, the P-type dopant concentration of the P-type clad layer 105 is such that, when Zn and Mg are P-type dopants, the Zn concentration is 1.0 × 10 16 to 3.0 × 10 18 atoms / cm. 3. The concentration of Mg can be in the concentration range of 1.0 × 10 16 to 5.0 × 10 17 atoms / cm 3 . Within such a concentration range, the gradient dope concentration profile as shown in FIG. 2 can be more reliably obtained in the heat treatment step, which is the next step.

　上記のように少なくともＰ型クラッド層１０５までの各層を形成後（この例ではさらに緩衝層１０６まで形成済み）、ＭＯＶＰＥ炉内で、例えばＰＨ３雰囲気下、７００℃以上、３時間以上の熱処理を施す。ここでは７００℃（エピタキシャル成長時と同程度の温度）で８時間の熱処理とする。このような熱処理によって、簡便に、図２に示すような傾斜ドープの濃度プロファイルとすることができる。熱処理を施すことでＰ型クラッド層１０５からドーパントが拡散式に従って活性層１０４内に拡散し、Ｎ型クラッド層１０３へ向かって漸減する濃度プロファイルを形成する。 After forming each layer up to at least the P-type clad layer 105 as described above (in this example, the buffer layer 106 has already been formed), heat treatment is performed in a MOVPE furnace, for example, in a PH 3 atmosphere at 700 ° C. or higher for 3 hours or longer. Give. Here, the heat treatment is performed at 700 ° C. (a temperature similar to that at the time of epitaxial growth) for 8 hours. By such a heat treatment, the concentration profile of the gradient dope as shown in FIG. 2 can be easily obtained. By applying the heat treatment, the dopant is diffused from the P-type clad layer 105 into the active layer 104 according to the diffusion formula, and forms a concentration profile that gradually decreases toward the N-type clad layer 103.

　なお、熱処理の温度、時間は特に限定されず、所望の傾斜ドープの濃度プロファイルが得られるよう適宜決定することができる。また上記のようにＰＨ３雰囲気で行えば、エピタキシャル層表面からのＰ（燐）の脱離を効果的に回避することができるので好ましい。 The temperature and time of the heat treatment are not particularly limited, and can be appropriately determined so as to obtain a desired gradient dope concentration profile. Further, it is preferable to carry out in a PH 3 atmosphere as described above because desorption of P (phosphorus) from the surface of the epitaxial layer can be effectively avoided.

　その後、第一の製造方法と同様にして、電流伝播層１０７をＨＶＰＥ法で形成する。
　なお、上記例では緩衝層１０６を形成後に熱処理したが、そのタイミングで熱処理を行うのではなく、代わりに電流伝播層１０７を形成後に熱処理（ＨＶＰＥ炉でＰＨ３雰囲気下、７００℃以上、３時間以上、特には、７００℃で８時間）を施して、活性層１０４において傾斜ドープの濃度プロファイルを形成することもできる。 Then, the current propagation layer 107 is formed by the HVPE method in the same manner as in the first manufacturing method.
In the above example, the buffer layer 106 was formed and then heat-treated, but instead of being heat-treated at that timing, the current propagation layer 107 was formed and then heat-treated (in an HVPE furnace under a PH 3 atmosphere, at 700 ° C. or higher for 3 hours). As described above, in particular, the concentration profile of the gradient dope can be formed in the active layer 104 by subjecting the active layer 104 at 700 ° C. for 8 hours).

　以下、本発明の実施例及び比較例を示して本発明をより具体的に説明するが、本発明はこれらに限定されるものではない。
（実施例１）
　以下のようにして本発明の製造方法により本発明の発光素子を製造した。
　［００１］方向に１５度傾斜したＧａＡｓ基板上に有機金属気相成長法（ＭＯＶＰＥ）法にて、１．０μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなるエッチストップ層、１．０μｍ厚のＮ型クラッド層、０．９μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる活性層、（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる１．０μｍ厚のＰ型クラッド層、ＧａｙＩｎ１－ｙＰ（０．０≦ｙ≦１．０）から成る中間組成層（緩衝層）、０．５μｍ以上の厚さを有するＧａＰ電流拡散層（電流伝播層）を順次積層した発光素子用ウェーハを形成した。 Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited thereto.
(Example 1)
The light emitting device of the present invention was manufactured by the manufacturing method of the present invention as follows.
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), a 1.0 μm thick N-type clad layer, and a 0.9 μm thick (Al x Ga 1-x ) y In 1-y P (0 ≦). An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).

　活性層は均一組成の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）層から成る。
　活性層にはＰ型クラッド層からＮ型クラッド層へ向かって濃度が漸減するようにＰ型ドーパント（ＺｎおよびＭｇの２種）をドープした。具体的には、活性層を形成しつつ、ＤＥＺｎ、Ｃｐ２Ｍｇを流してガスドープした。
　濃度プロファイルは、Ｐ型クラッド層との界面において、Ｐ型ドーパントとしてのＺｎの濃度が５×１０１６ａｔｏｍｓ／ｃｍ３、Ｐ型ドーパントとしてのＭｇの濃度が１×１０１６ａｔｏｍｓ／ｃｍ３であった。
　そして、Ｐ型クラッド層から深さ０．３μｍの位置（活性層全厚０．９μｍの１／３）までの領域のＺｎ平均濃度が２×１０１６ａｔｏｍｓ／ｃｍ３、Ｍｇ平均濃度が０．５×１０１６ａｔｏｍｓ／ｃｍ３であった（平均濃度の合計値：２．５×１０１６ａｔｏｍｓ／ｃｍ３）。
　また、深さ０．３μｍの位置から深さ０．６μｍの位置（全厚０．９μｍの１／３から２／３）までの領域におけるＺｎ平均濃度が０．５×１０１６ａｔｏｍｓ／ｃｍ３、Ｍｇ平均濃度が０．２×１０１６ａｔｏｍｓ／ｃｍ３であった（平均濃度の合計値：０．７×１０１６ａｔｏｍｓ／ｃｍ３）。
　それ以降の深さ（深さ２／３の位置からＮ型クラッド層まで）のＭｇ及びＺｎの各々の平均濃度の合計値は０．３×１０１６ａｔｏｍｓ／ｃｍ３以下であった。
　このようにして製造したウェーハに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。 The active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) layer having a uniform composition.
The active layer was doped with a P-type dopant (two types of Zn and Mg) so that the concentration gradually decreased from the P-type clad layer to the N-type clad layer. Specifically, while forming an active layer, DEZn and Cp 2 Mg were flowed and gas-doped.
The concentration profile is that the concentration of Zn as a P-type dopant is 5 × 10 16 atoms / cm 3 and the concentration of Mg as a P-type dopant is 1 × 10 16 atoms / cm 3 at the interface with the P-type clad layer. It was.
Then, the Zn average concentration in the region from the P-type clad layer to the position of 0.3 μm in depth (1/3 of the total thickness of the active layer of 0.9 μm) is 2 × 10 16 atoms / cm 3 , and the Mg average concentration is 0. It was 5 × 10 16 atoms / cm 3 (total average concentration: 2.5 × 10 16 atoms / cm 3 ).
In addition, the average Zn concentration in the region from the position of 0.3 μm in depth to the position of 0.6 μm in depth (1/3 to 2/3 of the total thickness of 0.9 μm) is 0.5 × 10 16 atoms / cm 3 , Mg average concentration was 0.2 × 10 16 atoms / cm 3 (total value of average concentration: 0.7 × 10 16 atoms / cm 3 ).
The total average concentration of each of Mg and Zn at the subsequent depths (from the position of 2/3 depth to the N-type clad layer) was 0.3 × 10 16 atoms / cm 3 or less.
Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.

（実施例２）
　以下のようにして本発明の製造方法により本発明の発光素子を製造した。
　［００１］方向に１５度傾斜したＧａＡｓ基板上に有機金属気相成長法（ＭＯＶＰＥ）法にて、１．０μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなるエッチストップ層、１．０μｍ厚のＮ型クラッド層、０．４８μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる活性層、（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる１．０μｍ厚のＰ型クラッド層、ＧａｙＩｎ１－ｙＰ（０．０≦ｙ≦１．０）から成る中間組成層（緩衝層）、０．５μｍ以上の厚さを有するＧａＰ電流拡散層（電流伝播層）を順次積層した発光素子用ウェーハを形成した。 (Example 2)
The light emitting device of the present invention was manufactured by the manufacturing method of the present invention as follows.
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), an N-type clad layer with a thickness of 1.0 μm, and a (Al x Ga 1-x ) y In 1-y P (0 ≦) with a thickness of 0.48 μm. An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).

　活性層は第一組成の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）層から成る発光再結合層と、第二組成の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）層から成る障壁層が交互に積層された多重障壁型活性層から構成される。
　第一組成のＡｌ比率は第二組成のＡｌ比率より少ない比率に設定した。 The active layer consists of a luminescent recombination layer composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) layer having the first composition, and a second composition. (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) It is composed of multiple barrier type active layers in which barrier layers are alternately laminated. Will be done.
The Al ratio of the first composition was set to be smaller than the Al ratio of the second composition.

　活性層にはＰ型クラッド層からＮ型クラッド層へ向かって濃度が漸減するようにＰ型ドーパント（ＺｎおよびＭｇの２種）をドープした。具体的には、活性層を形成しつつ、ＤＥＺｎ、Ｃｐ２Ｍｇを流してガスドープした。
　濃度プロファイルは、Ｐ型クラッド層との界面において、Ｐ型ドーパントとしてのＺｎの濃度が５×１０１６ａｔｏｍｓ／ｃｍ３、Ｐ型ドーパントとしてのＭｇの濃度が１×１０１６ａｔｏｍｓ／ｃｍ３であった。
　そして、Ｐ型クラッド層から深さ０．１６μｍの位置（活性層全厚０．４８μｍの１／３）までの領域のＺｎの平均濃度が２×１０１６ａｔｏｍｓ／ｃｍ３、Ｍｇ平均濃度が０．５×１０１６ａｔｏｍｓ／ｃｍ３であった（平均濃度の合計値：２．５×１０１６ａｔｏｍｓ／ｃｍ３）。
　また、深さ０．１６μｍの位置から深さ０．３２μｍの位置（全厚０．４８μｍの１／３から２／３）までの領域におけるＺｎ平均濃度が０．５×１０１６ａｔｏｍｓ／ｃｍ３、Ｍｇ平均濃度が０．２×１０１６ａｔｏｍｓ／ｃｍ３であった（平均濃度の合計値：０．７×１０１６ａｔｏｍｓ／ｃｍ３）。
　それ以降の深さ（深さ２／３の位置からＮ型クラッド層まで）のＭｇ及びＺｎの各々の平均濃度の合計値は０．３×１０１６ａｔｏｍｓ／ｃｍ３以下であった。
　このようにして製造したウェーハに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。 The active layer was doped with a P-type dopant (two types of Zn and Mg) so that the concentration gradually decreased from the P-type clad layer to the N-type clad layer. Specifically, while forming an active layer, DEZn and Cp 2 Mg were flowed and gas-doped.
The concentration profile is that the concentration of Zn as a P-type dopant is 5 × 10 16 atoms / cm 3 and the concentration of Mg as a P-type dopant is 1 × 10 16 atoms / cm 3 at the interface with the P-type clad layer. It was.
Then, the average concentration of Zn in the region from the P-type clad layer to the position of 0.16 μm in depth (1/3 of the total thickness of the active layer of 0.48 μm) is 2 × 10 16 atoms / cm 3 , and the average concentration of Mg is 0. It was .5 × 10 16 atoms / cm 3 (total average concentration: 2.5 × 10 16 atoms / cm 3 ).
Further, the average Zn concentration in the region from the position of 0.16 μm in depth to the position of 0.32 μm in depth (1/3 to 2/3 of the total thickness of 0.48 μm) is 0.5 × 10 16 atoms / cm 3 , Mg average concentration was 0.2 × 10 16 atoms / cm 3 (total value of average concentration: 0.7 × 10 16 atoms / cm 3 ).
The total average concentration of each of Mg and Zn at the subsequent depths (from the position of 2/3 depth to the N-type clad layer) was 0.3 × 10 16 atoms / cm 3 or less.
Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.

（比較例１）
　以下のようにして発光素子を製造した。
　［００１］方向に１５度傾斜したＧａＡｓ基板上に有機金属気相成長法（ＭＯＶＰＥ）法にて、１．０μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなるエッチストップ層、１．０μｍ厚のＮ型クラッド層、０．９μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる活性層、（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる１．０μｍ厚のＰ型クラッド層、ＧａｙＩｎ１－ｙＰ（０．０≦ｙ≦１．０）から成る中間組成層（緩衝層）、０．５μｍ以上の厚さを有するＧａＰ電流拡散層（電流伝播層）を順次積層した発光素子用ウェーハを形成した。 (Comparative Example 1)
A light emitting device was manufactured as follows.
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), a 1.0 μm thick N-type clad layer, and a 0.9 μm thick (Al x Ga 1-x ) y In 1-y P (0 ≦). An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).

　活性層は均一組成の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）層から成り、かつ、ガスドープ（ＤＥＺｎ、Ｃｐ２Ｍｇ使用）により活性層のＭｇ及びＺｎの各々の濃度の合計値は０．３×１０１６ａｔｏｍｓ／ｃｍ３以下とした。
　このようにして製造したウェーハに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。 The active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) layer having a uniform composition, and is gas-doped (DEZn, Cp 2 Mg). The total concentration of Mg and Zn in the active layer was set to 0.3 × 10 16 atoms / cm 3 or less.
Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.

（比較例２）
　以下のようにして発光素子を製造した。
　［００１］方向に１５度傾斜したＧａＡｓ基板上に有機金属気相成長法（ＭＯＶＰＥ）法にて、１．０μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなるエッチストップ層、１．０μｍ厚のＮ型クラッド層、０．９μｍ厚の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる活性層、（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）からなる１．０μｍ厚のＰ型クラッド層、ＧａｙＩｎ１－ｙＰ（０．０≦ｙ≦１．０）から成る中間組成層（緩衝層）、０．５μｍ以上の厚さを有するＧａＰ電流拡散層（電流伝播層）を順次積層した発光素子用ウェーハを形成した。 (Comparative Example 2)
A light emitting device was manufactured as follows.
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), a 1.0 μm thick N-type clad layer, and a 0.9 μm thick (Al x Ga 1-x ) y In 1-y P (0 ≦). An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).

　活性層は均一組成の（ＡｌｘＧａ１－ｘ）ｙＩｎ１－ｙＰ（０≦ｘ≦１，０．４≦ｙ≦０．６）層から成り、また、ガスドープ（ＤＥＺｎ、Ｃｐ２Ｍｇ使用）により活性層のＺｎの濃度を５×１０１６ａｔｏｍｓ／ｃｍ３、Ｍｇの濃度を１×１０１６ａｔｏｍｓ／ｃｍ３で一定とした（濃度の合計値：６×１０１６ａｔｏｍｓ／ｃｍ３）。
　このようにして製造したウェーハに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。 The active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) layer having a uniform composition, and is gas-doped (DEZn, Cp 2 Mg). (Use) made the Zn concentration of the active layer constant at 5 × 10 16 atoms / cm 3 and the Mg concentration at 1 × 10 16 atoms / cm 3 (total concentration: 6 × 10 16 atoms / cm 3 ). ..
Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.

　表２に実施例１、実施例２、比較例１、比較例２の発光素子について環境温度の違い（０℃ｖｓ６０℃）による光出力比及び寿命特性を示す。
　表２に示すように実施例１、２に関しては、環境温度の違いによる光出力比が０．８６以上であり、かつ、寿命特性は８７であり、これらの両方が良好な値であった。
　一方、比較例１は活性層にドーパントがほとんど存在しないため、寿命特性は良好であるが、環境温度の違いによる光出力比は０．８となり、環境温度による輝度の変化が大きかった。また、比較例２は環境温度の違いによる光出力比は良好であったが、活性層のドーパントを漸減させず一定としたことにより、寿命特性が６０％であり悪化してしまった。 Table 2 shows the light output ratio and the life characteristics of the light emitting elements of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 due to the difference in environmental temperature (0 ° C vs. 60 ° C).
As shown in Table 2, in Examples 1 and 2, the light output ratio due to the difference in environmental temperature was 0.86 or more, and the life characteristic was 87, both of which were good values.
On the other hand, in Comparative Example 1, since there was almost no dopant in the active layer, the lifetime characteristics were good, but the light output ratio was 0.8 due to the difference in the environmental temperature, and the change in brightness due to the environmental temperature was large. Further, in Comparative Example 2, the light output ratio was good due to the difference in the environmental temperature, but the lifetime characteristic was 60%, which was deteriorated by keeping the dopant of the active layer constant without gradually reducing it.

Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002

　また、ガスドープによる実施例１、２とは別に、少なくともＰ型クラッド層までの各層を形成後、熱処理を施してＰ型ドーパントをＰ型クラッド層から活性層に拡散させることで、実施例１、２と同等の傾斜ドープの濃度プロファイルを有し、かつ、同等の光出力比及び寿命特性を有する発光素子を製造できることを本発明者らは確認している。 Further, apart from Examples 1 and 2 by gas doping, each layer up to at least the P-type clad layer is formed, and then heat treatment is performed to diffuse the P-type dopant from the P-type clad layer to the active layer. The present inventors have confirmed that a light emitting device having the same gradient doping concentration profile as No. 2 and having the same light output ratio and lifetime characteristics can be manufactured.

　なお、本発明は、上記実施形態に限定されるものではない。上記実施形態は、例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。 The present invention is not limited to the above embodiment. The above embodiment is an example, and any one having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. It is included in the technical scope of the invention.

Claims (10)

　Ｎ型クラッド層と活性層とＰ型クラッド層がこの順序で形成された発光部を有する発光素子であって、
　前記活性層は、前記Ｐ型クラッド層側から前記Ｎ型クラッド層側へ濃度が漸減するＰ型ドーパントを含み、
　前記活性層において、前記Ｐ型クラッド層から前記活性層の１／３の厚さ分の位置までの領域の平均の前記Ｐ型ドーパントの濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１７ａｔｏｍｓ／ｃｍ３以下であることを特徴とする発光素子。 A light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
The active layer contains a P-type dopant whose concentration gradually decreases from the P-type clad layer side to the N-type clad layer side.
2. In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. A light emitting element having a concentration of 0 × 10 17 atoms / cm 3 or less. 　前記発光部は、ＡｌＧａＩｎＰ系の化合物半導体からなることを特徴とする請求項１に記載の発光素子。 The light emitting device according to claim 1, wherein the light emitting unit is made of an AlGaInP-based compound semiconductor. 　前記活性層において、前記Ｐ型クラッド層から前記活性層の１／３の厚さ分の位置から２／３の厚さ分の位置までの領域の平均の前記Ｐ型ドーパントの濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１６ａｔｏｍｓ／ｃｍ３以下であることを特徴とする請求項１または請求項２に記載の発光素子。 In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 thickness of the active layer to the position of 2/3 thickness is 0.3. The light emitting element according to claim 1 or 2, wherein the light emitting element is x10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less. 　前記活性層において、前記Ｐ型クラッド層から前記活性層の２／３の厚さ分の位置からＮ型クラッド層までの領域の平均の前記Ｐ型ドーパントの濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以下であることを特徴とする請求項３に記載の発光素子。 In the active layer, the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the active layer to the N-type clad layer is 0.3 × 10 16 atoms /. The light emitting element according to claim 3, wherein the light emitting element is cm 3 or less. 　Ｎ型クラッド層と活性層とＰ型クラッド層をこの順序で形成した発光部を有する発光素子の製造方法であって、
　前記活性層において、前記Ｐ型クラッド層側から前記Ｎ型クラッド層側へＰ型ドーパントの濃度が漸減し、かつ、
　前記活性層において、前記Ｐ型クラッド層から前記活性層の１／３の厚さ分の位置までの領域の平均の前記Ｐ型ドーパントの濃度が１．０×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１７ａｔｏｍｓ／ｃｍ３以下となるように前記Ｐ型ドーパントをドープして製造することを特徴とする発光素子の製造方法。 A method for manufacturing a light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
In the active layer, the concentration of the P-type dopant gradually decreases from the P-type clad layer side to the N-type clad layer side, and
3. In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. A method for manufacturing a light emitting device, which comprises doping the P-type dopant so as to be 0 × 10 17 atoms / cm 3 or less. 　前記発光部を、ＡｌＧａＩｎＰ系の化合物半導体からなるものとすることを特徴とする請求項５に記載の発光素子の製造方法。 The method for manufacturing a light emitting device according to claim 5, wherein the light emitting unit is made of an AlGaInP-based compound semiconductor. 　前記活性層に前記Ｐ型ドーパントをドープするとき、
　前記活性層において、前記Ｐ型クラッド層から前記活性層の１／３の厚さ分の位置から２／３の厚さ分の位置までの領域の平均の前記Ｐ型ドーパントの濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以上３．０×１０１６ａｔｏｍｓ／ｃｍ３以下となるようにドープすることを特徴とする請求項５または請求項６に記載の発光素子の製造方法。 When doping the active layer with the P-type dopant,
In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 thickness of the active layer to the position of 2/3 thickness is 0.3. The method for producing a light emitting element according to claim 5 or 6, wherein the light emitting element is doped so as to have a concentration of × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less. 　前記活性層に前記Ｐ型ドーパントをドープするとき、
　前記活性層において、前記Ｐ型クラッド層から前記活性層の２／３の厚さ分の位置からＮ型クラッド層までの領域の平均の前記Ｐ型ドーパントの濃度が０．３×１０１６ａｔｏｍｓ／ｃｍ３以下となるようにドープすることを特徴とする請求項７に記載の発光素子の製造方法。 When doping the active layer with the P-type dopant,
In the active layer, the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the P-type clad layer to the N-type clad layer is 0.3 × 10 16 atoms /. The method for manufacturing a light emitting element according to claim 7, wherein the light emitting element is doped so as to be cm 3 or less. 　前記活性層への前記Ｐ型ドーパントのドープを、
　前記活性層を形成しつつガスドープにより行うことを特徴とする請求項５から請求項８のいずれか一項に記載の発光素子の製造方法。 Doping the P-type dopant on the active layer,
The method for manufacturing a light emitting device according to any one of claims 5 to 8, wherein the active layer is formed and gas-doped. 　前記活性層への前記Ｐ型ドーパントのドープを、
　前記活性層を形成した後、前記Ｐ型ドーパントをドープした前記Ｐ型クラッド層を形成してから熱処理を施して、前記Ｐ型クラッド層にドープした前記Ｐ型ドーパントを前記活性層に拡散させることにより行うことを特徴とする請求項５から請求項８のいずれか一項に記載の発光素子の製造方法。
  Doping the P-type dopant on the active layer,
After forming the active layer, the P-type clad layer doped with the P-type dopant is formed and then heat-treated to diffuse the P-type dopant doped in the P-type clad layer into the active layer. The method for manufacturing a light emitting element according to any one of claims 5 to 8, wherein the method is performed according to the above.
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