TW201316378A - Compound semiconductor substrate, method for producing the same, and light-emitting element using the same - Google Patents

Abstract

This compound semiconductor substrate has, on a second GaP window layer, a light emitting layer configured of a double hetero structure composed of a lower cladding layer represented by the formula of (AlxGa1-x)yIn1-yP (0<x<1, 0<y<1), an active layer, and an upper cladding layer, and has a first GaP window layer on the light emitting layer. The compound semiconductor substrate is characterized in that the lattice constants of the lower cladding layer, the active layer, and the upper cladding layer match such that respective differences (??) between a Bragg angle on the (400) plane of a GaAs single crystal and respective Bragg angles on the (400) planes of the lower cladding layer, the active layer and the upper cladding layer are within the range of 50"-200" at a room temperature. Consequently, the high-quality compound semiconductor substrate is provided, said semiconductor substrate having improved light emitting service life characteristics, less variance of the light emitting service life characteristics within the plane, and furthermore, improved luminance.

Description

Compound semiconductor substrate, method for producing the same, and light-emitting element using the same

The present invention relates to a compound semiconductor substrate, a method for producing the same, and a light-emitting device using the compound semiconductor substrate.

In recent years, as a light-emitting element, for example, it is easy to obtain a high-luminance light-emitting ability in a range of green to red, a light-emitting element manufactured by a compound semiconductor substrate which is epitaxial on a GaAs substrate is often used. growth of _{(Al x Ga 1-x)} y in 1-y P ( hereinafter sometimes referred to as an AlGaInP) quaternary mixed crystal as a light emitting layer composed together.

However, in the case where a light-emitting layer such as AlGaInP having a different lattice constant than GaAs is formed on a GaAs substrate, the larger the difference in lattice constant, the influence on the luminance or luminescence lifetime characteristics of, for example, a light-emitting element The larger the value, the lower the characteristics. Further, it is also possible to cause dislocation in the compound semiconductor substrate.

Therefore, in the prior art, for example, as disclosed in Patent Document 1, when epitaxial growth of AlGaInP is performed, a method is performed in which the difference Δω of the Bragg angle of the lattice plane (400) of AlGaInP and GaAs becomes 0 〞 low. The lattice constant of AlGaInP and GaAs is matched in an angle manner, and the composition of AlGaInP is adjusted to form a light-emitting layer.

Moreover, several attempts have been made, such as forming a crystal in which the crystal lattice constant is gradually changed to gradually change the lattice constant from the lattice constant of GaAs to AlGaInP. The layer of the lattice constant or the layer which is used to relax the mismatch is used to thereby make the lattice constant of the AlGaInP layer grown by the epitaxy close to the lattice constant of GaAs.

However, only in the prior art, a manufacturing method in which the lattice constant in the epitaxial growth temperature is considered, or a method of forming a layer for reducing the difference in lattice constant of AlGaInP and GaAs in the middle, may result in The characteristics such as the luminance and the luminescence lifetime characteristics of the manufactured light-emitting element (compound semiconductor substrate) are unstable, and it is not guaranteed that satisfactory results can be obtained.

[Previous Technical Literature] (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. Hei 9-186360.

Further, it is known that when the AlGaInP is epitaxially grown, the lattice constant of AlGaInP and GaAs is matched so that the difference Δω of the Bragg angle of the lattice plane (400) of AlGaInP and GaAs becomes 0〞 to a low angle, and AlGaInP is adjusted. When the composition is formed to form a light-emitting layer, the difference in conductivity is likely to propagate to the light-emitting layer, so that the light-emitting lifetime characteristics of the entire compound semiconductor substrate are deteriorated or the light-emitting lifetime characteristics in the surface of the compound semiconductor substrate are not uniform. The degree of deterioration or unevenness also becomes uneasy in each batch of substrates set.

The present invention has been devised in order to solve the above problems, and an object thereof is to provide a high-quality compound semiconductor substrate which can increase luminescence lifetime characteristics and improve luminescence lifetime by suppressing diffusion into a luminescent layer by suppressing diffusion. In-plane variation of characteristics and further improvement in brightness. Further, an object of the present invention is to provide a light-emitting element using the above-described compound semiconductor substrate.

The present invention provides a compound semiconductor substrate having a light-emitting layer on a second GaP window layer and having a first GaP window layer on the light-emitting layer, and the light-emitting layer is made of (Al _x Ga _1-x ) _y In _1-y P (where 0<x<1, 0<y<1) constitutes a double heterostructure of the lower cladding layer, the active layer, and the upper cladding layer, and the characteristics of the compound semiconductor substrate The lattice constants of the lower cladding layer, the active layer, and the upper cladding layer are matched, and the lower cladding layer, the active layer, and the upper cladding layer are on the (400) surface. The difference Δω between the Bragg angle and the Bragg angle of the GaAs single crystal on the (400) plane (hereinafter sometimes simply referred to as Δω) is 50 〞 to 200 分别 at room temperature.

In this way, if the lattice constant of the lower cladding layer, the active layer, and the upper cladding layer is matched, and the compound semiconductor substrate having Δω of 50 Å to 200 Å at room temperature is obtained, the compound semiconductor substrates are each The stress relaxation between the layers effectively functions, and the misfit dislocation is prevented from being propagated to each layer of the light-emitting layer, thereby increasing the light-emitting lifetime characteristics, improving the in-plane unevenness of the light-emitting lifetime characteristics, and further improving the brightness. Compound Semiconductor substrate.

Further, it is preferred that the lattice constants of the lower cladding layer, the active layer, and the upper cladding layer are matched so that Δω becomes 50 〞 to 150 Å (especially 50 Å to 100 Å) at room temperature. Semiconductor substrate.

In the case of such a range of Δω, the stress relaxation between the layers of the compound semiconductor substrate is more effectively performed, and the unevenness of the misalignment is suppressed from being propagated to each layer of the light-emitting layer, thereby further improving the light-emitting lifetime characteristics and improving the light emission. A compound semiconductor substrate having in-plane unevenness in lifetime characteristics and further improving brightness.

Further, the present invention provides a light-emitting element characterized by being produced from the above-described compound semiconductor substrate.

In the case of such a light-emitting element, it becomes a light-emitting element which increases the light-emitting lifetime characteristics, improves the in-plane unevenness of the light-emitting lifetime characteristics, and further improves the luminance.

Moreover, the present invention provides a method of fabricating a compound semiconductor substrate, the method comprising the steps of: a light-emitting layer growth step of epitaxial growth on a GaAs substrate by (Al _x Ga _1-x ) _y In _1-y P (where 0<x<1, 0<y<1) represents a light-emitting layer composed of a double heterostructure of a lower cladding layer, an active layer, and an upper cladding layer; growth of the first GaP window layer a step of growing the first GaP window layer on the light-emitting layer in the first GaP window layer growth step, an etching step of etching away the GaAs substrate to expose the lower cladding layer, and a second GaP window layer growth step, The second GaP window layer growth step forms a second GaP window layer on the exposed lower cladding layer; wherein the manufacturing method is characterized in that in the step of growing the light-emitting layer, the lower cladding layer and the active layer are formed And the difference Δω between the Bragg angle of the upper cladding layer on the (400) plane and the Bragg angle of the GaAs substrate on the (400) plane is 50 〞 to 200 分别 at room temperature, respectively, in the GaAs The light-emitting layer is epitaxially grown on the substrate.

In the method for producing a compound semiconductor substrate having such a step of growing the light-emitting layer, it is a method for producing a compound semiconductor substrate, and the method can effectively produce stress relaxation between layers of the compound semiconductor substrate during production. Since the misalignment row is not easily propagated to each layer of the light-emitting layer, the light-emitting life characteristics are improved, the in-plane unevenness of the light-emitting life characteristics is improved, and the brightness is further improved.

Further, in the step of growing the light-emitting layer, it is preferable to epitaxially grow the light-emitting layer on the GaAs substrate so that Δω becomes 50 Å to 150 Å (especially, 50 Å to 100 Å) at room temperature.

In the case of such a light-emitting layer growth step, it is a method for producing a compound semiconductor substrate, which can produce a stress relaxation between layers of a compound semiconductor substrate more efficiently, and a misalignment row is arranged in a row. Since it is less likely to propagate to each layer of the light-emitting layer, the light-emitting life characteristics are further increased, the in-plane unevenness of the light-emitting life characteristics is improved, and the brightness is further improved.

As described above, if the lattice constants of the lower cladding layer, the active layer, and the upper cladding layer are matched, the Bragg angles of the lower cladding layer, the active layer, and the upper cladding layer on the (400) plane are When the difference Δω of the Bragg angle of the GaAs single crystal on the (400) plane becomes 50 〞 to 200 Å of the compound semiconductor substrate of the present invention at room temperature, the stress between the layers of the compound semiconductor substrate is alleviated, and the misalignment is suppressed. Since the row-equivalent row propagates to each layer of the light-emitting layer, the compound semiconductor substrate is improved in the in-plane unevenness of the light-emitting lifetime characteristics, and the luminance is further improved.

Hereinafter, the present invention will be described in more detail, but the present invention is not limited to the following embodiments. As described above, what is desired is a compound semiconductor substrate which can suppress the propagation of the difference row to the light-emitting layer.

The present inventors have found through repeated investigations on the above problems that it is found that if the lattice constants of the lower cladding layer, the active layer, and the upper cladding layer are matched, the lower cladding layer, the active layer, and the upper cladding layer are obtained. The difference Δω between the Bragg angle of the cladding layer on the (400) plane and the Bragg angle of the GaAs single crystal on the (400) plane becomes a compound semiconductor substrate of 50 Å to 200 Å at room temperature, respectively, and the compound semiconductor substrate is alleviated. The stress between the layers was found to suppress the spread of the misalignment and the like to the light-emitting layer, thereby improving the light-emitting lifetime characteristics, the unevenness of the in-plane light-emitting lifetime characteristics, and the brightness, and the like. Hereinafter, the details will be described with reference to Figs. 1 to 5 .

[Compound semiconductor substrate]

The present invention provides a compound semiconductor substrate having a light-emitting layer on a second GaP window layer and having a first GaP window layer on the light-emitting layer, and the light-emitting layer is made of (Al _x Ga _1-x ) _y In _1-y P (where 0<x<1, 0<y<1) constitutes a double heterostructure of the lower cladding layer, the active layer, and the upper cladding layer, and the characteristics of the compound semiconductor substrate The lattice constants of the lower cladding layer, the active layer, and the upper cladding layer are matched, and the lower cladding layer, the active layer, and the upper cladding layer are on the (400) surface. The difference Δω between the Bragg angle of the Bragg angle and the GaAs single crystal on the (400) plane becomes 50 〞 to 200 分别 at room temperature, respectively.

[1st GaP window layer and 2GaP window layer]

The first GaP window layer 1 and the second GaP window layer 6 in the present invention are not particularly limited as long as they are transparent conductive films composed of GaP (Fig. 1). The first GaP window layer and the second GaP window layer can be formed, for example, as a thick film transparent conductive film, and the thickness of the first GaP window layer is preferably 10 μm to 100 μm. Further, the thickness of the second GaP window layer is preferably 10 μm to 100 μm. Even in the case of the compound semiconductor substrate of the present invention, the first GaP window layer and the second GaP window layer of the thick film can improve the light-emitting lifetime characteristics, the unevenness of the in-plane light-emitting lifetime characteristics, and the brightness.

Further, the first GaP window layer and the second GaP window layer are preferably current spreading layers. When the first GaP window layer and the second GaP window layer are current diffusion layers, it is possible to efficiently emit light in a wide range not only in the vicinity of the electrodes.

[Light Emitting Layer]

The light-emitting layer 5 in the present invention is an under cladding layer 4 represented by (Al _x Ga _1-x ) _y In _1-y P (where 0 < x < 1, 0 < y < 1), active The double layer structure of the layer 3 and the upper cladding layer 2 is formed (Fig. 1).

The lattice constants of the lower cladding layer 4, the active layer 3, and the upper cladding layer 2 are matched so that the Bragg angles of the lower cladding layer 4, the active layer 3, and the upper cladding layer 2 on the (400) plane are The difference Δω of the Bragg angle of the GaAs single crystal on the (400) plane is 50 〞 to 200 分别 at room temperature, preferably 50 〞 to 150 〞, and more preferably 50 〞 to 100 〞.

As a method of calculating Δω, it is possible to measure the Bragg angle ω and the AlGaInP of the GaAs substrate on the (400) plane by using CuKα1 light having a wavelength of λ = 1.5405 Å as the X-ray for measurement. The Bragg angle ω' of the cladding layer, the active layer, and the upper cladding layer on the (400) plane, and the difference Δω (= ω ' - ω) is obtained.

Thus, by matching the lattice constants of the lower cladding layer, the active layer and the upper cladding layer, Δω is 50 〞 to 200 在 at room temperature, preferably 50 〞 to 150 Å, and More preferably, it is 50 Å to 100 Å, and the stress relaxation between the layers of the compound semiconductor substrate can be effectively performed, and the unevenness of the misalignment can be suppressed from being propagated to each layer of the light-emitting layer. Therefore, it is possible to obtain a compound semiconductor substrate in which the luminescence lifetime characteristics are improved, the in-plane unevenness of the luminescence lifetime characteristics is improved, and the luminance is further improved. Hereinafter, the details will be described with reference to FIGS. 2 and 3 .

Figure 2 (a) is the crystal of the cladding layer, the active layer and the upper cladding layer under matching In the schematic cross-sectional view of the compound semiconductor substrate when Δω is 0 〞 to a low angle at room temperature, the difference in the propagation direction of the internal stress is shown in Fig. 2, and Fig. 2(b) In the schematic cross-sectional view of the compound semiconductor substrate in the case where Δω is 50 〞 to 200 分别 at room temperature, the lattice constant of the under cladding layer, the active layer, and the upper cladding layer is matched, and The direction of propagation is accompanied by the difference in internal stress.

If Δω is 0〞~low angle at room temperature as shown in Fig. 2(a), the compression pressure is applied to (Al _x Ga _1-x ) _y In _1-y P (where 0 <x<1, 0<y<1) is shown on the lower cladding layer, the active layer, and the upper cladding layer, and the difference between the misalignment row and the like is propagated to the lower cladding layer, the active layer, and the upper layer. Therefore, in the prior art, the luminescence lifetime characteristic of the compound semiconductor substrate is deteriorated, and the luminescence lifetime characteristic in the surface of the compound semiconductor substrate is uneven, and the luminance is further deteriorated. On the other hand, as shown in Fig. 2 ( b), when Δω is 50 〞 to 200 分别 at room temperature, the stress applied to the lower cladding layer, the active layer, and the upper cladding layer is alleviated, and the lower cladding layer, the active layer, and the lower layer are inhibited. Further, the compound semiconductor substrate of the present invention has a higher variation in luminescence lifetime characteristics, improved in-plane unevenness in luminescence lifetime characteristics, and further improved brightness.

In order to show the relationship between Δω and the difference row, an X-ray surface topography photograph of the interface between the lower cladding layer of the compound semiconductor substrate and the second GaP window layer was taken. Fig. 3(a) shows the active layer of the compound semiconductor substrate in the case where the lattice constant of the lower cladding layer, the active layer and the upper cladding layer is matched, and Δω is 0 室温 at room temperature, respectively. X-ray surface topography. In addition, Figure 3 (b) shows the crystal matching the lower cladding layer, the active layer and the upper cladding layer. The X-ray surface topography of the active layer of the compound semiconductor substrate in the case where Δω is 100 分别 at room temperature, respectively.

When Δω is 0 在 at room temperature, the compression pressure is applied to the lower cladding layer, the active layer, and the upper cladding layer, and the internal stress balance between the layers of the compound semiconductor substrate is deteriorated. The difference between the lower cladding layer/the GaAs substrate removal surface (second GaP layer) is extended toward the light-emitting layer (see FIG. 2). As a result, as shown in FIG. 3(a), the activity is active. Differences occur in each layer of the light-emitting layer such as a layer, and the luminescence lifetime characteristics are deteriorated, the in-plane unevenness, and the luminance are lowered.

On the other hand, in the compound semiconductor substrate of the present invention, when Δω is 100 在 at room temperature, the internal stress is relieved by making Δω 50 〞 to 200 ,, and the difference is easily extended toward the second GaP layer. In the case where the interface from the lower cladding layer/GaAs substrate removal surface (second GaP layer) is extended in the direction of the light-emitting layer (see FIG. 2(b)), as shown in FIG. 3(b), the suppression is suppressed. The difference in retardation of each layer of the light-emitting layer such as the active layer, etc., therefore, the compound semiconductor substrate of the present invention increases the light-emitting lifetime characteristics, improves the in-plane unevenness of the light-emitting lifetime characteristics, and further improves the brightness.

[Method of Manufacturing Compound Semiconductor Substrate]

Moreover, the present invention provides a method of fabricating a compound semiconductor substrate, the method comprising the steps of: a light-emitting layer growth step of epitaxial growth on a GaAs substrate by (Al _x Ga _1-x ) _y In _1-y P (where 0<x<1, 0<y<1) represents a light-emitting layer composed of a double heterostructure of a lower cladding layer, an active layer, and an upper cladding layer; growth of the first GaP window layer a step of growing the first GaP window layer on the light-emitting layer in the first GaP window layer growth step, an etching step of etching away the GaAs substrate to expose the lower cladding layer, and a second GaP window layer growth step, The second GaP window layer growth step forms a second GaP window layer on the exposed lower cladding layer; wherein the manufacturing method is characterized in that in the step of growing the light-emitting layer, the lower cladding layer and the active layer are formed And the difference Δω between the Bragg angle of the upper cladding layer on the (400) plane and the Bragg angle of the GaAs substrate on the (400) plane is 50 〞 to 200 分别 at room temperature, respectively, in the GaAs The light-emitting layer is epitaxially grown on the substrate.

Hereinafter, it will be described in detail with reference to FIG.

[Preparation of GaAs Substrate (Step (I) of Fig. 4)]

The GaAs substrate is not particularly limited as long as it is generally used for growing an AlGaInP mixed crystal. For example, a substrate having an off angle of a plane orientation (100) of 2 to 15 degrees can be used. A GaAs substrate on which a compound semiconductor film such as GaAs, AlGaAs, AlGaInP, InGaP, GaP, or GaAsP is formed may be used on the GaAs substrate. When these compound semiconductor films are formed on a GaAs substrate by the MOVPE method, TMG (trimethylgallium), TMA (trimethylaluminum), TMI (trimethylindium), AsH ₃ , PH ₃ or the like is used. Further, as the gas for semiconductor impurities for controlling the conductivity type, DMZ (dimethyl zinc), DEZ (diethyl zinc) or Cp ₂ Mg, SiH ₄ , H ₂ Se or the like is used. The compound semiconductor film thus formed can be appropriately selected, for example, in accordance with the use of a light-emitting element such as a light-emitting diode.

[Light-emitting layer growth step (step (II) of Fig. 4)]

The step of growing the light-emitting layer in the present invention is that epitaxial growth on the GaAs substrate is represented by (Al _x Ga _1-x ) _y In _1-y P (where 0 < x < 1, 0 < y < 1) A light-emitting layer composed of a double heterostructure of a lower cladding layer, an active layer, and an upper cladding layer. In the step of growing the light-emitting layer, the difference Δω between the Bragg angle of the lower cladding layer, the active layer, and the upper cladding layer on the (400) plane and the Bragg angle of the GaAs substrate on the (400) plane is The light-emitting layer is epitaxially grown on the GaAs substrate at a temperature of 50 Å to 200 Å (preferably 50 Å to 150 Å, and more preferably 50 Å to 100 Å) at room temperature. The growth method of the light-emitting layer is not particularly limited, and it can be carried out by the MOVPE method under the conditions of a pressure reduction of 200 mbar or less and 600 ° C or more. For example, TMG (trimethylgallium), TMA (trimethylaluminum), TMI (trimethylindium), and PH _{3 are} used as the material gas, and DMZ is used as a gas for semiconductor impurities for controlling conductivity type. Dimethylzinc), DEZ (diethylzinc) or Cp ₂ Mg, SiH ₄ , H ₂ Se, and the like.

The adjustment conditions of the respective layers of the light-emitting layer composed of AlGaInP, for example, the Bragg angle of the lattice plane (400) of GaAs at room temperature and (Al _x Ga _1-x ) _y In _1-y P (where 0 < The Bragg angle of the lattice plane (400) of x<1,0<y<1) at room temperature, and then comparing the two to find out the adjustment condition for making Δω into the range of 50〞~200〞, Thereby, the adjustment conditions of the respective layers of the light-emitting layer are determined.

[First GaP Window Layer Growth Step (Step (III) of Fig. 4)]

In the first GaP window layer growth step in the present invention, the first GaP window layer is epitaxially grown on the light-emitting layer. The growth method is not particularly limited. For example, a thick film transparent conductive film (GaP) can be epitaxially grown by a VPE method under conditions of 600 ° C or higher. The thickness of the first GaP window layer is not particularly limited, but is preferably 10 μm to 100 μm. In the method of manufacturing the compound semiconductor substrate of the present invention, the first semiconductor wafer substrate of the present invention can produce a compound semiconductor substrate having improved luminescence lifetime characteristics, unevenness in luminescence lifetime characteristics, and luminance.

[etching step (step (IV) of Fig. 4)]

In the etching step of the present invention, the GaAs substrate is etched away to expose the lower cladding layer.

[2th GaP window layer growth step (step (V) of Fig. 4)]

In the second GaP window layer growth step of the present invention, the second GaP window layer may be epitaxially grown on the exposed under cladding layer, or the second GaP window layer may be formed by bonding the transparent conductive GaP substrate. The epitaxial growth method is not particularly limited, and can be carried out, for example, by a VPE method under conditions of 600 ° C or higher. Further, the joining method is not particularly limited, and it can be joined by heat treatment at 100 ° C or higher.

[Light-emitting element]

Further, the present invention provides a light-emitting element which is produced by the above-described compound semiconductor substrate. Although not particularly limited, an Au-based P-type and N-type ohmic electrode can be formed on the above-described compound semiconductor substrate, and then wafer-formed into an arbitrary size (for example, 250 μm to 300 μm square) to produce a light-emitting element (Fig. 4 (VI) step). According to such a light-emitting element, it is possible to provide a light-emitting element which has improved light-emitting lifetime characteristics, improved unevenness in light-emitting lifetime characteristics between light-emitting elements, and further improved brightness.

[Examples]

Hereinafter, the examples and comparative examples of the present invention will be described in further detail, but the present invention is not limited to the following examples.

(Example 1)

On the GaAs substrate, a GaAs buffer layer having an N-type Si doping (carrier concentration of 1×10 ¹⁸ /cm ³ ) and a thickness of 0.5 μm is epitaxially grown according to the MOVPE method and N-type Si doping (carrier concentration 1×10) ¹⁸ /cm ³ ) and a thickness of 1 μm under the coating of AlGaInP, and then epitaxial growth of an undoped AlGaInP active layer with a thickness of 1 μm, and epitaxial growth of P-type Mg doping (carrier concentration 1 × 10 ¹⁷ / cm ³⁾ and a thickness of 1μm on the AlGaInP cladding layer (light emitting layer growth step).

In the step of growing the light-emitting layer, the Bragg angle of the lower cladding layer, the active layer, and the upper cladding layer on the (400) plane is on the (400) plane of the GaAs substrate. The difference Δω of the upper Bragg angle was adjusted to 50 室温 at room temperature to adjust the crystal composition of the light-emitting layer, and the light-emitting layer was epitaxially grown on the GaAs substrate.

Then, as a first GaP window layer, a GaP window layer having a P-type Mg doping (carrier concentration of 3×10 ¹⁷ /cm ³ ) and a thickness of 2 μm is epitaxially grown, and then P-type Zn doping is epitaxially grown by VPE method. A thick film transparent conductive GaP layer (having a first GaP window layer growth step) having a carrier concentration of 8 × 10 ¹⁷ /cm ³ and a thickness of 50 μm, and then etching and removing the GaAs substrate (etching step). Finally, a GaP window layer (second GaP window layer forming step) having an N-type S doping (carrier concentration of 5 × 10 ¹⁷ /cm ³ ) and a thickness of 100 μm as a second GaP window layer is epitaxially grown by a VPE method. A compound semiconductor substrate is produced.

On the compound semiconductor substrate, an Au-based P-type and N-type ohmic electrode were formed and wafer-formed into an arbitrary size to produce a light-emitting element. The luminance and luminescence lifetime characteristics of the light-emitting element of the present invention thus produced were measured. The temperature at the time of measurement was 85 ° C, the humidity was 45%, the light output Po (mW) at a current of 20 mA was measured, and the light output was measured again after the current of 50 mA or more was applied for 100 hours to calculate the luminescence lifetime characteristic (%). . The measurement results are shown in Table 1.

Further, the Bragg angle of the lattice plane (400) of the AlGaInP active layer measured by the 2-crystal X-ray diffraction method, the deformation lattice constant calculated from the Bragg angle, and the relaxation lattice constant, and the GaAs single crystal and AlGaInP The results of the lattice mismatch ratio of the active layer are also shown in Table 1. Further, in the 2-crystal X-ray diffraction method, CuKα1 light having a wavelength λ = 1.5405 angstroms was used as X-ray for measurement.

Further, the deformation lattice constant, the relaxation lattice constant, and the lattice mismatch ratio can be obtained by the following formulas (1), (2), and (3).

The deformed lattice constant = 2 × CuKα1 wavelength λ / sin (the Bragg angle of the AlGaInP active layer at the (400) plane ω' π / 180) ... (1)

Relaxed lattice constant = 0.47 × GaAs lattice constant + 0.53 × deformation lattice constant...... (2)

Lattice mismatch rate = (moderate lattice constant - GaAs lattice constant) / GaAs lattice constant... (3)

Here, the GaAs lattice constant was set to 5.65325 Å.

(Example 2)

A light-emitting device was produced in the same manner as in Example 1 except that the crystal composition of the light-emitting layer was adjusted so that Δω became 75 Å at room temperature, and the light-emitting layer was epitaxially grown on the GaAs substrate.

(Example 3)

A light-emitting device was produced in the same manner as in Example 1 except that the crystal composition of the light-emitting layer was adjusted so that Δω became 100 Å at room temperature, and the light-emitting layer was epitaxially grown on the GaAs substrate.

(Example 4)

A light-emitting device was produced in the same manner as in Example 1 except that the crystal composition of the light-emitting layer was adjusted so that Δω became 150 Å at room temperature, and the light-emitting layer was epitaxially grown on the GaAs substrate.

(Example 5)

A light-emitting device was produced in the same manner as in Example 1 except that the crystal composition of the light-emitting layer was adjusted so that Δω became 200 Å at room temperature, and the light-emitting layer was epitaxially grown on the GaAs substrate.

(Comparative Example 1)

A light-emitting device was produced in the same manner as in Example 1 except that the crystal composition of the light-emitting layer was adjusted so that Δω became -100 Torr at room temperature, and the light-emitting layer was epitaxially grown on the GaAs substrate.

(Comparative Example 2)

A light-emitting device was produced in the same manner as in Example 1 except that the crystal composition of the light-emitting layer was adjusted so that Δω became 0 室温 at room temperature, and the light-emitting layer was epitaxially grown on the GaAs substrate.

The output Po (mW), the luminescence lifetime characteristic (%) of the light-emitting elements of Examples 1 to 5 and Comparative Examples 1 and 2 manufactured as described above, and the Bragg angle and deformation of the AlGaInP active layer on the lattice plane (400) The lattice constant, the relaxation lattice constant, and the lattice mismatch ratio are shown in Table 1.

Further, the results of measuring the luminescence lifetime characteristics and the in-plane luminescence lifetime characteristics of the light-emitting elements of Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Fig. 5. The horizontal axis of Fig. 5 indicates the in-plane position of the compound semiconductor substrate, and the vertical axis indicates the luminescence lifetime characteristic corresponding to the in-plane position.

As described above, the difference between the Bragg angle of the lower cladding layer, the active layer, and the upper cladding layer on the (400) plane and the Bragg angle of the GaAs substrate on the (400) plane at room temperature is Δω from - When 100 〞 is compared to +200 〞, the luminescence lifetime characteristic of Δω at 50 〞 to 200 上升 is known (Table 1). Further, in the drawings (Fig. 5), in Examples 1 to 5 of the compound semiconductor substrate of the present invention having Δω of 50 Å to 200 Å, the luminescence lifetime characteristics are improved, and the in-plane unevenness and output ( Brightness) has also been improved.

On the other hand, in Comparative Example 1 and Comparative Example 2 in which the difference Δω between the GaAs substrate and the AlGaInP active layer at the Bragg angle of the (400) plane was 0 〞 to the low angle side, the inside of each layer of the compound semiconductor substrate was The stress balance is poor, and the difference (dislocation, etc.) is extended from the lower cladding layer/GaAs substrate removal surface (second GaP layer) interface toward the light-emitting layer. Therefore, a difference is generated in the light-emitting layer, and the light-emitting lifetime characteristics are deteriorated. Unevenness and reduced brightness.

As explained above, if the lower cladding layer, the active layer, and The lattice constant of the upper cladding layer, and the difference between the Bragg angle of the lower cladding layer, the active layer, and the upper cladding layer on the (400) plane and the Bragg angle of the GaAs single crystal on the (400) plane Δω When the compound semiconductor substrate of the present invention is 50 Å to 200 Å at room temperature, the stress between the layers of the compound semiconductor substrate is alleviated, and the unevenness of the misalignment is suppressed from being propagated to each layer of the luminescent layer, thereby increasing the luminescence. A compound semiconductor substrate having a life characteristic, an in-plane unevenness in which the luminescence lifetime characteristics are improved, and a luminance is further improved.

Further, the present invention is not limited to the above embodiment. The above-described embodiments are merely illustrative, and any technique having substantially the same configuration as the technical idea described in the patent application of the present invention and exhibiting the same operational effects is also included in the technical scope of the present invention.

1‧‧‧1GaP window layer

2‧‧‧Upper coating

3‧‧‧Active layer

4‧‧‧Under cladding

5‧‧‧Lighting layer

6‧‧‧2GaP window layer

Fig. 1 is a schematic cross-sectional view showing a compound semiconductor substrate of the present invention.

Fig. 2(a) shows the compound semiconductor substrate in the case where the lattice constants of the lower cladding layer, the active layer and the upper cladding layer are matched, and Δω is made 0 〞 to a low angle at room temperature, respectively. In the schematic cross-sectional view, the propagation direction of the difference with the internal stress is shown. In the second (b), the lattice constant of the lower cladding layer, the active layer, and the upper cladding layer is matched, and Δω is obtained. In the schematic cross-sectional view of the compound semiconductor substrate in the case of 50 〞 to 200 Å at room temperature, the propagation direction of the difference in the internal stress is shown.

Fig. 3(a) shows the combination of the lattice constants of the lower cladding layer, the active layer and the upper cladding layer, and the case where Δω becomes 0 在 at room temperature, respectively. X-ray surface topography of the active layer of the semiconductor substrate; Figure 3 (b) shows the lattice constants of the lower cladding layer, the active layer and the upper cladding layer, so that Δω becomes respectively at room temperature X-ray surface topography of the active layer of the compound semiconductor substrate in the case of 100 Å.

Fig. 4 is a flow chart showing a method of producing a compound semiconductor substrate of the present invention.

Fig. 5 is a graph showing the luminescence lifetime characteristics and the luminescence lifetime characteristic unevenness of the light-emitting elements of Examples 1 to 5 and Comparative Examples 1 and 2.

1‧‧‧1GaP window layer

2‧‧‧Upper coating

3‧‧‧Active layer

4‧‧‧Under cladding

5‧‧‧Lighting layer

6‧‧‧2GaP window layer

Claims (8)

A compound semiconductor substrate having a light-emitting layer on a second GaP window layer and having a first GaP window layer on the light-emitting layer, and the light-emitting layer is made of (Al _x Ga _1-x ) _y In _{1- y} P (where 0<x<1, 0<y<1) is composed of a double heterostructure of a lower cladding layer, an active layer, and an upper cladding layer, and the compound semiconductor substrate is characterized by the foregoing The lattice constants of the cladding layer, the active layer, and the upper cladding layer are matched, and the Bragg angle and the GaAs of the lower cladding layer, the active layer, and the upper cladding layer on the (400) plane are matched. The difference Δω of the Bragg angle of the single crystal on the (400) plane is 50 〞 to 200 分别 at room temperature, respectively. The compound semiconductor substrate according to claim 1, wherein the lattice constants of the lower cladding layer, the active layer, and the upper cladding layer are matched, and the Δω is 50 〞 at room temperature. 150〞. The compound semiconductor substrate according to claim 1, wherein the lattice constants of the lower cladding layer, the active layer, and the upper cladding layer are matched, and the Δω is 50 〞 at room temperature. 100 years old. The compound semiconductor substrate according to claim 2, wherein the lattice constants of the lower cladding layer, the active layer, and the upper cladding layer are matched, and the Δω is 50 〞 at room temperature. 100 years old. A light-emitting element which is produced by the compound semiconductor substrate according to any one of claims 1 to 4. A method for fabricating a compound semiconductor substrate, the method comprising the steps of: a light-emitting layer growth step of epitaxial growth on a GaAs substrate by (Al _x Ga _1-x ) _y In _1-y P (wherein a light-emitting layer composed of a double heterostructure of a lower cladding layer, an active layer, and an upper cladding layer, represented by 0<x<1, 0<y<1); a first GaP window layer growth step, the first GaP window a layer growth step of epitaxially growing a first GaP window layer on the light-emitting layer; an etching step of etching the GaAs substrate to expose the lower cladding layer; and a second GaP window layer growth step, the second GaP window layer growing a step of forming a second GaP window layer on the exposed lower cladding layer; wherein the manufacturing method is characterized in that in the step of growing the light-emitting layer, the lower cladding layer, the active layer, and the upper cladding layer are coated The difference Δω between the Bragg angle of the layer on the (400) plane and the Bragg angle of the GaAs substrate on the (400) plane is 50 〞 to 200 分别 at room temperature, respectively, and epitaxial growth is performed on the GaAs substrate. Light-emitting layer. A method of producing a compound semiconductor substrate according to claim 6, wherein In the step of growing the light-emitting layer, the light-emitting layer is epitaxially grown on the GaAs substrate so that the Δω is 50 Å to 150 Å at room temperature. The method of producing a compound semiconductor substrate according to claim 7, wherein in the step of growing the light-emitting layer, epitaxy is performed on the GaAs substrate so that the Δω is 50 〞 to 100 在 at room temperature, respectively. The aforementioned light-emitting layer is grown.