JP5156305B2 - Group III nitride compound semiconductor light emitting device manufacturing apparatus and group III nitride compound semiconductor light emitting device manufacturing method - Google Patents

Description

  The present invention relates to a group III nitride compound semiconductor light emitting device manufacturing apparatus, a group III nitride compound semiconductor light emitting device manufacturing method suitably used for a light emitting diode (LED), a laser diode (LD), an electronic device, and the like, and The present invention relates to a group III nitride compound semiconductor light emitting device and a lamp using the group III nitride compound semiconductor light emitting device.

Group III nitride compound semiconductor light emitting devices have a direct transition type band gap of energy corresponding to the range of visible light to ultraviolet light, and are excellent in luminous efficiency. It is used.
Moreover, even when the group III nitride semiconductor is used in an electronic device, an electronic device having excellent characteristics can be obtained as compared with the case where a conventional group III-V compound semiconductor is used.

Such a group III nitride compound semiconductor is generally manufactured by MOCVD using trimethyl gallium, trimethyl aluminum and ammonia as raw materials.
The MOCVD method is a method in which a vapor of a raw material is included in a carrier gas and transported to the substrate surface, and the raw material is decomposed by reaction with a heated substrate to grow crystals.

On the other hand, studies have also been carried out to produce a group III nitride compound semiconductor crystal by sputtering. Specifically, for example, a method of forming a GaN layer on the (100) plane of Si and the (0001) plane of sapphire (Al ₂ O ₃ ) by high-frequency magnetron sputtering using N ₂ gas has been proposed. (For example, Non-Patent Document 1).

  Further, a method has been proposed in which a GaN layer is formed using an apparatus in which a cathode and a solid target face each other and a mesh is placed between the substrate and the target (for example, Non-Patent Document 2).

In addition, when forming a group III nitride compound semiconductor crystal composed of GaN as described above, for example, it is necessary to form a crystal in which a dopant element such as Si or Mg is doped in the GaN layer. At this time, a method of forming a GaN layer by sputtering using a target obtained by mixing a dopant element with a Ga element as a base material has been proposed (for example, Non-Patent Document 3).
Yukiko Ushibuchi (Y. USHIKU) et al., “Proceedings of the 21st Century Union Symposium”, Vol. 2nd, p295 (2003), T. Kikuma et al., “Vacuum”, Vol. 66, P233 (2002) “The 66th Japan Society of Applied Physics” brochure, 7a-N-6, 1 volume, p248 (Autumn 2005)

However, in the conventional sputtering method, it is difficult to finely adjust the doping concentration when a doped group III nitride semiconductor crystal is formed.
In addition, when depositing AlGaN or the like doped with Mg element using MOCVD, the amount of Mg taken into the crystal changes according to the Al composition, so when the Al composition is low Although Mg easily enters, there is a problem that Mg is difficult to enter when the Al composition is high.

Furthermore, in the method of Non-Patent Document 3, since a target in which a dopant element is mixed with a Ga element serving as a base material is used, a layer including a dopant element and a layer not including the dopant element are continuously formed on a substrate using a sputtering method. In the case of stacking, it is necessary to form a film by moving a substrate between the chambers using a sputtering apparatus having a plurality of chambers. For this reason, there existed a problem that process time became long while a sputtering device became large.
In addition, the method of Non-Patent Document 3 does not describe a specific method of doping. For example, when a dopant element is mixed with a Ga element that is liquid at room temperature, Since the dopant element in the Ga element floats or sinks due to the difference in specific gravity, the concentration of the dopant element in the obtained gallium nitride semiconductor crystal is not uniform. Here, it is conceivable to form the GaN layer by sputtering so that the Ga element does not become liquid, but in this case, the power cannot be sufficiently loaded, and the film formation rate is sufficiently increased. There was a case that could not be done.

The present invention has been made in view of the above problems, and can easily optimize the concentration of the dopant element in the crystal of the gallium nitride semiconductor, and can be efficiently formed using a sputtering method. An object of the present invention is to provide an apparatus for manufacturing a Group III nitride compound semiconductor.
Also provided is a method for producing a group III nitride compound semiconductor light-emitting device capable of easily optimizing the concentration of a dopant element in a crystal of a group III nitride semiconductor and capable of efficiently forming a film using a sputtering method. With the goal.
Furthermore, it aims at providing the group III nitride compound semiconductor light-emitting device and lamp | ramp which are obtained with said manufacturing method.

As a result of intensive investigations to solve the above problems, the present inventors made a manufacturing apparatus that can apply power simultaneously or alternately to a Ga target containing a Ga element and a dopant target composed of a dopant element. Thus, the inventors have found that the concentration of the dopant element in the crystal of the gallium nitride semiconductor can be easily optimized without making the apparatus large, and that the film can be efficiently formed using the sputtering method, and the present invention has been completed.
That is, the present invention relates to the following.

[1] A manufacturing apparatus for forming a semiconductor layer made of a group III nitride semiconductor of a group III nitride compound semiconductor light emitting device by a sputtering method, comprising a chamber and a Ga element installed in the chamber A group III nitride compound semiconductor comprising: a Ga target and a dopant target composed of a dopant element; and a power application unit that applies power to the Ga target and the dopant target simultaneously or alternately. manufacturing device.
[2] The apparatus for producing a group III nitride compound semiconductor light-emitting element according to [1], wherein the dopant element is Si or Mg.
[3] Ga in the gas phase when the semiconductor layer is formed by changing the ratio of the power applied to the Ga target and the power applied to the dopant target by the power applying means. The apparatus for producing a Group III nitride compound semiconductor light-emitting device according to [1] or [2], wherein the ratio of the element to the dopant element is controlled.
[4] The power application means applies the power by a pulse DC method, and changes the pulse ratio between a pulse applied to the Ga target and a pulse applied to the dopant target, thereby the semiconductor. The group III nitride compound semiconductor light-emitting device according to [1] or [2], wherein the ratio of Ga element to dopant element in the gas phase when forming the layer is controlled Manufacturing equipment.
[5] The dopant element is Si, and the ratio of Ga element to Si element in the gas phase when the power application unit forms the semiconductor layer is set to 1: 0.001 to 1: The apparatus for producing a Group III nitride compound semiconductor light-emitting device according to [3] or [4], which is controlled within a range of 0.00001.
[6] The dopant element is Mg, and the power application means sets the ratio of Ga element and Mg element in the gas phase when the semiconductor layer is formed to 1: 0.1 to 1: The apparatus for producing a Group III nitride compound semiconductor light-emitting device according to [3] or [4], which is controlled within a range of 0.001.
[7] The group III nitride compound semiconductor light-emitting device manufacturing apparatus according to any one of [1] to [6], wherein at least the surface layer of the Ga target is liquefied.

[8] The III according to any one of [1] to [7], wherein the dopant target is sputtered so as not to form a cluster composed of the dopant element having two or more atoms. Group nitride compound semiconductor light emitting device manufacturing apparatus.
[9] The III according to any one of [1] to [8], wherein the dopant target is sputtered at a voltage at which a cluster composed of two or more atoms of the dopant element is not formed. Group nitride compound semiconductor light emitting device manufacturing apparatus.

[10] A method for producing a group III nitride compound semiconductor light emitting device having a semiconductor layer in which an n-type semiconductor layer, a light emitting layer, and a p type semiconductor layer each made of a group III nitride semiconductor are stacked, Including a step of forming at least a part by a sputtering method, and when forming the semiconductor layer by a sputtering method, a Ga target containing a Ga element and a dopant target made of a dopant element are used as the sputtering target, and the Ga target A method of manufacturing a group III nitride compound semiconductor light emitting device, wherein power is applied simultaneously or alternately to the dopant target.
[11] The method for producing a group III nitride compound semiconductor light-emitting device according to [10], wherein the n-type semiconductor layer is formed by using Si as the dopant element.
[12] The ratio of Ga element to Si element in the gas phase during the formation of the semiconductor layer is in the range of 1: 0.001 to 1: 0.00001 [11] ] The manufacturing method of the group III nitride compound semiconductor light-emitting device of description.
[13] The method for producing a group III nitride compound semiconductor light-emitting device according to [10], wherein the p-type semiconductor layer is formed by using Mg as the dopant element.
[14] The ratio of Ga element to Mg element in the gas phase during the formation of the semiconductor layer is in the range of 1: 0.1 to 1: 0.001 [13] ] The manufacturing method of the group III nitride compound semiconductor light-emitting device of description.
[15] By the ratio of the area of the surface of the Ga target facing the substrate and the area of the surface of the dopant target facing the substrate,
The group III nitride according to any one of [10] to [14], wherein a ratio of a Ga element and a dopant element in a gas phase when the semiconductor layer is formed is controlled A method for producing a compound semiconductor light emitting device.
[16] By changing the ratio of the power applied to the Ga target and the power applied to the dopant target,
The group III nitride according to any one of [10] to [14], wherein a ratio of a Ga element and a dopant element in a gas phase when the semiconductor layer is formed is controlled A method for producing a compound semiconductor light emitting device.
[17] By applying the power by a pulse DC method and changing a pulse ratio between a pulse applied to the Ga target and a pulse applied to the dopant target,
The group III nitride according to any one of [10] to [14], wherein a ratio of a Ga element and a dopant element in a gas phase when the semiconductor layer is formed is controlled A method for producing a compound semiconductor light emitting device.
[18] The group III nitride compound semiconductor light emitting device according to any one of [10] to [17], wherein an intermediate layer made of a columnar crystal is formed between the substrate and the semiconductor layer. Device manufacturing method.
[19] The method for producing a group III nitride compound semiconductor light-emitting element according to any one of [10] to [18], wherein at least a surface layer is liquefied as the Ga target.

  The apparatus for producing a group III nitride compound semiconductor according to the present invention includes a Ga target containing a Ga element and a dopant target composed of a dopant element installed in the chamber, and the Ga target and the dopant target simultaneously or Since power application means for alternately applying power is provided, the concentration of the dopant element in the crystal of the semiconductor layer formed by sputtering can be easily controlled to the optimum value.

Moreover, since the Ga target and the dopant target are installed in the chamber of the group III nitride compound semiconductor manufacturing apparatus of the present invention, the layer containing the dopant element and the layer not containing the dopant element on the substrate in one chamber. Can be laminated continuously. Therefore, as compared with a sputtering apparatus in which only one target is disposed in the chamber, the apparatus can be made compact and the time required for the film forming process can be shortened.
In addition, since the group III nitride compound semiconductor manufacturing apparatus of the present invention forms a film using a sputtering method, the film can be formed efficiently at a higher speed than when forming a film using the MOCVD method or the MBE method. In addition, the apparatus has a simple configuration.

  In addition, according to the method for producing a group III nitride compound semiconductor light emitting device of the present invention, when a semiconductor layer is formed by sputtering, a Ga target containing a Ga element as a sputtering target and a dopant target composed of a dopant element, Since the power is applied to the Ga target and the dopant target simultaneously or alternately, the concentration of the dopant element in the crystal of the group III nitride compound semiconductor containing Ga can be easily controlled to the optimum value. The film can be efficiently formed using a sputtering method.

  Furthermore, since the group III nitride compound semiconductor light-emitting device and lamp of the present invention are obtained by the manufacturing method of the present invention, the dopant concentration in the crystal of the group III nitride compound semiconductor containing Ga is optimal. And have excellent light emission characteristics.

  BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a group III nitride compound semiconductor light emitting device manufacturing apparatus, a group III nitride compound semiconductor light emitting device manufacturing method, a group III nitride compound semiconductor light emitting device, and a lamp according to an embodiment of the present invention. The description will be given with reference as appropriate.

[Group III nitride compound semiconductor light emitting device]
FIG. 1 is a schematic cross-sectional view schematically showing an example of a group III nitride compound semiconductor light emitting device according to the present invention. FIG. 2 is a schematic view showing a planar structure of the group III nitride compound semiconductor light emitting device shown in FIG.
As shown in FIG. 1, the light-emitting element of the present embodiment is of a single-sided electrode type, and is a semiconductor made of a group III nitride compound semiconductor containing an intermediate layer 12 and Ga as a group III element on a substrate 11. The layer 20 is formed. As shown in FIG. 1, the semiconductor layer 20 is formed by laminating an n-type semiconductor layer 14, a light emitting layer 15, and a p-type semiconductor layer 16 in this order.

[Laminated structure of light-emitting elements]
<Board>
In the light emitting device 1 of the present embodiment, the material that can be used for the substrate 11 is not particularly limited as long as the group III nitride compound semiconductor crystal is epitaxially grown on the surface, and various materials are selected. Can be used. For example, sapphire, SiC, silicon, zinc oxide, magnesium oxide, manganese oxide, zirconium oxide, manganese zinc iron, magnesium aluminum oxide, zirconium boride, gallium oxide, indium oxide, lithium gallium oxide, lithium aluminum oxide, neodymium gallium oxide Lanthanum strontium oxide aluminum tantalum, strontium titanium oxide, titanium oxide, hafnium, tungsten, molybdenum and the like.

Of the above-described substrate materials, an oxide substrate or a metal substrate that is known to cause chemical modification by contact with ammonia at a high temperature is used, and the intermediate layer 12 is formed without using ammonia. In addition, when an underlayer constituting the n-type semiconductor layer 14 described later is formed by a method using ammonia, the intermediate layer 12 described later also functions as a coat layer. This is effective in preventing unwanted alteration.
In general, since the sputtering method can keep the temperature of the substrate 11 low, even when the substrate 11 made of a material that decomposes at a high temperature is used, the substrate 11 is not damaged. Each layer can be formed on top.

<Intermediate layer>
In the light emitting device 1 of the present embodiment, an intermediate layer 12 made of an aggregate of columnar crystals of a group III nitride compound is formed on a substrate 11. The intermediate layer 12 is for the purpose of protecting the substrate 11 from a chemical reaction at a high temperature, for the purpose of reducing the difference in lattice constant between the material of the substrate 11 and the semiconductor layer 20, or for promoting nucleation for crystal growth of the semiconductor layer. Formed as a layer.

Further, the intermediate layer 12 needs to cover at least 60% or more, preferably 80% or more, of the surface 11a of the substrate 11, and is preferably formed so as to cover 90% or more. The intermediate layer 12 is most preferably formed so as to cover 100% of the surface 11a, that is, the surface 11a of the substrate 11 without a gap.
When the region where the intermediate layer 12 covers the surface 11a of the substrate 11 is reduced, the substrate 11 is largely exposed. For this reason, the base layer 14a formed on the intermediate layer 12 and the base layer 14a formed directly on the substrate 11 have different lattice constants, resulting in a non-uniform crystal and hillocks and pits. There is a risk.

  Further, the intermediate layer 12 may be formed so as to cover the side surface in addition to the front surface 11 a of the substrate 11, and may further be formed so as to cover the back surface of the substrate 11.

<Semiconductor layer>
As shown in FIG. 1, the semiconductor layer 20 includes an n-type semiconductor layer 14, a light emitting layer 15, and a p-type semiconductor layer 16.
A semiconductor multilayer structure may be laminated on the base layer 14a made of a group III nitride compound semiconductor. For example, when forming a semiconductor multilayer structure for a light emitting device, an n-type conductive layer doped with an n-type dopant such as Si, Ge, or Sn, or a p-type conductive layer doped with a p-type dopant such as magnesium. Layers and the like can be stacked. As a material, InGaN can be used for the light emitting layer and the like, and AlGaN can be used for the cladding layer and the like. Thus, by forming a group III nitride semiconductor crystal layer having further functions on the base layer 14a, it has a semiconductor laminated structure used for manufacturing a light emitting diode, a laser diode, an electronic device or the like. A wafer can be produced.
"N-type semiconductor layer"
The n-type semiconductor layer 14 is stacked on the intermediate layer 12, and is composed of a base layer 14a, an n-type contact layer 14b, and an n-type cladding layer 14c. The n-type contact layer can also serve as an underlayer and / or an n-type cladding layer, but the underlayer can also serve as an n-type contact layer and / or an n-type cladding layer. is there.

(Underlayer)
The underlayer 14a of the n-type semiconductor layer 14 of the present embodiment is made of a group III nitride compound semiconductor. The material of the underlayer 14a may be the same as or different from that of the intermediate layer 12, but when the present inventors have experimented, a Group III nitride compound containing Ga, that is, a GaN-based compound semiconductor is preferable. It has become clear that it is more preferable to be composed of an Al _X Ga _1-X N layer (0 ≦ x ≦ 1, preferably 0 ≦ x ≦ 0.5, more preferably 0 ≦ x ≦ 0.1). .

If necessary, the underlayer 14a may be doped with n-type impurities within the range of 1 × 10 ¹⁷ to 1 × 10 ¹⁹ / cm ³ , but undoped (<1 × 10 ¹⁷ / cm ^3). ) And undoped is preferable in terms of maintaining good crystallinity.
For example, when the substrate 11 has conductivity, electrodes can be formed above and below the light emitting element 1 by doping the base layer 14a with a dopant to make it conductive. On the other hand, when an insulating material is used as the substrate 11, a chip structure in which the positive electrode and the negative electrode are provided on the same surface of the light emitting element 1 is employed. It is more preferable that the crystallinity is improved.
Although it does not specifically limit as an n-type impurity, For example, Si, Ge, Sn, etc. are mentioned, Preferably Si and Ge are mentioned.

(N-type contact layer)
The n-type contact layer 14b is made of a group III nitride compound semiconductor. The n-type contact layer 14b is made of an Al _X Ga _1-X N layer (0 ≦ x ≦ 1, preferably 0 ≦ x ≦ 0.5, more preferably 0 ≦ x ≦ 0.1), similarly to the base layer 14a. Preferably, it is configured.
The n-type contact layer 14b is preferably doped with an n-type impurity, and the n-type impurity is preferably 1 × 10 ¹⁷ to 1 × 10 ¹⁹ / cm ³ , preferably 1 × 10 ¹⁸ to 1 × 10 ^19. When it is contained at a concentration of / cm ³ , it is preferable in terms of maintaining good ohmic contact with the negative electrode, suppressing crack generation, and maintaining good crystallinity. Although it does not specifically limit as an n-type impurity, For example, Si, Ge, Sn, etc. are mentioned, Preferably it is Si and Ge.

The gallium nitride compound semiconductor constituting the base layer 14a and the n-type contact layer 14b preferably has the same composition, and the total film thickness thereof is 0.1 to 20 μm, preferably 0.5 to 15 μm, It is preferable to set in the range of 1 to 12 μm.
When the film thickness is within this range, the crystallinity of the semiconductor is maintained satisfactorily.

(N-type cladding layer)
It is preferable to provide an n-type cladding layer 14c between the n-type contact layer 14b and the light emitting layer 15. By providing the n-type cladding layer 14c, effects such as electron supply to the active layer and relaxation of the lattice constant difference can be provided.
The n-type cladding layer 14c can be formed of AlGaN, GaN, GaInN, or the like. Alternatively, a heterojunction of these structures or a superlattice structure in which a plurality of layers are stacked may be used.
Needless to say, when the n-type cladding layer 14c is made of GaInN, it is preferably larger than the band gap of GaInN of the light emitting layer 15.

The n-type doping concentration of the n-type cladding layer 14c is preferably in the range of 1 × 10 ¹⁷ to 1 × 10 ²⁰ / cm ³ , more preferably in the range of 1 × 10 ¹⁸ to 1 × 10 ¹⁹ / cm ³ . A doping concentration within this range is preferable in terms of maintaining good crystallinity and reducing the operating voltage of the light emitting element.

<Light emitting layer>
The light emitting layer 15 is a layer that is stacked on the n-type semiconductor layer 14 and a p-type semiconductor layer 16 is stacked thereon. The light emitting layer can take a multiple quantum well structure, a single well structure, a bulk structure, or the like. In the present embodiment, as shown in FIG. 1, the light emitting layer 15 is formed by laminating a barrier layer 15a made of a gallium nitride compound semiconductor and a well layer 15b made of a gallium nitride compound semiconductor containing indium alternately. In addition, a barrier layer 15a is disposed on the n-type semiconductor layer 14 side and the p-type semiconductor layer 16 side. In the example shown in FIG. 1, the light emitting layer 15 includes six barrier layers 15 a and five well layers 15 b that are alternately and repeatedly stacked, and the barrier layer 15 a is disposed on the uppermost layer and the lowermost layer of the light emitting layer 15. A multiple quantum well structure in which a well layer 15b is disposed between the barrier layers 15a.

As the barrier layer 15a, for example, a gallium nitride-based compound semiconductor such as Al _c Ga _1-c N (0 ≦ c <0.3) having a larger band gap energy than the well layer 15b can be preferably used.
Furthermore, the well layer 15b can be formed using indium as the semiconductor gallium nitride-based compound containing, for _example, can be used _{Ga 1-s In s N (} 0 <s <0.4) GaN such as indium.

<P-type semiconductor layer>
The p-type semiconductor layer 16 includes a p-type cladding layer 16a and a p-type contact layer 16b. The p-type contact layer may also serve as the p-type cladding layer.

(P-type cladding layer)
The p-type cladding layer 16a is not particularly limited as long as it has a composition larger than the band gap energy of the light emitting layer 15 and can confine carriers in the light emitting layer 15. Preferably, the Al _d Ga _{1-d is used.} N (0 <d ≦ 0.4, preferably 0.1 ≦ d ≦ 0.3). When the p-type cladding layer 16a is made of such AlGaN, it is preferable in terms of confining carriers in the light emitting layer 15.

The p-type doping concentration of the p-type cladding layer 16a is preferably 1 × 10 ¹⁸ to 1 × 10 ²¹ / cm ³ , more preferably 1 × 10 ¹⁹ to 1 × 10 ²⁰ / cm ³ . When the p-type dope concentration is in the above range, a good p-type crystal can be obtained without reducing the crystallinity. Although it does not specifically limit as a p-type impurity, For example, Preferably Mg is mentioned.

(P-type contact layer)
The p-type contact layer 16b is a nitride containing at least Al _e Ga _1-e N (0 ≦ e <0.5, preferably 0 ≦ e ≦ 0.2, more preferably 0 ≦ e ≦ 0.1). This is a gallium compound semiconductor layer. When the Al composition is in the above range, it is preferable in terms of maintaining good crystallinity and good ohmic contact with a p-ohmic electrode (see translucent electrode 17 described later).

Further, when the p-type contact layer 16b contains a p-type dopant at a concentration in the range of 1 × 10 ¹⁸ to 1 × 10 ²¹ / cm ³ , good ohmic contact can be maintained, cracking can be prevented, and good It is preferable at the point of crystalline maintenance, More preferably, it is the range of 5 * 10 < ¹⁹ > -5 * 10 < ²⁰ > / cm < ³ >. Although it does not specifically limit as a p-type impurity, For example, Preferably Mg is mentioned.

In addition, the semiconductor layer 20 which comprises the light emitting element 1 of this invention is not limited to the thing of embodiment mentioned above.
For example, as the material of the semiconductor layer constituting the present invention, addition to the foregoing, for example, the general formula _{Al X Ga Y In Z N 1} -A M A (0 ≦ X ≦ 1,0 ≦ Y ≦ 1,0 ≦ Z ≦ 1 and X + Y + Z = 1, the symbol M represents a group V element different from nitrogen (N), and 0 ≦ A <1)) is known. Also in the present invention, these known gallium nitride compound semiconductors can be used without any limitation.
In addition, a group III nitride compound semiconductor containing Ga as a group III element can contain other group III elements in addition to Al, Ga, and In. If necessary, Ge, Si, Mg, Ca, Zn , Be, P, and As can also be contained. Furthermore, it is not limited to the element added intentionally, but may include impurities that are inevitably included depending on the film forming conditions and the like, as well as trace impurities that are included in the raw materials and reaction tube materials.

<Translucent positive electrode>
The translucent positive electrode 17 is an electrode having translucency formed on the p-type semiconductor layer 16.
The material of the translucent positive electrode 17 is not particularly limited, but ITO (In ₂ O ₃ —SnO ₂ ), AZO (ZnO—Al ₂ O ₃ ), IZO (In ₂ O ₃ —ZnO), GZO (ZnO— A material such as Ga ₂ O ₃ ) can be used. Further, as the translucent positive electrode 17, any structure including a conventionally known structure can be used without any limitation.
The translucent positive electrode 17 may be formed so as to cover the entire surface on the p-type semiconductor layer 16, or may be formed in a lattice shape or a tree shape with a gap.

<Positive electrode bonding pad>
The positive electrode bonding pad 18 is a substantially circular electrode formed on the translucent positive electrode 17 as shown in FIG.
As the material of the positive electrode bonding pad 18, various structures using Au, Al, Ni, Cu and the like are well known, and those known materials and structures can be used without any limitation.
The thickness of the positive electrode bonding pad 18 is preferably in the range of 100 to 1000 nm. Further, in view of the characteristics of the bonding pad, the larger the thickness, the higher the bondability. Therefore, the thickness of the positive electrode bonding pad 18 is more preferably 300 nm or more. Furthermore, it is preferable to set it as 500 nm or less from a viewpoint of manufacturing cost.

<Negative electrode>
The negative electrode 19 is in contact with the n-type contact layer 14 b of the n-type semiconductor layer 14 constituting the semiconductor layer 20. Therefore, the negative electrode 19 is formed by removing a part of the p-type semiconductor layer 16, the light emitting layer 15, and the n-type semiconductor layer 14 to expose the n-type contact layer 14b, as shown in FIGS. A substantially circular shape is formed on the exposed region 14d.
As materials for the negative electrode 19, negative electrodes having various compositions and structures are well known, and these known negative electrodes can be used without any limitation.

Here, in explaining the manufacturing method of the light emitting element of the present invention, first, the manufacturing apparatus and manufacturing method of the semiconductor layer of the light emitting element will be described.
[Device for manufacturing semiconductor layer of light-emitting element]
FIG. 3 is a schematic view schematically showing an example of a group III nitride compound semiconductor light emitting device manufacturing apparatus according to the present invention. A manufacturing apparatus 40 for a group III nitride compound semiconductor light emitting device (hereinafter sometimes abbreviated as a light emitting device) shown in FIG. 3 constitutes a light emitting device made of a group III nitride compound semiconductor containing Ga as a group III element. The semiconductor layer to be used is used for forming a film on the substrate 11 by sputtering.

  As shown in FIG. 3, the light emitting element manufacturing apparatus 40 includes a chamber 41, a sputter target 47 installed in the chamber 41, and power application means 45 that applies power to the sputter target 47. Yes. Further, as shown in FIG. 3, in the chamber 41 of the light emitting element manufacturing apparatus 40, a holder 11 b for mounting the substrate 11 facing the sputter target 47 downward and a heater 44 for heating the substrate 11 are provided. The outside of the chamber 41 includes a matching box 46c conductively connected to the holder 11b, a power supply 48 conductively connected to the matching box 46c, a pump for controlling the pressure in the chamber 41, and the like. Pressure control means 49a, 49b, 49c and gas supply means 42a, 42b for supplying gas into the chamber 41 are provided.

  In the present embodiment, as shown in FIG. 3, the sputter target 47 includes a Ga target 47a and a dopant target 47b made of a dopant element. The Ga target 47a is placed on the electrode 43a for supplying power to the Ga target 47a, and the dopant target 47b is placed on the electrode 43b for supplying power to the dopant target 47b.

  The Ga target 47a contains a Ga element, may be composed of only the Ga element, or may contain other elements, and corresponds to the composition of the semiconductor layer to be deposited. It consists of materials. In the present embodiment, a solid target may be used as the Ga target 47a, or a liquefied one may be used. The liquefied Ga target 47a may be liquefied as a whole or in a state where only the surface layer is liquefied.

  In the light emitting element manufacturing apparatus 40 shown in FIG. 3, examples of the dopant element constituting the dopant target 47b include Si, Ge, Sn, Mg, Be, Zn, Cd, and Ca, and are not particularly limited. When the semiconductor layer to be formed is an n-type semiconductor layer, Si is preferable, and when the semiconductor layer to be formed is a p-type semiconductor layer, Mg is preferable.

  The power applying means 45 applies predetermined power to the Ga target 47a and the dopant target 47b simultaneously or alternately. As shown in FIG. 3, the electrodes 43a and 43b, the electrodes 43a, The matching boxes 46a and 46b are conductively connected to 43b, and the power supply 48 is conductively connected to the matching boxes 46a and 46b. The power applied to the Ga target 47a can be adjusted by controlling the matching box 46a, and the power applied to the dopant target 47b can be adjusted by controlling the matching box 46b. Yes. Thus, the power applied to the Ga target 47a and the dopant target 47b can be controlled independently.

  In the present embodiment, the power (applied power) applied to the Ga target 47a and the dopant target 47b is applied by a pulse DC method or an RF (high frequency) method. In the case where the semiconductor layer is formed by the reactive sputtering method using the manufacturing apparatus 40 shown in FIG. 3, the applied power is set to the RF (high frequency) method because the film formation rate can be easily controlled. More preferred. Further, when the semiconductor layer is formed by the reactive sputtering method using the manufacturing apparatus 40 shown in FIG. 3, the Ga target 47a and the dopant target 47b are charged up when the electric field is continuously applied with DC. Since it is difficult to increase the film formation rate, it is preferable that the applied power is a pulse DC system in which a bias is applied in a pulse manner.

In this embodiment, the matching boxes 46a and 46b of the power application unit 45 are supplied into the gas phase by changing the ratio of the power applied to the Ga target 47a and the power applied to the dopant target 47b. By changing the amount of Ga and dopant element particles, the ratio of Ga element to dopant element in the gas phase during the formation of the semiconductor layer can be controlled.
Since the amount of Ga and dopant element particles supplied in the gas phase matches the ratio of Ga and dopant element in the crystal of the semiconductor layer to be deposited, Ga and dopant element supplied in the gas phase By controlling the amount of the particles, the doping concentration in the crystal of the semiconductor layer to be formed can be controlled.
Here, the ratio of the power applied to the Ga target 47a and the power applied to the dopant target 47b can be arbitrarily changed by controlling the power supplied to the matching boxes 46a and 46b.

In the case where the power is applied by the pulse DC method, the matching boxes 46a and 46b of the power applying means 45 have a pulse ratio between the pulse applied to the Ga target 47a and the pulse applied to the dopant target 47b. By changing the amount of Ga and dopant element particles supplied to the gas phase, the ratio of the Ga element and the dopant element in the gas phase when the semiconductor layer is formed is controlled. It may be a thing.
Here, the pulse ratio between the pulse applied to the Ga target 47a and the pulse applied to the dopant target 47b can be arbitrarily changed by causing the matching boxes 46a and 46b to control the power on / off time. .

When the dopant element is Si, the ratio of Ga element to Si element in the gas phase when the semiconductor layer is formed by the power application means 45 is (Ga element: Si element) 1: It is desirable to be controlled in the range of 0.001 to 1: 0.00001.
When the dopant element is Mg, the ratio of Ga element to Mg element in the gas phase when the semiconductor layer is formed by the power application means 45 is (Ga element: Mg element) 1: It is desirable to be controlled in the range of 0.1 to 1: 0.001.

In addition, the light emitting element manufacturing apparatus 40 shown in FIG. 3 can perform sputtering so that the dopant target 47b does not form a cluster composed of a dopant element having two or more atoms.
The dopant element is preferably present uniformly in the crystal of the group III nitride compound semiconductor in order to efficiently generate carriers. In order to make the dopant element uniformly exist in the crystal, the dopant element in the crystal is preferably dispersed and doped in a single atom state. Moreover, when the dopant element in the crystal | crystallization of a group III nitride compound semiconductor exists as a cluster formed by combining two or more atoms, it is considered that the dopant element cannot effectively generate carriers.

  When supplying a dopant element by sputtering the dopant target 47b, if the kinetic energy of sputtered particles hitting the dopant target 47b such as argon is too large, the dopant element may jump out of the dopant target 47b as a cluster. For this reason, it is preferable to sputter the dopant target 47b so that the kinetic energy of the sputtered particles is reduced and no clusters are formed. Specifically, an apparatus / method for sufficiently reducing the voltage for accelerating the sputtered particles hitting the dopant target 47b and a method using an element having a small atomic weight as the sputtered particles so as not to form clusters.

In the present embodiment, the power application means 45 controls the voltage for accelerating the sputtered particles hitting the dopant target 47b, so that when the dopant target 47b is sputtered, a cluster composed of two or more dopant elements is formed. It is not formed.
Further, for example, when performing high-frequency sputtering, there is a case where power for generating plasma is applied to the target and the inner wall. In this case, if the voltage for attracting the sputtered particles to the target is reduced, plasma may not be generated. For this reason, it is desirable to use a manufacturing apparatus that can individually control the power for generating plasma and the voltage for attracting sputtered particles to the target. Specifically, for example, the manufacturing apparatus 50 shown in FIG. 6 can be preferably used.
FIG. 6 is a schematic view schematically illustrating another example of a group III nitride compound semiconductor light emitting device manufacturing apparatus according to the present invention. In FIG. 6, the same members as those in FIG. In the manufacturing apparatus 50 shown in FIG. 6, the high-frequency inductively coupled plasma generator 22 is installed above the dopant target 47 b in the chamber 41. In the manufacturing apparatus 50 shown in FIG. 6, the acceleration voltage of particles hitting the dopant target 47b can be freely set by generating plasma in the high frequency dielectric coupled plasma generator 22.

Whether or not a cluster composed of a dopant element having two or more atoms is formed can be examined using, for example, the manufacturing apparatus 50 shown in FIG. The light emitting element manufacturing apparatus 50 shown in FIG. 6 includes an air inlet 21a provided near the substrate 11 in the chamber 41, and a mass spectrum analyzer 21b connected to the air inlet 21a by piping. In the light emitting element manufacturing apparatus 50 shown in FIG. 6, particles formed by sputtering the dopant target 47b are sucked from the inlet 21a and measured by the mass spectrum analyzer 21b.
For example, when the dopant element is Si, if the particle made of the dopant element sucked from the air inlet 21a is a single atom, a mass spectrum peak appears at a mass number of 28, and if it is a diatomic molecule, the mass is at a mass number of 56. A spectral peak appears.

  In the present embodiment, the case where a cluster composed of two or more dopant elements is examined using a mass spectrum analyzer has been described as an example. Whether or not a cluster is formed may be examined using other apparatuses and methods such as a method using plasma spectroscopy. In the method using plasma spectroscopy, the emission wavelength differs depending on the element, but the emission spectrum may be hidden in the background, making it difficult to separate the emission spectrum. Also, in the method using plasma spectroscopy, the emission spectrum may not be shown depending on the element, or the difference between the case where the particle is a cluster and the case where the particle is not so is small, and it may be difficult to understand whether the cluster is formed. . Therefore, when examining whether or not clusters are formed, it is preferable to use a mass spectrum analyzer rather than using plasma spectroscopy.

  The light emitting device manufacturing apparatus 40 shown in FIG. 3 includes a sputtering target 47 composed of a Ga target 47a and a dopant target 47b, and a power applying unit that applies power to the Ga target 47a and the dopant target 47b simultaneously or alternately. Therefore, the power application means 45 can arbitrarily control the ratio of Ga element and dopant element in the gas phase when the semiconductor layer is formed, and contains Ga to be formed. The concentration of the dopant element in the group III nitride compound semiconductor crystal can be easily optimized.

  In the light emitting element manufacturing apparatus 40 shown in FIG. 3, when at least the surface layer of the Ga target 47a is liquefied, particles having high energy can be taken out and supplied onto the substrate 11. In addition, a semiconductor layer made of a group III nitride semiconductor with good crystallinity can be grown with higher efficiency. In addition, when at least the surface layer of the Ga target 47a is liquefied, the Ga target 47a can be used uniformly without being partially biased. Therefore, the material constituting the Ga target 47a should be used efficiently. Can do.

In general, when a layer made of a plurality of materials is formed on a substrate by using a sputtering method, a sputtering apparatus having the same number of chambers as the number of material targets and one target in each chamber is used. The method of forming a film by moving between each chamber was used. The sputtering apparatus used in such a method has a problem that it is large due to the large number of chambers and requires a long time for film formation.
On the other hand, the manufacturing apparatus of this embodiment arranges the Ga target 47a and the dopant target 47b in the chamber and applies power to the Ga target 47a and the dopant target 47b simultaneously or alternately. The manufacturing apparatus can be greatly simplified, and it is not necessary to move between chambers as in the case of using a sputtering apparatus in which one target is disposed in each chamber, and the time required for film formation can be shortened. Can do.

In the present embodiment, as shown in FIG. 3, the sputtering apparatus 40 in which the two sputtering targets of the Ga target 47a and the dopant target 47b are provided in the chamber 41 has been described as an example. The manufacturing apparatus is not limited to this.
For example, in the case where a plurality of semiconductor layers having different compositions are formed on a substrate, a plurality of targets corresponding to the composition of the semiconductor layer to be formed are placed in the chamber. A plurality of semiconductor layers each having a predetermined composition can be successively formed on the substrate. When the manufacturing apparatus of the present invention has such a configuration, the manufacturing apparatus can be simplified, the process time can be shortened, and film formation can be performed with high efficiency.

Further, in the light emitting device manufacturing apparatus 40 shown in FIG. 3, since the dopant target 47b is sputtered so as not to form a cluster, the dopant element is uniformly dispersed and doped in a single atom state in the crystal. The group III nitride compound semiconductor can be produced, and a group III nitride compound semiconductor capable of efficiently generating carriers can be obtained.
Further, in the light emitting element manufacturing apparatus 40 shown in FIG. 3, since the dopant target 47b is sputtered at a voltage at which no cluster is formed, the kinetic energy of the sputtered particles can be easily controlled to form a cluster. The dopant target 47b can be sputtered without any problem.

[Method for Manufacturing Semiconductor Layer of Light-Emitting Element]
In the present embodiment, a method for forming a semiconductor layer of a light emitting element on a substrate 11 by reactive sputtering will be described as an example of a method for manufacturing a light emitting element using the manufacturing apparatus 40 shown in FIG.
In order to form a semiconductor layer of a light emitting element on the substrate 11 by sputtering using the manufacturing apparatus 40 shown in FIG. 3, first, the pressure in the chamber 41 is set to a predetermined pressure by the pressure control means 49a, 49b, 49c. At the same time, the gas supply means 42a and 42b are used to supply argon gas and active gas as a nitride material into the chamber 41 at a predetermined supply amount, respectively, so that the chamber 41 has a predetermined atmosphere.

  The pressure in the chamber 41 is preferably 0.3 Pa or higher. If the pressure in the chamber 41 is less than 0.3 Pa, the abundance of nitrogen becomes too small, and the sputtered metal may adhere to the substrate 11 without becoming nitride. Further, the upper limit of the pressure in the chamber 41 is not particularly limited, but it is necessary to suppress the pressure to such a level that plasma can be generated.

Moreover, as a nitride raw material used as an active gas in the present embodiment, generally known nitrogen compounds can be used without any limitation, but ammonia and nitrogen (N ₂ ) are easy to handle. It is preferable because it is relatively inexpensive and available.
Ammonia has good decomposition efficiency and can be deposited at a high growth rate. However, because of its high reactivity and toxicity, it requires a detoxification facility and a gas detector. It is necessary to make these materials chemically stable.
When nitrogen (N ₂ ) is used, a simple apparatus can be used, but a high reaction rate cannot be obtained. However, if the nitrogen is decomposed by an electric field, heat, or the like and then introduced into the apparatus, a sufficient film formation rate that can be used for industrial production can be obtained although the reaction rate is lower than that of ammonia. For this reason, considering the balance with the apparatus cost, nitrogen (N ₂ ) is most preferable as the active gas.

Next, the heater table 44 is heated by heating means (not shown) provided in the heater table 44 so that the substrate 11 has a predetermined temperature, that is, an optimum growth temperature for a semiconductor layer grown on the substrate 11. Warm up.
The temperature of the substrate 11 when forming the semiconductor layer is preferably in the range of room temperature to 1200 ° C, more preferably in the range of 300 to 1000 ° C, and most preferably in the range of 500 to 800 ° C. preferable. In addition, although room temperature here is temperature influenced also by the environment of a process, etc., as specific temperature, it is the range of 0-30 degreeC.
When the temperature of the substrate 11 is lower than the lower limit, migration on the substrate 11 is suppressed, and a crystal of a semiconductor layer with good crystallinity may not be formed. Further, if the temperature of the substrate 11 exceeds the above upper limit, the crystals of the semiconductor layer may be decomposed.

  Then, while the substrate 11 is heated, current is supplied to the electrodes 43a and 43b through the matching boxes 46a and 46b, and power is applied to each of the Ga target 47a and the dopant target 47b simultaneously or alternately, A current is supplied to the holder 11 b to apply a bias to the substrate 11.

  As a result, particles containing Ga particles are ejected from the Ga target 47a into the gas phase in the chamber 41, and dopant element particles are ejected from the dopant target 47b. Then, particles such as Ga particles and dopant element particles in the gas phase are supplied and deposited so as to collide with the surface of the substrate 11 attached to the holder 11 b, thereby forming a semiconductor layer on the substrate 11. Is done.

  In the present embodiment, the dopant target 47b is sputtered at a voltage at which a cluster composed of a dopant element having two or more atoms is not formed.

Here, the ratio of the Ga element and the dopant element in the vapor phase when forming the semiconductor layer is determined by using, for example, at least one of the following three methods in the vapor phase. The amount of Ga and dopant element particles to be supplied is changed and controlled.
(1) It is controlled by the ratio of the area of the surface of the Ga target 47a facing the substrate 11 (upper surface in FIG. 3) and the area of the surface of the dopant target 47b facing the substrate 11 (upper surface in FIG. 3).
(2) The ratio of the power applied to the Ga target 47a and the power applied to the dopant target 47b is controlled. Here, the ratio of the power applied to the Ga target 47a and the power applied to the dopant target 47b can be changed by controlling the power supplied to the matching boxes 46a and 46b.
(3) The power is applied by the pulse DC method, and the pulse ratio between the pulse applied to the Ga target 47a and the pulse applied to the dopant target 47b is controlled. Here, the pulse ratio between the pulse applied to the Ga target 47a and the pulse applied to the dopant target 47b can be changed by causing the matching boxes 46a and 46b to control the power on / off time.

For example, when an n-type semiconductor layer is formed on the substrate 11 using the manufacturing apparatus 40 shown in FIG. 3, Si is used as the dopant element, and at least one of the above methods (1) to (3) is used. Thus, it is desirable that the ratio of Ga element to Si element in the vapor phase when forming the semiconductor layer is in the range of 1: 0.001 to 1: 0.00001.
This makes it possible to control the doping concentration in the n-type semiconductor layer using Si as the dopant element in the range of 1 × 10 ¹⁷ cm ⁻³ to 1 × 10 ¹⁹ cm ⁻³ .

Further, for example, when forming a p-type semiconductor layer on the substrate 11 using the manufacturing apparatus 40 shown in FIG. 3, Mg is used as the dopant element, and at least one of the above methods (1) to (3) It is desirable that the ratio of Ga element and Mg element in the gas phase during the formation of the semiconductor layer is set to a range of 1: 0.1 to 1: 0.001.
This makes it possible to control the doping concentration in the p-type semiconductor layer using Mg as the dopant element in the range of 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²¹ cm ⁻³ .

  Further, when the temperature around the Ga target 47a of the sputtering apparatus 40 when the semiconductor layer is formed is 29 ° C. or higher, Ga is a low melting point metal having a melting point of 29 ° C. May be liquid. Further, when the temperature around the Ga target 47a of the sputtering apparatus 40 when the semiconductor layer is formed is less than 29 ° C., the Ga target 47a becomes solid.

When forming the semiconductor layer, when the Ga target 47a is solid, it is preferable to liquefy at least the surface layer of the Ga target 47a.
As a method for liquefying the Ga target 47a, for example, a method of setting the power applied to the Ga target 47a to a certain level or more can be mentioned. Here, the power applied to the Ga target 47a to liquefy the Ga target 47a is preferably 0.1 W / cm ² or more. When a power of 0.1 W / cm ² or more is applied to the Ga target 47a, even if the Ga target 47a is in a solid state, the surface layer of the Ga target 47a is melted by being exposed to plasma. It can be liquefied.
Further, if the power applied to the Ga target 47a is less than 0.1 W / cm ² , it may not be liquefied when the Ga target 47a is in a solid state.

  Further, as another method for liquefying the Ga target 47a, a method of heating the Ga target 47a with a heating means can be mentioned. The heating means used in this case is not particularly limited, and an electric heater or the like can be appropriately selected and used.

Further, in the present embodiment, more it is preferably in the range of power applied to the Ga target 47a of ^{0.1W / cm 2 ~100W / cm 2} , 1W / cm 2 ~50W / cm 2 range ^preferably, and most preferably in the range of ^{1.5W / cm 2 ~50W / cm 2} .
By setting the power applied to the Ga target 47a within the above range, a reactive species having a large power can be generated, and this reactive species can be supplied to the substrate 11 with high kinetic energy. As a result, migration on the substrate 11 becomes active, and it becomes easy to loop dislocations so that the deposited semiconductor layer does not inherit the crystallinity of the underlying layer.

  In the present embodiment, the film formation rate when forming the semiconductor layer is preferably in the range of 0.01 nm / s to 10 nm / s. If the film formation rate is less than 0.01 nm / s, the film formation process takes a long time, and waste is increased in industrial production. Further, when the film formation rate exceeds 10 nm / s, it is difficult to obtain a good film.

  In the manufacturing method of this embodiment, when the semiconductor layer is formed by sputtering, the Ga target 47a and the dopant target 47b are used, and power is applied to the Ga target 47a and the dopant target 47b simultaneously or alternately. Therefore, the doping concentration of the dopant element in the crystal of the group III nitride compound semiconductor containing Ga can be easily optimized, and the semiconductor layer can be efficiently formed using the sputtering method.

In the manufacturing method of this embodiment, since the semiconductor layer is formed by sputtering, the film formation rate is increased as compared with the case where the film is formed by MOCVD (metal organic chemical vapor deposition). The film formation (manufacturing) time can be shortened. Further, by reducing the manufacturing time, impurities can be prevented from entering the chamber to a minimum, and a good semiconductor layer with little contamination can be obtained.
Further, in the manufacturing method of the present embodiment, since the reactive sputtering method for supplying an active gas made of a nitride material into the chamber is used, the crystallinity of the obtained semiconductor layer becomes good and uniform.

Further, in the manufacturing method of the present embodiment, when at least the surface layer of the Ga target 47a is liquefied, particles having high energy can be taken out and supplied onto the substrate 11, so that the crystallinity is good on the substrate 11. A semiconductor layer made of a group III nitride semiconductor can be grown with higher efficiency.
Further, when at least the surface layer of the Ga target 47a is liquefied, the Ga target 47a can be used uniformly without being partially biased, so that the material constituting the Ga target 47a can be used efficiently. .

  In the manufacturing method of the present embodiment, the reactive sputtering method for supplying an active gas made of a nitride material into the chamber has been described as an example, but the present invention is not limited to the reactive sputtering method. .

  Further, in the present embodiment, dopants such as a method of setting a target hitting voltage to a small value and a method of controlling the target hitting voltage separately from the plasma generating voltage using a high frequency dielectric coupled plasma generator disposed in the chamber are used. Although the preferred manufacturing apparatus and manufacturing method in which the target 47b is sputtered at a voltage at which a cluster composed of a dopant element of 2 atoms or more is not formed have been described as an example, the present invention is limited only to the manufacturing apparatus and manufacturing method in which no cluster is formed. Instead, a dopant element containing single atoms and clusters may be supplied by sputtering.

  The manufacturing method of the present invention is not limited to the above-described embodiment. For example, when the semiconductor layer is formed, the magnetic field is rotated with respect to the Ga target 47a and the dopant target 47b, or A method of swinging the magnetic field may be used. A specific magnet movement method can be appropriately selected depending on the type of the sputtering apparatus. For example, the magnet can be swung or rotationally moved.

In addition, the semiconductor layer to be formed may be formed so as to cover the side surface in addition to the surface of the substrate 11, and may further be formed so as to cover the back surface of the substrate 11.
As a method of forming a film on the surface and side surfaces of the substrate, for example, the film is formed while changing the position of the substrate facing the Ga target 47a and the dopant target 47b by swinging or rotating the substrate. The method of doing is mentioned. By adopting such a method, it becomes possible to form the surface and side surfaces of the substrate 11 in a single process, and then the film formation process on the back surface of the substrate 11 is performed in a total of two processes. It is possible to cover the entire surface. In addition, as another method for forming the surface and side surfaces of the substrate 11, a method of forming a film on the entire surface of the substrate 11 by placing the substrate 11 in the chamber 41 without holding the substrate 11 can be cited.

  Further, the Ga target 47a and the dopant target 47b may be formed over the entire surface of the substrate 11 without moving the substrate 11 by using a large area and capable of moving the position. As such a method, an RF (high frequency) type sputtering is performed in which the position of the magnet of the Ga target 47a and the dopant target 47b is moved within the target by swinging or rotating the magnet. Law.

  Further, in the case of performing film formation by an RF (high frequency) sputtering method, a method of moving both the substrate 11 side and the Ga target 47a and dopant target 47b side may be employed. Further, by arranging the Ga target 47a and the dopant target 47b in the vicinity of the substrate 11, the generated plasma is not supplied to the substrate 11 in the form of a beam, but is supplied so as to wrap around the substrate 11. Thus, simultaneous film formation on the surface and side surfaces of the substrate 11 becomes possible.

[Method for Manufacturing Light-Emitting Element]
To manufacture the light emitting device 1 shown in FIG. 1, first, the laminated semiconductor 10 shown in FIG. 4 in which the semiconductor layer 20 is formed on the substrate 11 is formed. In order to form the laminated semiconductor 10 shown in FIG. 4, first, the substrate 11 is prepared. It is desirable to use the substrate 11 after pretreatment.
As the pretreatment of the substrate 11, for example, when the substrate 11 made of silicon is used as the substrate 11, a wet method such as a well-known RCA cleaning method is performed and the surface is hydrogen-terminated. be able to. This stabilizes the film forming process.

Further, the pretreatment of the substrate 11 may be performed, for example, by a method in which the substrate 11 is placed in a chamber of a sputtering apparatus and sputtering is performed before the intermediate layer 12 is formed. Specifically, a pretreatment for cleaning the surface can be performed in the chamber by exposing the substrate 11 to Ar or N ₂ plasma. By causing plasma such as Ar gas or N ₂ gas to act on the surface of the substrate 11, organic substances and oxides attached to the surface of the substrate 11 can be removed. In this case, if a voltage is applied between the substrate 11 and the chamber without applying power to the target, the plasma particles efficiently act on the substrate 11.

After pre-processing the substrate 11, the intermediate layer 12 shown in FIG. 4 is formed on the substrate 11 by sputtering.
Then, in accordance with the semiconductor layer manufacturing method described above, the reactive sputtering method using the light emitting element manufacturing apparatus 40 shown in FIG. 3 described above is performed on the substrate 11 on which the intermediate layer 12 is formed as shown in FIG. A base layer 14a and an n-type contact layer 14b of the n-type semiconductor layer 14 are continuously formed.

  First, the manufacturing apparatus 40 shown in FIG. 3 in which the substrate 11 on which the intermediate layer 12 is formed, the Ga target 47a, and the dopant target 47b made of a dopant element are installed in the chamber 41 is prepared. The dopant element here is an n-type impurity such as Si, Ge, or Sn used when forming the n-type contact layer 14b or when forming the base layer 14a and the n-type contact layer 14b.

Next, the pressure in the chamber 41 is set to a predetermined pressure, and an argon gas and an active gas made of a nitride raw material are supplied into the chamber 41 at predetermined supply amounts, respectively, and a chamber for forming the base layer 14a is formed. The inside of 41 is set to a predetermined atmosphere, and the substrate 11 is heated to a predetermined temperature.
Here, it is preferable that the temperature of the substrate 11 when forming the base layer 14a, that is, the growth temperature of the base layer 14a, be 800 ° C. or higher. This is because by increasing the temperature of the substrate 11 when forming the base layer 14a, atom migration is easily caused, and dislocation looping easily proceeds. Note that the temperature of the substrate 11 when forming the base layer 14a needs to be lower than the temperature at which the crystal decomposes, and is preferably less than 1200 ° C. If the temperature of the substrate 11 when forming the underlayer 14a is within the above temperature range, the underlayer 14a with good crystallinity can be obtained.

  When an undoped semiconductor layer is formed as the underlayer 14a, a predetermined current is supplied only to the electrode 43a through the matching box 46a, and no power is applied to the dopant target 47b, and only to the Ga target 47a. While applying power, a current is supplied to the holder 11 b to apply a bias to the substrate 11, and the base layer 14 a is formed on the intermediate layer 12 of the substrate 11 at a predetermined film formation rate.

  In addition, when a doped semiconductor layer is formed as the base layer 14a, a predetermined current is supplied to the electrodes 43a and 43b via the matching boxes 46a and 46b, and simultaneously applied to each of the Ga target 47a and the dopant target 47b. Alternatively, power is applied alternately, current is supplied to the holder 11b, a bias is applied to the substrate 11, and the base layer 14a is formed on the intermediate layer 12 at a predetermined film formation rate.

  Subsequently, as in the case of forming the underlayer 14a made of a doped semiconductor layer, the inside of the chamber 41 for forming the n-type contact layer 14b is set to a predetermined atmosphere, and the underlayer 14a is formed. The substrate 11 is heated to a predetermined temperature. The deposition temperature of the n-type contact layer 14b is the same as that of the base layer 14a. Then, as in the case of forming the base layer 14a made of a doped semiconductor layer, a predetermined power is applied to each of the Ga target 47a and the dopant target 47b simultaneously or alternately to form the base layer 14a of the substrate 11 on the base layer 14a. The n-type contact layer 14b is formed at a predetermined film formation rate.

  When the base layer 14a and the n-type contact layer 14b are made of doped semiconductor layers, the dopant elements may be the same or different. When the dopant elements in the two layers are different, the light emitting device manufacturing apparatus 40 includes a dopant target and two matching boxes and electrodes for applying power to the dopant target. Can be easily formed by selecting a dopant target to which power is applied in accordance with the dopant element of the semiconductor layer to be formed.

  Next, the n-type cladding layer 14c of the n-type semiconductor layer 14, the light-emitting layer 15 including the barrier layer 15a and the well layer 15b, and the p-type cladding layer 16a of the p-type semiconductor layer 16 are formed by MOCVD (organometallic) with good crystallinity. The film is formed by a chemical vapor deposition method.

In the MOCVD method, hydrogen (H ₂ ) or nitrogen (N ₂ ) as a carrier gas, trimethyl gallium (TMG) or triethyl gallium (TEG) as a Ga source which is a group III source, trimethyl aluminum (TMA) or triethyl aluminum as an Al source (TEA), trimethylindium (TMI) or triethylindium (TEI) as an In source, ammonia (NH ₃ ), hydrazine (N ₂ H ₄ ), or the like as an N source as a group V source.

In addition, as the n-type impurity of the dopant element, monosilane (SiH ₄ ) or disilane (Si ₂ H ₆ ) is used as a Si raw material, germane gas (GeH ₄ ) is used as a Ge raw material, and tetramethyl germanium ((CH ₃ ) ₄ Ge ) And tetraethylgermanium ((C ₂ H ₅ ) ₄ Ge) can be used.
For the n-type impurity of the dopant element, for example, biscyclopentadienylmagnesium (Cp ₂ Mg) or bisethylcyclopentadienylmagnesium (EtCp ₂ Mg) can be used as the Mg raw material.

  Next, the p-type contact layer 16b of the p-type semiconductor layer 16 is formed on the p-type cladding layer 16a of the p-type semiconductor layer 16 by reactive sputtering using the above-described light emitting device manufacturing apparatus 40 shown in FIG. To do.

  The p-type contact layer 16b of the p-type semiconductor layer 16 is performed using a p-type impurity such as Mg as a dopant element of the dopant target 47b. More specifically, the inside of the chamber 41 is set to a predetermined atmosphere for forming the p-type contact layer 16b, and the substrate 11 on which the layers up to the p-type cladding layer 16a are formed is heated to a predetermined temperature. Then, a predetermined power is applied to each of the Ga target 47a and the dopant target 47b simultaneously or alternately to form the p-type contact layer 16b at a predetermined film formation rate.

The translucent positive electrode 17 and the positive electrode bonding pad 18 are sequentially formed on the p-type contact layer 16b of the laminated semiconductor 10 shown in FIG. 4 thus obtained by using a photolithography method.
Next, the exposed region 14d on the n-type contact layer 14b is exposed by dry etching the laminated semiconductor 10 on which the translucent positive electrode 17 and the positive electrode bonding pad 18 are formed.
Thereafter, the negative electrode 19 is formed on the exposed region 14d using a photolithography method, whereby the light emitting device 1 shown in FIGS. 1 and 2 is obtained.

In the light emitting device of this embodiment, among the semiconductor layers 20, the base layer 14a and the n type contact layer 14b of the n type semiconductor layer 14 and the p type contact layer 16b of the p type semiconductor layer 16 are shown in FIG. Since the film is formed by the above-described sputtering method using this manufacturing apparatus, the productivity is excellent.
In addition, the light emitting device of this embodiment is a layer made of a doped semiconductor layer among the base layer 14a and the n-type contact layer 14b of the n-type semiconductor layer 14 and the p-type contact layer 16b of the p-type semiconductor layer 16. In this case, the doping concentration of the dopant element in the crystal is the optimum concentration. Therefore, the light emitting device 1 of the present embodiment has excellent light emission characteristics.

In the present embodiment, only the base layer 14a and the n-type contact layer 14b of the n-type semiconductor layer 14 and the p-type contact layer 16b of the p-type semiconductor layer 16 among the semiconductor layers 20 of the light emitting element 1 are shown in FIG. However, the present invention is not limited to the above-described example, and at least a part of the semiconductor layer 20 is formed by the sputtering method of the present invention. It only has to be.
For example, in the present embodiment, the n-type cladding layer 14c of the n-type semiconductor layer 14 and the p-type cladding layer 16a of the p-type semiconductor layer 16 are formed by MOCVD, but the n-type cladding layer 14c and the p-type cladding layer 16a are formed. Can also be formed by the sputtering method of the present invention.

  The light-emitting element 1 of the present invention only needs to be formed at least part of the semiconductor layer 20 by the sputtering method of the present invention. The semiconductor layer 20 is formed by the sputtering method of the present invention and the conventional method. Performed in combination with any method capable of growing a semiconductor layer, such as sputtering, MOCVD (metal organic chemical vapor deposition), HVPE (hydride vapor deposition), MBE (molecular beam epitaxy), etc. May be.

  The group III nitride compound semiconductor light-emitting device of the present invention can be used for a photoelectric conversion device such as a laser device or a light receiving device, or an electronic device such as HBT or HEMT, in addition to the above light-emitting device. Many of these semiconductor elements have various structures, and the structure of the group III nitride compound laminated semiconductor 10 according to the present invention is not limited in any way including these known element structures.

[lamp]
The lamp of the present invention uses the light emitting device of the present invention.
As a lamp | ramp of this invention, the thing formed by combining the light emitting element of this invention and fluorescent substance can be mentioned, for example. A lamp in which a light emitting element and a phosphor are combined can have a configuration well known to those skilled in the art by means well known to those skilled in the art. Conventionally, a technique for changing the emission color by combining a light emitting element and a phosphor is known, and such a technique can be adopted in the lamp of the present invention without any limitation.

  For example, by appropriately selecting the phosphor used for the lamp, it becomes possible to obtain light emission having a longer wavelength than the light emitting element, and by mixing the emission wavelength of the light emitting element itself with the wavelength converted by the phosphor. A lamp that emits white light can also be used.

  FIG. 5 is a schematic view schematically showing an example of a lamp configured using the group III nitride compound semiconductor light emitting device according to the present invention. The lamp 3 shown in FIG. 5 is a cannonball type, and the light emitting element 1 shown in FIG. 1 is used. As shown in FIG. 5, the positive electrode bonding pad (see reference numeral 18 shown in FIG. 1) of the light emitting element 1 is bonded to one of the two frames 31 and 32 (the frame 31 in FIG. 5) with a wire 33 to emit light. The light emitting element 1 is mounted by joining the negative electrode of the element 1 (see reference numeral 19 shown in FIG. 1) to the other frame 32 with a wire 34. The periphery of the light emitting element 1 is molded with a transparent resin 35.

Since the lamp of the present invention uses the light emitting device of the present invention, the lamp is excellent in productivity and has excellent light emission characteristics.
Further, the lamp of the present invention can be used for any purpose such as a bullet type for general use, a side view type for portable backlight use, and a top view type used for a display.

  EXAMPLES Next, although an Example and a comparative example are shown and this invention is demonstrated in detail, this invention is not limited only to these Examples.

[Example 1]
As shown below, the laminated semiconductor 10 shown in FIG. 4 was produced, and the light emitting element shown in FIG. 1 and FIG. 2 was produced.
First, the substrate 11 made of mirror-polished sapphire was prepared, and the following pretreatment was performed. That is, the substrate 11 is placed in a chamber of a sputtering apparatus in which a target made of metal Al for forming the intermediate layer 12 is placed, and the substrate 11 is heated to 500 ° C., and nitrogen gas is supplied at a flow rate of 15 sccm. The surface of the substrate 11 was cleaned by exposing it to nitrogen plasma while maintaining the pressure in the chamber at 1.0 Pa, applying a high-frequency bias of 50 W to the substrate 11 side without applying power to the target. .

After the pretreatment, the pressure in the chamber is set to 0.5 Pa, and 5 sccm of argon gas and 15 sccm of nitrogen gas are circulated in the chamber (the ratio of nitrogen in the whole gas is 75%) to form the intermediate layer 12. For the atmosphere. Next, with the substrate 11 held at 500 ° C., a power of 1 W / cm ² is applied to the metal Al target, no bias is applied to the substrate 11, and the substrate 11 is deposited at a film formation rate of 0.12 nm / s by sputtering. A 50 nm thick intermediate layer 12 made of an aggregate of AlN columnar crystals was formed thereon.

  Next, the substrate 11 on which the intermediate layer 12 is formed is taken out from the sputtering apparatus, and the base layer 14a made of undoped GaN and Si are doped by reactive sputtering using the light emitting element manufacturing apparatus 40 shown in FIG. An n-type contact layer 14b made of a GaN layer was continuously formed.

First, the substrate 11 on which the intermediate layer 12 was formed, the Ga target 47a made of Ga, and the dopant target 47b made of Si were installed in the chamber 41 of the manufacturing apparatus 40 shown in FIG. The Ga target 47a and the dopant target 47b used here have a ratio of the area exposed in the chamber (Ga target: dopant target = 1: 0.01) of Si in the n-type contact layer 14b to be formed. The concentration is set in advance so as to be 1 × 10 ¹⁹ cm ⁻³ .

  Next, the pressure in the chamber 41 is set to 0.5 Pa, and 5 sccm of argon gas and 15 sccm of nitrogen gas are circulated in the chamber 41 (the ratio of nitrogen in the whole gas is 75%), and the base layer 14a and the n-type contact layer An atmosphere for forming a film 14b was used.

Next, the substrate 11 is heated to 1000 ° C., and power is supplied to the electrode 43a through the matching box 46a while moving the position where the magnetic field is applied by sweeping the magnet into the Ga target 47a. In addition to applying a power of / cm ² , power is supplied to a holder 11 b provided with a heater 44 to form a film for 90 minutes while applying an RF (high frequency) bias of 0.5 W / cm ² to the substrate 11. A 6 μm film was formed thereon at a film formation rate of 1 nm / s to form a base layer 14a.

Thereafter, with the temperature and bias of the substrate 11 kept the same, a power of 1 W / cm ² was continuously applied to the Ga target 47a and the Si target, and film formation was continued for another 30 minutes. As a result, an n-type contact layer 14b having a film thickness of 2 μm made of a GaN layer doped with Si on the underlying layer 14a was obtained.

The Si concentration in the n-type contact layer 14b obtained here was quantified by a general SIMS (secondary ion mass spectrum) method. As a result, it was confirmed that Si was doped at a concentration of 1 × 10 ¹⁹ cm ⁻³ .

Next, the substrate 11 on which the layers up to the n-type contact layer 14b of the n-type semiconductor layer 14 are formed is introduced into a MOCVD furnace, and In _0.02 Ga ₀ doped with Si on the n-type contact layer 14b. _An n-type cladding layer 14c made of _.98 N and a light emitting layer 15 made of a barrier layer 15a and a well layer 15b were formed.
First, an n-type cladding layer 14c having a thickness of 20 nm is formed, and a barrier layer 15a made of GaN having a thickness of 16 nm, each of which starts with the barrier layer 15a and ends with the barrier layer 15a. Then, a light emitting layer (multiple quantum well structure) 15 was formed by alternately stacking five well layers made of In _0.2 Ga _0.8 N with the thickness of each layer being 3 nm.

Next, the substrate 11 on which the layers up to the final barrier layer 15b of the light emitting layer 15 are laminated is taken out of the MOCVD furnace, and the p-type cladding layer 16a and the p-type cladding layer 16a are formed by reactive sputtering using the light emitting device manufacturing apparatus 40 shown in FIG. A p-type contact layer 16b was formed.
First, a p-type cladding layer 16a was formed. First, as a chamber 41 for forming the p-type cladding layer 16a, a chamber 41 different from the chamber in which the base layer 14a and the n-type contact layer 14b are formed is prepared, and a Ga target 47a is formed in the chamber 41. A material made of a mixed metal of Al and Ga was installed, and a material made of Mg was installed as the dopant target 47b. The mixing ratio of Ga and Al in the Ga target 47a installed in the chamber 41 for forming the p-type cladding layer 16a was set to 7% Al composition. Further, the ratio of the areas of the Ga target 47a and the dopant target 47b exposed in the chamber 41 was 1: 0.01.

Then, the substrate 11 in which the layers up to the final barrier layer 15b of the light emitting layer 15 are stacked is introduced into the chamber 41 for forming the p-type cladding layer 16a, and is applied to the electrodes 43a and 43b via the matching boxes 46a and 46b. A current is supplied, and a power of 1 W / cm ² is applied to the Ga target 47a by RF (high frequency) method. At the same time, a power of 1.5 W / cm ² is also applied to the dopant target 47b to bias to the substrate side. The p-type cladding layer 16a made of an Al _0.07 Ga _0.93 N layer doped with Mg is formed by depositing 20 nm on the light-emitting layer 15 at a deposition rate of 1 nm / s without applying voltage. did.

The Mg concentration in the p-type cladding layer 16a obtained here was quantified by a general SIMS method in the same manner as the Si concentration described above. As a result, it was confirmed that Mg was doped at a concentration of 1.5 × 10 ²⁰ cm ⁻³ .

  Next, a p-type contact layer 16b was formed. In the chamber 41 for forming the p-type contact layer 16b, a Ga target 47a made of a mixed metal of Al and Ga was placed, and a dopant target 47b made of Mg was placed. The mixing ratio of Ga and Al in the Ga target 47a installed in the chamber 41 for forming the p-type contact layer 16b was set to 3% Al composition. Further, the ratio of the areas of the Ga target 47a and the dopant target 47b exposed in the chamber 41 was 1: 0.01.

Then, the substrate 11 on which the layers up to the p-type cladding layer 16a are stacked is introduced into a chamber for forming the p-type contact layer 16b, and current is supplied to the electrodes 43a and 43b through the matching boxes 46a and 46b. A power of 1 W / cm ² is applied to the Ga target 47a by RF (high frequency) method, and at the same time, a power of the same density is applied to the dopant target 47b, and a bias of 1 nm / s is not applied to the substrate side A p-type contact layer 16b made of an Al _0.02 Ga _0.98 N layer doped with Mg was formed by depositing 20 nm on the p-type cladding layer 16a at a deposition rate.

The Mg concentration in the p-type contact layer 16b obtained here was quantified by a general SIMS method in the same manner as the Si concentration described above. As a result, it was confirmed that Mg was doped at a concentration of 1 × 10 ²⁰ cm ⁻³ .

On the p-type contact layer 16b of the laminated semiconductor 10 obtained in this way shown in FIG. 4, a transparent electrode 17 made of ITO and a titanium in order from the surface side of the transparent electrode 17 using a photolithography method. Then, a positive electrode bonding pad 18 having a structure in which aluminum and gold are laminated is sequentially formed.
Next, the laminated semiconductor 10 in which the translucent electrode 17 and the positive electrode bonding pad 18 are formed is dry-etched to expose the exposed region 14d on the n-type contact layer 14b, and a photolithography method is performed on the exposed region 14d. Using this, a negative electrode 19 composed of four layers of Ni, Al, Ti and Au was formed, and the light emitting device 1 shown in FIGS. 1 and 2 was obtained.

  The back side of the substrate 11 of the light-emitting element 1 thus obtained was ground and polished to form a mirror-like surface, which was cut into a 350 μm square to obtain a chip. Then, the chip was placed on the lead frame with the electrode facing up, and was connected to the lead frame with a gold wire to obtain a light emitting diode.

A forward current was passed between the positive electrode bonding pad 18 and the negative electrode 19 of the light-emitting diode thus obtained.
As a result, the forward voltage at a current of 20 mA was 3.0V. Moreover, when the light emission state was observed through the translucent electrode 17 on the p-type semiconductor layer 16 side, the light emission wavelength was 460 nm and the light emission output was 15 mW. From this, it was confirmed that the light-emitting element 1 of Example 1 had excellent light-emitting characteristics.

[Example 2]
The light emitting device manufacturing apparatus 50 shown in FIG. 6 was used, except that the ratio of the area of the Ga target 47a to the area of the dopant target 47b was 1: 1 and the film formation conditions for the n-type contact layer 14b were The laminated semiconductor 10 shown in FIG. 4 was manufactured in the same manner as in FIG. 1, and the light emitting element shown in FIGS. 1 and 2 was manufactured.
More specifically, in the second embodiment, unlike the first embodiment, the exposed area of the area of the Ga target 47a and the area of the dopant target 47b is the same, and the power applied to the Ga target 47a and the power applied to the dopant target 47b. Is set in advance so that the concentration of Si in the n-type contact layer 14b to be deposited is 8 × 10 ¹⁸ cm ⁻³ . That is, the value of the RF power applied to the dopant target 47b was set to 1/100 of the Ga target 47a, that is, 0.01 W / cm ² . At this time, plasma was generated by the high frequency dielectric coupled plasma generator 22 installed in the chamber 41 of the light emitting device manufacturing apparatus 50 shown in FIG. 6, and the voltage applied to the dopant target 47b was set to 100V. Other conditions such as the bias value, the substrate temperature, and the film forming rate were the same as those in Example 1.

The Si concentration in the n-type contact layer 14b thus obtained was quantified by a general SIMS (secondary ion mass spectrum) method. As a result, it was confirmed that Si was doped at a concentration of 8 × 10 ¹⁸ cm ⁻³ .

  The laminated structure thus obtained was used as a light emitting diode in the same manner as in Example 1, and a forward current was passed between the positive electrode bonding pad 18 and the negative electrode 19 of the obtained light emitting diode. As a result, the forward voltage at a current of 20 mA was 3.2V. Moreover, when the light emission state was observed through the translucent electrode 17 on the p-type semiconductor layer 16 side, the light emission wavelength was 470 nm and the light emission output was 13.5 mW. From this, it was confirmed that the light-emitting element 1 of Example 2 had excellent light-emitting characteristics.

[Example 3]
Using the same manufacturing apparatus 40 as that for manufacturing the light-emitting element of Example 1 shown in FIG. 3, the ratio of the area of the Ga target 47a to the area of the dopant target 47b was 1: 1, and the formation of the n-type contact layer 14b Except for the film conditions, the laminated semiconductor 10 shown in FIG. 4 was produced in the same manner as in Example 1, and the light emitting device shown in FIGS. 1 and 2 was produced.
More specifically, in the third embodiment, unlike the first embodiment, the exposed area of the Ga target 47a and the area of the dopant target 47b are the same, and the pulse applied to the Ga target 47a and the pulse applied to the dopant target 47b. The pulse ratio was set in advance so that the Si concentration in the n-type contact layer 14b to be deposited was 1.1 × 10 ¹⁹ cm ⁻³ . That is, the pulse ratio of the RF power applied to the dopant target 47b is 1/100 of the Ga target 47a, that is, the power is continuously applied to the Ga target 47a, but the power is applied to the dopant target 47b for 1 millisecond. The sequence was to stop the power for 100 milliseconds. Other conditions such as the bias value, the substrate temperature, and the film forming rate were the same as those in Example 1.

The Si concentration in the n-type contact layer 14b thus obtained was quantified by a general SIMS (secondary ion mass spectrum) method. As a result, it was confirmed that Si was doped at a concentration of 1.1 × 10 ¹⁹ cm ⁻³ .

  The laminated structure thus obtained was used as a light emitting diode in the same manner as in Example 1, and a forward current was passed between the positive electrode bonding pad 18 and the negative electrode 19 of the obtained light emitting diode. As a result, the forward voltage at a current of 20 mA was 3.1V. Moreover, when the light emission state was observed through the translucent electrode 17 on the p-type semiconductor layer 16 side, the light emission wavelength was 470 nm and the light emission output was 13.2 mW. From this, it was confirmed that the light-emitting element 1 of Example 3 had excellent light-emitting characteristics.

[Example 4]
Using the same manufacturing apparatus 40 as that for manufacturing the light-emitting element of Example 1 shown in FIG. 3, except for the film formation conditions of the n-type cladding layer 14c, the stacked semiconductor 10 shown in FIG. The light emitting element shown in FIGS. 1 and 2 was manufactured.
More specifically, unlike Example 1, Example 3 was provided with a Ga target 47a made of an alloy of In and Ga and a dopant target 47b made of Si. The ratio of the area exposed in the chamber between the Ga target 47a and the dopant target 47b used here is Ga target: dopant target = 1: 0.01. The Ga target 47a is a mixture of In and Ga so that the In composition in InGaN to be deposited is 2%.

The n-type cladding layer 14c is formed by placing the substrate 11 on which the layers up to the n-type contact layer 14b are formed in the chamber 41, heating the substrate 11 to 700 ° C., and sweeping the magnet in the Ga target 47a. While moving the position where the magnetic field is applied, power is supplied to the electrode 43a through the matching box 46a, 1 W / cm ² power is applied to the Ga target 47a, and 0.1 W / cm ² RF power is applied to the Si target 47b. Is intermittently applied at a time ratio of 1/10, and further, electric power is supplied to the holder 11b provided with the heater 44 and an RF (high frequency) bias of 0.5 W / cm ² is applied to the substrate 11 A film was formed for 10 minutes, and a 20 nm film was formed on the substrate 11 at a film formation rate of 0.03 nm / s to form an n-type cladding layer 14c.

The Si concentration in the n-type contact layer 14b thus obtained was quantified by a general SIMS (secondary ion mass spectrum) method. As a result, it was confirmed that Si was doped at a concentration of 1 × 10 ¹⁷ cm ⁻³ cm ⁻³ .

  The laminated structure thus obtained was used as a light emitting diode in the same manner as in Example 1, and a forward current was passed between the positive electrode bonding pad 18 and the negative electrode 19 of the obtained light emitting diode. As a result, the forward voltage at a current of 20 mA was 3.3V. Moreover, when the light emission state was observed through the translucent electrode 17 on the p-type semiconductor layer 16 side, the light emission wavelength was 470 nm and the light emission output was 14.1 mW. From this, it was confirmed that the light-emitting element 1 of Example 4 had excellent light-emitting characteristics.

[Comparative Example 1]
1 and FIG. 1 except that the n-type contact layer 14b of the laminated semiconductor 10 was formed using a sputtering apparatus having a chamber provided with a sputtering target in which granular Si was mixed in Ga. The light emitting element 1 shown in FIG. 2 was produced.

[Examples 1 to 3, Comparative Example 1]
Further, the film formation of the n-type contact layer 14b constituting the light-emitting element 1 of Examples 1 to 3 and Comparative Example 1 was continued for one week, and the amount of Si contained in the obtained n-type contact layer 14b The variation of was investigated.
As a result, in Example 1 to Example 3, the variation in the amount of Si was in the range of 1.01 × 10 ¹⁹ cm ^{−3 to} 0.99 × 10 ¹⁹ cm ⁻³ . On the other hand, in Comparative Example 1, the amount of Si varied in the range of 0.8 × 10 ¹⁹ cm ^{−3 to} 1.5 × 10 ¹⁹ cm ⁻³ .
Accordingly, in Examples 1 to 3, the amount of Si contained in the n-type contact layer 14b is controlled with higher accuracy than in the comparative example 1, and is contained in the n-type contact layer 14b. It was confirmed that the amount of Si was optimized.

Further, the formation of the n-type contact layer 14b constituting the light emitting device 1 of Examples 1 to 3 and Comparative Example 1 is continued for one week, and the Ga target 47a for forming the n-type contact layer 14b is formed. The state of was investigated.
As a result, in any of Examples 1 to 3 and Comparative Example 1, the Ga target 47a was frequently liquefied due to power fluctuations and cooling water temperature fluctuations.
At this time, in the Ga target 47a of Comparative Example 1, a phenomenon was observed in which the mixed granular Si floated and aggregated on the surface of Ga due to the difference in specific gravity.
From this, in Comparative Example 1, it is presumed that the variation in the amount of Si contained in the obtained n-type contact layer 14b is larger than that in Examples 1 to 3.

Moreover, the magnitude | size of the leakage current of the light emitting element 1 of Example 1- Example 3 and the comparative example 1 was investigated.
As a result, in Examples 1 to 3, the leak current that flows when a voltage of 20 V was applied in the reverse direction was in the range of 1 μA to 3 μA. On the other hand, in Comparative Example 1, the leakage current was 10 μA.
From this, it was confirmed that in Examples 1 to 3, the crystallinity was excellent as compared with Comparative Example 1.

  The group III nitride compound semiconductor light-emitting device obtained by the present invention has a group III nitride compound semiconductor layer having good crystallinity and has excellent light emission characteristics. Therefore, a semiconductor element such as a light emitting diode, a laser diode, or an electronic device having excellent light emission characteristics can be manufactured.

FIG. 1 is a schematic cross-sectional view schematically showing an example of a group III nitride compound semiconductor light emitting device according to the present invention. FIG. 2 is a schematic diagram showing a planar structure of the group III nitride compound semiconductor light-emitting device shown in FIG. FIG. 3 is a schematic view schematically showing an example of a group III nitride compound semiconductor light emitting device manufacturing apparatus according to the present invention. FIG. 4 is a view for explaining the manufacturing method of the group III nitride compound semiconductor light-emitting device shown in FIG. 1, and is a schematic cross-sectional view schematically showing a laminated semiconductor. FIG. 5 is a schematic view schematically showing an example of a lamp configured using the group III nitride compound semiconductor light emitting device according to the present invention. FIG. 6 is a schematic view schematically illustrating another example of a group III nitride compound semiconductor light emitting device manufacturing apparatus according to the present invention.

Explanation of symbols

      DESCRIPTION OF SYMBOLS 1 ... Group III nitride compound semiconductor light emitting element (light emitting element), 3 ... Lamp, 10 ... Multilayer semiconductor, 11 ... Substrate, 11a ... Surface, 12 ... Intermediate layer, 14a ... Underlayer, 14 ... N-type semiconductor layer, 15 DESCRIPTION OF SYMBOLS ... Light emitting layer, 16 ... p-type semiconductor layer, 17 ... Translucent positive electrode, 40 ... Manufacturing apparatus, 41 ... Chamber, 43a, 43b ... Electrode, 45 ... Power application means, 46a, 46b ... Matching box, 47 ... Sputter target 47a ... Ga target, 47b ... dopant target.

Claims (19)

A manufacturing apparatus for forming a semiconductor layer made of a group III nitride semiconductor of a group III nitride compound semiconductor light emitting device by a sputtering method,
A chamber;
A dopant target comprising a Ga target containing a Ga element and a dopant element installed in the chamber;
An apparatus for manufacturing a Group III nitride compound semiconductor light emitting device, comprising: a power applying unit that applies power to the Ga target and the dopant target simultaneously or alternately.   2. The apparatus for manufacturing a group III nitride compound semiconductor light-emitting element according to claim 1, wherein the dopant element is Si or Mg.   The power application means changes the ratio of the power applied to the Ga target and the power applied to the dopant target, thereby changing the Ga element and dopant in the gas phase when forming the semiconductor layer. The apparatus for manufacturing a group III nitride compound semiconductor light-emitting element according to claim 1 or 2, wherein a ratio with an element is controlled.   The power applying means applies the power by a pulse DC method, and the semiconductor layer is formed by changing a pulse ratio between a pulse applied to the Ga target and a pulse applied to the dopant target. 3. The apparatus for manufacturing a group III nitride compound semiconductor light-emitting element according to claim 1, wherein the ratio of Ga element and dopant element in a gas phase during film formation is controlled.   The dopant element is Si, and the power application means sets the ratio of Ga element and Si element in the gas phase when forming the semiconductor layer to 1: 0.001 to 1: 0.00001. The apparatus for manufacturing a group III nitride compound semiconductor light-emitting element according to claim 3 or 4, wherein the apparatus is controlled to fall within the range.   The dopant element is Mg, and the power application means sets the ratio of Ga element and Mg element in the gas phase when forming the semiconductor layer to 1: 0.1 to 1: 0.001. The apparatus for manufacturing a group III nitride compound semiconductor light-emitting element according to claim 3 or 4, wherein the apparatus is controlled to fall within the range.   The apparatus for manufacturing a group III nitride compound semiconductor light-emitting element according to claim 1, wherein at least a surface layer of the Ga target is liquefied.   The group III nitride compound semiconductor according to any one of claims 1 to 7, wherein the dopant target is sputtered so as not to form a cluster composed of the dopant element having two or more atoms. Light emitting device manufacturing equipment.   The group III nitride compound semiconductor according to any one of claims 1 to 8, wherein the dopant target is sputtered at a voltage at which a cluster composed of two or more atoms of the dopant element is not formed. Light emitting device manufacturing equipment. A method of manufacturing a group III nitride compound semiconductor light emitting device having a semiconductor layer in which an n-type semiconductor layer, a light emitting layer, and a p type semiconductor layer each made of a group III nitride semiconductor are stacked,
Forming at least a part of the semiconductor layer by sputtering,
When forming the semiconductor layer by sputtering, a Ga target containing a Ga element and a dopant target made of a dopant element are used as a sputtering target, and power is applied to the Ga target and the dopant target simultaneously or alternately. A method for producing a Group III nitride compound semiconductor light-emitting device, wherein:   The method of manufacturing a group III nitride compound semiconductor light-emitting device according to claim 10, wherein the n-type semiconductor layer is formed by using Si as the dopant element.   12. The ratio of Ga element to Si element in the gas phase when forming the semiconductor layer is in the range of 1: 0.001 to 1: 0.00001. A method for producing a Group III nitride compound semiconductor light-emitting device of   The method of manufacturing a group III nitride compound semiconductor light-emitting element according to claim 10, wherein the p-type semiconductor layer is formed by using Mg as the dopant element.   The ratio of Ga element and Mg element in the gas phase when forming the semiconductor layer is in the range of 1: 0.1 to 1: 0.001. A method for producing a Group III nitride compound semiconductor light-emitting device of By the ratio of the area of the surface of the Ga target facing the substrate and the area of the surface of the dopant target facing the substrate,
The group III nitride compound semiconductor according to any one of claims 10 to 14, wherein a ratio of a Ga element and a dopant element in a gas phase when the semiconductor layer is formed is controlled. Manufacturing method of light emitting element. By changing the ratio of the power applied to the Ga target and the power applied to the dopant target,
The group III nitride compound semiconductor according to any one of claims 10 to 14, wherein a ratio of a Ga element and a dopant element in a gas phase when the semiconductor layer is formed is controlled. Manufacturing method of light emitting element. By applying the power by a pulse DC method and changing a pulse ratio between a pulse applied to the Ga target and a pulse applied to the dopant target,
The group III nitride compound semiconductor according to any one of claims 10 to 14, wherein a ratio of a Ga element and a dopant element in a gas phase when the semiconductor layer is formed is controlled. Manufacturing method of light emitting element.   18. The method for producing a group III nitride compound semiconductor light-emitting element according to claim 10, wherein an intermediate layer made of a columnar crystal is formed between the substrate and the semiconductor layer.   The method for producing a group III nitride compound semiconductor light-emitting device according to any one of claims 10 to 18, wherein at least a surface layer is liquefied as the Ga target.

Images