JP4369970B2 - Method for manufacturing compound semiconductor light emitting device and compound semiconductor light emitting device - Google Patents

Description

  The present invention relates to a method for manufacturing a compound semiconductor light emitting device and a compound semiconductor light emitting device, and more particularly to a method for manufacturing a semiconductor laser diode or a light emitting diode capable of emitting light in a blue region and a compound semiconductor light emitting device.

  FIG. 17 is a diagram showing a schematic cross section of a conventional AlGaN / InGaN / AlGaN compound semiconductor light emitting device (semiconductor laser, light emitting diode) capable of emitting light in the blue region.

Referring to the figure, a semiconductor light emitting device includes a sapphire (0001) substrate 1, a GaN or AlN buffer layer 2, an n-type GaN layer 3, and an n-type Al _Z Ga _1-Z that are sequentially stacked on the sapphire (0001) substrate 1. N (0 ≦ Z ≦ 1) lower cladding layer 4, non-doped or Zn-doped In _Y G
a _1-Y N (0 ≦ Y ≦ 1) active layer (also called light emitting layer) 5, p-type Al _Z Ga _1-Z N (
0 ≦ Z ≦ 1) The upper clad layer 7 and the p-type GaN cap layer 8 are used. An n-type electrode 10 is formed on the n-type GaN layer 3, and a p-type electrode 9 is formed on the p-type GaN cap layer 8.

  Such a compound semiconductor light emitting device is generally manufactured through the following steps by a metal organic chemical vapor deposition method (hereinafter referred to as “MOCVD method”).

(1) Surface treatment of the sapphire substrate 1 is performed at a temperature of about 1050 ° C.
(2) The substrate temperature is lowered to about 510 ° C., and a thin GaN or AlN buffer layer 2 is grown.

(3) Raise the substrate temperature to 1020 ° C. and grow the n-type GaN layer 3.
(4) The n-type AlGaN lower cladding layer 4 is grown at the same temperature.

  (5) The substrate temperature is lowered to about 800 ° C., and the non-doped InGaN-based active layer (or Zn-doped light emitting layer) 5 is grown to a thickness of about 100 to 500 mm.

  (6) The substrate temperature is raised to about 1020 ° C., and the p-type AlGaN upper cladding layer 7 is grown.

(7) The p-type GaN cap layer 8 is grown at the same temperature.
(8) After etching, the p-type electrode 9 and the n-type electrode 10 are formed.

  In the process described above, the temperature when growing the active layer 5 containing In is about 800 ° C., because the vapor pressure of In is relatively high, so that a desired In ratio is obtained at a growth temperature of 1000 ° C. or higher. It is because it cannot be obtained. The growth temperature of the AlGaN cladding layer is set to 1020 ° C. because the AlGaN cladding layer cannot be made a film having good crystal quality unless it is grown at a temperature of 1000 ° C. or higher.

  Therefore, the light emitting element follows the growth temperature profile shown in FIG. 16 between the above-described steps (4) to (6). In FIG. 16, the horizontal axis represents the growth direction of the semiconductor, and the vertical axis represents the growth temperature.

  However, in the above-described conventional method for manufacturing a compound semiconductor, when the substrate temperature is raised to about 1020 ° C. in order to grow the p-type AlGaN upper cladding layer 7, the active layer containing In formed in the previous step is used. (Light emitting layer) There was a problem that liberation of In occurred from 5. The liberation of In leads to the deterioration of the interface between the active layer 5 and the upper cladding layer 7 and the difficulty in controlling the thickness of the active layer 5 and the mixed crystal ratio of In. It was.

  The present invention has been made to solve the above-described problems. In the manufacturing process of a compound semiconductor light emitting device, the liberation of In is suppressed as much as possible, crystal growth excellent in controllability is possible, and an activity containing high-quality In is provided. It is an object of the present invention to provide a method for producing a compound semiconductor light emitting device having an interface between a layer and a good quality active layer, and a compound semiconductor light emitting device.

According to one aspect of the present invention, a method for manufacturing a compound semiconductor light emitting device is a method for manufacturing a compound semiconductor light emitting device using metal organic vapor phase epitaxy, and a first step of forming a lower cladding layer on a substrate. A second step of forming an active layer containing In at a first temperature on the lower cladding layer; and evaporation of In at a second temperature equal to or higher than the first temperature on the active layer. A third step of forming an Al _X Ga _1-X N (0 <X ≦ 1) layer, which is an evaporation preventing layer for suppressing, and a third step higher than the second temperature on the evaporation preventing layer. comprising a fourth step of forming a _{Al z Ga 1-z N (} 0 ≦ z ≦ 1) layer at a temperature which is an upper cladding layer, on said upper cladding layer, and a fifth step of forming a cap layer , The Al composition of the evaporation prevention layer, the evaporation prevention layer and the upper cladding The Al composition of the upper cladding layer is larger than the Al composition so as to give a clear difference in chemical composition of the material between the layers.

According to another aspect of the present invention, a compound semiconductor light emitting device is a compound semiconductor light emitting device including a substrate, an n-type lower cladding layer, an active layer containing In, and a p-type upper cladding layer, wherein the p The mold upper clad layer is composed of an Al _z Ga _1-z N (0 ≦ z ≦ 1) layer, has a p-type cap layer on the upper clad layer, and is formed between the active layer and the p-type upper clad layer. Having a p-type Al _x Ga _1-x N (0 <x ≦ 1) layer which is an evaporation preventing layer, the evaporation preventing layer being at a temperature lower than the growth temperature of the p-type upper cladding layer and the active layer A layer grown at a temperature equal to or higher than the growth temperature of the layer, and the Al composition of the evaporation prevention layer is such that the chemical composition of the material between the evaporation prevention layer and the upper cladding layer has a clear difference. It is characterized by being larger than the Al composition of the upper cladding layer.

  The compound semiconductor light emitting device of the present invention includes an evaporation preventing layer on the active layer. Due to the presence of this evaporation preventing layer, the liberation of In in the active layer, which has conventionally occurred during the production of a compound semiconductor light emitting device, is prevented.

  Hereinafter, embodiments of the present invention will be described in order. In this embodiment, the growth conditions, the type of organometallic compound gas, the materials used, etc. are not limited to the following. This embodiment can be variously modified within the scope of the claims.

(First embodiment)
In the first embodiment, a sapphire (0001) c plane is used as a substrate, and each layer is grown by MOCVD. Trimethylgallium (TMG), trimethylaluminum (TMA), and trimethylindium (TMI) are used as the group III gas source, ammonia (NH ₃ ) is used as the group V gas source, and monosilane (SiH ₄ ) as the n-type dopant source. ), Biscyclopentadienyl magnesium (Cp ₂ Mg) is used as the p-type dopant source, and H ₂ is used as the carrier gas.

FIG. 1 is a schematic cross-sectional view of a semiconductor laser diode according to a first embodiment of the present invention.
Referring to the drawing, the semiconductor laser diode in this example is formed by sequentially forming a GaN or AlN buffer layer 2, an n-type GaN layer 3, and an n-type Al on a sapphire substrate 1 and a sapphire (0001) c-plane substrate 1. _0.1 Ga _0.9 N lower cladding layer 4, non-doped or Si-doped In _0.2 Ga _0.8 N active layer (also called light emitting layer) 5, thin p-type Al _0.05 Ga _0.95 N evaporation preventing layer 6, p-type Al _0.1 Ga _0.9 N The upper cladding layer 7 and the p-type GaN cap layer 8 are included. An n-type electrode 10 is formed on the n-type GaN layer 3, and a p-type electrode 9 is formed on the p-type GaN cap layer 8.

  The semiconductor lamination state is different from the conventional semiconductor lamination state shown in FIG. 17 in that the evaporation prevention layer 6 is provided between the active layer 5 and the upper cladding layer 7.

The semiconductor laser shown in FIG. 1 is formed by the steps shown below.
(1) The sapphire substrate 1 is introduced into the MOCVD apparatus, and the substrate temperature is about 1 in H _2.
The substrate is heated at 050 ° C. for surface treatment.

  (2) The substrate temperature is lowered to about 500 ° C., and the GaN or AlN buffer layer 2 is grown. At this time, the thickness of the buffer layer 2 is 250 Å for GaN and 500 で あ れ ば for AlN.

  (3) The substrate temperature is raised to about 1020 ° C., and the n-type GaN layer 3 is grown to a thickness of about 4 μm. At this point, the laminated structure shown in FIG. 3 is formed.

(4) The n-type Al _0.1 Ga _0.9 N lower cladding layer 4 is grown to a thickness of about 1 μm at the same substrate temperature. The laminated state of the substrate at this time is shown in FIG.

(5) The substrate temperature is lowered to about 800 ° C., and a non-doped or Si-doped In _0.2 Ga _0.8 N active layer (or light emitting layer) is grown to a thickness of about 200 mm. The laminated state of the substrate at this time is shown in FIG.

(6) A thin p-type Al _0.05 Ga _0.95 N evaporation preventing layer at a growth temperature of about 500 to 800 ° C. by lowering the substrate temperature below the growth temperature of the non-doped or Si-doped In _0.2 Ga _0.8 N active layer (or light emitting layer). Grow 6 The laminated state of the substrate at this time is shown in FIG.

(7) The substrate temperature is raised to about 1020 ° C., and the p-type Al _0.1 Ga _0.9 N upper cladding layer 7 is grown to a thickness of about 1 μm.

  (8) Next, the p-type electrode GaN cap layer 8 is grown to a thickness of about 1 μm at the same temperature. The laminated state of the substrate at this time is shown in FIG.

The thin p-type Al _0.05 Ga _0.95 N evaporation prevention layer 6 becomes a high-quality film while the substrate temperature is raised to about 1020 ° C.

The wafer manufactured as described above is subjected to thermal annealing in N ₂ at a temperature of about 700 ° C. By the thermal annealing, the thin p-type Al _0.05 Ga _0.95 N evaporation prevention layer 6, the p-type Al _0.1 Ga _0.9 N upper cladding layer 7 and the p-type GaN cap layer 8 are changed to a high-concentration p-type layer.

  Next, in order to perform electrode attachment, a part of the wafer is etched until the n-type GaN layer 3 is exposed, and then a p-type electrode 9 and an n-type electrode 10 are formed. The AlGaN / InGaN / AlGaN semiconductor laser diode shown in FIG. 1 is manufactured through the above steps.

  FIG. 2 is a diagram showing a crystal growth temperature profile during the formation of the lower cladding layer 4 to the upper cladding layer 7 of the semiconductor laser diode of FIG.

  Thus, in the compound semiconductor light emitting device of this example, after the active layer 5 is formed, the evaporation preventing layer 6 is formed at a temperature lower than the growth temperature of the active layer 5, and then the upper cladding layer 7 is formed at a substrate temperature of about 1020 ° C. It is formed. Therefore, liberation of In contained in the active layer 5 is prevented, thereby making it possible to provide a compound semiconductor light emitting device having an interface between an active layer containing good quality In and a good quality active layer, and In the manufacturing process, crystal growth with excellent controllability is possible.

  FIG. 8 is a schematic cross-sectional view of a light emitting diode which is a modification of the present embodiment. Referring to FIG. 8, the light emitting diode differs from the semiconductor laser diode shown in FIG. 1 in that p-type electrode 9 is formed small. This is because the light emitted from the active layer 5 is also output upward through the upper cladding layer 7 and the cap layer 8.

(Second embodiment)
FIG. 9 is a diagram showing a growth temperature profile from the lower cladding layer to the upper cladding layer of the compound semiconductor light emitting device in the second embodiment of the present invention.

  Since the laminated structure of the compound semiconductor light emitting device in this example is the same as that of the first example shown in FIGS. 1 and 8, description thereof will not be repeated here. The compound semiconductor light emitting device in the second embodiment is characterized in that the evaporation preventing layer is formed at a substrate temperature not lower than the growth temperature of the active layer containing In and not higher than the growth temperature of the upper cladding layer.

In the second embodiment, MOCVD is used for crystal growth, and a sapphire (0001) c plane is used as the substrate. Trimethylgallium (TMG), trimethylaluminum (TMA), and trimethylindium (TMI) are used as the group III gas source, and ammonia (NH ₃ ) is used as the group V gas source. Further, monosilane (SiH ₄ ) is used as an n-type dopant source, biscyclopentadienyl magnesium (Cp ₂ Mg) is used as a p-type dopant source, and H ₂ is used as a carrier gas. The manufacturing process will be described below.

(1) A sapphire substrate is introduced into the MOCVD apparatus, and the substrate temperature is about 10 in H _2.
The substrate is heated at 50 ° C. to perform surface treatment.

  (2) The substrate temperature is lowered to about 500 ° C., and a GaN or AlN buffer layer is formed. At this time, the thickness of the buffer layer is 250 mm for GaN and 500 mm for AlN.

  (3) Raise the substrate temperature to about 1020 ° C. and grow the n-type GaN layer by about 4 μm.

(4) The n-type Al _0.1 Ga _0.9 N lower clad layer 4 is grown by about 1 μm at the same substrate temperature.

(5) The substrate temperature is lowered to about 800 ° C., and a non-doped or Si-doped In _0.2 Ga _0.8 N active layer (also referred to as “light emitting layer”) is grown to a thickness of about 200 mm.

(6) Thin layer p-type Al _0.05 at about 900 ° C., where the substrate temperature is above the growth temperature of the non-doped or Si-doped In _0.2 Ga _0.8 N active layer and below the growth temperature of the p-type Al _0.1 Ga _0.9 N upper cladding layer. A Ga _0.95 N evaporation prevention layer is grown.

(7) The substrate temperature is raised to about 1020 ° C., and a p-type Al _0.1 Ga _0.9 N upper cladding layer is grown to about 1 μm.

(8) A p-type electrode GaN cap layer is grown by about 1 μm. The thin p-type Al _0.05 Ga _0.95 N evaporation preventive layer becomes a high-quality film while the substrate temperature is raised to about 1020 ° C.

  After the crystal growth, the wafer is subjected to thermal annealing and etching, and then an electrode is formed. Since these steps are the same as those of the first embodiment, description thereof will not be repeated here.

  As described above, in this embodiment, after the formation of the active layer containing In, the evaporation prevention layer is formed at a temperature higher than the growth temperature of the active layer and lower than the growth temperature of the upper cladding layer. Thus, crystal growth with excellent controllability is possible, and it becomes possible to provide an active layer containing good quality In and an interface between the active layers.

(Third embodiment)
Since the stacked state of the compound semiconductor light emitting device manufactured in the third embodiment is the same as the stacked state of the compound semiconductor light emitting device in the first embodiment shown in FIGS. 1 and 8, description thereof will not be repeated here. .

  FIG. 10 is a diagram showing a temperature profile during the formation of the upper cladding layer from the lower cladding layer of the compound semiconductor light emitting device in the third embodiment of the present invention.

  The manufacturing process of the compound semiconductor light emitting device in the present embodiment is characterized in that the growth temperature of the evaporation prevention layer is made substantially the same as the growth temperature of the active layer containing In.

In this embodiment, the MOCVD method is used as a method for manufacturing the compound semiconductor light emitting device. Further, a sapphire (0001) c surface is used as a substrate, trimethylgallium (TMG), trimethylaluminum (TMA), and trimethylindium (TMI) are used as a group III gas source, and ammonia (NH ₃ ) is used as a group V gas source. Monosilane (SiH ₄ ) is used as an n-type dopant source, biscyclopentadienyl magnesium (Cp ₂ Mg) is used as a p-type dopant source, and H ₂ is used as a carrier gas. The manufacturing process will be described below.

(1) A sapphire substrate is introduced into the MOCVD apparatus, and the substrate temperature is about 10 in H _2.
The substrate is heated at 50 ° C. to perform surface treatment.

  (2) The substrate temperature is lowered to about 500 ° C., and a GaN or AlN buffer layer is grown. At this time, the thickness of the buffer layer is 250 mm for GaN and 500 mm for AlN.

(3) The substrate temperature is raised to about 1020 ° C., and an n-type GaN layer is grown to about 4 μm.
(4) An n-type Al _0.1 Ga _0.9 N lower cladding layer is grown by about 1 μm at the same substrate temperature.

(5) Lower the substrate temperature to about 800 ° C. and grow a non-doped or Si-doped In _0.2 Ga _0.8 N active layer with a layer thickness of about 200 Å.

(6) A thin p-type Al _0.05 Ga _0.95 N evaporation preventing layer is grown at a growth temperature substantially the same as the growth temperature of the non-doped or Si-doped In _0.2 Ga _0.8 N active layer.

(7) The substrate temperature is raised to about 1020 ° C., and a p-type Al _0.1 Ga _0.9 N upper cladding layer is grown to about 1 μm.

(8) A p-type GaN cap layer is grown by about 1 μm. The thin p-type Al _0.05 Ga _0.95 N evaporation preventive layer becomes a high-quality film while the substrate temperature is raised to about 1020 ° C.

  Further, the manufactured wafer is subjected to thermal annealing, etching, and electrode formation processes to be elements such as a semiconductor laser and a light emitting diode. Since these steps are substantially the same as those of the first embodiment, description thereof will not be repeated here.

(Fourth embodiment)
FIG. 11 is a schematic cross-sectional view of a compound semiconductor light emitting device in a fourth embodiment of the present invention.

Referring to the figure, the compound semiconductor light emitting device in this example includes an n-type electrode 10, an n-type GaAs substrate 11, an n-type GaAs buffer layer 12, an n-type Al _0.8 Ga _0.2 As lower cladding layer 13, and an active layer. 20, p-type (Mg doped) Al _0.8 Ga _0.2 As upper clad layer 17, insulating layer 18, p-type GaAs cap layer 19 and p-type electrode 9. The active layer 20 is composed of a compound semiconductor in which a non-doped GaAs layer 14, a non-doped In _0.15 Ga _0.85 As strained quantum well active layer 15, and a non-doped GaAs evaporation prevention layer 16 are stacked in this order from the bottom.

  The energy level in the vicinity of the active layer is shown in FIG. In the compound semiconductor light emitting device of this embodiment, a ridge waveguide structure having a width of 3 μm is formed by photolithography and wet etching.

The compound semiconductor light emitting device in this example is formed by MOCVD. In this embodiment, GaAs is used as the substrate, trimethylgallium (TMG), trimethylaluminum (TMA), and trimethylindium (TMI) are used as the group III gas source, and arsine (AsH ₃ ) is used as the group V gas source. S as an n-type dopant source
e is Mg and Zn as a p-type dopant source, and H ₂ is used as a carrier gas. And the compound semiconductor light-emitting device in a present Example is manufactured by the following processes.

  (1) The n-type (100) GaAs substrate 11 is introduced into the MOCVD apparatus, the substrate temperature is raised to about 800 ° C., and the GaAs buffer layer 12 is grown. The thickness of the GaAs buffer layer is 0.5 μm.

(2) The n-type Al _0.8 Ga _0.2 As lower cladding layer 13 is grown to a thickness of about 1.4 μm at the same temperature.

(3) The non-doped GaAs layer 14 is grown about 100 mm.
(4) The substrate temperature is lowered to about 630 ° C., and the non-doped In _0.15 Ga _0.85 As strained quantum well active layer 15 is grown to a thickness of about 110 mm.

  (5) A non-doped GaAs evaporation prevention layer 16 is grown to a thickness of about 100 mm. Note that the temperature of the substrate in the growth of the evaporation preventing layer can be set according to any growth temperature profile shown in FIGS. That is, in FIG. 13, the evaporation prevention layer is formed at about 550 ° C., which is lower than 630 ° C., which is the growth temperature of the strained quantum well active layer. In FIG. 14, the evaporation preventing layer can be grown at about 700 ° C., which is a growth temperature of about 630 ° C. which is the growth temperature of the strained quantum well active layer, and about 800 ° C., which is the growth temperature of the upper cladding layer. In FIG. 15, the evaporation preventing layer can be grown at about 630 ° C., which is substantially the same temperature as the growth temperature of the strained quantum well active layer.

(6) A p-type (Mg-doped) Al _0.8 Ga _0.2 As upper cladding layer 17 is grown to a thickness of about 1.4 μm.

(7) A p-type (Zn-doped) GaAs cap layer 19 is grown with a layer thickness of about 1 μm.
A conventional photolithography and wet etching technique is used for the wafer that has undergone the above steps, and a ridge waveguide structure having a width of 3 μm shown in FIG. 11 is formed. A p-type and n-type electrode is formed on the wafer on which the ridge waveguide structure is formed, and an element is formed.

(Fifth embodiment)
Since the stacked state of the compound semiconductor light emitting device formed in the fifth embodiment is the same as the stacked structure of the compound semiconductor light emitting device in the first embodiment shown in FIGS. 1 and 8, description thereof will not be repeated here. . The feature of the fifth embodiment is that Al _0.4 Ga _0.6 N is used as a material for forming the evaporation preventing layer. This makes it possible to make a clear difference in the chemical composition of the material between the evaporation preventing layer and the upper cladding layer, thereby facilitating the verification of the evaporation preventing layer after device fabrication.

The MOCVD method is used for manufacturing the compound semiconductor light emitting device in this example, and a sapphire (0001) c plane is used as a substrate. Trimethylgallium (TMG), trimethylaluminum (TMA), and trimethylindium (TMI) are used as the group III gas source, and ammonia (NH ₃ ) is used as the group V gas source. Further, monosilane (SiH ₄ ) is used as an n-type dopant source, biscyclopentadienyl magnesium (Cp ₂ Mg) is used as a p-type dopant source, and H ₂ is used as a carrier gas.

And the compound semiconductor light-emitting device in a present Example is formed through the following processes.
(1) A sapphire substrate is introduced into the MOCVD apparatus, and the substrate is heated at a substrate temperature of about 1050 ° C. in H ₂ to perform surface treatment of the substrate.

  (2) The substrate temperature is lowered to about 500 ° C., and a GaN or AlN buffer layer is grown. At this time, the thickness of the buffer layer is 250 mm for GaN and 500 mm for AlN.

  (3) Raise the substrate temperature to about 1020 ° C. and grow an n-type GaN layer with a thickness of about 4 μm.

(4) An n-type Al _0.1 Ga _0.9 N lower cladding layer is grown at a layer thickness of about 1 μm at the same substrate temperature.

(5) The substrate temperature is lowered to about 800 ° C., and a non-doped or Si-doped In _0.2 Ga _0.8 N active layer (also referred to as a light emitting layer) is grown to a thickness of about 200 mm.

(6) A thin p-type Al _0.4 Ga _0.6 N evaporation prevention layer is grown. The substrate temperature at this time can be arbitrarily selected between about 600 ° C. and about 900 ° C. For example, about 600 ° C., about 800 ° C., about 900 ° C., etc. can be selected.

(7) The substrate temperature is raised to about 1020 ° C., and a p-type Al _0.1 Ga _0.9 N upper cladding layer is grown to a thickness of about 1 μm.

(8) A p-type GaN cap layer is grown to a thickness of about 1 μm. Thin layer p-type Al _0.4
The Ga _0.6 N evaporation preventing layer becomes a high-quality film while the substrate temperature is raised to about 1020 ° C.

The wafer having the layer structure is subjected to thermal annealing in N ₂ at about 700 ° C.
The thin p-type Al _0.4 Ga _0.6 N evaporation prevention layer, the p-type Al _0.1 Ga _0.9 N upper clad layer, and the p-type GaN cap layer are changed to a high-concentration p-type layer by the thermal annealing.

  Next, in order to form an n-type electrode, etching is performed until the n-type GaN layer is exposed, and p-type and n-type electrodes are formed on the etched wafer.

  In the description of the examples, the MOCVD method is used for crystal growth, but the MBE method (molecular beam epitaxial growth method) or the like can be used as the growth method. In addition, changes in materials used, growth conditions, and the like can be made within the scope of the claims.

Further, in the first to third and fifth embodiments, the sapphire (0001) c plane is used as the substrate, but SiC, MgO, ZnO, MgAl ₂ O ₄ or the like can be used as the substrate.

Further, a substance such as a chemical formula Al _x Ga _1-X N (0 <X <1) can be used as the buffer layer.

Further, the active layer has a chemical formula of Al _X Ga _Y In _Z N (X + Y + Z = 1 and 0 ≦ X · Y ≦ 1,0 <
Any substance may be used as long as it is a substance constituted by Z ≦ 1).

Furthermore it is possible to use a substance composed of n-type _{Al Z Ga 1-Z N (} 0 ≦ Z ≦ 1) as a lower cladding layer, p-type _{Al Z Ga 1-Z N (} 0 ≦ as an upper cladding layer A substance constituted by Z ≦ 1) can be used.

Further, a material composed of non-doped Al _x Ga _1-x As (0 ≦ X ≦ 1) can be used as the material constituting the non-doped GaAs layer 14 in the fourth embodiment, and non-doped In _0.15 Ga _0.85 As. Non-doped In _y Ga _1-y As (0 <y ≦ 1) can be used as the material constituting the strain quantum well active layer. Furthermore, in the fourth embodiment, a material composed of p-type Al _x Ga _1-x As (0 ≦ X ≦ 1) can be used as the evaporation preventing layer.

[Effects of the embodiment]
According to the compound semiconductor light emitting device of the present invention, since the evaporation preventing layer is provided, the liberation of In can be suppressed as much as possible, crystal growth excellent in controllability can be achieved, and an active layer (light emitting layer) containing good quality In and It becomes possible to provide a compound semiconductor light emitting device including an interface of the active layer.

  In addition, according to the method for manufacturing a compound semiconductor light emitting device of the present invention, since the liberation of In contained in the active layer can be suppressed as much as possible, crystal growth with excellent controllability is possible, and an active material containing good quality In is included. It is possible to provide an interface between the layer and the active layer.

It is a schematic cross section of the semiconductor laser diode in one Example of this invention. It is a figure which shows the growth temperature profile of the compound semiconductor light-emitting device in the 1st Example of this invention. It is a 1st figure which shows the manufacturing process of a compound semiconductor light-emitting device. It is a 2nd figure which shows the manufacturing process of a compound semiconductor light-emitting device. It is a 3rd figure which shows the manufacturing process of a compound semiconductor light-emitting device. It is a 4th figure which shows the manufacturing process of a compound semiconductor light-emitting device. It is a 5th figure which shows the manufacturing process of a compound semiconductor light-emitting device. It is a schematic cross section of the light emitting diode in one Example of this invention. It is a figure which shows the growth temperature profile of the compound semiconductor light-emitting device in the 2nd Example of this invention. It is a figure which shows the growth temperature profile of the compound semiconductor light-emitting device in the 3rd Example of this invention. It is a schematic cross section of the semiconductor laser diode in the 4th Example of this invention. It is a figure which shows the energy level of the active layer vicinity in FIG. FIG. 12 is a first diagram showing a temperature profile in the process of manufacturing the laser diode of FIG. 11. FIG. 12 is a second diagram showing a temperature profile in the process of manufacturing the laser diode of FIG. 11. FIG. 12 is a third diagram showing a temperature profile in the process of manufacturing the laser diode of FIG. 11. It is a figure which shows the temperature profile in the manufacturing process of the conventional compound semiconductor light-emitting device. It is a schematic cross section of the conventional compound semiconductor light emitting element.

Explanation of symbols

1 Sapphire (0001) substrate, 2 GaN or AlN buffer layer, 3 n-type GaN layer, 4 n-type Al _Z Ga _{1 -Z} N (0 ≦ Z ≦ 1) lower cladding layer, 5 non-doped or Si-doped In _Y Ga ₁ -YN (0 <Y ≦ 1) active layer (or light emitting layer), 6 thin p-type Al _x Ga ₁ -XN (0 ≦ X ≦ 1) evaporation prevention layer, 7 p-type Al _Z Ga _{1 -ZN} (0 ≦ Z ≦ 1) upper cladding layer, 8 p-type GaN cap layer, 9 p-type electrode, 10 n-type electrode, 11 n-type GaAs substrate, 12 n-type GaAs buffer layer, 13 n-type Al _Z Ga _1-Z As (0 ≦ Z ≦ 1) lower clad layer, 14 non-doped Al _x Ga _1-x As (0 ≦ X ≦ 1) layer, 15 non-doped In _Y Ga _1-Y As (0 <Y ≦ 1) strain quantum well active layer, 16 p-type _{Al X Ga 1-X As (} 0 ≦ X ≦ 1) evaporation prevention layer, 17 p-type A _{Z Ga 1-Z As (0} ≦ Z ≦ 1) upper clad layer, 18 an insulating layer, 19 p-type GaAs cap layer, 20 an active layer.

Claims (2)

A method for producing a compound semiconductor light emitting device using metal organic vapor phase epitaxy,
A first step of forming a lower cladding layer on the substrate;
A second step of forming an active layer containing In at a first temperature on the lower cladding layer;
On the active layer, an Al _x Ga _1-X N (0 <X ≦ 1) layer, which is an evaporation preventing layer for suppressing evaporation of In at a second temperature not lower than the first temperature, is formed. 3 steps,
The evaporation preventing layer, a fourth step of forming the second at higher than the temperature of the third temperature is the upper cladding layer _{Al z Ga 1-z N (} 0 ≦ z ≦ 1) layer,
And a fifth step of forming a cap layer on the upper cladding layer,
The Al composition of the evaporation preventing layer is made larger than the Al composition of the upper cladding layer so as to give a clear difference in chemical composition of the material between the evaporation preventing layer and the upper cladding layer , A method for producing a compound semiconductor light emitting device. A compound semiconductor light emitting device including a substrate, an n-type lower cladding layer, an active layer containing In, and a p-type upper cladding layer,
The p-type upper cladding layer is composed of an Al _z Ga _1-z N (0 ≦ z ≦ 1) layer,
A p-type cap layer on the upper cladding layer;
A p-type Al _x Ga _1-x N (0 <x ≦ 1) layer that is an evaporation preventing layer between the active layer and the p-type upper cladding layer;
The evaporation prevention layer is a layer grown at a temperature lower than the growth temperature of the p-type upper cladding layer and a temperature equal to or higher than the growth temperature of the active layer,
The Al composition of the anti-evaporation layer is greater than the Al composition of the upper cladding layer so as to make a clear difference in the chemical composition of the material between the anti-evaporation layer and the upper cladding layer . Semiconductor light emitting device.

Images