JP3459003B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a manufacturing method thereof, and more particularly to a semiconductor device having an oxide layer used as a current confining means and a light distribution limiting means for a compound semiconductor element and a manufacturing method thereof. is there.

[0002]

2. Description of the Related Art Optoelectronic devices made of compound semiconductors have improved operating characteristics by using a structure that locally restricts current and light, and can realize devices with higher performance or new functions. it can. For example, a semiconductor laser is provided with a current constriction structure that spatially limits a current path, and by increasing the current density of the active layer, laser oscillation can be obtained with a low operating current. In general, such a current confinement structure is formed by selectively growing a pnpn thyristor structure or a high resistance layer serving as a current limiting layer, or by growing the entire surface and then etching a part thereof as a current path portion. To be done.

However, such a method requires several crystal growth steps and complicated fabrication steps, resulting in high cost. Therefore, from the viewpoint of mass production and price reduction,
There is a demand for an element structure that has high quality characteristics and can be manufactured by a simpler process. Thus, in the structure using the insulating film as the current limiting layer of the semiconductor laser, a sufficient breakdown voltage can be obtained even with a single thin film. Therefore, simplification of the element structure and simplification of the manufacturing process can be realized, and improvement in yield and high output can be expected. Since such advantages are obtained, a layer containing aluminum (AlI
A current confinement structure using an oxide film obtained by selectively oxidizing (nAs, AlGaAs, AlAs, etc.) has been proposed and tried.

N. Iwai et al. "1999 International Confer
ence on Indium Phosphide and Related Materials, Co
Inference Proceedings, pp.219-222 ”, the In sandwiched between InP layers on the InP substrate.
A laser having a structure in which an AlAs layer and an active layer are sequentially laminated and then etched in a ridge type and heat treated in a steam atmosphere to selectively oxidize the AlInAs layer from the lateral direction to provide a current limiting layer is manufactured. Also,
Y. Hayashi et al. "Electronics Letters, Vol.31 pp.560-
561 (1995) ”, a structure having a Bragg reflector in which AlAs and GaAs are alternately laminated on a GaAs substrate is manufactured, and a part of the AlAs layer is selectively oxidized in the lateral direction to limit the current. A surface emitting laser having a layered structure is manufactured.

[0005]

Layers containing aluminum (AlInAs, AlGaA) grown on a semiconductor substrate.
s, AlAs, etc.) is selectively oxidized by H. Gebre
tsadik et al. "Applied Physics Letters, Vol.72, N
o.2 pp.135-137 (1998) '',
The film peeling problem occurs. This is because the volume of the layer containing aluminum contracts after oxidation. In particular, in a structure in which the distribution of aluminum composition that contributes to oxidation is steep, the stress due to the volume contraction of the film concentrates at the interface, and cracks easily occur at the interface. An object of the present invention is to solve the above problems, and its purpose is to be able to suppress the occurrence of cracks after oxidation at the interface, by which, selectively oxidized. The present invention aims to provide a structure that uses layers to spatially limit current, light, etc. with higher reliability.

[0006]

To achieve the above object, according to the present invention, a group III-V semiconductor layer containing aluminum is formed on a semiconductor substrate, and at least one of the group III-V semiconductor layers is formed. Part is oxidized,
The III-V semiconductor layer is formed so that the aluminum composition ratio gradually or gradually increases. The aluminum composition ratio gradually or gradually increases and then gradually or gradually decreases. The V group element vacancy density is gradually or stepwise increased, and the V group element vacancy density is gradually or stepwise increased. Is formed so as to gradually or gradually decrease, a semiconductor device is provided. Further, preferably, the III-V semiconductor layer is formed on a side surface of a semiconductor mesa which includes an active layer and is formed in a stripe shape or a circular (or polygonal) shape.

In order to achieve the above object, according to the present invention, (1) II containing aluminum on a semiconductor substrate is used.
A step of forming an I-V group semiconductor layer, and (2) the III-
In the step (1), the group III-V semiconductor layer is patterned, and (3) the patterned group III-V semiconductor layer is oxidized from the side surface. The semiconductor layer is formed such that the aluminum composition ratio gradually or gradually increases, the aluminum composition ratio gradually or gradually increases, and then gradually or gradually decreases, Group V element Forming so that the vacancy density gradually or gradually increases, so that the V group element vacancy density gradually or gradually increases and then the V group element vacancy density gradually or gradually decreases. There is provided a method for manufacturing a semiconductor device, characterized in that the semiconductor device is formed under any one of the conditions.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. [First Embodiment] FIGS. 1A to 1C are sectional views showing the first embodiment of the present invention in the order of steps. As shown in FIG. 1A, an aluminum-containing III-V group semiconductor layer 1 is formed on a compound semiconductor substrate 101 made of GaAs, InP, or the like.
02 is epitaxially grown. The aluminum-containing III-V semiconductor layer 102 has a lattice constant close to that of the semiconductor substrate in the lowermost layer, and the composition ratio of aluminum is the lowest in the semiconductor layer. Then, as the growth proceeds, the aluminum composition ratio is gradually increased, maximized near the center of the layer, and then gradually decreased, and the composition ratio in the uppermost layer is returned to the minimum again. On top of that, II
A cap layer 103 lattice-matched with the uppermost layer of the IV semiconductor layer 102 is epitaxially grown.

Subsequently, as shown in FIG. 1B, the cap layer 103 and the III-V group semiconductor layer 102 are selectively removed by photolithography and etching to form a pattern such as a stripe shape. Next, as shown in FIG. 1C, heat treatment is performed in an oxidizing atmosphere to form an oxide film 102a on the side surface of the III-V semiconductor layer 102. At this time, aluminum containing III-V
In the group semiconductor layer 102, the higher the aluminum composition ratio is, the faster the oxidation progresses. Therefore, the central portion is deeply oxidized, and the III-V group semiconductor layer 102 is left in a drum shape.

The first embodiment can be modified as follows. Insulating film without forming cap layer III-V
Thermal oxidation is performed with the group semiconductor layer 102 being covered, and then a compound semiconductor layer is epitaxially grown on the III-V group semiconductor layer 102. In this case, the aluminum composition ratio of the III-V semiconductor layer 102 may be set higher in the upper layer so that the uppermost layer has the highest composition ratio. Instead of continuously changing the aluminum composition ratio, the aluminum composition ratio is changed stepwise. Instead of changing the aluminum composition ratio, the aluminum composition ratio is kept constant throughout the layer, and the density of the vacancy where the group V element is vacant is III-
In the lowermost layer of the Group V semiconductor layer, the lowest density is gradually increased toward the uppermost layer so as to become the maximum near the central portion, and further gradually decreased toward the uppermost layer so that the lowest density is obtained in the uppermost layer. To Or III-
It is lowest in the lowermost layer of the group V semiconductor layer and gradually increases toward the uppermost layer so that the highest density is obtained in the uppermost layer. Instead of the method of continuously changing the density of the group V element vacancies, the vacancies are changed stepwise.
Further, the compound semiconductor substrate 101 does not have to be a pure semiconductor substrate, and may be a substrate including some of buffer layers, clad layers, active layers, and the like.

[Second Embodiment] FIGS. 2A to 2C are sectional views in order of the steps, showing a second embodiment of the present invention. Figure 2
As shown in (a), aluminum containing III is formed on a compound semiconductor substrate 201 made of GaAs, InP, or the like.
The group V semiconductor layer 202 is epitaxially grown. The aluminum-containing III-V semiconductor layer 202 is III
Similar to the -V semiconductor layer 102, the lattice constant of the lowermost layer is close to that of the semiconductor substrate and the composition ratio of aluminum is the lowest in this semiconductor layer. Then, the aluminum composition ratio is maximized in the vicinity of the central portion and is minimized in the uppermost layer. S on the III-V semiconductor layer 202
An insulating film 204 made of an iO ₂ film or the like is formed.

Subsequently, as shown in FIG. 2B, the insulating film 20 is formed by photolithography and etching.
The 4 and III-V semiconductor layers 202 are selectively removed to form stripe-shaped openings. Next, as shown in FIG. 2C, a mesa semiconductor layer 205 including a clad layer, an active layer, a clad layer and the like is grown by a selective epitaxial growth method. Next, as shown in FIG. 2D, the insulating film 204 and the III-V group semiconductor layer 202 other than the stripe pattern sandwiching the mesa semiconductor layer 205 are selectively removed by photolithography and etching.

Then, as shown in FIG. 2E, heat treatment is performed in an oxidizing atmosphere to form an oxide film 202a on the side surface of the III-V semiconductor layer 202. At this time, in the aluminum-containing III-V semiconductor layer 202, the higher the aluminum composition ratio, the faster the oxidation proceeds.
The whole is oxidized in the central part, but III-
The group V semiconductor layer 202 is left as it is.

In the second embodiment, as in the first embodiment, the modification described in paragraph [0010] can be applied. In addition, the mesa semiconductor layer 205 and II
The pattern of the I-V group semiconductor layer 202 does not necessarily have to be a stripe shape, and is circular for surface emission or the like.
It may be processed into a polygonal shape (its donut shape).

[Third Embodiment] FIGS. 3A to 3D are sectional views in order of the processes, showing a third embodiment of the present invention. Figure 3
As shown in (a), a semiconductor layer 305a including a clad layer, an active layer and a clad layer is epitaxially grown on a compound semiconductor substrate 301 made of GaAs, InP or the like, and an insulating film made of a SiO ₂ film or the like is formed thereon. Three
To form 04. Next, as shown in FIG.
The insulating film 3 is formed by photolithography and etching.
04 and the semiconductor layer 305a are selectively removed to form a stripe-shaped mesa semiconductor layer 305.

Subsequently, as shown in FIG. 3C, the aluminum-containing III is formed by the selective epitaxial growth method.
Growing the -V semiconductor layer 302. Like the III-V semiconductor layer 102, the aluminum-containing III-V semiconductor layer 302 has a lattice constant close to that of the semiconductor substrate in the lowermost layer and has the lowest aluminum composition ratio in the semiconductor layer. Then, the aluminum composition ratio is continuously changed and maximized near the central portion,
The lowest is done in the top layer. Subsequently, as shown in FIG. 3D, by photolithography and etching, the stripe pattern portion sandwiching the III-V semiconductor layer 302 sandwiching the mesa semiconductor layer 305 is left and the others are removed by etching.

After that, as shown in FIG. 3E, heat treatment is performed in an oxidizing atmosphere to form an oxide film 302a on the side surface of the III-V semiconductor layer 302. At this time, in the aluminum-containing III-V semiconductor layer 302, the higher the aluminum composition ratio, the faster the oxidation proceeds.
The whole is oxidized in the central part, but III-
The group V semiconductor layer 302 is left as it is. Also in the third embodiment, similarly to the second embodiment, the paragraph [001
The modified example described in [4] can be applied.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 4A is a sectional view of the layer structure of the first embodiment of the present invention. This example relates to an example of selectively oxidizing an AlInAs layer grown on an InP substrate.
MOVPE (Metalorganic Vapor Pha) is formed on the InP substrate 1.
Al _x In _1-x As layer 2 (thickness 1
00 nm) and the InP cap layer 3 (thickness 200 nm) are grown under the condition that the substrate temperature is 650 ° C. At this time, Al _x
As shown in FIG. 4B, the Al composition x of the In _1-x As layer is from 0 to 0.55 from the substrate to the center of the film, and from 0.55 to 0 from the film center to the surface. Grow continuously changing. The Al composition x of Al _x In _1-x As that is lattice-matched with the InP substrate is 0.48.
The compressive strain occurs in the portion where the Al composition x is less than 0.48,
A portion larger than 0.48 is subject to tensile strain.

As described above, when a region having a lattice constant larger than that of the substrate and a region having a lattice constant smaller than that of the substrate are grown, the compressive strain and the tensile strain are balanced with each other, so that good quality crystal growth is possible without using a lattice matching system. After the crystal growth, the sample in which the side surfaces of the Al _x In _1-x As layer are exposed by etching in a mesa shape using the resist patterned in the stripe shape as a mask is heat-treated in a high temperature and high humidity atmosphere to form Al _x In _{1 -x}
The As layer is selectively oxidized from the lateral direction. Figure 5 shows Al _x
FIG. 3 is a diagram showing a relationship between an Al composition and an oxidation rate when an In _1-x As layer (thickness: 50 nm) is oxidized at a temperature of 500 ° C. in a nitrogen gas atmosphere in which water at a temperature of 80 ° C. is bubbled.

As shown in FIG. 5, Al _x In _1-x A
The oxidation rate of the s layer largely depends on the Al composition. In particular,
If the Al composition is about 30% or less, the oxidation rate becomes very slow. Therefore, in the layer structure as shown in FIG. 4, Al _x In _1-x
Oxidation proceeds rapidly and strongly toward the center of the As layer.
As a result, the degree of oxidation gradually decreases from the center of the Al _x In _1-x As layer toward the interface, and the stress generated by the oxidation is dispersed over a wide range in the crystal growth direction, so InP / Al _x In Generation of cracks at the _1-x As interface is suppressed.

FIGS. 6 (a) and 6 (b) are a sectional view of the layer structure of the second embodiment of the present invention and an aluminum composition distribution chart thereof. Al was formed on the surface of the InP substrate 1 by the MOVPE method.
_0.20 In _0.80 As layer 4 (thickness 10 nm), Al _0.30 In
_0.70 As layer 5 (thickness 10 nm), Al _0.55 In _0.45 As
Layer 6 (thickness 100 nm), Al _0.30 In _0.70 As layer 7
(Thickness 10 nm), Al _0.20 In _0.80 As layer 8 (thickness 1
0 nm) and an InP cap layer 3 (thickness 200 nm) are sequentially grown.

After that, etching is performed in a mesa shape to form Al _x I.
n _1-x selectively oxidizing the Al _x In _1-x As layer laterally by As the sample side surface is exposed the layer is heat-treated in a high-temperature and high-humidity atmosphere Al _x In _1-x As selective oxidation Form an area. In this manner, a plurality of layers having different Al compositions are laminated in the order of increasing Al composition from the InP substrate 1 and in the opposite order toward the InP cap layer 3 and selectively oxidized in the lateral direction, which results after oxidation. Generation of cracks is suppressed by the stress being gradually dispersed at the interface of each layer.

7 (a) and 7 (b) are a sectional view of the layer structure of the third embodiment of the present invention and an aluminum composition distribution diagram thereof, respectively. The surface of the InP substrate 1 is In
_0.52 Ga _0.48 As layer 9 (thickness 10 nm), In _0.52 (G
a _y Al _1-y ) _0.48 As layer 10 (thickness 10 nm), Al
_0.48 In _0.52 As layer 11 (thickness 50 nm), In _0.52 (
Ga _y Al _1-y ) _0.48 As layer 12 (thickness 10 nm), In
_{A 0.52} Ga _0.48 As layer 13 (thickness 10 nm) and an InP cap layer 3 (thickness 200 nm) are sequentially grown. After that, the AlInAs oxide film is formed by selectively oxidizing in the lateral direction in a high temperature and high humidity atmosphere. In _0.52 (G
The composition y of a _y Al _1-y ) _0.48 As gradually decreases from 0.47 to 0. On the other hand, In _0.52 (Ga
_y Al _{1-y) 0.48} As composition y of gradually increases from 0 to 0.47. Since this structure is a lattice matching system with the InP substrate, there is no limitation on the film thickness for obtaining good quality crystal growth. When this structure is oxidized, the same effect as in the above embodiment can be obtained.

FIG. 8A is a sectional view of the layer structure of the fourth embodiment of the present invention. On the InP substrate 1, Al _0.48 In _0.52 As layer 14 (thickness 100 nm) and I were formed by MOVPE method.
The nP cap layer 3 (thickness 200 nm) is grown. A
When growing the _0.48 In _0.52 As layer 14, the molar ratio (V / III ratio) of the group V source and the group III source is shown in FIG.
As shown in FIG. 1, the substrate is grown while continuously changing from 300 to 50 from the center of the film and from 50 to 300 from the center of the film to the surface. InP on it
The cap layer 3 (thickness 200 nm) is grown. 9 Al _0.48 In _{0. 52} As layer 14 when the temperature 80 ° C. Water is oxidized in a nitrogen gas atmosphere was bubbled in the (thickness 100 nm) Temperature 500 ° C., the raw material gas supplied during the growth V / III It is a figure which shows the relationship between a ratio and an oxidation rate.

As shown in FIG. 9, Al _0.48 In _0.52
The oxidation rate of the As layer becomes slower as the V / III ratio increases. This is because the smaller the V / III ratio, the higher the density of V group vacancies in the film, and the easier the diffusion of oxygen when oxidized. Therefore, when the sample of FIG. 8 is laterally oxidized, the same effect as that of the first embodiment can be obtained.

FIG. 10A is a sectional view of the layer structure of the fifth embodiment of the present invention. MOVP on n-type InP substrate 15
Al _x In _1-x As layer 2 (thickness 100 nm) by E method
And InP pad layer 16 (thickness 30 nm) are grown.
At this time, the Al composition of the Al _x In _1-x As layer 2 is as shown in FIG.
As shown in (b), 0 to 0.55 from the substrate to the center of the film and 0.55 from the film center to the surface.
Grow continuously while changing from 0 to 0. After the growth, a SiO ₂ film is vapor-deposited on the surface, and stripe-shaped openings are formed in the SiO ₂ film.

Using the patterned SiO ₂ film as a mask, the central portion of the element is selectively etched with a mixed solution of HBr, hydrogen peroxide solution and pure water to form a current path portion. Then, using the SiO ₂ film mask, the first clad layer 17, the active layer 18, and the
The second cladding layer 19 is sequentially grown. After removing the SiO ₂ film mask, the InP buried layer 20 (thickness 2 μm
m), p-type InGaAs contact layer 21 (thickness 200
nm) is grown. Then, the side surface of the Al _x In _1-x As layer 2 is exposed by mesa etching to a temperature of 500 ° C.
In the above, the Al _x In _1-x As layer 2 is selectively oxidized in a nitrogen gas atmosphere in which pure water at a temperature of 80 ° C. is bubbled.

The oxidation rate of the Al _x In _1-x As layer 2 is Al
Oxidation proceeds slowly and weakly toward the interface of the Al _x In _1-x As layer 2 because it largely depends on the composition. As a result, the degree of oxidation gradually decreases from the center of the Al _x In _1-x As layer 2 toward the interface, and the stress generated by the oxidation is dispersed over a wide range in the crystal growth direction, so InP / Al _x Generation of cracks at the In _1-x As interface is suppressed. Therefore, by selectively oxidizing the Al _x In _1-x As layer 2, a crack-free oxide film current limiting layer can be formed. After the selective oxidation, the p-side electrode 22 and the n-side electrode 23 are formed on the front surface and the back surface of the substrate by vapor deposition and lift-off, and the reflective surface is formed by cleavage to complete the laser device of this embodiment.

FIG. 11A is a sectional view of the layer structure of the sixth embodiment of the present invention. In the sixth embodiment, the layer structure of the Al _x In _1-x As layer 2 in the fifth embodiment is changed to Al _0.48 In.
_{The 0.52} As layer 14 is replaced, and this layer is
As shown in FIG. 11B, the V / III ratio is continuously changed from 300 to 50 from the substrate to the center of the film, and from 50 to 300 from the center of the film to the surface. It was formed. Al _0.48
Since the In _0.52 As layer has a smaller oxidation rate as the V / III ratio increases, the same effect as in the fourth embodiment can be obtained by oxidizing this structure.

[0030]

As described above, the use of the layer structure of the present invention can suppress the occurrence of cracks at the interface when selectively oxidizing the compound semiconductor layer containing aluminum. Furthermore, the rate of oxidation and the quality of the oxide film can be easily controlled. Therefore, according to the present invention, it is possible to reliably provide an optical device having a simple manufacturing method and a simple layer structure.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a second embodiment of the present invention.

FIG. 3 is a diagram for explaining a third embodiment of the present invention.

FIG. 4 is a diagram for explaining the first embodiment of the present invention.

FIG. 5 is a graph showing the relationship between the Al composition of an Al _x In _1-x As layer and the oxidation rate.

FIG. 6 is a diagram for explaining a second embodiment of the present invention.

FIG. 7 is a diagram for explaining a third embodiment of the present invention.

FIG. 8 is a diagram for explaining a fourth embodiment of the present invention.

FIG. 9 is a diagram showing the relationship between the V / III ratio supplied during the growth of an Al _0.48 In _0.52 As layer and the oxidation rate.

FIG. 10 is a schematic cross-sectional view of a semiconductor laser having a current limiting layer of selectively oxidized Al _x In _1-x As layer.

FIG. 11 is a schematic sectional view of a semiconductor laser having a current limiting layer of selectively oxidized Al _0.48 In _0.52 As layer.

[Explanation of symbols]

1 InP substrate 2 Al _x In _1-x As layer 3 InP cap layer 4 Al _0.20 In _0.80 As layer 5 Al _0.30 In _0.70 As layer 6 Al _0.55 In _0.45 As layer 7 Al _0.30 In _0.70 As layer 8 Al _0.20 In _0.80 As Layer 9 In _0.52 Ga _0.48 As layer 10 In _0.52 (Ga _y Al _1-y ) _0.48 As layer 11 Al _0.48 In _0.52 As layer 12 In _0.52 (Ga _y Al _1-y ) _0.48 As layer 13 In _0.52 Ga _0.48 As layer 14 Al _0.48 In _0.52 As layer 15 n-type InP substrate 16 InP pad layer 17 first cladding layer 18 active layer 19 second cladding layer 20 InP buried layer 21 p-type InGaAs contact layer 22 p-side electrode 23 n-side electrode 101, 201 , 301 compound semiconductor substrate 102, 202, 302 III-V semiconductor layer 102a, 202a, 302a oxide film 103 cap layer 204, 304 Insulating films 205, 305 Mesa semiconductor layer

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-135564 (JP, A) JP-A-8-250801 (JP, A) JP-A-2000-147284 (JP, A) JP-A-2000-183461 ( JP, A) ELECTRONICS LETTE RS, July 18, 1996, Vol. 32, No. 15, pp. 1406-1408 (58) Fields investigated (Int.Cl. ⁷ , DB name) H01S 5/00-5/50 H01L 21/205

Claims (15)

(57) [Claims] 1. A III-V group semiconductor layer is formed on a semiconductor substrate, which comprises aluminum such that the composition ratio of aluminum in the lower layer is low and the composition ratio of the aluminum is gradually or gradually increased toward the upper layer. In the semiconductor device in which at least a part of the III-V semiconductor layer is oxidized ,
A semiconductor mesa having a group V semiconductor layer including an active layer.
A semiconductor device formed on a side surface of the semiconductor device. To 2. A semiconductor substrate, an aluminum, AlInAs layer comprises as its composition ratio the composition ratio lower portion toward the upper lower gradually or stepwise increase is formed, of the AlInAs layer A semiconductor device, wherein at least a part thereof is oxidized. 3. A semiconductor substrate containing aluminum such that its composition ratio is high in the vicinity of the central portion and the composition ratio gradually or gradually decreases toward the upper and lower layers.
A semiconductor device, wherein a III-V group semiconductor layer is formed, and at least a part of the III-V group semiconductor layer is oxidized. 4. A semiconductor substrate containing aluminum containing II
The I-V group semiconductor layer has a V group element vacancy (vacanc
y) The density is low, and the V group element vacancy density is gradually or stepwise increased toward the upper layer.
A semiconductor device in which at least a part of a -V semiconductor layer is oxidized. 5. II containing aluminum on a semiconductor substrate
The I-V group semiconductor layer is formed such that the V group element vacancy density is high near the central portion of the layer and the V group element vacancy density gradually or gradually decreases toward the upper and lower layers.
A semiconductor device, wherein at least a part of a III-V semiconductor layer is oxidized. 6. The semiconductor device according to claim 3 , wherein at least a portion of the III-V semiconductor layer having the highest aluminum composition ratio is entirely oxidized. 7. The semiconductor device according to claim 3 , wherein the III-V semiconductor layer is formed on a side surface of a semiconductor mesa including an active layer. 8. The III-V semiconductor layer is AlInA
claim, characterized in that it is formed by s 3 to 7
The semiconductor device according to any one of 1. 9. The III-V semiconductor layer has a bottom surface,
And / or its upper surface is an InGaAs layer or In
The semiconductor device according to claim 1, 2 or 8 further characterized in that formed in contact with the AlGaAs layer. 10. (1) A step of forming a III-V group semiconductor layer containing aluminum on a semiconductor substrate, (2) a step of patterning the III-V group semiconductor layer, and (3) the patterned pattern. And a step of oxidizing the III-V group semiconductor layer from a side surface, wherein the step (1) comprises:
The family semiconductor layer, (b) formed as the aluminum composition ratio is gradually or stepwise increased will then gradually or stepwise reduced, (ii) V group element vacancy density gradually or stepwise Which is formed so as to increase, or (c) the V group element vacancy density gradually or gradually increases and then the V group element vacancy density gradually or gradually decreases. A method for manufacturing a semiconductor device, which is formed under the above conditions. 11. A step of (1) forming a group III-V semiconductor layer containing aluminum on a semiconductor substrate, and (2) a group III-V semiconductor layer obtained by selectively etching the group III-V semiconductor layer. A step of forming an opening in the layer, (3) forming a mesa semiconductor layer including an active layer in the opening by selective epitaxial growth, and (4) placing the III-V group semiconductor layer on the side surface of the mesa semiconductor layer. a step of patterning so as to leave a portion in contact, (5) the patterned the III -V semiconductors layer includes a step of oxidizing the side surface, and said in the process of the (1), the III -V
Forming a group semiconductor layer such that the aluminum composition ratio gradually or gradually increases, forming so that the aluminum composition ratio gradually or gradually increases and thereafter gradually or gradually decreasing, group V Form so that the element vacancy density gradually or gradually increases, so that the V group element vacancy density gradually or gradually increases, and then the V group element vacancy density gradually or gradually decreases. The method for manufacturing a semiconductor device is characterized in that the semiconductor device is formed under any one of the conditions below. 12. A step of (1 ′) epitaxially growing a semiconductor layer including an active layer and patterning the same to form a mesa semiconductor layer, and (2 ′) III-V containing aluminum by selective epitaxial growth on the semiconductor substrate. Forming a group semiconductor layer so as to surround the mesa semiconductor layer; and (3 ') patterning the group III-V semiconductor layer selectively to leave a portion in contact with the side surface of the mesa semiconductor layer. a step, in the step (4 ') includes a patterned step of oxidizing the side surface of the III -V semiconductors layers, wherein the first (2'), the III -
A group V semiconductor layer is formed such that the aluminum composition ratio gradually or gradually increases, and an aluminum composition ratio gradually or gradually increases and then gradually or gradually decreases, V Forming so that the group element vacancy density gradually or gradually increases, the group V element vacancy density gradually or gradually increasing, and then the group V element vacancy density gradually or gradually decreasing A method for manufacturing a semiconductor device, characterized in that the semiconductor device is formed under any of the following conditions. 13. The semiconductor device according to claim 10, wherein the step (1) or the step (2 ′) is performed by a metal organic chemical vapor deposition (MOVPE) method. Production method. 14. The above (b) or (c) or the above
14. The method of manufacturing a semiconductor device according to claim 13 , wherein the method is performed by changing the ratio (V / III ratio) of the number of moles of the group V raw material to the number of moles of the group III raw material. The method according to claim 15 wherein the step of the oxidation, and performing in a nitrogen atmosphere was bubbled water claim 1
The method of manufacturing a semiconductor device according to any one of 0 to 12 .