JPH10190144A - Buried ridge type semiconductor laser and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a buried ridge type semiconductor laser which uses a semiconductor thin film containing Al as a buried layer at a high yield. SOLUTION: At the time of forming a ridge by utilizing the etching rate difference between a clad layer 104 of a second conductivity and an intermediate layer 105 of the second conductivity which occurs when the semiconductor materials or compositions of the layers 104 and 105 are made different from each other, the hood of the intermediate layer 105 is formed. A buried layer 106 containing Al can be prevented from being etched in a process for removing an oxide film mask by using HF or BHF by forming an area where the buried layer 106 does not grow due to the shadow effect of the hood of the layer 105 at the time of growing the buried layer 106. Therefore, the deterioration of the characteristics and yield of a buried ridge type semiconductor laser resulting from the coming-off of the buried layer 106 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a buried ridge type semiconductor laser and a method of manufacturing the same, and more particularly to a ridge type semiconductor laser having a semiconductor thin film containing Al as a buried layer and a method of manufacturing the same.

[0002]

BACKGROUND OF THE INVENTION In most applications of semiconductor lasers,
It is desirable that the transverse mode is a single mode and unimodal. To this end, as shown in FIG. 15, a structure in which a lateral mode is stabilized by a buried ridge structure is disclosed. FIG. 15 is an illustration of Electronics Letters (198
FIG. 7 is a lateral cross-sectional view of an AlGaInP-based red semiconductor laser reported in Vol. 23, pp. 938-939, in which a ridge is buried with GaAs 512 to provide a refractive index difference near the active layer 505. Locks landscape mode.

[0005] The AlGaInP red semiconductor laser shown in FIG. 15 has an oscillation wavelength of 630 to 690 nm.
It has been put to practical use as a light source for barcode readers and laser pointers. Further, at present, the light source for high-density optical disks is being put to practical use.

In order to manufacture the semiconductor laser having the buried ridge structure shown in FIG. 15, three epitaxial growths are required. First, a vertical structure is formed in the first growth, and then a stripe-shaped silicon oxide mask is formed. Is formed, and then GaAs 512 is selectively buried and grown so as to bury the ridge in the second growth. Then, after removing the silicon oxide mask, GaAs 5
13 can be formed by growing.

FIGS. 16A to 16E show a manufacturing process.
(1) An n-type GaAs buffer layer 502 is grown on an n-type GaAs substrate 501, and (2) an n-type AlGaI
An nP cladding layer 503 is grown, and (3) Ga
Growing an InP active layer 505, (4) growing an inner p-type AlGaInP cladding layer 506 thereon,
(5) growing an etching stop layer 507 thereon,
(6) An outer p-type AlGaInP cladding layer 5 thereon
06 is grown, and (7) a P-type GaAs cap layer 510 is further grown to form a double hetero (DH) structure substrate (FIG. 16A).

Next, a silicon oxide film 114 is deposited, and subsequently, the silicon oxide film 11 is formed by photolithography.
4 is processed into a stripe shape having a width of several μm (FIG. 16).
(B)).

Next, using the silicon oxide film 114 as a mask, the DH structure substrate is etched to form a ridge 520 (FIG. 16C).

Next, using the silicon oxide film 114 as a mask, an n-type GaAs buried layer 512 is selectively grown (FIG. 16D).

Next, after removing the silicon oxide film 114 with hydrofluoric acid (HF) or buffered hydrofluoric acid (BHF) (FIG. 16E), a p-type GaAs contact layer 513 is formed.
By growing AlGaIn shown in FIG.
A P-based red semiconductor laser is obtained.

However, in the AlGaInP red semiconductor laser shown in FIG. 15, the n-type GaAs selective burying layer 512 absorbs light of 630 to 690 nm, so that the optical loss in the waveguide increases and the external differential quantum efficiency decreases. There is a disadvantage that. Therefore, a structure using Al _0.5 In _0.5 P or Al _x Ga _{1 -x} As, which is transparent to a laser beam, for the buried layer has been proposed by the IEEE Journal of Technology.
Selected Topics in Quantum Electronics (1995, Vol. 1, pp. 723-727)
Has been reported to. FIG. 17 shows the laser structure.

On the other hand, InP-based long wavelength semiconductor lasers
However, instead of conventional InP as a selective burying layer,
Al_0.48In_0.52The structure using As is a journal
Bu Crystal Growth (1994, Vol. 145,
263-270). FIG.
The structure is shown. In a long wavelength semiconductor laser, InP is
Need to worry about waveguide loss to work as transparent waveguide
There is no. Rather, Al _0.48In_0.52As compared to InP
Current confinement due to large band cap
And has the advantage that leakage current can be reduced.
You.

[0012]

As described above, as described above, Al
A buried ridge structure using InP, AlGaAs, or AlInAs as a selective burying layer is important for improving the performance of a laser because it can perform high-efficiency laser oscillation and effective current confinement. However, AlInP and AlGaAs
Since the buried growth of s, AlInAs is regrowth on the ridge structure, there is a disadvantage that oxygen or carbon existing at the growth interface lowers the crystallinity of the buried layer.
Further, since the plane orientation of the side surface of the ridge is different from that of the substrate (001), when AlInP or AlInAs is buried and grown, the composition ratio of Al and In is different and lattice mismatch occurs. As a result, there is a disadvantage that the crystallinity on the side surface of the ridge is further reduced.

By the way, in the process of manufacturing the buried ridge structure, as shown in FIG. 16E, a step of removing the mask of the silicon oxide film with HF or BHF after selective burying growth is required. However, HF and BHF have an effect of etching an Al-based semiconductor thin film having poor crystallinity. Therefore, when a ridge structure in which a semiconductor thin film containing Al is buried is formed by the conventional structure / process shown in FIGS. 16A to 16E, AlInP or AlGaAs on the side surface of the ridge having poor crystallinity during HF or BHF processing. , AlInAs is disadvantageously etched.

That is, in the step of removing the silicon oxide film 114 having the ridge structure in which the semiconductor thin film 511 containing Al formed as shown in FIG.
The silicon oxide film 114 is removed by the action of the etching, and the semiconductor thin film 511 containing Al is also etched to have a shape as shown in FIG. As a result, laser oscillation and effective current confinement cannot be performed with high efficiency, and there is a disadvantage that the yield is reduced due to deterioration of laser characteristics.

An object of the present invention is to provide a buried ridge type semiconductor laser using a semiconductor thin film containing Al for a buried layer.
The goal is to provide a good yield.

[0016]

According to a first aspect of the present invention, there is provided a semiconductor laser having a first conductivity type clad layer, an active layer, and a second conductivity type clad layer having a ridge formed on a first conductivity type semiconductor substrate. In a semiconductor laser embedded with a semiconductor layer containing Al, the ridge has an intermediate layer of the second conductivity type, and the intermediate layer forms an eave structure in a transverse cross section.

According to a second aspect of the present invention, there is provided a semiconductor laser.
The semiconductor laser according to claim 1, wherein the active layer includes GaInP or AlGaInP or a quantum well thereof,
And the second conductivity type cladding layer are made of AlGaInP or
Containing AlInP, and the buried layer is made of AlInP or Al
Contains GaAs.

According to a third aspect of the present invention, there is provided a semiconductor laser.
In the semiconductor laser described above, the active layer includes GaAs or InGaAs or AlGaAs or a quantum well thereof, and the first and second conductivity type cladding layers are AlGaAs.
s, and the buried layer is AlInP or AlGaAs.
Contains.

According to a fourth aspect of the present invention, there is provided a semiconductor laser.
In the semiconductor laser described above, the active layer is made of InGaAsP.
, The first and second conductivity type cladding layers include InP, and the buried layer includes AlInAs.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a semiconductor laser, comprising the steps of: forming a first conductive type clad layer on a first conductive type semiconductor substrate;
Sequentially forming an active layer and a second conductivity type cladding layer including a second conductivity type intermediate layer to form a double hetero structure;
Depositing an insulating film on the second conductive type cladding layer and selectively etching the insulating film to form a stripe-shaped mask; and forming the second conductive type cladding layer in a ridge shape using the mask. And forming the second conductive intermediate layer in an eaves shape on the ridge, embedding the ridge with a semiconductor layer containing Al using selective growth, and removing the insulating film mask.

[0021]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a buried ridge type semiconductor laser of the present invention in a lateral direction.
(A)-(e) is sectional schematic drawing which showed the manufacturing method of this invention in process order.

In FIG. 1, a first conductive type semiconductor substrate 10
1, a first conductivity type cladding layer 102 and an active layer 10
3. A second conductivity type cladding layer 104 is formed. As for the shape of the cladding layer 104 of the second conductivity type, the upper part forms the ridge 110 in the vertical direction. A second conductivity type intermediate layer 105 is provided at an intermediate portion of the ridge 110, and the intermediate layer 1
05 is formed in an eave shape so as to project from the left and right side surfaces of the ridge 110 in a transverse cross section.

An Al-based buried layer 106 is formed below the lower root of the eave, and the buried layer 106 is formed so as to be thinner and gradually thicker downward at the lower root of the eave, and further to have a second conductive layer. It covers the lower upper surface of the mold cladding layer 104.

A first conductivity type current blocking layer 107 is provided above the buried layer 106 with a gap from the ridge 110, and a second conductivity type contact layer 108 is further provided thereabove.
Are formed so as to cover the upper part of the ridge 110 including the intermediate layer 105 of the second conductivity type and the current blocking layer 107 of the first conductivity type, thereby forming a buried ridge type semiconductor laser.

Next, a method of manufacturing a buried ridge type semiconductor laser according to the present invention will be described with reference to FIGS. First, a first conductivity type cladding layer 102, an active layer 103, an inner second conductivity type cladding layer 104, a second conductivity type intermediate layer 105, and an outer second conductivity type cladding layer are formed on a first conductivity type semiconductor substrate 101. The crystals 104 are sequentially grown to form a double heterostructure (FIG. 2A).

Next, the outer second conductivity type cladding layer 104 is formed.
An insulating film 114 is deposited thereon, and the insulating film is selectively etched in the vertical direction to form a stripe-shaped mask (FIG. 2B).

The etching rate of the second conductive type cladding layer 104 and the second conductive type intermediate layer 105 can be changed by previously changing the material and composition of the two. Therefore, the second conductivity type cladding layer 104 and the second conductivity type intermediate layer 1 are formed using the insulating film 114 as a mask.
When the ridge 110 is formed by selectively etching the second conductive type 05 and the second conductive type intermediate layer 105, the materials and compositions of the two are set in advance so that the etching rate of the second conductive type cladding layer 104 is lower than that of the second conductive type cladding layer 104. Set it.

The ridge 110 is formed by selectively etching the second conductivity type cladding layer 104 and the second conductivity type intermediate layer 105 using the insulating film 114 as a mask for the double hetero structure formed as described above. . Since the etching rate of the second conductivity type intermediate layer 105 is low at the time of etching, eaves are formed to protrude laterally on both side surfaces of the ridge 110 formed by the second conductivity type cladding layer 104 (FIG. 2).
(C)).

Next, using the insulating layer 114, the buried layer 106 of the semiconductor containing Al and the first conductivity type current blocking layer 1 are formed.
07 is continuously and selectively grown. Here, the second conductivity type intermediate layer 105 serves as an eave, and a thin area or a non-growing area of the buried layer 106 is formed at the base of the intermediate layer 105 by the eaves shadow effect (FIG. 2).
(D)).

Next, the insulating film 114 is removed by dipping in an HF or BFH solution. At this time, the buried layer 106 containing Al is also subjected to the etching action and is etched above the eaves, but the portion of the buried layer 106 below the eaves formed by the second conductivity type intermediate layer 105 is
Since the buried layer 106 is thin or has not grown, the etching remains without progress (FIG. 2E).

Thus, the semiconductor thin film 1 containing Al
A buried ridge-type semiconductor laser having the buried layer 06 as shown in FIG. 1 can be manufactured with a high yield.

[Embodiment 1] FIGS. 3 to 8 show an AlGaInP having an Al _0.5 In _0.5 P buried layer according to the present invention.
FIG. 3 is a schematic cross-sectional view showing a process of an example of a red semiconductor laser. The laser is three times metalorganic vapor phase epitaxy (MOVP
It is produced by the method E). AlGaInP, A as raw material
For growth of lInP and GaInP, trimethyl aluminum (TMAl), triethyl gallium (TEGa), trimethyl indium (TMIn), phosphine (PH
₃₎ used, the GaAs growth, using trimethyl gallium (TMGa) and arsine (AsH _3). Also,
For the n-type and p-type dopants, disilane (Si ₂ H
₆ ) and diethylzinc (DEZn). The growth temperature was 660 ° C., and the growth pressure was 70 torr. The growth rate is 1.8 μm for AlGaInP, AlInP, and GaInP.
/ Hr, GaAs was 4.5 μm / hr.

The steps will be described below with reference to FIGS.
However

[Drawing] and

[Explanation of symbols]

 In the column, of the elements constituting each crystal described below
The composition is omitted. First, the n-type GaAs substrate 301 is
After cleaning the surface by etching with a sulfuric acid solution, the MO
The n-type GaAs buffer layer 30 is set in a VPE reaction tube.
2, n-type (Al_{0. 7} Ga_0.3 )_0.5 In_0.5 P clad
Layer 303, non-doped (Al_0.5 Ga_0.5)_0.5 In_0.5
 P light guide layer 304, active layer 305, non-doped (A
l_0.5 Ga _0.5 )_0.5.In_0.5 P light guide layer 304, p
Type (Al_0.7 Ga_0.3 )_0.5 In_{0. Five} P clad layer 30
6, etching stop layer 307, p-type Ga_0.5 In_o.5 P
Hetero buffer layer 309, p-type GaAs cap layer 31
0 is sequentially grown to obtain a heterostructure (FIG. 3).

Next, the reaction tube is taken out of the reaction tube and subjected to thermal CVD (40
(0 ° C.) to deposit silicon oxide to a thickness of 0.3 μm.
Then, this silicon oxide is etched into a stripe shape having a width of 4 μm by a photolithography technique to form a silicon oxide mask 114 (FIG. 4).

Next, using the silicon oxide mask 114 as a mask, the p-type GaAs cap layer 310 and the p-type Ga _0.5
In _0.5 P hetero buffer layer 309, p-type (Al _0.7 G
selectively etching a _{0. 3) 0.5} In _0.5 P cladding layer 306 to the etch stop layer 307. Where p
Mold (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 30
By increasing the side etching amount of No. 6, p
-Type GaAs cap layer 310 and p-type Ga _0.5 In
The _0.5 P hetero buffer layer 309 can be formed ridge structure and eaves (Fig. 5).

The substrate was placed in the reaction tube again, and the silicon oxide was
N-type Al _0.5 In_0.5 P fill
Embedded layer 311 and n-type GaAs current block layer 312
Selectively grow continuously. Here, p-type Ga_0.5 In_0.5 
The P hetero buffer layer 309 functions as an eaves,
N-type Al_0.5 In_0.5 P buried layer
The very thin region of 311 is p-type Ga_0.5 In_0.5 P
It is formed at the base of the Telova afa layer 309 (FIG. 6).

Thereafter, the silicon oxide mask 114 is taken out of the reaction tube and removed by dipping it in a HF or BHF solution. At this time, the etching stops below the p-type Ga _0.5 In _0.5 P hetero-buffer layer 309 because the n-type Al _0.5 In _0.5 P buried layer 311 is thin. as a result,
The n-type Al _0.5 In _0.5 P buried layer 311 below the p-type Ga _0.5 In _0.5 P hetero buffer layer 309 remains without being etched (FIG. 7).

The p-type GaAs contact layer 313 is grown in the reaction tube again, and the AlInP
An AlGaInP-based red laser of No. 11 is formed (FIG. 8). When the cross section of the laser thus formed was observed with a scanning electron microscope, the embedded AlIn
It was confirmed that the P layer 311 remained without being etched below the eaves. From the evaluation of the laser characteristics (threshold current, external differential quantum efficiency), the yield was remarkably improved from about 10% to 70% or more of the related art.

[Embodiment 2] FIGS. 9 to 14 show AlGaAs having a buried layer of Al _0.6 Ga _0.4 As according to the present invention.
It is a cross-sectional schematic diagram which shows the process of the Example of an s-system short wavelength semiconductor laser. The laser is three times metalorganic vapor phase epitaxy (MOVP
It is produced by the method E). Raw materials include trimethyl aluminum (TMAl) and trimethyl gallium (TMG).
a), trimethylindium (TMIn) and arsine (AsH ₃ ) were used. Silane (SiH ₄ ) and diethylzinc (DEZ) are used as n-type and p-type dopants.
n) was used. The growth temperature is 720 ° C and the growth pressure is 70t
orr. The growth rate was 2.0 μm /
hr and GaAs were 4.5 μm / hr.

The steps will be described below with reference to FIGS.

[Drawing] and

[Explanation of symbols]

 Omission of the composition of each element in the column is the same as in Example 1.
It is like. First, an n-type GaAs substrate 401 is placed on a sulfuric acid-based solution.
MOVPE reaction after cleaning the surface by etching
N-type GaAs buffer layer 402, n-type A
l_0.4 Ga_0.6 As clad layer 403, non-doped Al
_0.15Ga_0.85As light guide layer 404, active layer 405,
Doped Al_0.15Ga_0.85As light guide layer 404, p-type
Al_0.4 Ga _0.6 As cladding layer 406, etching stop
Stop layer 407, p-type Al_0.9 Ga_0.1 As intermediate layer 408,
A p-type GaAs cap layer 410 is sequentially grown to form a heterostructure.
Obtain the structure (FIG. 9).

Next, it is taken out of the reaction tube and subjected to thermal CVD (40
(0 ° C.) to a thickness of 0.1 μm. Then, the silicon oxide is etched into a stripe shape having a width of 6 μm by a photolithography technique to form a silicon oxide mask 114 (FIG. 10).

Next, the silicon oxide mask 114 is masked.
P-type GaAs cap layer 410, p-type Al_0.4 
Ga_0.6 As clad layer 406, p-type Al_0.9 Ga_0.1 
The As intermediate layer 408 is selectively etched. here,
p-type Al_0.4 Ga_0.6 As clad layer 406 and p-type A
l_0.9 Ga_0.1.The Al composition is different from that of the As intermediate layer 408.
Therefore, the etching rate is different. Using this property, p
Type Al_0.4 Ga_0.6 Side edge of As clad layer 406
By increasing the amount of ting, p-type Al _0.9 Ga
_0.1 Form ridge structure with As intermediate layer 408 as eaves
(FIG. 11).

The substrate was placed in the reaction tube again, and the silicon oxide was
N-type Al _0.6 Ga_0.4 As buried
Embedded layer 411 and n-type GaAs current blocking layer 412
Is continuously and selectively grown. Here, p-type Al_0.9 Ga
_0.1 The As intermediate layer 408 serves as an eave and its shadow
N-type Al_0.6 Ga_0.4 As buried layer 4
11 very thin regions are p-type Al_0.9 Ga_0.1 As
It is formed at the base of the interlayer 408 (FIG. 12).

Thereafter, the silicon oxide mask 114 is taken out of the reaction tube and immersed in an HF or BHF solution and removed. At this time, the p-type Al _0.9 Ga _0.1 As intermediate layer 408
In the lower part of the eave, the etching is stopped because the n-type Al _0.6 Ga _0.4 As buried layer 411 is thin. As a result, the n-type Al _0.6 Ga _0.4 As buried layer 411 below the p-type Al _0.9 Ga _0.1 As intermediate layer 408 remains without being etched (FIG. 13).

The substrate is placed again in the reaction tube, and the p-type GaAs contact layer 413 is grown to obtain the structure shown in FIG.

[0046]

As described above, in the ridge-embedded semiconductor laser and the method of manufacturing the same according to the present invention, by forming a ridge structure having an eaves, Al is removed in the step of removing the silicon oxide film by HF or BHF. Since the selective buried layer including the buried layer can be prevented from being etched by HF or BHF, a ridge-buried semiconductor laser using an Al-based semiconductor thin film for the buried layer can be used.
There is an effect that it can be manufactured with a high yield.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a structure of a semiconductor laser of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating a method of manufacturing a semiconductor laser according to the present invention in the order of steps.

FIG. 3 shows AlInP embedded A shown in Example 1 of the present invention.
It is a cross-sectional schematic diagram which shows one process of a manufacturing process order of 1GaInP-type red semiconductor laser.

FIG. 4 shows AlInP embedded A shown in Example 1 of the present invention.
It is a cross-sectional schematic diagram which shows one process of a manufacturing process order of 1GaInP-type red semiconductor laser.

FIG. 5 shows an AlInP embedded A shown in Example 1 of the present invention.
It is a cross-sectional schematic diagram which shows one process of a manufacturing process order of 1GaInP-type red semiconductor laser.

FIG. 6 shows AlInP embedded A shown in Example 1 of the present invention.
It is a cross-sectional schematic diagram which shows one process of a manufacturing process order of 1GaInP-type red semiconductor laser.

FIG. 7 shows AlInP embedded A shown in Example 1 of the present invention.
It is a cross-sectional schematic diagram which shows one process of a manufacturing process order of 1GaInP-type red semiconductor laser.

FIG. 8 shows AlInP embedded A shown in Example 1 of the present invention.
It is a cross-sectional schematic diagram which shows one process of a manufacturing process order of 1GaInP-type red semiconductor laser.

FIG. 9 is a schematic cross-sectional view showing one step in a manufacturing order of the AlGaAs-embedded AlGaAs-based short-wavelength semiconductor laser according to the second embodiment of the present invention.

FIG. 10 is a schematic cross-sectional view showing one step in a manufacturing process order of the AlGaAs-embedded AlGaAs-based short-wavelength semiconductor laser according to the second embodiment of the present invention.

FIG. 11 is a schematic cross-sectional view showing one step in a manufacturing order of the AlGaAs-embedded AlGaAs-based short-wavelength semiconductor laser according to the second embodiment of the present invention.

FIG. 12 is a schematic cross-sectional view showing one step in a manufacturing order of the AlGaAs-embedded AlGaAs-based short-wavelength semiconductor laser according to the second embodiment of the present invention.

FIG. 13 is a schematic cross-sectional view showing one step in a manufacturing order of the AlGaAs-embedded AlGaAs-based short-wavelength semiconductor laser according to the second embodiment of the present invention.

FIG. 14 is a schematic cross-sectional view showing one step in a manufacturing order of the AlGaAs-embedded AlGaAs-based short-wavelength semiconductor laser according to the second embodiment of the present invention.

FIG. 15 shows GaAs-embedded AlGa according to the prior art.
FIG. 2 is a schematic cross-sectional view illustrating a structure of an InP-based red semiconductor laser.

FIG. 16 shows a GaAs-embedded AlGaI shown in FIG.
6 is a schematic cross-sectional view of an nP-based red semiconductor laser in a manufacturing process order.

FIG. 17 shows an AlInP-embedded AlG according to a conventional technique.
1 is a schematic lateral cross-sectional view showing the structure of an aInP-based red semiconductor laser.

FIG. 18 shows an AlInAs embedded In according to the prior art.
It is a transverse cross section schematic diagram showing the structure of a P system long wavelength semiconductor laser.

FIG. 19 is a schematic cross-sectional view showing a step of removing a silicon oxide mask of an AlGaInP-based red semiconductor laser embedded with AlInP by a conventional manufacturing method.

[Explanation of symbols]

Reference Signs List 101 First conductivity type substrate 102 First conductivity type cladding layer 103 Active layer 104 Second conductivity type cladding layer 105 Second conductivity type intermediate layer 106 Al-based buried layer 107 First conductivity type current blocking layer 108 Second conductivity type contact layer 110,520 Ridge 114 Silicon oxide mask / insulating film 301,401,501,701 n-type GaAs substrate 302,402,502 n-type GaAs buffer layer 303,503,703 n-type AlGaInP cladding layer 304 n-type AlGaInP optical guide layer 305 , 405, 505, 705 Active layer 306, 506, 706 p-type AlGaInP cladding layer 307, 407, 507 Etching stop layer 309, 709 p-type GaInP heterobuffer layer 310, 410, 510, 710 P-type GaAs cap layer 311 11,711 n-type AlInP buried layer 312,412,512,712 n-type GaAs current blocking layer 313,413,513,713 p-type GaAs contact layer 403 n-type AlGaAs cladding layer 404 n-type AlGaAs optical guide layer 406 p-type AlGaAs Clad layer 408 p-type AlGaAs intermediate layer 411 n-type AlGaAs buried layer 801 n-type InP substrate 802 active layer 803 AlInAs / InP buried layer 804 n-type InP current block layer 805 p-type InP clad layer 806 p-type InGaAs contact layer

Claims (5)

[Claims] A semiconductor laser in which a first conductivity type clad layer, an active layer, and a second conductivity type clad layer having a ridge are formed on a first conductivity type semiconductor substrate, and the ridge is embedded with a semiconductor layer containing Al. 5. The semiconductor laser according to claim 1, wherein the ridge includes a second conductivity type intermediate layer, and the intermediate layer forms an eaves structure in a transverse cross section. 2. The method according to claim 1, wherein the active layer is GaInP or AlG.
aInP or a quantum well thereof, wherein the first and second conductivity type cladding layers are made of AlGaInP or Al
InP, wherein the buried layer is AlInP or Al
2. The semiconductor laser according to claim 1, comprising GaAs. 3. The method according to claim 1, wherein the active layer is GaAs or InGa.
As or AlGaAs or a quantum well thereof, wherein the first and second conductivity type cladding layers are made of AlGaAs.
Wherein the buried layer is made of AlInP or AlGa
2. The semiconductor laser according to claim 1, comprising As. 4. The semiconductor laser according to claim 1, wherein said active layer includes InGaAsP, said first and second conductivity type cladding layers include InP, and said buried layer includes AlInAs. 5. A step of sequentially forming a first conductivity type clad layer, an active layer, and a second conductivity type clad layer including a second conductivity type intermediate layer on a first conductivity type semiconductor substrate to form a double hetero structure. Depositing an insulating film on the second conductivity type cladding layer and selectively etching the insulating film to form a stripe-shaped mask; and using the mask to form the second conductivity type cladding layer. Forming the second conductive type intermediate layer in an eaves-like shape in the ridge, embedding the ridge in the semiconductor layer containing Al using selective growth, and forming the insulating film mask. And a step of removing the semiconductor laser.