JP2007266255A - Semiconductor laser element and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing it in a simplified process, and to provide a high-output semiconductor laser element of which COD is suppressed. <P>SOLUTION: A first clad layer 3, an active layer 4, a second clad layer 5, an etching stop layer 6, a third clad layer 7, and a contact layer 8 are sequentially stacked on a semiconductor substrate 1. The third clad layer and the contact layer are selectively etched to form a ridge 14. On the ridge and the etching stop layer, an insulating layer 18, extending in stripe in the direction almost orthogonal with respect to the extending direction of the ridge, is formed. With the insulating layer as a mask, the contact layer is selectively etched, and with the insulating layer as a mask, impurities are selectively diffused to form an impurity diffusion region, and removing the insulating layer on the ridge. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a semiconductor laser device and a semiconductor laser device, and more particularly to a method of manufacturing an edge emitting semiconductor laser device and a semiconductor laser device.

The semiconductor laser element is used for recording / reproduction of video, music, and other digital information as well as optical communication. In particular, a high-power semiconductor laser element of, for example, 30 mW or more is used as a writing light source for an optical disk drive. Further, as a high-power semiconductor laser element, an edge emitting semiconductor laser element is usually used.
However, a high-power semiconductor laser element is likely to cause optical damage called COD (Catastrophic Optical Damage), and this optical damage causes a problem that the reliability of the semiconductor laser element is lowered. .

This COD is generated when the vicinity of the resonator surface of the active layer is an absorption region for the laser light generated in the active layer inside the device.
Usually, in a manufacturing process of a semiconductor laser element, a semiconductor wafer that has undergone a predetermined process is cleaved to obtain a plurality of semiconductor laser elements whose cleaved surfaces are resonator surfaces. At that time, since cleavage is performed in the atmosphere, the vicinity of the surface including the resonator surface reacts with oxygen in the atmosphere and is oxidized.
Since the band gap of the active layer in the oxidized region is narrower than the band gap of the active layer inside the non-oxidized element, it becomes a laser light absorption region. For this reason, when laser oscillation occurs, the temperature of the oxidized active layer in the active region rises, and this temperature rise further narrows the band gap of the oxidized active layer in the active region, thereby absorbing laser light. Increasingly more likely. As a result, the temperature of the oxidized active layer in the active region continues to rise, and finally the cavity surface melts and the semiconductor laser device is destroyed.

  As a method of suppressing the generation of COD, the active layer in the vicinity of the resonator surface of the active layer in the semiconductor laser device is disordered so that the band gap in the vicinity of the resonator surface of the active layer is wider than the active layer inside the device. There is a way to do it. An example of a semiconductor laser element having a window structure that reduces absorption of laser light in the vicinity of the resonator surface by this method is described in Patent Document 1.

According to the description of Patent Document 1, the Zn concentration of the second p-type cladding layer is set to a high concentration of 5E18 cm ⁻³ or more, and before forming the ridge, Zn is formed in the vicinity of the surface including the resonator surface. It is said that COD generation can be suppressed by diffusing and disordering the vicinity of the surface including the resonator surface in the active layer.
JP 2004-288894 A

However, in the method of manufacturing a semiconductor laser device as described in Patent Document 1, before the ridge is formed, Zn diffusion is performed to disorder the resonator surface of the active layer and the region in the vicinity thereof. Annealing must be performed.
In addition, the etching stop layer is also disordered by this annealing and mixed with the adjacent cladding layer, and the etching resistance of the etching stop layer may be deteriorated.
When the etching resistance deteriorates, it becomes difficult to stop the etching with the etching stop layer when forming the ridge, so that a part of the cladding layer may be etched.
The semiconductor laser device in which a part of the cladding layer is etched in this way has a problem that the laser characteristics are deteriorated, for example, the light emission efficiency is lowered, depending on the degree of the removal.

  In addition, in the method of manufacturing a semiconductor laser device as described in Patent Document 1, since the process for disordering the resonator surface of the active layer and the region in the vicinity thereof is complicated, the process can be simplified. It is desired.

  Therefore, the problem to be solved by the present invention is to provide a method for manufacturing a semiconductor laser device in which a high-power semiconductor laser device in which COD is suppressed is manufactured by simplifying the process. An object of the present invention is to provide an output semiconductor laser device.

In order to solve the above problems, each invention of the present application has the following means.
1) End-emitting semiconductor laser device (50) having a pair of resonator surfaces (Aa, Ba) parallel to each other and impurity diffusion regions (Za, Zb) formed in the vicinity of each resonator surface. In the method of manufacturing a semiconductor laser device for manufacturing a semiconductor device, at least a first conductive type first cladding layer (3), an active layer (4), and a second conductive type are formed on a first conductive type semiconductor substrate (1). A second conductive type cladding layer (5), a second conductive type etching stop layer (6), a second conductive type third cladding layer (7), and a second conductive type contact layer (8) are sequentially stacked. A laminating step, and a ridge forming step of forming a substantially parallel stripe-shaped second conductivity type ridge (14) having a predetermined interval by selectively etching the third cladding layer and the contact layer; The ridge and the etch An insulating layer forming step of forming a substantially parallel striped insulating layer (18) having a predetermined interval on the stop layer so as to extend in a direction substantially perpendicular to the direction in which the ridge extends; A contact layer removing step of selectively etching the contact layer left in the ridge forming step while leaving the range where the insulating layer is formed using the insulating layer as an etching mask; and impurity diffusion of the insulating layer Diffusion using the mask as a mask, selectively diffusing impurities from the ridge side in the direction opposite to the stacking direction, leaving the region where the insulating layer is formed, and using the region where the impurities are diffused as the impurity diffusion region A method of manufacturing a semiconductor laser device, comprising: a step; and a removing step of removing the insulating layer on the ridge.
2) End-emitting semiconductor laser device (50) having a pair of parallel resonator surfaces (Aa, Ba) and impurity diffusion regions (Za, Zb) formed in the vicinity of the resonator surfaces. 1, a first conductivity type semiconductor substrate (1), a first conductivity type first cladding layer (3) stacked on the semiconductor substrate, and an active layer (4) stacked on the first cladding layer. ), A second conductivity type second clad layer (5) laminated on the active layer, and the second clad layer formed on the second clad layer so as to extend in a direction perpendicular to the respective resonator surfaces. A ridge (14) of the second conductivity type, an insulating layer (18) formed by leaving the range where the ridge is formed on the second cladding layer and the range of each resonator surface and the vicinity of the surface; The ridge includes a third clad layer (7) of the second conductivity type and the third clad layer. And a second conductive type contact layer (8) formed on the resonator layer leaving the surface of each resonator and the vicinity of the surface, and the first cladding layer, the active layer, and the second cladding layer , And the third cladding layer has the impurity diffusion region in each resonator face and in the vicinity of the face.
3) Edge-emitting semiconductor laser device (100) having a pair of mutually parallel resonator surfaces (Ab, Bb) and impurity diffusion regions (Zc, Zd) formed in the vicinity of the resonator surfaces. In the method of manufacturing a semiconductor laser device for manufacturing a semiconductor device, at least a first conductivity type first cladding layer (3), an active layer (4), and a second conductivity type are formed on a first conductivity type semiconductor substrate (1). A laminating step of sequentially laminating the second clad layer (5) of the conductive type, and a ridge for forming the second conductive type ridge (61) in a substantially parallel stripe shape having a predetermined interval on the second clad layer. Forming a current confinement layer (65) on the second cladding layer so as to fill the step of the ridge, and forming a current confinement layer (65) on the current confinement layer and the ridge; , Second conductivity type contact layer (6 And a substantially parallel striped insulating layer having a predetermined interval so as to extend on the contact layer in a direction substantially orthogonal to the direction in which the ridge extends. An insulating layer forming step of forming (69), a contact layer removing step of selectively etching the contact layer while leaving the range where the insulating layer is formed using the insulating layer as an etching mask, and the insulating Using the layer as an impurity diffusion mask, the impurity is selectively diffused from the ridge side to the middle of the first cladding layer in the direction opposite to the stacking direction, leaving the range where the insulating layer is formed. A semiconductor laser device manufacturing method, comprising: a diffusion step of using a diffused region as the impurity diffusion region; and a removal step of removing the insulating layer on the ridge. It is the law.
4) End-emitting semiconductor laser device (100) having a pair of resonator surfaces (Ab, Bb) parallel to each other and impurity diffusion regions (Zc, Zd) formed in the vicinity of each resonator surface. 1, a first conductivity type semiconductor substrate (1), a first conductivity type first cladding layer (3) stacked on the semiconductor substrate, and an active layer (4) stacked on the first cladding layer. ), A second conductivity type second clad layer (5) laminated on the active layer, and the second clad layer formed on the second clad layer so as to extend in a direction perpendicular to the respective resonator surfaces. A second conductivity type ridge (61), a first conductivity type current confinement layer (65) formed on the second clad layer so as to fill the step of the ridge, and the current confinement layer and the ridge The second conductivity type contour formed by leaving the resonator surfaces and the range in the vicinity of the surfaces. A first layer, an active layer, and a second clad, and an insulating layer (69) formed on the contact layer, leaving a range where the ridge is formed. The layer, the ridge, and the current confinement layer have the impurity diffusion regions in the resonator surfaces and in the vicinity of the surfaces.

  According to the present invention, in the method of manufacturing a semiconductor laser device, the process of the high output semiconductor laser device in which COD is suppressed is simplified by the procedure described in the above item 1) and the procedure described in the item 3). There is an effect that it is possible to manufacture by manufacturing.

  In addition, according to the present invention, in the semiconductor laser device, the configuration described in the above item 2) and the configuration described in the item 4) can obtain a high-power semiconductor laser device in which COD is suppressed. Play.

  The preferred embodiments of the present invention will be described with reference to FIGS.

First, the first embodiment will be described as steps A1 to A8 with reference to FIGS.
1 to 8 are perspective views for explaining steps A1 to A8 in the first embodiment of the semiconductor laser device and the manufacturing method thereof according to the present invention.

<First embodiment>
In the n-type substrate 1 described below, a plurality of semiconductor laser elements 50 are formed in a matrix, and a plurality of single semiconductor laser elements 50 can be obtained by cleaving and dividing the n-type substrate 1 at a predetermined interval. Although possible, in FIG. 1 to FIG. 8, the structure of the single semiconductor laser element 50 is shown from the beginning of the process for easy understanding of the description.

(Step A1) [See FIG. 1]
On an n-type substrate 1 made of GaAs, an n-type clad layer 3 made of AlGaAs 3, an active layer 4, a first p-type clad layer 5 made of AlGaAs, an etching stop layer 6, and a second p-type clad layer made of AlGaAs 7 and a p-type contact layer 8 made of GaAs are sequentially stacked by, for example, metal organic vapor phase epitaxy (MOVPE).
The etching stop layer 6 is provided so that the first p-type cladding layer 5 which is the lower layer is not damaged by etching due to etching for forming a ridge 14 described later.

Next, a SiO ₂ (silicon dioxide) film 10 is formed on the entire surface of the p-type contact layer 8 by, for example, sputtering.
Thereafter, the SiO ₂ film 10 is selectively etched by a photolithographic method, so that the etching mask layer 12 extending in a direction orthogonal to the surfaces to be the resonator surfaces Aa and Ba is formed in a substantially parallel stripe shape. A plurality are formed. FIG. 1 shows one of the plurality of etching mask layers 12 formed.
Here, the resonator surface Aa indicates the entire right side surface in FIG. 1, the resonator surface Ba indicates the entire side surface opposite to the resonator surface Aa, and the resonator surface Aa, the resonator surface Ba, Are parallel to each other.

(Process A2) [Refer to FIG. 2]
By etching the second p-type cladding layer 7 and the p-type contact layer 8 corresponding to the range not protected by the etching mask layer 12, that is, the range where the p-type contact layer 8 is exposed, the second p-type contact layer 8 is etched. A plurality of ridges 14 composed of the mold cladding layer 7 and the p-type contact layer 8 are formed in a substantially parallel stripe shape having a predetermined interval. FIG. 2 shows one of the plurality of ridges 14 formed.
Thereafter, the etching mask layer 12 is removed.

  At this stage, the etching stop layer 6 has sufficient etching resistance because annealing that deteriorates the etching resistance is not performed. Therefore, the etching described above can be accurately stopped by the etching stop layer 6, so that the lower first p-type cladding layer 5 can be prevented from being etched by this etching.

(Step A3) [Refer to FIG. 3]
A SiO ₂ film 16 is formed by sputtering, for example, so as to cover the ridge 14 and the etching stop layer 6 exposed in the A2 step.
Next, the SiO ₂ film 16 is selectively etched by a photolithographic method so that the ridge 14 and the etching stop layer 6 corresponding to the range in the vicinity of the surfaces serving as the resonator surfaces Aa and Ba are exposed, and the etching mask layer 18. And

(Step A4) [Refer to FIG. 4]
The p-type contact layer 8 corresponding to a range not protected by the etching mask layer 18, that is, a range in the vicinity of the surfaces to be the resonator surfaces Aa and Ba, is etched with, for example, an ammonia hydrogen peroxide solution.
The reason for etching the p-type contact layer 8 corresponding to the range in the vicinity of the resonator surfaces Aa and Ba will be described later.

(Step A5) [Refer to FIG. 5]
A diffusion source layer 20, which is a mixed crystal film of ZnO (zinc oxide) and SiO ₂ , is formed so as to cover the etching mask layer 18, the etching stop layer 6, and the second p-type cladding layer 7 exposed by the A4 process. To do.

(Step A6) [Refer to FIG. 6]
By annealing the n-type substrate 1 that has undergone the A5 process, the diffusion source layer 20 moves toward the n-type substrate 1 side, passes through the etching stop layer 6 and the active layer 4, and reaches the middle of the n-type cladding layer 3. In the region, Zn (zinc) in the diffusion source layer 20 is diffused as an impurity.
During this diffusion, the etching mask layer 18 also functions as a diffusion mask. Therefore, the second p-type cladding layer 7, the etching stop layer 6, and the first p-type corresponding to the range where the etching mask layer 18 is formed. The aforementioned Zn does not diffuse into the cladding layer 5, the active layer 4, and the n-type cladding layer 3.
Therefore, due to this diffusion, the second p-type cladding layer 7, the etching stop layer 6, the second region corresponding to the range not protected by the etching mask layer 18, that is, the range in the vicinity of the surface to be the resonator surfaces Aa and Ba. Zn is diffused into the p-type cladding layer 5, the active layer 4, and the n-type cladding layer 3 of 1 to form impurity diffusion regions Za and Zb.
In FIG. 5, the impurity diffusion regions Za and Zb are shown in a shaded range for easy understanding.

  Also, annealing conditions are set so that the active layer 4 in the impurity diffusion regions Za and Zb is sufficiently disordered by this annealing. In order for the active layer 4 in the impurity diffusion regions Za and Zb to be sufficiently disordered, it is only necessary to increase the annealing temperature or lengthen the annealing time to further diffuse Zn as an impurity in the active layer 4. . In the first example, the annealing temperature was about 625 ° C. and the annealing time was about 20 minutes.

This annealing condition is not limited to the present embodiment.
As a result of intensive studies by the inventors, the difference between the photoluminescence wavelength of the active layer 4 in the impurity diffusion regions Za and Zb and the photoluminescence wavelength of the active layer 4 in regions other than the impurity diffusion regions Za and Zb is 40 nm or more. For example, it has been found that the active layer 4 in the impurity diffusion regions Za and Zb is sufficiently disordered.
Therefore, the annealing conditions may be set so that the above-described difference in photoluminescence wavelength is 40 nm or more. Specifically, the above-described difference in photoluminescence wavelength can be increased by increasing the annealing temperature or increasing the annealing time. However, when the annealing temperature exceeds 800 ° C., Zn diffusion from the first p-type cladding layer 5 adjacent to the active layer 4 to the active layer 4 occurs, and the active layer 4 in regions other than the impurity diffusion regions Za and Zb also There is a risk of being disordered. If the active layer 4 in the region other than the impurity diffusion regions Za and Zb is disordered, the manufactured semiconductor laser device will not oscillate.
Therefore, it is necessary to set the annealing temperature to 800 ° C. or lower.

  By the way, since the etching stop layer 6 is disordered by this annealing, the etching resistance of the etching stop layer 6 is deteriorated, but the process of forming the ridge 10 that requires etching resistance (process A2) has already been completed. There are no manufacturing and structural problems.

(Step A7) [Refer to FIG. 7]
The diffusion source layer 20 and the etching mask layer 18 corresponding to the range where the p-type contact layer 8 is formed are etched to expose the p-type contact layer 8.

(Step A8) [Refer to FIG. 8]
A P-side electrode 22 is formed on the exposed p-type contact layer 8. The P-side electrode 22 may be formed on the etching mask layer 18 as shown in FIG.
Further, the n-side electrode 24 is formed on the surface of the n-type substrate 1 opposite to the above-described stacking direction (the lower surface in FIG. 8).

Next, the n-type substrate 1 on which the P-side electrode 22 and the n-side electrode 24 are formed by the above-described process is cleaved along a plane that bisects the diffusion regions Za and Zb, and the cleavage plane is Bars (not shown) that form the resonator surfaces Aa and Ba are formed.
The bar is cut at a plane that passes through the center line between the ridges 14 formed in a stripe shape and is orthogonal to the surface of the n-type substrate 1 that has undergone the above-described steps, whereby the semiconductor laser device 50 of the first embodiment is formed. obtain.

  A current is injected into the semiconductor laser element 50 from the p-side electrode 20 side toward the n-side electrode 21 side. When this injected current exceeds the oscillation threshold value, laser oscillation occurs in the active layer 4 corresponding to the lower portion of the ridge 14, and laser light is emitted from one surface Aa of the resonator surfaces Aa and Ba of the active layer 4. It is emitted from.

  In the semiconductor laser element 50, since the etching mask layer 18 functions as an insulating film, the current injected into the p-side electrode 20 flows intensively in the ridge 14, so that laser oscillation occurs in the active layer 4 corresponding to the lower portion of the ridge 14. Can occur efficiently. Therefore, the semiconductor laser element 50 can emit a high-power laser beam.

  In addition to functioning as an insulating film, the etching mask layer 18 functions as an etching mask in the A4 process and functions as a diffusion mask in the A6 process, so that it is not necessary to newly form a diffusion mask or an insulating film. The manufacturing process can be simplified.

  By the way, when the semiconductor laser element 50 is laser-oscillated, the current flowing in the active layer 4 in the impurity diffusion regions Za and Zb in which Zn is diffused in the above-described step A6 is a so-called leak current that does not contribute to laser oscillation. Therefore, in the A4 step, the p-type contact layer 8 corresponding to the area in the vicinity of the resonator surfaces Aa and Ba is removed by etching, thereby suppressing the current flowing through the active layer 4 in the impurity diffusion regions Za and Zb. Therefore, leakage current can be reduced.

Next, a second embodiment will be described as a B1 process to a B11 process with reference to FIGS.
9 to 19 are perspective views for explaining the B1 process to the B11 process in the second embodiment of the semiconductor laser device of the present invention and the manufacturing method thereof, respectively.
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals.

<Second embodiment>
In the n-type substrate 1 described below, a plurality of semiconductor laser elements 100 are formed in a matrix, and a plurality of single semiconductor laser elements 100 can be obtained by cleaving and dividing the n-type substrate 1 at a predetermined interval. Although possible, in FIGS. 9 to 19, the structure of the single semiconductor laser device 100 is shown from the beginning of the process for easy understanding.

(Step B1) [Refer to FIG. 9]
On an n-type substrate 1 made of GaAs, an n-type clad layer 3 made of AlGaAs 3, an active layer 4, a first p-type clad layer 5 made of AlGaAs, an etching stop layer 6, and a second p-type clad made of AlGaAs. The layer 7 is sequentially deposited by, for example, metal organic vapor phase epitaxy (MOVPE).
The etching stop layer 6 is provided so that the first p-type cladding layer 5 which is the lower layer is not damaged by etching due to etching for forming a ridge 61 described later.

Next, a SiO ₂ (silicon dioxide) film 10 is formed on the entire surface of the second p-type cladding layer 7 by, for example, a sputtering method.
Thereafter, the SiO ₂ film 10 is selectively etched by a photolithographic method, so that the etching mask layer 12 extending in a direction perpendicular to the surfaces to be the resonator surfaces Ab and Bb is formed in a substantially parallel stripe shape. A plurality are formed. FIG. 9 shows one of the plurality of etching mask layers 12 formed.
Here, the resonator surface Ab indicates the entire right side surface in FIG. 9, the resonator surface Bb indicates the entire side surface opposite to the resonator surface Ab, and the resonator surface Ab and the resonator surface Bb Are parallel to each other.

(Step B2) [Refer to FIG. 10]
By etching the second p-type cladding layer 7 corresponding to the range not protected by the etching mask layer 12, that is, the range where the second p-type cladding layer 7 is exposed, the second p-type cladding layer is etched. A plurality of ridges 61 made of 7 are formed in a substantially parallel stripe shape having a predetermined interval. FIG. 10 shows one of the plurality of ridges 61 formed.
Thereafter, the etching mask layer 12 is removed.

  At this stage, the etching stop layer 6 has sufficient etching resistance because annealing that deteriorates the etching resistance is not performed. Therefore, the above-described etching can be accurately stopped by the etching stop layer 6, so that the lower first p-type cladding layer 5 can be prevented from being etched by this etching.

(Step B3) [Refer to FIG. 11]
An n-type semiconductor film 63 made of AlGaAs is formed by, for example, metal organic chemical vapor deposition so as to cover the ridge 61 and the etching stop layer 6 exposed in the B2 process and fill the step of the ridge 61.

(Step B4) [Refer to FIG. 12]
By selectively etching the n-type semiconductor film 63 corresponding to the range where the ridge 61 is formed, the ridge 61 is exposed.
In addition, the n-type semiconductor film 63 becomes the n-type current confinement layer 65 by this etching.

(Step B5) [Refer to FIG. 13]
A p-type contact layer 67 made of GaAs is formed by, for example, a metal organic chemical vapor deposition method so as to cover the ridge 61 and the n-type current confinement layer 65.

(Step B6) [Refer to FIG. 14]
The SiO ₂ film 16 is formed on the entire surface of the p-type contact layer 67 by sputtering, for example.
Next, the SiO ₂ film 16 is selectively etched by a photolithography method to form an etching mask layer 69 so that the p-type contact layer 67 corresponding to the range in the vicinity of the surfaces serving as the resonator surfaces Ab and Bb is exposed. .

(Step B7) [Refer to FIG. 15]
The p-type contact layer 67 corresponding to a range not protected by the etching mask layer 69, that is, a range in the vicinity of the surface to be the resonator surfaces Ab and Bb, is etched with, for example, an ammonia hydrogen peroxide solution.
The reason for etching the p-type contact layer 67 corresponding to the range in the vicinity of the surfaces serving as the resonator surfaces Ab and Bb is the same as the reason for etching the p-type contact layer 8 in the first embodiment.

(Step B8) [Refer to FIG. 16]
A diffusion source layer 71 which is a mixed crystal film of ZnO (zinc oxide) and SiO ₂ is formed on the surfaces of the ridge 61 and the n-type current confinement layer 65 exposed by the B7 step. At this time, the diffusion source layer 71 is also formed on the surface of the etching mask layer 69.

(Step B9) [Refer to FIG. 17]
By annealing the n-type substrate 1 that has undergone the B8 process, the diffusion source layer 71 moves toward the n-type substrate 1 side, passes through the etching stop layer 6 and the active layer 4, and reaches the middle of the n-type cladding layer 3. In the region, Zn (zinc) in the diffusion source layer 71 is diffused as an impurity.
During this diffusion, the etching mask layer 69 also functions as a diffusion mask. Therefore, the second p-type cladding layer 7, the n-type current confinement layer 65, and the etching stop layer corresponding to the range where the etching mask layer 69 is formed. 6, Zn does not diffuse into the first p-type cladding layer 5, the active layer 4, and the n-type cladding layer 3.
Therefore, due to this diffusion, the second p-type cladding layer 7 and the n-type current confinement layer 65 corresponding to the range not protected by the etching mask layer 69, that is, the range in the vicinity of the surfaces serving as the resonator surfaces Aa and Ba. , Zn is diffused into the etching stop layer 6, the first p-type cladding layer 5, the active layer 4, and the n-type cladding layer 3 to form impurity diffusion regions Zc and Zd.
In FIG. 17, the impurity diffusion regions Zc and Zd are shown in a shaded range for easy understanding.

  Also, annealing conditions are set so that the active layer 4 in the impurity diffusion regions Zc and Zd is sufficiently disordered by this annealing. In order for the active layer 4 in the impurity diffusion regions Zc and Zd to be sufficiently disordered, the annealing temperature may be increased or the annealing time may be increased to further diffuse Zn as an impurity in the active layer 4. . In the second embodiment, the annealing temperature was about 625 ° C. and the annealing time was about 20 minutes.

  This annealing condition is not limited to this example, and for the same reason as described in detail in the first example, the photoluminescence wavelength of the active layer 4 in the impurity diffusion regions Zc and Zd, and the impurity diffusion region The annealing conditions may be set so that the difference from the photoluminescence wavelength of the active layer 4 in the region other than Zc and Zd is 40 nm or more.

  By the way, since the etching stop layer 6 is disordered by this annealing, the etching resistance of the etching stop layer 6 is deteriorated, but the process of forming the ridge 61 (B2 process) that requires etching resistance has already been completed. There are no manufacturing and structural problems.

(Step B10) [Refer to FIG. 18]
The diffusion source layer 71 and the etching mask layer 69 corresponding to the range where the second p-type cladding layer 7 is formed are etched to expose the second p-type cladding layer 7.

(Step B11) [Refer to FIG. 19]
A P-side electrode 73 is formed on the exposed second p-type cladding layer 7. The P-side electrode 73 may be formed on the etching mask layer 69 as shown in FIG.
Further, the n-side electrode 75 is formed on the surface of the n-type substrate 1 opposite to the above-described stacking direction (the lower surface in FIG. 19).

Next, the n-type substrate 1 on which the P-side electrode 73 and the n-side electrode 75 are formed by the above-described process is cleaved along a plane that bisects the diffusion regions Zc and Zd, and the cleavage plane is Bars (not shown) that form the resonator surfaces Ab and Bb are formed.
The bar is cut at a plane that passes through the center line between the ridges 61 formed in a stripe shape and is orthogonal to the surface of the n-type substrate 1 that has been subjected to the above-described steps, whereby the semiconductor laser device 100 of the second embodiment is formed. obtain.

  A current is injected into the semiconductor laser element 100 from the p-side electrode 73 side toward the n-side electrode 75 side. When this injected current exceeds the oscillation threshold value, laser oscillation occurs in the active layer 4 corresponding to the lower portion of the ridge 61, and the laser light is emitted from one of the resonator surfaces Ab and Bb of the active layer 4. It is emitted from.

  In the semiconductor laser device 100, since the etching mask layer 69 functions as an insulating film, the current injected into the p-side electrode 73 flows intensively in the ridge 61, so that the active layer 4 corresponding to the lower portion of the ridge 61 performs laser oscillation. Can occur efficiently. Therefore, the semiconductor laser element 100 can emit a high-power laser beam.

  In addition to functioning as an insulating film, the etching mask layer 18 functions as an etching mask in the B7 process and functions as a diffusion mask in the B9 process, so that it is not necessary to newly form a diffusion mask or an insulating film. The manufacturing process can be simplified.

  The embodiment of the present invention is not limited to the configuration and procedure described above, and it goes without saying that modifications may be made without departing from the scope of the present invention.

For example, in the first embodiment, the diffusion source layer 20 is formed, and the impurity diffusion regions Za and Zb are formed by diffusing Zn as an impurity from the diffusion source layer 20. However, the present invention is not limited to this. Impurity diffusion regions Za and Zb may be formed by implanting impurities such as Zn and diffusing the implanted impurities by annealing.
Similarly, in the second embodiment, the diffusion source layer 71 is formed, and the impurity diffusion regions Zc and Zd are formed by diffusing Zn as an impurity from the diffusion source layer 71. However, the present invention is not limited to this. The impurity diffusion regions Zc and Zd may be formed by ion-implanting impurities such as Zn and diffusing the ion-implanted impurities by annealing.

In the second embodiment, the ridge 61 is composed of the second p-type cladding layer 7, but the present invention is not limited to this.
For example, the ridge 61 has a laminated structure including the second p-type cladding layer 7 and the p-type contact layer 8 laminated on the second p-type cladding layer 7 in the same manner as the ridge 14 of the first embodiment. It is good. In this case, in the step B7, when the p-type contact layer 67 corresponding to the range in the vicinity of the surfaces to be the resonator surfaces Ab and Bb is etched with the ammonia hydrogen peroxide solution, the resonator surface Ab is etched with this etching solution. , Bb, the p-type contact layer 8 corresponding to the range in the vicinity of the surface can be etched.

  In addition, each of the n-type layers in the first and second embodiments may be p-type and each of the p-type layers may be n-type, and the same effect as in the first and second embodiments can be obtained. Can do.

It is a perspective view for demonstrating the A1 process in 1st Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the A2 process in 1st Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the A3 process in 1st Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the A4 process in 1st Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the A5 process in 1st Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the A6 process in 1st Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the A7 process in 1st Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the A8 process in 1st Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B1 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B2 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B3 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B4 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B5 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B6 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B7 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B8 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B9 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B10 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method. It is a perspective view for demonstrating the B11 process in 2nd Example of the semiconductor laser element of this invention, and its manufacturing method.

Explanation of symbols

1 substrate, 3, 5, 7 cladding layer, 4 active layer, 6 etching stop layer, 8, 67 contact layer, 10, 16 SiO ₂ film, 12, 69 etching mask layer, 14, 61 ridge, 18 etching mask layer, 20, 71 diffusion source layer, 22, 24, 73, 75 electrode, 50, 100 semiconductor laser element, 63 semiconductor film, 65 current confinement layer, Aa, Ba, Ab, Bb resonator face, Za, Zb, Zc, Zd Impurity diffusion region

Claims (4)

In a method of manufacturing a semiconductor laser device for manufacturing an edge emitting semiconductor laser device having a pair of resonator surfaces parallel to each other and an impurity diffusion region formed in the vicinity of each resonator surface,
On the first conductivity type semiconductor substrate, at least a first conductivity type first cladding layer, an active layer, a second conductivity type second cladding layer, a second conductivity type etching stop layer, and a second conductivity type second cladding layer. A laminating step of sequentially laminating three clad layers and a second conductivity type contact layer;
A ridge forming step of forming a substantially parallel stripe-shaped second conductivity type ridge having a predetermined interval by selectively etching the third cladding layer and the contact layer;
Forming an insulating layer on the ridge and the etching stop layer to form a substantially parallel stripe-shaped insulating layer having a predetermined interval so as to extend in a direction substantially perpendicular to a direction in which the ridge extends. Process,
A contact layer removing step of selectively etching the contact layer left in the ridge forming step, leaving the range where the insulating layer is formed, using the insulating layer as an etching mask;
Using the insulating layer as an impurity diffusion mask, leaving an area where the insulating layer is formed, and selectively diffusing impurities from the ridge side in a direction opposite to the stacking direction, A diffusion step to be an impurity diffusion region;
A removing step of removing the insulating layer on the ridge;
A method for manufacturing a semiconductor laser device, comprising: In an edge-emitting semiconductor laser device having a pair of resonator surfaces parallel to each other and an impurity diffusion region formed in the vicinity of each resonator surface,
A first conductivity type semiconductor substrate;
A first conductivity type first clad layer laminated on the semiconductor substrate;
An active layer laminated on the first cladding layer;
A second conductivity type second clad layer laminated on the active layer;
A ridge of a second conductivity type formed on the second cladding layer so as to extend in a direction perpendicular to each of the resonator surfaces;
An insulating layer formed on the second cladding layer, leaving the area where the ridge is formed and the area near each resonator surface and the surface;
And having
The ridge includes a second conductivity type third clad layer, and a second conductivity type contact layer formed on the third clad layer leaving the surface of each resonator and the vicinity of the surface,
2. The semiconductor laser device according to claim 1, wherein the first cladding layer, the active layer, the second cladding layer, and the third cladding layer have the impurity diffusion regions in the resonator surfaces and in the vicinity of the surfaces. In a method of manufacturing a semiconductor laser device for manufacturing an edge emitting semiconductor laser device having a pair of resonator surfaces parallel to each other and an impurity diffusion region formed in the vicinity of each resonator surface,
A stacking step of sequentially stacking at least a first conductivity type first cladding layer, an active layer, and a second conductivity type second cladding layer on a first conductivity type semiconductor substrate;
A ridge forming step of forming a substantially parallel stripe-shaped second conductivity type ridge having a predetermined interval on the second cladding layer;
Forming a current confinement layer of the first conductivity type on the second cladding layer so as to fill the step of the ridge;
A contact layer forming step of forming a second conductivity type contact layer on the current confinement layer and the ridge;
An insulating layer forming step of forming a substantially parallel stripe-shaped insulating layer having a predetermined interval on the contact layer so as to extend in a direction substantially orthogonal to a direction in which the ridge extends;
A contact layer removing step of selectively etching the contact layer while leaving the range where the insulating layer is formed using the insulating layer as an etching mask;
Using the insulating layer as an impurity diffusion mask, leaving an area where the insulating layer is formed, selectively diffusing impurities from the ridge side to the middle of the first cladding layer in the direction opposite to the stacking direction, A diffusion step in which a region in which impurities are diffused is the impurity diffusion region;
A removing step of removing the insulating layer on the ridge;
A method for manufacturing a semiconductor laser device, comprising: In an edge-emitting semiconductor laser device having a pair of resonator surfaces parallel to each other and an impurity diffusion region formed in the vicinity of each resonator surface,
A first conductivity type semiconductor substrate;
A first conductivity type first clad layer laminated on the semiconductor substrate;
An active layer laminated on the first cladding layer;
A second conductivity type second clad layer laminated on the active layer;
A ridge of a second conductivity type formed on the second cladding layer so as to extend in a direction perpendicular to each of the resonator surfaces;
A current confinement layer of a first conductivity type formed on the second cladding layer so as to fill the step of the ridge;
A contact layer of a second conductivity type formed on the current confinement layer and the ridge, leaving the surface of each resonator and the vicinity of the surface;
An insulating layer formed on the contact layer leaving the range where the ridge is formed;
And having
The semiconductor laser characterized in that the first cladding layer, the active layer, the second cladding layer, the ridge, and the current confinement layer have the impurity diffusion regions in each resonator surface and in the vicinity of the surface. element.