JP2001177180A - Semiconductor laser device and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide a semiconductor laser device excellent in long-term reliability at high output operation and a method of manufacturing the same. SOLUTION: A surface oxide film formed on a light emitting end face is removed, and the light emitting end face from which the surface oxide film has been removed is Zn.
After coating with atoms and S atoms, the light emitting end face is formed of a dielectric film A as a light emitting end face protective film for protecting the active layer.
l ₂ O ₃ film 18, Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃
A film 19 is formed. Al ₂ O ₃ film 18, Al ₂ O ₃ / Si / A
By diffusing Ga atoms and As atoms into the l ₂ O ₃ / Si / Al ₂ O ₃ film 19, the Al ₂ O ₃ film 18 and the Al ₂ O ₃ / Si / Al ₂ O ₃ / A region containing Ga atoms and As atoms is formed in the Si / Al ₂ O ₃ film 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor laser device and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, various semiconductor laser devices have been widely used as light sources for optical disk devices. In particular, high-output 780 nm band AlGaAs-based semiconductor laser devices are used in MD (Mini Disc) players and CD-R (Compact D
It is used as a light source for writing to discs such as isc-recordable drives.

Conventionally, as a semiconductor laser device,
FIGS. 11A and 11B show examples. This semiconductor laser device is manufactured as follows.

First, an n-type GaAs buffer layer 10 is formed on an n-type GaAs substrate 101 by using a metal organic chemical vapor deposition method.
2. n-type AlGaAs first cladding layer 103, n-type Al
A second GaAs cladding layer 104, a light guide layer 105, a multiple quantum well (MQW) active layer 106, a light guide layer 107,
p-type AlGaAs first cladding layer 108, p-type GaAs
An etching stop layer 109, a p-type AlGaAs second cladding layer 110, and a p-type GaAs protection layer 111 are sequentially formed.

Next, after a stripe-shaped mask is formed on the surface of the p-type GaAs protective layer 111, p-type is formed in a region not covered with the mask by wet etching.
Etching is performed until the p-type GaAs etching stop layer 109 appears, and the p-type AlGaAs second cladding layer 1 is formed.
A ridge stripe 150 of a current path composed of the P-type GaAs protective layer 111 and the p-type GaAs protective layer 111 is formed. After the formation of the ridge stripe 150, the mask formed on the ridge stripe 150 is removed, and then the n-type AlGaAs current confinement layer 112 and the n-type G
aAs current confinement layer 113, p-type GaAs planarization layer 114
Are sequentially formed, and a current confinement region is provided on the side surface of the ridge stripe 150. At this time, the ridge stripe 15
Unnecessary n-type AlGaAs current confinement layer 112, n-type GaAs current confinement layer 113, p-type GaAs planarization layer 11
4 is formed, a mask is formed on the current confinement region,
An unnecessary layer on the ridge stripe 150 is removed. After removing the unnecessary layer, the mask formed on the current confinement region is removed, and then the p-type GaAs is again formed using the metal organic chemical vapor deposition method.
An s-contact layer 115 is formed. Then, the p-side electrode 1
16 and an n-side electrode 117 are formed and divided into a plurality of bars so as to have an arbitrary resonator length.

[0006] Immediately after the bar division, a plurality of bars are aligned and put into an electron beam evaporation machine, and A
An l ₂ O ₃ film 118 is formed, and Al ₂ O ₃ film is
An O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃ film 119 is formed. Then, when the bar is divided into chips, FIG.
The semiconductor laser device shown in (a) and (b) is completed.

[0007]

By the way, in a semiconductor laser device, when the drive current is increased to increase the light output, the light output is suddenly reduced, and irreversible destruction occurs. Such a phenomenon is caused by optical damage (COD; Catast
It is called “rophic optical damage” and occurs with an increase in light output density in the active layer region near the light emitting end face.

[0008] The cause of the COD is that the active layer region near the light emitting end face is an absorption region for laser light. At the light emitting end face, unlike the inside of the crystal, many bonds of lattice atoms are left behind at the portion facing the crystal surface. That is, dangling bonds exist on the light emitting end face, and many non-radiative recombination centers called surface states or interface states exist. Since the carriers injected into the active layer region near the light emitting end face are lost by the non-radiative recombination, the injected carrier density in the active layer area near the light emitting end face is smaller than that in the central portion of the active layer. As a result, the active layer region near the light emitting end face becomes an absorption region with respect to the wavelength of the laser light generated by the high injected carrier density at the center of the active layer region.

As described above, in the active layer region near the light emitting end face, when the light output density increases, local heat generation increases, the temperature rises, and the band gap decreases. As a result, positive feedback that the absorption coefficient further increases and the temperature rises is applied, so that the temperature of the absorption region of the active layer finally reaches the melting point and COD occurs.

In the conventional semiconductor laser device shown in FIG.
Is used as a light-emitting end face protective film to suppress COD generation.
Al_TwoO_ThreeFilm 118, Al_TwoO_Three/ Si / Al_TwoO_Three/ Si / A
l_TwoO _ThreeUse a dielectric film with high thermal conductivity such as film 119
And the temperature of the region of the MQW active layer 106 near the light emitting end face.
The rise has been suppressed. However, the light emitting end face protective film and
In the vicinity of the boundary with the active layer, there is a spot
Since many impurities such as traps and oxygen are present,
Area occurs. Therefore, the critical light output of the COD is
It does not increase, so long-term reliability at high output
There is a problem of inviting.

The present invention, as a result of studying the above problems, has invented a semiconductor laser device excellent in long-term reliability at high output operation and a method of manufacturing the same.

[0012]

In order to achieve the above object, a semiconductor laser device of the present invention comprises a first conductive type first cladding layer, an active layer, A second cladding layer of the conductivity type and a ridge stripe that is a third cladding layer of the second conductivity type are laminated, and a current confinement layer of the first conductivity type is formed so as to sandwich the ridge stripe from both sides, In a semiconductor laser device in which a dielectric film as a light emitting end face protective film for protecting the region of the active layer is formed on the light emitting end face, the dielectric film near the light emitting end face contains a group III atom and a group V atom. It is characterized by having a region containing atoms.

According to the semiconductor laser device having the above structure, a dielectric film as a light-emitting end surface protection film for protecting the region of the active layer is formed on the light-emitting end surface, and is formed in the dielectric film near the light-emitting end surface. , Forming a region including group III atoms and group V atoms suppresses diffusion of group III atoms, group V atoms, and the like from the active layer to the dielectric film side during high-power driving. That is, it is possible to suppress point defects on the light emitting end surface in the active layer region during high-output driving. As a result, the active layer region near the light emitting end face is less likely to be an absorption region with respect to the wavelength of the laser light generated by the high injected carrier density at the center of the active layer. Therefore, local heat generation is suppressed in the active layer near the light emitting end face, and CO 2
The critical light output of D is high, and C
It is possible to suppress a decrease in the critical light output of the OD.

In one embodiment of the present invention, a semiconductor laser device includes a first conductive type first clad layer, an active layer, and a second conductive type second clad layer on a first conductive type substrate. A ridge stripe, which is a third cladding layer of the second conductivity type, is formed, and a current confinement layer of the first conductivity type is formed so as to sandwich the ridge stripe from both sides, thereby protecting the region of the active layer. In a semiconductor laser device in which a dielectric film as a light emitting end face protective film is formed on the light emitting end face, a group II atom, a group III atom, a group V atom, and a group VI atom are included in the dielectric film near the light emitting end face. It is characterized by having a region containing atoms.

According to the semiconductor laser device of the embodiment of the present invention, a dielectric film serving as a light emitting end face protection film for protecting the region of the active layer is formed on the light emitting end face, and the dielectric film near the light emitting end face is formed. By having a region containing group II, group III, group V, and group VI atoms in the body film, group III and group V atoms from the active layer to the dielectric film side during high-power driving can be obtained. Can be suppressed. Even if the group III atoms and group V atoms diffuse from the active layer to the dielectric film side, vacancies such as group III atoms and group V atoms exist in the dielectric film near the light emitting end face. Since the group II atoms and the group VI atoms that are provided complement each other, it is possible to suppress the generation of point defects. As a result, the active layer region near the light emitting end face is less likely to be an absorption region with respect to the wavelength of the laser light generated by the high injected carrier density at the center of the active layer. Therefore, local heat generation is suppressed in the active layer near the light emitting end face, the critical light output of the COD is high, and a decrease in the critical light output of the COD during high output driving can be further suppressed.

In one embodiment, the semiconductor laser device according to the invention is characterized in that the group II atom is one of zinc, beryllium, and magnesium.

According to the semiconductor laser device of the embodiment of the present invention, since the group II atom is any one of zinc, beryllium, and magnesium, the increase in the number of non-radiative recombination centers is more effectively suppressed. Therefore, long-term reliability in high-output driving can be further improved.

In one embodiment, the semiconductor laser device according to the invention is characterized in that the group VI atom is sulfur.

According to the semiconductor laser device of the embodiment of the present invention, since the group VI atom is sulfur, the increase in the number of non-radiative recombination centers can be suppressed more effectively. Long-term reliability in output driving can be further improved.

In one embodiment of the invention, a semiconductor laser device has a current non-injection region formed near the light emitting end face.

According to the semiconductor laser device of the embodiment of the present invention, since the current non-injection region is formed near the light emitting end face, a very small amount of non-current exists in the active layer area near the light emitting end face. Since it is possible to suppress carrier loss due to the radiative recombination center and to suppress surface leakage current generated by group II atoms and group VI atoms present on the light emitting end face, there is an effect of reducing operating current and high efficiency. Long-term reliability in output driving can be improved.

In one embodiment of the present invention, a disordered region is formed in a region of the active layer near the light emitting end face, and a band gap of the disordered region is set at a central portion of the active layer. It is characterized by being larger than the band gap.

According to the semiconductor laser device of the embodiment of the present invention, since the disordered region formed in the region of the active layer near the light emitting end face has a larger band gap than the central portion of the active layer, the light emitting device can emit light. Laser absorption by group II atoms and group VI atoms existing in the region of the active layer near the end face is reduced, and long-term reliability at high output driving can be improved.

The method for manufacturing a semiconductor laser device of the present invention
On a substrate of the first conductivity type, a first cladding layer of the first conductivity type, an active layer, a second cladding layer of the second conductivity type, and a third cladding layer of the second conductivity type are laminated, and wet. In the method of manufacturing a semiconductor laser device, the third cladding layer of the second conductivity type is formed into a ridge stripe by etching, and a current confinement layer of the first conductivity type is formed so as to sandwich the ridge stripe from both sides. The method is characterized by comprising a step of removing a surface oxide film formed on the emission end face, and a step of covering the light emission end face from which the surface oxide film has been removed with group II atoms and group VI atoms.

According to the method of manufacturing a semiconductor laser device having the above structure, the surface oxide film formed on the light emitting end face is removed, and the light emitting end face from which the surface oxide film has been removed is replaced with a group II atom or a group VI atom. Since the dangling bonds on the light emitting end face are reduced by coating with the atoms, the effect of reducing the surface level of the light emitting end face and suppressing the attachment of oxygen atoms to the light emitting end face can be obtained. By the time the dielectric film is formed on the end face, the effect of suppressing the detachment and evaporation of group VI atoms and the effect of suppressing the formation of an oxide film on the light emitting end face can be obtained. That is, non-radiative recombination centers, which are referred to as surface states or interface states, can be reduced as much as possible, and proliferation of non-radiative recombination centers during high-output driving can be suppressed. As a result, the active layer region near the light emitting end face is less likely to be an absorption region with respect to the wavelength of the laser light generated by the high injected carrier density at the center of the active layer. Therefore, a semiconductor laser device having excellent long-term reliability at high output operation can be manufactured.

According to one embodiment of the present invention, a method of manufacturing a semiconductor laser device includes the steps of: providing a first conductive type first cladding layer, an active layer, and a second conductive type second cladding layer on a first conductive type substrate; A clad layer and a third clad layer of the second conductivity type are laminated, the third clad layer of the second conductivity type is formed into a ridge stripe by wet etching, and the second ridge stripe is sandwiched from both sides. In a method of manufacturing a semiconductor laser device for forming a current confinement layer of one conductivity type, a step of removing a surface oxide film formed on a light emitting end face, and the step of removing the light emitting end face from which the surface oxide film has been removed is a group II atom. And a step of coating with a group VI atom, a step of forming a dielectric film as a light emission end face protective film for protecting the region of the active layer on the light emission end face, and a group III atom and A step of diffusing group V atoms It is characterized by having.

According to the method of manufacturing a semiconductor laser device of the embodiment of the present invention, the surface oxide film formed on the light-emitting end face is removed, and the light-emitting end face from which the surface oxide film has been removed is group II. After coating with atoms and group VI atoms, a dielectric film is formed on the light emitting end face as a light emitting end face protective film for protecting the active layer, and a group III atom and a group V atom are included in the dielectric film. By diffusion, a region containing Group II atoms, Group III atoms, Group V atoms, and Group VI atoms is formed in the dielectric film near the light emitting end face. An excellent semiconductor laser device can be manufactured.

In one embodiment of the present invention, in the method of manufacturing a semiconductor laser device, the dielectric film is formed after performing a heat treatment so that the temperature of the light emitting end face becomes 150 ° C. or more and 300 ° C. or less. It is characterized by doing.

According to the method of manufacturing a semiconductor laser device of the embodiment of the present invention, the temperature of the light emitting end face is 150 ° C.
The heat treatment is performed so as to be not less than 300 ° C. to evaporate the moisture attached to the light emitting end face after covering the light emitting end face from which the surface oxide film has been removed with the group II and group VI atoms. And the re-evaporation of Group III, Group V, Group II, and Group VI atoms near the light emitting end face can be suppressed. Therefore, a point defect on the light emitting end face in the region of the active layer does not multiply, and a semiconductor laser device excellent in long-term reliability in high output driving can be stably obtained.

Further, when the heat treatment is performed so that the temperature of the light emitting end face is lower than 150 ° C., the dielectric material is kept in a state where the moisture attached to the group II and VI atoms coated on the light emitting end face is not completely evaporated. Since the body film is formed, an oxide film is formed on the light emitting end face. As a result, the oxide film grows at the time of high output driving, and the group III atom, VI
The group atoms diffuse to the oxide film side, and point defects multiply on the light emitting end face in the active layer region.

In the case where the heat treatment is performed so that the temperature of the light emitting end face exceeds 300 ° C., the temperature near the light emitting end face is reduced.
Group II atoms, group III atoms, group V atoms, and group VI atoms evaporate and form many point defects on the light emitting end face.

In one embodiment of the invention, a method of manufacturing a semiconductor laser device is characterized in that a surface oxide film formed on the light emitting end face is removed with an ammonia sulfide solution.

According to the method of manufacturing a semiconductor laser device of the embodiment of the present invention, in the step of removing the surface oxide film formed on the light emitting end face in the region of the active layer, the surface oxide film is treated with an ammonia sulfide solution. Since the removal is performed, the step of removing the surface oxide film formed on the light emitting end face of the active layer region and the step of covering the light emitting end face from which the surface oxide film has been removed with group VI atoms can be performed simultaneously. Therefore,
The number of work steps is reduced, and productivity can be improved.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor laser device and a method of manufacturing the same according to the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1A is a plan view of a semiconductor laser device according to a first embodiment of the present invention as viewed from a light emitting end face, and FIG. It is sectional drawing seen from the side surface side. 2 to 5 are views for explaining a method for manufacturing the semiconductor laser device.

A method of manufacturing the semiconductor laser device shown in FIGS. 1A and 1B will be described below.

First, an n-type GaAs buffer layer 2 and a first cladding of the first conductivity type are formed on an n-type GaAs substrate 1 as a substrate of the first conductivity type by first crystal growth by metal organic chemical vapor deposition. N-type AlGaAs first cladding layer 3 as a layer, n-type AlGaAs second cladding layer 4, light guide layer 5, multiple quantum well (MQW) active layer 6 as an active layer, light guide layer 7, and second conductivity type A p-type AlGaAs first cladding layer 8 as a second cladding layer, a p-type GaAs etching stop layer 9, a p-type AlGaAs second cladding layer 10 as a second conductivity type third cladding layer, and a p-type GaAs protection layer 11 Laminate sequentially.

Next, a stripe-shaped mask having a desired width is formed on the p-type GaAs protective layer 11, and an area not covered with the stripe-shaped mask by a mixed solution of sulfuric acid and hydrogen peroxide solution. P-type GaAs protective layer 11
Then, a part of the p-type AlGaAs second cladding layer 10 is etched. Subsequently, in order to remove the remaining p-type AlGaAs second cladding layer 10 in a region not covered by the mask, etching is performed with hydrofluoric acid until the p-type GaAs etching stop layer 9 is exposed.
A ridge stripe 50 of a current path composed of the p-type AlGaAs second cladding layer 10 and the p-type GaAs protection layer 11 is formed.

After forming the ridge stripe 50,
Removing the mask formed on the ridge stripe 50,
In the second crystal growth by metal organic chemical vapor deposition, an n-type AlGaAs current blocking layer 12 as a first conductivity type current confinement layer and an n-type GaAs as a first conductivity type current confinement layer
A current block layer 13 and a p-type GaAs planarization layer 14 are sequentially stacked.

Thereafter, in order to remove unnecessary layers of 12 to 14 (the n-type AlGaAs current blocking layer 12, the n-type GaAs current blocking layer 13, and the p-type GaAs planarizing layer 14) formed on the ridge stripe 50. Then, a mask is formed in a region outside the ridge stripe 50. Then, the n-type GaAs current blocking layer 13 and the p-type GaAs planarization layer 14 formed on the ridge stripe 50 are removed by etching with a mixed solution of aqueous ammonia and aqueous hydrogen peroxide, and then sulfuric acid and aqueous hydrogen peroxide are used. And n-type AlGa formed on the ridge stripe 50 by the mixed solution of
The As current blocking layer 12 is removed by etching. After removing the unnecessary layer on the ridge stripe 50, the mask formed in the region outside the ridge stripe 50 is removed.

Then, p which became the outermost surface after the unnecessary layer was removed was removed.
A p-type GaAs contact layer 15 is formed on the surfaces of the p-type GaAs protective layer 11 and the p-type GaAs planarization layer 14 by third crystal growth by metal organic chemical vapor deposition. Thereafter, a p-side metal electrode 16 is deposited on the surface of the p-type GaAs contact layer 15, and an n-side metal electrode 17 is deposited on the surface of the n-type GaAs substrate 1.

The wafer (substrate) on which a plurality of such semiconductor laser element structures are formed is cleaved in a direction perpendicular to the direction in which the ridge stripe 50 extends so that the cavity length becomes 800 μm, and the bar shape is formed. The bar 21 shown in FIG.

Then, the bar 21 is immersed in a mixed solution of sulfuric acid and hydrogen peroxide solution for 10 seconds, and then washed with pure water. By this processing, the surface oxide films 20, 20 formed on the light emitting end face are removed.

Next, the bar 21 from which the surface oxide films 20, 20 have been removed is immersed in an ammonium sulfide solution for 10 seconds, and then washed with pure water. As a result of this processing, the light emitting end face is covered with sulfur (S) atoms 25, 25 to form the bar 22 shown in FIG.

Next, the bar 22 is placed in a zinc acetate solution for 3 hours.
After immersion for 0 second, washing with pure water, and drying. By this processing, the light emitting end face is covered with sulfur (S) atoms 25, 25 and zinc (Zn) atoms 26, 26 to form the bar 23 shown in FIG.

Thereafter, the plurality of bars 23 are aligned and put into an electron beam evaporator, and heated so that the end face temperature of the bars 23, that is, the temperature of the light emitting end face becomes, for example, 250 ° C., and then the light emitting end face on the front side is formed. Al ₂ O ₃ as a dielectric film
While the film 18 is formed, an Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃ film 19 as a dielectric film is formed on the light emitting end face on the rear surface side.
Is formed into the bar 24 shown in FIG. This bar 2
When the semiconductor laser device 4 is divided into chips, the semiconductor laser device of the present invention shown in FIGS. 1A and 1B is completed.

Further, for comparison with the semiconductor laser device of the present embodiment, immediately after the bar division, a plurality of bars are aligned and put into an electron beam evaporator, and the light emitting end face on the front side is made of Al ₂ O _{2. 3} film 118 is formed, an Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃ film 119 is formed on the light emitting end face on the rear surface side, and the bar is divided into chips. FIG.
The semiconductor laser devices shown in FIGS.

The semiconductor laser device shown in FIGS. 1A and 1B obtained by the manufacturing method of the present embodiment and the semiconductor laser device shown in FIGS.
In the conventional semiconductor laser device of (b), the Al ₂ film formed on the light emitting end surface (front surface) near the MQW active layers 6 and 106 is formed.
The distribution of impurity atoms in the O ₃ films 18 and 118 in the depth direction was measured by a secondary ion mass spectrometer (SIMS), and the measurement results are shown in FIGS. FIG. 6 shows the measurement results of the semiconductor laser device of the present embodiment, and FIG.
10B shows the measurement results of the conventional semiconductor laser device. 6 and 7, the vertical axes indicate the number of secondary ions detected per second (c / s), and the horizontal axes indicate the depth (Å) from the surface of the Al ₂ O ₃ film.

[0049] As shown in FIG. 6, the semiconductor laser in the Al ₂ O ₃ film 18 of the light emitting edge surface vicinity of the device of this embodiment, in the range of about 400Å from the light emitting end face / the Al ₂ O ₃ film interface , A group III atom and As a group V element. On the other hand, as shown in FIG. 7, the G ₂ O ₃ film 118 near the light emitting end face of the conventional semiconductor laser device has G
a and As do not exist. Further, in the conventional semiconductor laser device, a peak of oxygen atoms is observed at the light emitting end face / Al ₂ O ₃ film interface, but in the semiconductor laser device of the present embodiment of the present invention, the light emitting end face / Al ₂ O ₃ film No oxygen atom peak is observed at the interface.

The characteristics of the semiconductor laser device of the present embodiment and the conventional semiconductor laser device were measured.

As a result, the oscillation wavelengths of the present embodiment and the conventional semiconductor laser device were both 785 nm,
As a result of the maximum output test, the maximum optical output of the semiconductor laser device of the present embodiment was 270 mW, and the maximum optical output of the conventional semiconductor laser device was 220 mW. In other words, the semiconductor laser device of the present embodiment is about two times less than the conventional one.
0% maximum light output was improved.

According to the results of the reliability test at 60 ° C. and 85 mW, the average life of the conventional semiconductor laser device is 190 hours, while the semiconductor laser device of the present embodiment is approximately 3 hours.
As a result, the average life was improved by about 15 times as compared with the conventional case.

The reason that the life of the semiconductor laser device of the present embodiment is improved over the life of the conventional semiconductor laser device is that the semiconductor laser device from the MQW active layer 6 to the dielectric film side at the time of high output driving is driven.
It is considered that the diffusion of the group III atoms (Ga) and the group V atoms (As) was suppressed, and the point defect of the light emitting end face in the region of the MQW active layer 6 at the time of high output driving was suppressed. .

As described above, the Al ₂ O ₃ film 18, Al ₂ O ₃ / Si /
A dielectric film of the Al ₂ O ₃ / Si / Al ₂ O ₃ film 19 is formed, and a region containing a group III atom (Ga) and a group V atom (As) is formed in the dielectric film near the light emitting end face. This shows that long-term reliability in high-output driving can be improved.

In the first embodiment, Al ₂ O ₃ is used to form the dielectric film. However, for example, AlxOy, Si
Similar effects can be obtained by using at least one of xOy, AlxNy, and SixNy (x and y are 1 or more).

In the first embodiment, AlGaAs is used.
s-containing semiconductor laser element was used.
Similar effects can be obtained by using a semiconductor laser device including at least one of InP, InGaAs, InGaAsP, and the like.

In the first embodiment, a mixed solution of sulfuric acid and hydrogen peroxide is used in the step of removing the surface oxide film formed on the light emitting end face. The same effect can be obtained by using a solution such as hydrofluoric acid.

In the first embodiment, the ammonium sulfide solution is used in the step of coating the light emitting end face from which the surface oxide film has been removed with group VI atoms. For example, a solution of abrasive sulfide, a solution of gallium sulfide, The same effect can be obtained by using any one of the aluminum sulfide solutions.

In the first embodiment, the Al ₂ O ₃ film near the light emitting end face, Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂
Although a zinc (Zn) atom is used as the group II atom contained in the O ₃ film, a similar effect can be obtained by using any one of beryllium and magnesium.

In the first embodiment, a zinc acetate solution is used in the step of coating the light emitting end face from which the surface oxide film has been removed with group II atoms. For example, zinc chloride, beryllium chloride, magnesium chloride, The same effect can be obtained by using any one of zinc sulfate, beryllium sulfate, and magnesium sulfate.

(Second Embodiment) A semiconductor laser device according to a second embodiment of the present invention is manufactured as follows.

A wafer (substrate) on which a plurality of the semiconductor laser device structures described in the first embodiment are formed is loaded with a resonator length of 8
The wall is opened in a direction perpendicular to the direction in which the ridge stripe extends so as to have a thickness of 00 μm, and is divided into bars. The following processing is performed on a plurality of bars formed by the bar division. First, after immersion in an ammonium sulfide solution for 60 seconds, cleaning is performed with pure water. Then, after being immersed in a zinc acetate solution for 30 seconds, the substrate is washed with pure water and dried.

Thereafter, the plurality of bars are aligned and put into an electron beam evaporator, and heated so that the end face temperature of the bar, that is, the temperature of the light emitting end face becomes, for example, 250 ° C., and then a dielectric material is applied to the front light emitting end face. Forming an Al ₂ O ₃ film as a film,
Al ₂ O ₃ / Si / A which is a dielectric film is formed on the light emitting end face on the rear side.
A bar is divided into chips by forming an l ₂ O ₃ / Si / Al ₂ O ₃ film.

In the semiconductor laser device obtained by the above manufacturing method, the light emitting end face (front face) near the MQW active layer
The distribution of impurity atoms in the Al ₂ O ₃ film in the depth direction was measured by a secondary ion mass spectrometer (SIMS), and the measurement results are shown in FIG. In FIG. 8, the vertical axis indicates the number of detected secondary ions per second (c / s), and the horizontal axis indicates the depth (Å) from the surface of the Al ₂ O ₃ film.

As can be seen from FIG. 8, in the Al ₂ O ₃ film in the vicinity of the light emitting end face, Ga and V, which are Group III atoms, are within a range of about 400 ° from the light emitting end face / Al ₂ O ₃ film interface. There is a high concentration of As which is a group atom, and there is also S which is a group VI atom and Zn which is a group II atom.

As described above, the presence of S atoms and Zn atoms in the Al ₂ O ₃ film near the light emitting end face of the semiconductor laser device is formed on the light emitting end face by using an ammonium sulfide solution. As a result of simultaneously performing the step of removing the surface oxide film that has been removed and the step of covering the light emitting end face from which the surface oxide film has been removed with S atoms, the natural oxide film existing at the light emitting end face / Al ₂ O ₃ interface is removed. It can be completely removed and Al ₂
During the formation of the O ₃ film, the diffusion of Ga and As atoms toward the Al ₂ O ₃ film side becomes active, and accordingly, the S atoms and Zn atoms existing at the light emitting end face / Al ₂ O ₃ film interface diffuse. I think that it was.

When the characteristics of the semiconductor laser device were measured, the oscillation wavelength of the semiconductor laser device was 785 nm, 8
The operating current at 5 mW was 110 mA, and the maximum light output of the semiconductor laser device was 300 mW. As can be seen from the results, the maximum output of the semiconductor laser device was improved as compared with the first embodiment.

When a reliability test was conducted at 60 ° C. and 85 mW, the semiconductor laser device of this embodiment was found to have a reliability of about 400
At 0 hours, the average life was improved compared to the semiconductor laser device of the first embodiment.

As described above, the reason why the average life of the semiconductor laser device of the present embodiment is improved over that of the semiconductor laser device of the first embodiment is that before the high-power driving, the laser diode near the light-emitting end face has a higher lifetime.
Since a region containing Ga atom, As atom, Zn atom and S atom is formed in the l ₂ O ₃ film and the Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃ film, high output is obtained. A small number of group III atoms (Ga) and group V atoms diffused from the MQW active layer to the dielectric film side during operation
The holes of (As) are formed by the Al ₂ O ₃ film and Al ₂ O ₃ near the light emitting end face.
II present in the ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃ film
This is because the group-atom (Zn) and the group-VI atom (S) complemented each other and suppressed the generation of point defects.

As described above, Al ₂ O ₃ near the light emitting end face
Film, Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃
Since the region including atoms, As atoms, Zn atoms, and S atoms was formed, it can be seen that long-term reliability at high output driving can be improved.

As shown in FIG. 8, the light emitting end face / A
Since there is no oxygen atom peak at the l ₂ O ₃ film interface, it is clear that the ammonium sulfide solution has an action of removing the surface oxide film formed on the light emitting end face. . Therefore, by using the ammonium sulfide solution, the step of removing the surface oxide film formed on the light emitting end face in the region of the MQW active layer and the step of covering the light emitting end face from which the surface oxide film has been removed with S atoms are simultaneously performed. It can be seen that it is possible to improve the productivity by reducing the number of work steps.

In the second embodiment, Al ₂ O ₃ is used to form the dielectric film. For example, AlxOy, Si
Similar effects can be obtained by using at least one of xOy, AlxNy, and SixNy (x and y are 1 or more).

In the second embodiment, AlGaAs is used.
s-containing semiconductor laser element was used.
Similar effects can be obtained by using a semiconductor laser device including at least one of InP, InGaAs, InGaAsP, and the like.

In the second embodiment, the Al ₂ O ₃ film, Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ near the light emitting end face is used.
Although a zinc (Zn) atom is used as the group II atom contained in the O ₃ film, a similar effect can be obtained by using any one of beryllium and magnesium.

In the second embodiment, a zinc acetate solution is used in the step of coating the light emitting end face from which the surface oxide film has been removed with group II atoms. For example, zinc chloride, beryllium chloride, magnesium chloride, The same effect can be obtained by using any one of zinc sulfate, beryllium sulfate, and magnesium sulfate.

(Third Embodiment) In a third embodiment of the present invention, an Al ₂ O ₃ film as a dielectric film and an Al ₂ O ₃ / Si / A
In the process of forming the l ₂ O ₃ / Si / Al ₂ O ₃ film on the light emitting end face, the temperature of the light emitting end face for forming an optimum dielectric film is studied.

The semiconductor laser device of the third embodiment is manufactured as follows.

A wafer (substrate) on which a plurality of the semiconductor laser structures described in the first embodiment are formed is loaded with a resonator length of 800
The wall is opened in a direction perpendicular to the direction in which the ridge stripe extends so as to have a thickness of μm, and divided into bars. The plurality of bars formed by the bar division are immersed in an ammonium sulfide solution for 60 seconds, washed with pure water, then immersed in a zinc acetate solution for 30 seconds, washed with pure water, and dried.

Thereafter, the plurality of bars are aligned and put into an electron beam evaporator, and the bar end surface temperature, that is, the temperature of the light emitting end surface is 100 ° C., 150 ° C., 200 ° C., 25
After heating to 0 ° C., 300 ° C., and 350 ° C., an Al ₂ O ₂ film is formed on the front light emitting end face, and Al ₂ O ₃ / Si / Al ₂ O ₃ is formed on the rear light emitting end face. A bar is divided into chips by forming a / Si / Al ₂ O ₃ film. As a result, the temperatures of the light emitting end faces were 100 ° C., 150 ° C., 200 ° C., respectively.
Six types of semiconductor laser devices manufactured by heating to 250 ° C., 300 ° C., and 350 ° C. are obtained.

As a result of measuring the characteristics of the semiconductor laser device obtained by the above manufacturing method, the oscillation wavelengths of the semiconductor laser devices were all 785 nm, and the maximum optical outputs of the semiconductor laser devices were all 270 mW to 300 mW. ,
There is almost no difference from the second embodiment.

FIG. 9 shows the results of a reliability test conducted at 60 ° C. and 85 mW. In FIG. 9, the vertical axis represents the average life (h), and the horizontal axis represents the bar end face temperature (° C.).

As can be seen from FIG. 9, the bar end face temperature was 15
In the range of 0 ° C. to 300 ° C., the average life is 3000 hours or more, which is a good result. On the other hand, when the average life is less than 150 ° C. or exceeds 300 ° C., the average life of the semiconductor laser element is rapidly deteriorated. The reason for this is that if the Al ₂ O ₃ film is formed after performing the heat treatment at which the bar end face temperature is lower than 150 ° C., the Zn, V
Since the Al ₂ O ₃ film is formed without completely evaporating the water attached on the S of the group I atom, the light emitting end face / Al ₂ O 3
_An oxide film is formed at the interface between the _three films. As a result, the oxide film grows at the time of high output driving, and with the growth of the oxide film,
Ga atoms of group III atoms and As atoms of group V atoms diffuse to the oxide film side. As a result, point defects are concentrated on the light emitting end face in the region of the active layer. On the other hand, after the above-mentioned heat treatment in which the bar end face temperature exceeds 300 ° C., Al ₂ O ₃
When the film is formed, the group II atom Z
The S of the n, VI group atoms and the As of the III group atoms, Ga, V atoms in the vicinity of the light emitting end face evaporate to form a number of point defects on the light emitting end face of the Al ₂ O ₃ film. Formation.

Therefore, in the present embodiment, when the bar end face temperature is lower than 150 ° C. or higher than 300 ° C., the average life of the semiconductor laser device is suddenly deteriorated, as described above. It is considered that a point defect exists on the light emitting end face.

The difference between the reliability test and the maximum light output test is almost the same.
The amount of the non-radiative recombination center at the light-emitting end face of the active layer region is almost the same, but the rate of decrease in the maximum light output is also different because the rate of increase of the non-radiative recombination center during high-power driving is different. I think it is different.

As described above, in the step of forming the dielectric film on the light emitting end face of the active layer region, the heating is performed so that the temperature of the light emitting end face of the active layer region becomes 150 ° C. or more and 300 ° C. or less. It can be seen that a semiconductor laser device having high long-term reliability in output driving can be stably manufactured.

In the third embodiment, Al ₂ O ₃ is used to form a dielectric film. However, for example, AlxOy, Si
Similar effects can be obtained by using at least one of xOy, AlxNy, and SixNy (x and y are 1 or more).

In the third embodiment, AlGaAs is used.
s-containing semiconductor laser element was used.
Similar effects can be obtained by using a semiconductor laser device including at least one of InP, InGaAs, InGaAsP, and the like.

In the third embodiment, the Al ₂ O ₃ film, Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ near the light emitting end face is used.
Although a zinc (Zn) atom is used as the group II atom contained in the O ₃ film, a similar effect can be obtained by using any one of beryllium and magnesium.

In the third embodiment, a zinc acetate solution is used in the step of coating the light-emitting end face from which the surface oxide film has been removed with group II atoms. For example, zinc chloride, beryllium chloride, magnesium chloride, The same effect can be obtained by using any one of zinc sulfate, beryllium sulfate, and magnesium sulfate.

(Fourth Embodiment) FIG. 10A shows a fourth embodiment of the present invention.
FIG. 10B is a cross-sectional view of the semiconductor laser device of the embodiment as viewed from the light emitting end face side, and FIG. 10B is a cross-sectional view as viewed from line BB of FIG.

A method of manufacturing the semiconductor laser device shown in FIGS. 10A and 10B will be described below.

First, an n-type GaAs buffer layer 202 and a first cladding of the first conductivity type are formed on an n-type GaAs substrate 201 as a substrate of the first conductivity type by first crystal growth by metal organic chemical vapor deposition. N-type AlGaAs first cladding layer 203 and n-type AlGaAs second cladding layer 20 as layers
4. Light guide layer 205, multiple quantum well as active layer
(MQW) Active layer 206, light guide layer 207, p-type AlGaAs first clad layer 208 as second conductive type second clad layer, p-type GaAs etching stop layer 20
9. p-type AlGa as third cladding layer of second conductivity type
As second cladding layer 210, p-type GaAs protective layer 211
Are sequentially laminated.

After that, a stripe-shaped mask having a desired width is formed on the p-type GaAs protective layer 211, and the p-type GaAs protective layer in a region not covered with the mask by a mixed solution of sulfuric acid and hydrogen peroxide. 211 and p-type AlGa
A part of the As second cladding layer 210 is etched.
Subsequently, the remaining p in the region not covered by the mask is
The AlGaAs second cladding layer 210 is etched with hydrofluoric acid until the p-type GaAs etching stop layer 209 is exposed, and the p-type GaAs protective layer 2 is etched.
A ridge stripe 250 of a current path composed of the second cladding layer 11 and the p-type AlGaAs second cladding layer 210 is formed.

Then, after the formation of the ridge stripe 250, the mask formed on the ridge stripe 250 is removed, and the second crystal growth by the metal organic chemical vapor deposition method is used to form n as the current confinement layer of the first conductivity type. An AlGaAs current block layer 212, an n-type GaAs current block layer 213 as a current confinement layer of the first conductivity type, and a p-type GaAs planarization layer 214 are sequentially stacked.

Then, in order to form a current non-injection region near the light emitting end face, a mask is formed on the outer area of the ridge stripe 250, on the surface of the p-type GaAs planarization layer 214 on the ridge stripe 250 and near the light emitting end face. Is formed, and an n-type GaAs current blocking layer 213 formed on the ridge stripe 250 excluding the vicinity of the light emitting end face by a mixed solution of ammonia water and hydrogen peroxide solution,
The aAs planarization layer 214 is removed by etching, and an n-type AlGaAs formed on the ridge stripe 250 excluding the vicinity of the light emitting end face by a mixed solution of sulfuric acid and hydrogen peroxide.
The s current block layer 212 is removed by etching. After removing the unnecessary layer formed on the ridge stripe 250 except for the vicinity of the light emitting end face, the region outside the ridge stripe 250 and the p-type GaAs on the ridge stripe 250 are removed.
When the mask formed on the surface of the s planarization layer 214 and near the light emitting end face is removed, n on the ridge stripe 250 is removed.
-Type AlGaAs current block layer 212 and n-type GaAs
A current non-injection region 251 including the current blocking layer 213 is formed.

Then, a p-type GaAs contact layer 215 is formed by the third crystal growth by metal organic chemical vapor deposition, and a p-side metal electrode 216 is deposited on the surface of the p-type GaAs contact layer 215 to form an n-type GaAs contact layer. An n-side metal electrode 217 is deposited on the surface of the GaAs substrate 201.

The wafer (substrate) on which a plurality of such semiconductor laser structures are formed is cleaved in a direction perpendicular to the direction in which the ridge stripe 250 extends so that the cavity length is 800 μm, and is formed into a bar shape. To divide.

The plurality of bars formed by the above-mentioned bar division are immersed in an ammonium sulfide solution for 60 seconds, and then washed with pure water. Next, it is immersed in a zinc acetate solution for 30 seconds, washed with pure water, and dried.

[0099] Then, to align the plurality of bars placed in the electron beam evaporation machine, after the temperature of the bar end surface temperatures, i.e. light emitting end surface is heated for example to be 250 ° C., Al ₂ on the light emitting end surface of the front side An O ₃ film 218 is provided on the light emitting end face on the rear surface side, and an Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃ film 219 is provided.
When the bar is divided into chips, FIG. 10 (a),
The semiconductor laser device shown in FIG.

The characteristics of the semiconductor laser device obtained by the above manufacturing method were measured. As a result, the oscillation wavelength of the semiconductor laser device was 785 nm, and the operating current at 85 mW was 1
05 mA. When a reliability test was conducted at 60 ° C. and 85 mW, the average life was improved to about 5000 hours.

The current non-injection region 25 is located near the light emitting end face.
The reason why the average lifetime was improved by having 1 is that the light emitting end face generated due to the existence of the group II atom (Zn) and the group VI atom (S) in the Al ₂ O ₃ film 218 near the light emitting end face. This is considered to be because the surface leakage current flowing along the line disappeared, and the heat generation of the semiconductor laser device at 60 ° C. and 85 mW was suppressed due to the reduction of the operating current.

From the above, it is understood that the provision of the current non-injection region 251 formed in the vicinity of the light emitting end surface can improve long-term reliability in high-output driving.

In the fourth embodiment, Al ₂ O ₃ is used to form the dielectric film. For example, AlxOy, Si
Similar effects can be obtained by using at least one of xOy, AlxNy, and SixNy (x and y are 1 or more).

In the fourth embodiment, AlGaAs is used.
s-containing semiconductor laser element was used.
Similar effects can be obtained by using a semiconductor laser device including at least one of InP, InGaAs, InGaAsP, and the like.

In the fourth embodiment, the Al ₂ O ₃ film, Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ near the light emitting end face is used.
Although a zinc (Zn) atom is used as the group II atom contained in the O ₃ film, a similar effect can be obtained by using any one of beryllium and magnesium.

In the fourth embodiment, a zinc acetate solution is used in the step of coating the light emitting end face from which the surface oxide film has been removed with group II atoms. For example, zinc chloride, beryllium chloride, magnesium chloride, The same effect can be obtained by using any one of zinc sulfate, beryllium sulfate, and magnesium sulfate.

In the fourth embodiment, the current non-injection region 251 is formed near the light emitting end face by using the unnecessary layer formed on the ridge stripe 250. The same effect can be obtained even if the current non-implanted region is formed by the ion implantation method.

(Fifth Embodiment) In a semiconductor laser device according to a fifth embodiment of the present invention, a disordered region is formed in the active layer near the light emitting end face.

The semiconductor laser device of the fifth embodiment is manufactured as follows.

First, in the first crystal growth by metal organic chemical vapor deposition, an n-type GaAs buffer layer and a first conductive type first clad layer are formed on an n-type GaAs substrate as a first conductive type substrate. N-type AlGaAs first cladding layer, n-type AlGaAs second cladding layer, optical guide layer, multiple quantum well (MQW) active layer as active layer, optical guide layer, and p as second conductive type second clad layer. A first AlGaAs first cladding layer, a p-type GaAs etching stop layer, a second p-type AlGaAs cladding layer as a third cladding layer of the second conductivity type, and a p-type GaAs protective layer are sequentially laminated.

Next, a stripe-shaped SiO ₂ film is formed near the light emitting end face of the semiconductor laser element and on the surface of the p-type GaAs protective layer. Then, by rapidly increasing the temperature to 900 ° C., the p under the SiO ₂ film is reduced.
Ga holes are formed in the type GaAs protective layer. Thereafter, the temperature is maintained at 900 ° C. for 1 minute to remove Ga vacancies from the multiple quantum wells (MQ).
W) Diffusion to the active layer. As a result, the vicinity of the light emitting end face of the multiple quantum well (MQW) active layer is disordered, and a disordered region is formed. This multiple quantum well
The band gap of the disordered region formed near the light emitting end face of the (MQW) active layer is larger than the band gap at the center of the multiple quantum well (MQW) active layer.

Then, the SiO ₂ film formed on the surface of the p-type GaAs protective layer is removed to form a stripe-shaped mask having a desired width. Then, the p-type GaAs protective layer and a part of the p-type AlGaAs second cladding layer in the region not covered by the mask are etched by a mixed solution of sulfuric acid and hydrogen peroxide solution.

Subsequently, in order to remove the remaining p-type AlGaAs second cladding layer in the region not covered with the mask, etching is performed with hydrofluoric acid until the p-type GaAs etching stop layer is exposed. And p-type A
A ridge stripe of a current path composed of an lGaAs second cladding layer and a p-type GaAs protective layer is formed.

After the formation of the ridge stripe, the mask formed on the ridge stripe is removed. Then, an n-type AlGaAs current blocking layer as a first-conductivity-type current confinement layer is formed by the second crystal growth by metal organic chemical vapor deposition,
An n-type GaAs current blocking layer and a p-type GaAs planarization layer as a first-conductivity-type current confinement layer are sequentially stacked.

Thereafter, in order to remove the unnecessary layer formed on the ridge stripe, a mask is formed in the outer region of the ridge stripe, and the mask is formed on the ridge stripe with a mixed solution of aqueous ammonia and hydrogen peroxide. The n-type GaAs current blocking layer and the p-type GaAs planarization layer thus formed are removed by etching. Further, n formed on the ridge stripe by a mixed solution of sulfuric acid and hydrogen peroxide solution.
The type AlGaAs current block layer is removed by etching.
After removing the unnecessary layer formed on the ridge stripe, the mask formed in the outer region of the ridge stripe is removed.

P-type GaAs on the outermost surface after removal of unnecessary layers
On the s protective layer and the p-type GaAs planarization layer, a p-type GaAs contact layer is formed by third crystal growth by metal organic chemical vapor deposition. Thereafter, a p-side metal electrode is deposited on the p-type GaAs contact layer, and n-type GaAs is formed.
An n-side metal electrode is deposited on the substrate.

The wafer (substrate) on which a plurality of such semiconductor laser structures are formed is cleaved in the direction perpendicular to the ridge stripe so as to have a resonator length of 800 μm, and divided into bars.

Then, the plurality of bars formed by the above-mentioned bar division are immersed in an ammonium sulfide solution for 60 seconds, and then subjected to a treatment of cleaning with pure water to form a surface oxide film formed on the light emitting end face. Is removed.

Next, the bars from which the surface oxide film has been removed are immersed in a zinc acetate solution for 30 seconds, washed with pure water, and then dried.

Thereafter, the plurality of bars are aligned and put into an electron beam evaporator, and heated so that the temperature of the bar end face, that is, the light emitting end face becomes, for example, 250 ° C., and then the Al ₂ O ₃ is added to the front light emitting end face. A film is formed, and an Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃ film is formed on the light emitting end face on the rear surface side.
Then, the bar was divided into chips to produce a semiconductor laser device.

The characteristics of the semiconductor laser device obtained by the above manufacturing method were measured. As a result, the oscillation wavelength of the semiconductor laser device was 785 nm. Further, when a reliability test was conducted at 60 ° C. and 85 mW, it was found that the average life was improved to about 5000 hours.

From the above, it can be seen that by forming the disordered region in the region of the MQW active layer near the light emitting end face, the long-term reliability at high output driving can be improved.

In the fifth embodiment, Al ₂ O ₃ is used to form a dielectric film. However, for example, AlxOy, Si
Similar effects can be obtained by using at least one of xOy, AlxNy, and SixNy (x and y are 1 or more).

In the fifth embodiment, AlGaAs is used.
s-containing semiconductor laser element was used.
Similar effects can be obtained by using a semiconductor laser device including at least one of InP, InGaAs, InGaAsP, and the like.

In the fifth embodiment, the Al ₂ O ₃ film, Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ near the light emitting end face is used.
Although a zinc (Zn) atom is used as the group II atom contained in the O ₃ film, a similar effect can be obtained by using any one of beryllium and magnesium.

In the fifth embodiment, a zinc acetate solution is used in the step of coating the light emitting end face from which the surface oxide film has been removed with group II atoms. For example, zinc chloride, beryllium chloride, magnesium chloride, The same effect can be obtained by using any one of zinc sulfate, beryllium sulfate, and magnesium sulfate.

In the fifth embodiment, the disordered region formed in the active layer region near the light emitting end face is formed by the method of diffusing Ga vacancies. However, the disordered region is formed by the method of diffusing impurities such as Zn atoms. The same effect can be obtained even if it is formed.

In the fifth embodiment, only the disordered region is formed in the active layer region near the light emitting end face. However, the disordered region is formed in the active layer region near the light emitting end face, and the disordered region is formed. The same effect can be obtained by forming a current non-injection region near the emission end face and on the ridge stripe.

[0129]

As is clear from the above, in the semiconductor laser device of the present invention, a dielectric film is formed on the light emitting end face as a light emitting end face protective film for protecting the active layer region, and the vicinity of the light emitting end face is formed. Since a region containing group III atoms and group V atoms is formed in the dielectric film, the occurrence of point defects on the light emitting end face in the active layer area during high-power driving is suppressed, and the vicinity of the light emitting end face is reduced. The active layer region is unlikely to become an absorption region, and COD
Is high in critical light output, and CO
It is possible to suppress a decrease in the critical light output of D. Therefore, long-term reliability in high-output driving can be improved.

A semiconductor laser device according to one embodiment of the present invention
A dielectric film as a light emitting end face protective film for protecting the region of the active layer is formed on the light emitting end face, and in the dielectric film near the light emitting end face, a group II atom, a group III atom, a group V atom, By forming a region containing group VI atoms, even if group III atoms and group V atoms diffuse from the active layer to the dielectric film side,
Voids such as Group III atoms and Group V atoms are complemented by Group II atoms and Group VI atoms present in the dielectric film near the light-emitting end face, so that point defects can be more effectively generated. It can be suppressed. As a result, the active layer region near the light emitting end face is less likely to be an absorption region for the wavelength of the laser light generated by the high injected carrier density at the center of the active layer, and the critical light output of the COD can be further increased. it can.
That is, it is possible to further suppress a decrease in the critical light output of the COD during the high output driving.

A semiconductor laser device according to one embodiment of the present invention
Group II atom is one of zinc, beryllium, and magnesium
With this configuration, the increase in the number of non-radiative recombination centers can be more effectively suppressed, and the long-term reliability in high-output driving can be further improved.

A semiconductor laser device according to one embodiment of the present invention
When the group VI atom is sulfur, the increase in the number of non-radiative recombination centers can be more effectively suppressed, so that the long-term reliability in high-output driving can be further improved.

A semiconductor laser device according to one embodiment of the present invention
Since there is a current non-injection region formed in the vicinity of the light emitting end face, carrier loss due to a non-radiative recombination center that is extremely small in the region of the active layer near the light emitting end face is suppressed,
Surface leakage current generated by group II atoms and group VI atoms present on the light emitting end face is suppressed, the operating current can be reduced, and the long-term reliability in high-output driving can be improved.

The semiconductor laser device according to one embodiment of the present invention
Since the band gap of the disordered region formed in the region of the active layer near the light emitting end face is larger than the band gap of the central portion of the active layer, the group II atoms, VI present in the active layer region near the light emitting end face Laser absorption by group atoms is reduced, and long-term reliability in high-power driving can be further improved.

The method for manufacturing a semiconductor laser device of the present invention
The surface oxide film formed on the light emitting end face is removed, and the light emitting end face from which the surface oxide film has been removed is replaced with group II atoms and VI.
By coating with group atoms, dangling bonds on the light emitting end face are reduced, so that the effect of reducing the surface state of the light emitting end face and suppressing the attachment of oxygen atoms to the light emitting end face is obtained, and By the time the dielectric film is formed on the emission end face, the effects of suppressing the desorption and evaporation of group VI atoms and suppressing the formation of an oxide film on the light emission end face can be obtained. That is, non-radiative recombination centers, which are referred to as surface states or interface states, can be reduced as much as possible, and proliferation of non-radiative recombination centers during high-output driving can be suppressed. As a result, for the wavelength of the laser light created by the high injected carrier density in the center of the active layer,
The active layer region near the light emitting end face is unlikely to be an absorption region,
A semiconductor laser device excellent in long-term reliability at high output operation can be manufactured.

In one embodiment of the present invention, a method for manufacturing a semiconductor laser device includes removing the surface oxide film formed on the light emitting end face and removing the light emitting end face from which the surface oxide film has been removed to group II atoms and VI atoms. After coating with group atoms, forming a dielectric film as a light emitting end surface protective film for protecting the active layer on the light emitting end surface, and diffusing group III atoms and group V atoms into the dielectric film. As a result, a region containing Group II, Group III, Group V, and Group VI atoms is formed in the dielectric film near the light emitting end face, so that a semiconductor that has superior long-term reliability at high output operation A laser element can be manufactured.

According to the method of manufacturing a semiconductor laser device of one embodiment of the present invention, the surface oxide film is removed by performing the heat treatment so that the temperature of the light emitting end face becomes 150 ° C. or more and 300 ° C. or less. After coating the light emitting end face with the group II atoms and the group VI atoms, the moisture attached to the light emitting end face can be evaporated, and the
Re-evaporation of group III, group V, group II and group VI atoms can be suppressed. Therefore, a point defect on the light emitting end face in the region of the active layer does not multiply, and a semiconductor laser device excellent in long-term reliability in high output driving can be stably obtained.

In the method of manufacturing a semiconductor laser device according to one embodiment of the present invention, in the step of removing the surface oxide film formed on the light emitting end face in the region of the active layer, the surface oxide film is removed with an ammonia sulfide solution. The step of removing the surface oxide film formed on the light emitting end face of the active layer region and the step of coating the group VI atoms on the light emitting end face from which the surface oxide film has been removed can be performed at the same time. Productivity can be improved.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a semiconductor laser device according to a first embodiment of the present invention as viewed from a light emitting end face side.
FIG. 2B is a cross-sectional view of the semiconductor laser device as viewed from the side.

FIG. 2 is a diagram for explaining a method of manufacturing the semiconductor laser device according to the first embodiment.

FIG. 3 is a view for explaining a method for manufacturing the semiconductor laser device of the first embodiment.

FIG. 4 is a diagram for explaining a method of manufacturing the semiconductor laser device according to the first embodiment.

FIG. 5 is a diagram for explaining a method of manufacturing the semiconductor laser device according to the first embodiment.

FIG. 6 is a diagram showing a depth direction distribution of impurity atoms of the semiconductor laser device of the first embodiment.

FIG. 7 is a diagram showing a depth direction distribution of impurity atoms in a conventional semiconductor laser device.

FIG. 8 is a diagram illustrating a depth direction distribution of impurity atoms in a semiconductor laser device according to a second embodiment of the present invention.

FIG. 9 is a diagram showing a relationship between bar end surface temperature and average life in a semiconductor laser device according to a third embodiment of the present invention.

FIG. 10A is a cross-sectional view of a semiconductor laser device according to a fourth embodiment of the present invention as viewed from the light emitting end face side, and FIG. 10B is a line BB of FIG. 10A. It is sectional drawing seen from.

FIG. 11A is a cross-sectional view of a conventional semiconductor laser device viewed from a light emitting end face side, and FIG. 11B is a cross-sectional view of the conventional semiconductor laser device viewed from a side surface side. .

[Explanation of symbols]

1,101,201 n-type GaAs substrate 2,102,202 n-type GaAs buffer layer 3,203,103 n-type AlGaAs first cladding layer 4,104,204 n-type AlGaAs second cladding layer 5,7,105,107 , 205,207 Light guide layer 6,106,206 Multiple quantum well (MQW) active layer 8,108,208 p-type AlGaAs first cladding layer 9,109,209 p-type GaAs etching stop layer 10,110,210 p-type AlGaAs second cladding layer 11,111,211 p-type GaAs protective layer 12,112,212 n-type AlGaAs current blocking layer 13,113,213 n-type GaAs current blocking layer 14,114,214 p-type GaAs planarization layer 15, 115,215 p-type GaAs contact layer 16,116,216 p-side metal electrode 17,117,217 n-side metal electrode 8,218 III Group, Al ₂ O ₃ having a region containing a group V atoms
Film 19,219 Al ₂ O ₃ having a region containing group III and group V atoms
/ Si / Al ₂ O ₃ / Si / Al ₂ O ₃ film 118 Al ₂ O ₃ film 119 Al ₂ O ₃ / Si / Al ₂ O ₃ / Si / Al ₂ O ₃ film 50,150,250 Ridge stripe 251 Current Non-implanted area

Claims (10)

[Claims] 1. A first conductive type first clad layer, an active layer, a second conductive type second clad layer, and a second conductive type third clad layer on a first conductive type substrate. A certain ridge stripe is laminated, a current confinement layer of the first conductivity type is formed so as to sandwich the ridge stripe from both sides, and a dielectric film as a light emitting end surface protection film for protecting the region of the active layer is formed. A semiconductor laser device formed on a light emitting end face, wherein the dielectric film near the light emitting end face has a region containing Group III atoms and Group V atoms. 2. A first conductive type first clad layer, an active layer, a second conductive type second clad layer, and a second conductive type third clad layer on a first conductive type substrate. A certain ridge stripe is laminated, a current confinement layer of the first conductivity type is formed so as to sandwich the ridge stripe from both sides, and a dielectric film as a light emitting end surface protection film for protecting the region of the active layer is formed. In the semiconductor laser device formed on the light emitting end face, a group II atom, III
A semiconductor laser device characterized by having a region containing Group III atoms, Group V atoms, and Group VI atoms. 3. The semiconductor laser device according to claim 2, wherein said group II atom is any one of zinc, beryllium, and magnesium. 4. The semiconductor laser device according to claim 2, wherein said group VI atom is sulfur. 5. The semiconductor laser device according to claim 1, further comprising a current non-injection region formed near the light emitting end face. 6. The semiconductor laser device according to claim 1, wherein a disordered region is formed in a region of the active layer near the light emitting end face, and a band gap of the disordered region is reduced. A semiconductor laser device having a larger band gap than a central portion of the active layer. 7. A first conductive type first clad layer, an active layer, a second conductive type second clad layer, and a second conductive type third clad layer on a first conductive type substrate. And a third cladding layer of the second conductivity type is formed into a ridge stripe by wet etching, and a current confinement layer of the first conductivity type is formed so as to sandwich the ridge stripe from both side surfaces. In the manufacturing method, there is a step of removing a surface oxide film formed on the light emitting end face, and a step of covering the light emitting end face from which the surface oxide film has been removed with group II atoms and group VI atoms. Manufacturing method of a semiconductor laser device. 8. A first conductive type first clad layer, an active layer, a second conductive type second clad layer, and a second conductive type third clad layer on a first conductive type substrate. And a third cladding layer of the second conductivity type is formed into a ridge stripe by wet etching, and a current confinement layer of the first conductivity type is formed so as to sandwich the ridge stripe from both side surfaces. In the manufacturing method, a step of removing a surface oxide film formed on a light emitting end face; a step of coating the light emitting end face from which the surface oxide film has been removed with group II atoms and group VI atoms; A step of forming a dielectric film as a light emitting end face protective film for protecting the region of the active layer, and a step of diffusing group III atoms and group V atoms in the dielectric film. Of manufacturing a semiconductor laser device. 9. The method for manufacturing a semiconductor laser device according to claim 8, wherein the heat treatment is performed so that the temperature of the light emitting end surface is 150 ° C. or more and 300 ° C. or less, and then the dielectric film is formed. A method of manufacturing a semiconductor laser device. 10. The method for manufacturing a semiconductor laser device according to claim 7, wherein the surface oxide film formed on the light emitting end face is removed with an ammonia sulfide solution. .