JP2003163414A - Semiconductor laser element and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve covering property of an insulating film and a metal film in a semiconductor laser element including a groove or an end face which is partly removed. <P>SOLUTION: On an n-GaAs buffer layer 2, an n-Al<SB>0.64</SB>Ga<SB>0.36</SB>As lower clad layer 3, an active layer, a p-Al<SB>0.64</SB>Ga<SB>0.36</SB>As upper first clad layer 5, an InGaAsP etching stop layer 6, an n-In<SB>0.49</SB>(Al<SB>0.3</SB>Ga<SB>0.7</SB>)<SB>0.51</SB>P current constriction layer 7, a p-Al<SB>0.64</SB>Ga<SB>0.36</SB>As upper second clad layer 8, and a p-GaAs contact layer 9, are formed. A groove is formed, in parallel to the current injection area, by removing, with the etching process, the contact layer 9 and upper second clad layer 8 with a mixed solution of the aqueous solution of tartaric acid and hydrogen peroxide water using a resist mask. Side wall of the contact layer 9 is drawn using a mixed solution of aqueous solution of NH<SB>4</SB>OH and hydrogen peroxide water, and the resist mask is removed. Thereafter, the current constriction layer 7 is selectively etched with the aqueous solution of HCl. Using a mask of SiO<SB>2</SB>insulation film 10, the etching is performed up to the buffer 2 with the mixed solution of methanol and bromine to form an insulation film 11 and a p-electrode layer 12. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device having a groove in a region other than a current injection region, a semiconductor laser device in which a part of an end portion of the device is removed, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Semiconductor laser devices have various purposes such as formation of a ridge waveguide for improving laser oscillation efficiency, reduction of electric capacitance of a cladding layer for improvement of high frequency characteristics, and improvement of cleavage. Therefore, a groove may be formed. Such a groove is formed by selecting an etching solution corresponding to the epitaxial crystal material forming the semiconductor laser, but in the structure in which a plurality of materials are stacked, the side wall of the groove formed by etching recedes, and There is a case where the side wall has a concavo-convex shape, or the side wall has a vertically raised shape. Usually, in order to electrically insulate these grooves, an insulating film such as SiO ₂ or silicon nitride is coated, and an electrode material is formed in the upper layer. When the side wall shape described above is uneven or vertical, the coverage of the insulating film and the electrode layer is significantly reduced, which may cause a problem in electrical characteristics such as short circuit or disconnection.

For example, a conventional 1060 nm semiconductor laser device has an n-GaAs substrate 81 and an n-
GaAs buffer layer 82, p-Al _0.64 Ga _0.36 As lower cladding layer 83, i or n-In _0.49 Ga _0.51 P optical waveguide layer 84, i-GaAs first intermediate layer 85, In _0.3 Ga _0.7 As
Active layer 86, i-GaAs second intermediate layer 87, i or p-I
n _0.49 Ga _0.51 P optical waveguide layer 88, p-Al _0.64 Ga _0.36 A
s upper first cladding layer 89, InGaAsP etching stop layer _{90, n-In 0.49 (Ga} 0.7 Al 0.3) 0. 51 P current confinement layer 91 and p-Al _0.64 Ga _0.36 As second upper cladding layer 92, p-GaAs There is one in which the contact layer 93 is laminated.

[0004]

[Problems to be Solved by the Invention]
In a stack of char crystal materials, p-Al_0.64Ga_0.36
As upper second cladding layer 92 and p-GaAs contact
Layer 93 with a mixture of tartaric acid solution and hydrogen peroxide solution.
N-In_0.49(Ga_0.7Al_0.3) _0.51P
The current confinement layer 91 is etched with an aqueous HCl solution, and
Groove with further etching with a mixed solution of bromine and bromine.
Uto, n-In_0.49(Ga_0.7Al_0.3)_{0. 51}P current constriction
The sidewall portion of layer 91 selectively recedes in a concave shape. this
The insulating film 94 and the metal are formed on the laminated body in which the groove is formed.
When the layer 95 is formed, the electrode layer 95 is not covered and
There was a problem that continuity could not be obtained. Therefore, the electrical characteristics
In order to obtain a semiconductor laser device with stable properties, the insulating film and
And a manufacturing method for obtaining a groove shape with good coverage of the electrode layer.
And it is necessary to newly devise a semiconductor laser device.

In view of the above circumstances, the present invention provides a semiconductor laser device having a groove in a region other than the current injection region, and a semiconductor laser device in which a part of the device end portion is removed, which is on the groove or in the part thereof. Provided are a highly reliable semiconductor laser device having good insulation film and metal layer coating formed on the removed region, and a method of manufacturing a semiconductor laser device capable of satisfactorily covering the insulation film and metal layer. The purpose is to do.

[0006]

A semiconductor laser device of the present invention comprises a laminated body including an active layer and a plurality of layers made of semiconductor materials different from each other, and is provided in a region other than a current injection region of the laminated body. In the region, a groove having a depth from the upper surface of the stacked body to at least the active layer is provided, and in the semiconductor laser device including the insulating film and the metal layer in this order on the stacked body having the groove, the groove is A first groove and a second groove having a width narrower than a width of the first groove located in the first groove.
The width of the first groove and the second groove is gradually narrowed toward the bottom surface of the groove, and the insulating film and the metal layer on the side wall of the groove are 50% or more. It is characterized by having step coverage.

Another semiconductor laser device of the present invention is
It is composed of a laminated body having a stripe for current injection, which is formed by laminating a plurality of layers made of different semiconductor materials including an active layer, and an insulating film and a metal layer are provided in this order on the laminated body. In the semiconductor laser device, at least one end parallel to the stripe of the laminated body has a first inclined surface having an inclination such that the width of the laminated body gradually expands toward a lower layer of the laminated body, and the first inclined surface. A horizontal plane continuous to the lower end of the horizontal plane and a second inclined plane continuous to the outer edge of the horizontal plane and having an inclination such that the width of the laminated body gradually expands toward the lower layer of the laminated body. The insulating film and the metal layer have a step coverage of 50% or more.

The laminated body is composed of GaAs and AlGaA.
s, InGaP, InGaAs, InGaAsP and InGaAlP are preferable.

The laminated body comprises a first GaAs crystal layer and a first Al layer.
GaAs crystal layer, first InGaP crystal layer, second GaAs
Crystal layer, InGaAs crystal layer, third GaAs crystal layer, second InGaP crystal layer, second AlGaAs crystal layer, InG
aAsP crystal layer, InGaAlP crystal layer, third AlGa
It is desirable that the As crystal layer and the fourth GaAs crystal layer are laminated in this order.

The metal layer is preferably made of a metal containing at least one of Ti, Pt, Au, Pd and Mo.

The method of manufacturing a semiconductor laser device according to the present invention comprises:
First GaAs crystal layer, first AlGaAs crystal layer, first I
nGaP crystal layer, second GaAs crystal layer, InGaAs crystal layer, third GaAs crystal layer, second InGaP crystal layer, second AlGaAs crystal layer, InGaAsP crystal layer, InG
aAlP crystal layer, third AlGaAs crystal layer, and fourth G
to form a laminated body in which aAs crystal layers are laminated in this order,
A first opening having an opening in a region other than the current injection region of the laminate;
The fourth GaAs crystal layer and the third Al using the mask of
The GaAs crystal layer is etched with a mixed solution of a tartaric acid aqueous solution and a hydrogen peroxide solution, and subsequently, the vicinity of the sidewall of the fourth GaAs crystal layer exposed by the etching is etched with a mixed solution of an NH ₄ OH aqueous solution and a hydrogen peroxide solution. And then InG
The aAlP crystal layer is etched with a HCl aqueous solution to form a first layer.
Of the InGaAsP crystal layer and at least the first InGaP crystal layer is formed by using a second mask having an opening having a width narrower than the opening width of the first mask in a region corresponding to the opening region of the first mask. Etching up to the layer with a mixed solution of bromine and methanol to form a second groove in the first groove, and then on the laminated body in which the first groove and the second groove are formed. It is characterized in that an insulating film and a metal layer are formed in this order.

When the first mask is made of a resist, the first mask is removed after etching with a mixed solution of an NH ₄ OH aqueous solution and a hydrogen peroxide solution, and at least the third AlGaAs crystal layer is formed. As a mask
The AlP crystal layer may be etched with an aqueous HCl solution to form a first groove, and then a second mask made of an insulating film may be formed. In that case, the second mask is preferably made of any one of SiO ₂ , silicon nitride and Al ₂ O ₃ .

When the first mask is made of an insulating film, after forming the first groove, a second mask made of a resist is formed on the first mask without removing the first mask. You may. In that case, the first mask is SiO ₂ ,
It is desirable to be made of any one of silicon nitride and Al ₂ O ₃ .

[0014]

According to the semiconductor laser device of the present invention, the groove includes the first groove and the second groove having a width narrower than the width of the first groove located in the first groove. The widths of the first groove and the second groove are gradually narrowed toward the bottom surface of the groove, and the insulating film and the metal layer on the sidewall of the groove have a step coverage of 50% or more. Since there is no short circuit or disconnection and the electrical characteristics are stable, high reliability can be obtained.

Further, according to another semiconductor laser device of the present invention, the end portion parallel to the stripe has the first inclined surface, the horizontal surface and the second inclined surface, and the insulating film and the metal layer on the end portion are 5
By having a step coverage of 0% or more, similarly to the above, there is no short circuit or disconnection and the electrical characteristics are stable, so high reliability can be obtained.

Further, according to the method of manufacturing a semiconductor laser device of the present invention, by using the mask and the etching solution as described above, the second groove having a width narrower than the width of the first groove is formed in the first groove. Since the groove is formed and there is no recessed portion that has been conventionally generated and the width of the groove is gradually narrowed toward the bottom surface of the groove, the insulating film and the metal formed on the side wall of the groove are formed. The layers can be coated well, and the occurrence of short circuit, disconnection, etc. can be eliminated. Therefore, a highly reliable semiconductor laser device having stable electric characteristics can be obtained.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

The semiconductor laser device according to the first embodiment of the present invention will be described along with its manufacturing method. Figure 1
2A and 2B are cross-sectional views of the manufacturing process of the two semiconductor laser elements, and FIG. 2 is a mounting view of the semiconductor laser element.

As shown in FIG. 1A, low pressure MOCVD is performed.
N-GaAs substrate 1 (1.0.0 plane orientation, Si =
2 x 10¹⁸cm^-3N-GaAs buffer on top of dope)
Layer 2 (Si = 5 × 10¹⁷cm^-3Dope, thickness 0.5μ
m), n-Al_0.64Ga_0.36As lower clad layer 3 (S
i = 5 × 10¹⁷cm^-3Dope, thickness 1 μm), Ando
SCH (Separate Confinement Heterostructure)
Active layer 4, p-Al_0.64Ga _0.36As upper first clad
Layer 5 (Zn = 7 × 10¹⁷cm dope, thickness 0.2 μm),
InGaAsP etching stop layer 6, n-In_0.49
(Al_0.3Ga_0.7)_{0. 51}P current constriction layer 7 (thickness 0.5 μ
m), GaAs cap layer (thickness 0.2 μm, not shown)
To form.

A stripe opening having a width of 3 μm is formed parallel to the orientation flat by a photolithography method, and the GaAs cap layer is removed by etching using a mixed solution of a tartaric acid aqueous solution and a hydrogen peroxide solution. Remove the resist and remove GaA
Using the s cap layer as a mask, an aqueous HCl solution was used to
n _0.49 (Al _0.3 Ga _0.7 ) _0.51 P The current confinement layer 7 is removed by etching. Then, the InGaAsP etching stop layer 6 and the GaAs cap layer are removed using a mixed solution of a tartaric acid aqueous solution and a hydrogen peroxide solution to form a current injection region.

Next, p-Al _0.64 Ga _0.36 As upper second
Clad layer 8 (Zn = 7 × 10 ¹⁷ cm ⁻³ doped, thickness 2
μm) and p-GaAs contact layer 9 (Zn = 2)
× 10 ¹⁹ cm ⁻³ dope, thickness 0.3 μm) is formed.

The undoped SCH active layer 4 consists of an i or n-In _0.49 Ga _0.51 P optical waveguide layer, an i-GaAs first intermediate layer, an In _0.3 Ga _0.7 As quantum well layer (undoped, thickness 10 nm), i. -GaAs second intermediate layer and i or p-in _0.49 Ga _0.51 P optical waveguide layer is formed by laminating in this order.

Next, on the p-GaAs contact layer 9,
A resist is applied and a groove stripe pattern opening is formed by a photolithography method so as to be parallel to the stripes to be the current injection region and to form a groove between the stripes. A p-GaAs contact layer 9 and a p-GaAs contact layer 9 and a p-GaAs contact layer 9 were formed using a mixed solution of a tartaric acid aqueous solution and a hydrogen peroxide solution.
-Al _0.64 Ga _0.36 As The upper second cladding layer 8 is simultaneously removed by etching. At this time, n-In _0.49 (Al
_0.3 Ga _0.7 ) _0.51 P When reaching the current confinement layer 7, the etching is stopped without proceeding with the mixed solution of the tartaric acid aqueous solution and the hydrogen peroxide solution.

Next, only the p-GaAs contact layer 9 is selectively back-etched with a mixed solution of an aqueous NH ₄ OH solution and a hydrogen peroxide solution, and then the resist is peeled off.

Next, n-In _0.49 (Al _0.3 Ga _0.7 )
_{The 0.51} P current confinement layer 7 is selectively etched with an HCl aqueous solution capable of obtaining a crystal orientation plane and stopped on the InGaAs etching stop layer 6. Here, the first groove is formed.

Next, a SiO ₂ insulating film 10 is formed as a mask, a resist is applied on the SiO ₂ insulating film 10, and the first groove is formed by photolithography in a region corresponding to the first groove in parallel with the first groove. A resist pattern of a groove stripe having a width a narrower than the width of the mask used for forming the groove is formed. Further, using this resist pattern as a mask, the SiO ₂ insulating film 10 is removed with a buffered hydrofluoric acid solution. Then, the resist is peeled off.

Next, using a mask made of the SiO ₂ insulating film 10, a mixed solution of methanol and bromine was used to remove InGaA.
sP etching stop layer 6, p-Al _0.64 Ga _0.36 A
s upper first cladding layer 5, undoped SCH active layer 4,
n-Al _0.64 Ga _0.36 As cladding layer 3 and n-Ga
The As buffer layer 2 is sequentially removed by etching. Here, the second groove is formed. The n-GaAs substrate 1 may be partially etched. The insulating film 10 serving as a mask is made of Si
Silicon nitride or Al ₂ O ₃ may be used instead of O ₂ .

Next, as shown in FIG. 1 (b), the SiO ₂ insulating film 10 used as a mask is entirely removed by buffered hydrofluoric acid, and then a new insulating film 11 is coated, and photolithography is performed. After the current injection region is opened in the insulating film 11 by etching, the p electrode layer 12 is formed. After polishing the entire thickness to about 100 μm, an n electrode layer 13 is formed on the n-GaAs substrate 1 side. The sample prepared in this way is cleaved into bars and separated into one of the resonator end faces.
10% low reflection (LR) passivation film 15, 95 on the other
% High reflection (HR) passivation film 16 is formed. Further, the semiconductor laser device 17 is completed by cleaving each device along the groove 14.

In the method of manufacturing a semiconductor laser device according to the present embodiment, first, a first groove is formed up to the surface of the etching stop layer 6 by wet etching using a resist mask, and then wet etching is performed using a SiO ₂ film mask. By forming the second groove up to the surface of the GaAs substrate 1 by etching, the second groove having a width narrower than that of the first groove and the first groove is formed.
And a groove of which the width is gradually narrowed toward the bottom surface.

The semiconductor laser device according to the present embodiment is
A first GaAs crystal layer composed of an n-GaAs substrate 1 and an n-GaAs buffer layer 2, n-Al _0.64 Ga _0.36 As
First AlGaAs crystal layer composed of lower clad layer 3, first InGaP crystal layer composed of undoped SCH active layer 4, second GaAs crystal layer, InGaAs crystal layer, 3G
aAs crystal layer and second InGaP crystal layer, p-Al
_0.64 Ga _0.36 As Second A consisting of upper first cladding layer 5
lGaAs crystal layer, InGaAsP crystal layer composed of InGaAsP etching stop layer 6, n-In _0.49 (A
l _0.3 Ga _0.7 ) _0.51 P InGaA composed of current confinement layer 7
lP crystal layer, the 3AlGaAs crystal layer made of p-Al _0.64 Ga _0.36 As second upper cladding layer 8, p-GaAs
The fourth GaAs crystal layer composed of the contact layer 9 is laminated in this order, and the end portion parallel to the stripe of the device is formed from the p-GaAs contact layer to I.
The first inclined surface to the surface of the nGaAsP etching stop layer, the horizontal surface which is the surface of the InGaAsP etching stop layer, and the n plane from the InGaAsP etching stop layer
-Since it has the second inclined surface up to the surface of the GaAs substrate, the insulating film 11 and the p electrode layer 12 can have good coverage. Assuming that the film thickness of the insulating film 11 in a flat place is d _i and the film thickness of the insulating film 11 on the side wall is d _i1 , the step coverage (%) of the insulating film 11 on the side wall is d.
It is represented by _{i 1} / d _i × 100, and the value is 50% or more. Further, the thickness of a flat place of the p-electrode layer 12 and d _m, and the thickness of the p-electrode layer 12 on the side wall and d _m1, step coverage of the p electrode layer 12 in the side wall (%) of d _m1 /
It is represented by d _m × 100, and the value is 50% or more.

As shown in FIG. 2, the mounting form of the semiconductor laser device is such that the surface of the p-electrode layer 12 of the semiconductor laser device 17 is placed on the stem.
After the solder material 19 is bonded to 18, the surface of the n-electrode layer 13 is bonded to another terminal 21 by an Au wire 20.

The semiconductor laser device according to the present invention has no short circuit which is caused by contact of a solder material or the like with a defective coating portion of the insulating film on the side wall as in the conventional case, and good electrical characteristics can be obtained.

Further, a groove formed in the present semiconductor laser device
Since 14 is the depth reaching the n-GaAs substrate 1, cleavage is easy, and chip separation (cleavage) with good reproducibility can be performed.

Next, a semiconductor laser device according to the second embodiment of the present invention will be described. FIG. 3 is a sectional view showing the process of manufacturing the two semiconductor laser devices.

As shown in FIG. 3A, low pressure MOCVD is performed.
N-GaAs substrate 31 (1.0.0 plane orientation, Si =
2 x 10¹⁸cm^-3N-GaAs buffer on top of dope)
Layer 32 (Si = 5 × 10¹⁷cm^-3Dope, thickness 0.5μ
m), n-Al_0.64Ga_0.36As lower clad layer 33 (S
i = 5 × 10¹⁷cm^-3Dope, thickness 1 μm), Ando
SCH (Separate Confinement Heterostructure)
Active layer 34, p-Al_0.64Ga_0.36As upper first clad
Layer 35 (Zn = 7 × 10¹⁷cm dope, thickness 0.2 μm),
InGaAsP etching stop layer 36, n-In_0.49
(Al_0.3Ga_0.7) _0.51P current constriction layer 37 (thickness 0.5μ
m), GaAs cap layer (thickness 0.2 μm, not shown)
To form.

A stripe having a width of 3 μm is formed parallel to the orientation flat by the photolithography method, and the GaAs cap layer is etched using a mixed solution of a tartaric acid aqueous solution and a hydrogen peroxide solution. The resist was peeled off, and the GaAs cap layer was used as a mask to form an n-In
_0.49 (Al _0.3 Ga _0.7 ) _0.51 P The current confinement layer 37 is etched. Then, the InGaAsP etching stop layer 36 is removed using a mixed solution of a tartaric acid aqueous solution and a hydrogen peroxide solution to form a current injection region having a width of 3 μm.

Next, p-Al _0.64 Ga _0.36 As upper second
Clad layer 38 (Zn = 7 × 10 ¹⁷ cm ^-3 doped, thickness 2
μm) and p-GaAs contact layer 39 (Zn = 2)
× 10 ¹⁹ cm ⁻³ dope, thickness 0.3 μm) is formed.

The undoped SCH active layer 34 is composed of i or n-In _0.49 Ga _0.51 P optical waveguide layer, i-GaAs first intermediate layer, In _0.3 Ga _0.7 As quantum well layer (undoped, thickness 10 nm), i. -GaAs second intermediate layer and i or p-in _0.49 Ga _0.51 P optical waveguide layer is formed by laminating in this order.

Next, on the p-GaAs contact layer 39,
An insulating film 40 to be a first mask is formed, a resist is further applied, and a resist is applied to the resist by photolithography so that a groove is formed in parallel with stripes to be a current injection region and between the stripes. An opening having a groove stripe pattern is formed. Further, the insulating film 40 is removed with a buffered hydrofluoric acid solution using this resist pattern as a mask. Next, using a mixed solution of a tartaric acid aqueous solution and a hydrogen peroxide solution, the p-GaAs contact layer 39 and the p-Al are formed.
_{The 0.64} Ga _0.36 As upper second cladding layer 38 is simultaneously removed by etching. At this time, n-In _0.49 (Al _0.3 Ga
_0.7 ) When reaching the _0.51 P current constriction layer 37, etching does not proceed with the mixed solution of the tartaric acid aqueous solution and the hydrogen peroxide solution and stops.

Next, only the side wall of the p-GaAs contact layer 39 is selectively recessed and etched by a mixed solution of NH ₄ OH aqueous solution and hydrogen peroxide solution, and then the resist is peeled off.

Next, n-In _0.49 (Al _0.3 Ga _0.7 )
_{The 0.51} P current confinement layer 37 is selectively etched with an HCl aqueous solution capable of obtaining a crystal orientation plane, and stopped at the surface of the InGaAsP etching stop layer 36. Here, the first groove is formed.

Next, while leaving the SiO ₂ insulating film 40, a resist 41 serving as a second mask is applied on the SiO ₂ insulating film 40, and the opening width of the insulating film 40 serving as the first mask is narrower by photolithography. A groove stripe resist pattern having a width a is formed. Using this resist pattern as a mask, an InGaAsP etching stop layer 36, p-Al _0.64 Ga _0.36 As upper first layer was formed with a mixed solution of methanol and bromine.
Cladding layer 35, undoped SCH active layer 34, n-Al
_{The 0.64} Ga _0.36 As cladding layer 33 and the n-GaAs buffer layer 32 are sequentially removed by etching. Here, the second groove is formed. Note that a part of the n-GaAs substrate 31 may be etched.

After that, the resist 41 used as the second mask is peeled off, and finally, the insulating film used for forming the first groove is formed.
40 is entirely removed with a buffered hydrofluoric acid solution.

Next, as shown in FIG. 3B, the insulating film 42
And a p-electrode layer 43 is formed on the current injection region by photolithography to form a p-electrode layer 43, and the entire thickness is polished to about 100 μm.
An n electrode layer 44 is formed on the back surface of the GaAs substrate 31. The sample thus produced is cleaved into bars to form a 10% low reflection (LR) passivation film on one of the cavity end faces and a 95% high reflection (HR) passivation film on the other. Further, the semiconductor laser device is completed by cleaving each device in the groove 14.

In the method of manufacturing the semiconductor laser device according to the present embodiment, the insulating film is used as the mask for forming the first groove, and the insulating film which is the first mask is used as the mask for forming the second groove. A resist formed on the film without removing the film is used.

The semiconductor laser device according to the present embodiment is
A first groove having a depth to the surface of the InGaAsP etching stop layer and a second groove having a depth to the surface of the n-GaAs substrate 31.
A groove 14 having a gradually narrowing width is formed. This semiconductor laser device is similar to the semiconductor laser device according to the first embodiment in that the insulating film 42 and the p electrode layer are formed.
The step coverage on the side wall of the groove 43 is 50% or more, and good electrical characteristics can be obtained.

Next explained is a semiconductor laser device according to the third embodiment of the invention. A sectional view of the semiconductor laser device is shown in FIG. In the semiconductor laser device according to the present embodiment, the same elements as those of the semiconductor laser device according to the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

The semiconductor laser device according to the present embodiment is
As shown in FIG. 4, two grooves 14 each having a first groove and a second groove, the width of which gradually narrows toward the groove bottom, are formed in parallel on both sides of the light emitting region. . Further, since the semiconductor laser device is bonded by the wire 50 not on the narrow p electrode layer 12 on the light emitting region but on the adjacent wide laminated body with the groove 14 interposed therebetween, the bonding is performed well. Further, since there is no influence of strain due to bonding to the active layer, a highly reliable beam can be obtained.

In the mixed solution of the tartaric acid aqueous solution and the hydrogen peroxide solution, the volume mixing ratio is 50% tartaric acid aqueous solution 1 to
1 to 30% hydrogen peroxide solution is preferable to 3.

In addition, in the mixed liquid of methanol and bromine, the volume mixing ratio is such that bromine is 2 to 1000 to methanol.
8 is preferable.

The concentration of the HCl aqueous solution is preferably 36% by weight.

Further, in the mixed solution of the NH ₄ OH aqueous solution and the hydrogen peroxide solution, the volume mixing ratio is preferably 30 to 60% of 30% hydrogen peroxide solution to 1 of 29% NH ₄ OH aqueous solution.

The laminated structure of the p-electrode is Ti / Pt / Au, Ti / Pt / Ti / Pt / Au, Ti in the order of lamination.
/ Pd / Au, Ti / Pd / Au / Mo / Au, or Ti
/ Pt / Au / Mo / Au and the like are preferable.

The method of manufacturing a semiconductor laser device according to the present invention comprises:
It can be applied to a cleavage groove for chip separation, formation of a ridge waveguide for improving laser oscillation efficiency, and formation of a groove for reducing capacitance of a cladding layer for improving high frequency characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view showing a process of manufacturing two semiconductor laser devices according to a first embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a state in which the semiconductor laser device according to the first embodiment of the present invention is mounted.

FIG. 3 is a sectional view showing a process of manufacturing two semiconductor laser devices according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a semiconductor laser device according to a third embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional semiconductor laser device.

[Description of Reference Signs] 1 n-GaAs substrate 2 n-GaAs buffer layer 3 n-Al _0.64 Ga _0.36 As lower cladding layer 4 undoped SCH active layer 5 p-Al _0.64 Ga _0.36 As upper first cladding layer 6 InGaAsP etching stop layer 7 n-In _0.49 (Al _0.3 Ga _0.7 ) _0.51 P current confinement layer 8 p-Al _0.64 Ga _0.36 As upper second cladding layer 9 p-GaAs contact layer 10 SiO ₂ insulating film 11 insulating film 12 p electrode layer 13 n electrode Layer 14 groove

Claims (4)

[Claims] 1. A laminated body including an active layer, wherein a plurality of layers made of semiconductor materials different from each other are laminated, and a region other than the current injection region of the laminated body is at least the active layer from the upper surface of the laminated body. A groove having a depth penetrating the groove, and a semiconductor laser device having an insulating film and a metal layer in this order on a laminated body provided with the groove, wherein the groove is a first groove, and A second groove located within the first groove and having a width narrower than the width of the first groove,
The width of the first groove and the second groove is gradually narrowed toward the bottom surface of the groove, and the insulating film and the metal layer on the side wall of the groove have a step coverage of 50% or more. A semiconductor laser device characterized by: 2. A laminate having a stripe for current injection, which is formed by laminating a plurality of layers made of different semiconductor materials, including an active layer, and an insulating film and a metal layer on the laminate. In the semiconductor laser device having the above order, at least one end portion parallel to the stripe of the stacked body has a slope such that the width of the stacked body gradually widens toward a lower layer of the stacked body. And a horizontal plane continuous to the lower end of the first inclined surface, and continuous to the outer edge of the horizontal plane,
A second inclined surface having an inclination such that the width of the laminated body gradually expands toward a lower layer of the laminated body, and the insulating film and the metal layer on the end portion have a step coverage of 50% or more. A semiconductor laser device having. 3. A first GaAs crystal layer, a first AlGaAs
A crystal layer, a first InGaP crystal layer, a second GaAs crystal layer,
InGaAs crystal layer, third GaAs crystal layer, second InG
aP crystal layer, second AlGaAs crystal layer, InGaAsP
A first laminate having a crystal layer, an InGaAlP crystal layer, a third AlGaAs crystal layer, and a fourth GaAs crystal layer, which are laminated in this order, and has an opening in a region other than the current injection region of the first laminate.
The fourth GaAs crystal layer and the third
The AlGaAs crystal layer is etched with a mixed solution of a tartaric acid aqueous solution and a hydrogen peroxide solution, and then, the vicinity of the side wall of the fourth GaAs crystal layer exposed by the etching is NH ₄ OH.
Etching with a mixed solution of an aqueous solution and hydrogen peroxide solution, further etching the InGaAlP crystal layer with an aqueous HCl solution to form a first groove, and then, a region corresponding to the opening region of the first mask. A second opening having a width narrower than that of the first mask
Using the mask, the InGaAsP crystal layer to at least the first InGaP crystal layer are etched with a mixed liquid of bromine and methanol to form a second groove in the first groove, and then the first groove is formed. 2. A method for manufacturing a semiconductor laser device, comprising: forming an insulating film and a metal layer in this order on a laminated body in which the groove and the second groove are formed. 4. The first mask is made of resist,
After the etching with the mixed solution of the NH ₄ OH solution and the hydrogen peroxide solution is completed, the first mask is removed, and the InGaAlP crystal layer is etched with the HCl solution using at least the third AlGaAs crystal layer as a mask. To form the first groove, and then form the second groove made of an insulating film.
4. The method of manufacturing a semiconductor laser device according to claim 3, wherein the mask is formed.