JPH10144989A - Manufacture of semiconductor laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor laser for specifying the forward output direction of laser beams to a single direction by forming a mark indicating the forward output side of laser beams. SOLUTION: After a plurality of crystal layers are grown on an off-angle substrate, electrodes are formed on upper and bottom surfaces. An electrode 17a on an upper surface forms an arrow shape toward the extension direction of a stripe 14a, and the direction indicated by the arrow is set as the forward output side of the laser beams. A reflection factor control film 18a for controlling the forward output of laser beams is formed on an end face 10a indicated by the arrow, and a reflection factor control film 18b for controlling the backward output of laser beams is formed on an end face 10b at an opposite side, thus specifying the forward output direction of the semiconductor laser 10 to one direction and avoiding the formation of two types of semiconductor lasers 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor laser manufacturing method for manufacturing a semiconductor laser by growing a plurality of crystal layers on an off-angle substrate.

[0002]

2. Description of the Related Art Semiconductor laser materials that have been put into practical use include AlGaAs-based materials and GaInAsP materials.
And AlGaInP-based materials. Of the semiconductor lasers using these materials, the AlGaAs type has a light emitting region of 0.8 μm band and is used for optical disks and the like. The GaInAsP system has a light emitting region of 1.3 to 1.
The band is 5 μm and used for communication. On the contrary,
The AlGaInP system has a short-wavelength 0.6 μm band light emission region and can emit light in the red visible light region. It is used for

In this AlGaInP-based semiconductor laser, it is preferable that the emission wavelength is short because the spot diameter at the time of reading and writing to the disk can be reduced and the density of the disk can be increased. Further, particularly in the red region, the shorter the emission wavelength, the higher the visibility. However, Al
Since a GaInP-based material forms a natural superlattice during crystal growth, shortening the wavelength of the (001) just substrate is practically limited to about 0.68 μm.

As a method of eliminating the natural superlattice, there is a method in which the substrate surface is used by being tilted from the just substrate. In fact, by using an off-angle substrate that is inclined from the (001) in the <011> direction by about 7 to 15 °, the off-angle substrate becomes 0.635 to 0.
Light emission in a wavelength region of 68 μm is obtained. In addition, this method using an off-angle substrate has a problem that abnormal growth is unlikely to occur because the crystal surface is a mirror surface, and that various conditions such as impurity doping amount, crystal growth rate, and diffusion are changed and the design range is expanded. AlGa
It is widely used not only for InP-based semiconductor lasers.

[0005]

However, when a semiconductor laser is manufactured using an off-angle substrate as described above, the shape of the end face perpendicular to the laser light emission direction is a parallelogram. Further, in the resonator direction, <0-11> and <01
-1>, as shown in FIG. 20 and FIG. 21, the end faces 50a, 50
Two types of semiconductor lasers 50 and 60 are formed in which the parallelograms 0b, 60a, and 60b have mutually opposite inclinations. In this specification,

An element which is originally represented by an overline, such as ## EQU1 ##, is represented by a negative sign, such as "-1".

Accordingly, the semiconductor lasers 5 whose inclinations are opposite to each other
When the semiconductor lasers 50 and 60 are arranged in a package in a state where the semiconductor lasers 50 and 60 are mixed, atan θ (where a is the thickness of the semiconductor lasers 50 and 60 and θ is the off-angle) ) Occurs. Therefore, there is a problem that the semiconductor lasers 50 and 60 cannot be arranged properly when there is no margin in the package capacitance, the interval between adjacent elements, and the like.

In general, when arranging the semiconductor lasers 50 and 60 in a package, the position of the specific portion of the package and the position of the specific portion of the semiconductor laser are grasped by image recognition. The relative positional relationship with other elements may be a problem. For example, as shown in FIG. 22, the semiconductor lasers 50 and 60 and the photodetector 7
In the case where 0 and 0 are separately provided on the package 80, if their relative positional relations are shifted, the spread of the laser beam occurs, or the sensitivity of the photodetector 70 is reduced depending on the light receiving area. .

However, if the semiconductor lasers 50 and 60 having mutually opposite inclinations are mixed and aligned with reference to the upper surface, the position of the bottom surface is shifted from the position of the upper surface by the inclination of each semiconductor laser 50 and 60. They are shifted in directions opposite to each other by a tan θ. More specifically, when the thickness a of the semiconductor lasers 50 and 60 is 120 μm and the off-angle θ is 15 °, the shift amount at is described.
anθ is about 32 μm, and there is a problem that the sensitivity of the photodetector 70 is reduced.

Further, as shown in FIG. 23, semiconductor lasers 50 and 60 are connected to an IC (integrated circuit) including a photodetector 70.
Also, when the semiconductor lasers 50 and 60 are positioned on the grated circuit 90, the relative positional relationship with the photodetector 70 shifts when the semiconductor lasers 50 and 60 are aligned with respect to the bottom surface, and the sensitivity of the photodetector 70 is reduced. On the other hand, if the operation is performed with reference to the pattern on the upper surface (that is, the position of the light emitting point), the disposition position on the IC 90 is shifted, and
There is a problem that a short circuit may occur.

In addition, a stripe may be formed in the refractive index guided semiconductor laser, and the stripe is generally formed by wet etching. Since this wet etching has etching anisotropy, when a crystal is grown on an off-angle substrate, the etching rate differs depending on the crystal orientation plane. That is, as shown in FIGS. 24 and 25, the cross-sectional shapes of the stripes 54a and 64a are asymmetrical, and have a mirror-symmetrical relationship with each other.
Thus, semiconductor lasers 50 and 60 of different types can be obtained. Further, the asymmetry of the cross-sectional shape of the stripes 54a and 64a is related to characteristics such as light confinement.
The fact that there are two types of cross-sectional shapes of 4a and 64a means that the near-field image and the far-field image differ depending on the cross-sectional shape.

However, for example, depending on the recording / reading method of the optical disk, a near-field image or a far-field image of one of the two types of semiconductor lasers 50 and 60 may be suitable. That is, one of the semiconductor lasers 5
The performance of the optical disk system can be improved if only 0 and 60 can be separated and taken out. However, there is also a problem that the performance is limited when two types of semiconductor lasers 50 and 60 are mixed. there were.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object thereof is to specify a forward output direction of laser light in one direction by forming a mark indicating a forward output side of laser light. It is an object of the present invention to provide a method for manufacturing a semiconductor laser.

[0013]

A method of manufacturing a semiconductor laser according to the present invention is for manufacturing a semiconductor laser by growing a plurality of crystal layers on an off-angle substrate. The forward output side of the laser beam is set by forming a mark indicating the side.

In the method of manufacturing a semiconductor laser, a semiconductor laser is formed by growing a plurality of crystal layers on an off-angle substrate. At this time, a mark is formed to set the front output side of the laser beam. Therefore, the forward output direction of the laser light is specified in one direction.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 13 show each step of the method for manufacturing the semiconductor laser 10 according to the first embodiment of the present invention. 1, 3, 6 to 13.
Is a plan view, and FIGS. 2, 4 and 5 show <0-1-1.
It is sectional drawing which expands and shows a part of direction. FIG.
6 is a cross-sectional view along the line BB in FIG. 3, and FIG. 5 is a cross-sectional view along the line CC in FIG.

In the method of manufacturing the semiconductor laser 10 according to the present embodiment, first, as shown in FIG.
1) to the <011> direction in the off angle θ (for example, 7 to 15).
°) An off-angle substrate (in this case, a wafer) 11 made of inclined GaAs is prepared.

Next, as shown in FIG. 2, a molecular beam epitaxy (Molecula)
A plurality of crystal layers are grown by r Beam Epitaxy (MBE). That is, the first cladding layer 12 made of AlGaInP mixed crystal, the active layer 13 made of a superlattice layer of GaInP mixed crystal and AlGaInP mixed crystal, and the AlGaInP
A second cladding layer 14 made of a mixed crystal is sequentially grown.

Subsequently, as shown in FIG. 3, the second cladding layer 14 is wet-etched using an appropriate etching solution such as hydrochloric acid: acetic acid or hydrochloric acid: phosphoric acid or sulfuric acid, and a part thereof is etched. By selectively removing, <01-1>
A plurality of stripes 14a extending in the direction are formed at predetermined intervals in the <0-1-1> direction. At that time, <01-
The 1> direction is determined using the orientation flat (OF) 11a of the off-angle substrate 11 as a guide.

Since the wet etching generally has etching anisotropy and the etching rate differs depending on the crystal orientation plane, the cross-sectional shape of the stripe 14 a is asymmetrical according to the off-angle substrate 11 as shown in FIG. Becomes That is, <0-1-1> of the stripe 14a
The left and right inclination angles θ ₁ and θ ₂ in the directions have different magnitudes.

After the stripes 14a are formed in this manner, as shown in FIG. 5, GaAs, AlGaAs is formed on the second cladding layer 14 by, for example, the MBE method.
buried layer 15 made of s, AlGaInP or AlInP and contact layer 16 made of GaAs
Are sequentially grown. After that, for example, gold (Au) is vapor-deposited on the contact layer 16 to form the electrode 17a, and gold is also vapor-deposited on the back surface of the off-angle substrate 11 to form the electrode 17b. As shown in FIG. 6, the electrodes 17a extend in the <01-1> direction and are formed in plural at predetermined positions at positions corresponding to the stripes 14a. Although not shown, a plurality of electrodes 17b are formed similarly to the electrode 17a. At this time, the <01-1> direction is determined using the OF 11a of the off-angle substrate 11 as a guide.

The plane shape of the electrode 17a is, as shown in FIG.
In the direction (ie, the extension direction of the stripe 14a), it is asymmetric (for example, an arrow shape). That is,
It is set here which of the extending directions of the stripe 14a is to be the forward output side of the laser beam with the electrode 17a as a mark. Incidentally, here, the right side is set as the front output side, which is indicated by an arrow.
Note that, even when the off-angle substrate 11 is cleaved in a later step and divided into a plurality of semiconductor lasers, at least one mark is present in each semiconductor laser or in each minimum unit at the time of mounting. It is repeatedly formed in the <01-1> direction according to the size of the semiconductor laser. That is,
At least one mark is formed between each cleavage position of the off-angle substrate 11 indicated by a dashed line in FIG.

The planar shape of the electrode 17a is not limited to the arrow shape but may be any asymmetrical shape so that the front output side of the laser beam can be identified. For example, the saw-tooth shape shown in FIG. 8, the band-shaped triangle shown in FIG. 9, and the triangle-shaped hole shown in FIG. Good. However, also in this case, <01− according to the size of the semiconductor laser, so that at least one mark for identifying the front output side of the laser light is present in each semiconductor laser or for each minimum unit at the time of mounting. 1> Repeatedly in the direction.

After forming the electrodes 17a and 17b, the off-angle substrate 11 is cleaved with a predetermined width in a direction perpendicular to the stripe 14a (ie, in the <0-1-1> direction).
As shown in FIG. 1, a plurality of bars 11b are provided. After the off-angle substrate 11 is cleaved into a plurality of bars 11b, the bars 11b
The shape of the electrode 17a is checked by an optical microscope or confirmed by image recognition, and the cleavage end faces 11c, 1c of the bar 11b are checked.
It is determined which of 1d is set as the front output side. That is, the arrow of the electrode 17a is confirmed, and the side indicated by the arrow is determined to be the front output side.

After that, as shown in FIG.
For example, aluminum oxide (Al) is applied to the cleaved end face 11c on the front output side of the bar 11b while protecting the bars 7a and 17b.
₂ O ₃ ) film, silicon dioxide (SiO ₂ ) film, silicon nitride (S
i ₃ N ₄ ) film and silicon (Si) film are deposited and CVD (Ch
The reflectance control film 18a is formed by appropriately laminating the films by emical vapor deposition or sputtering.
At this time, the structure of the reflectance control film 18a is adjusted so that laser light used for a system or the like can be directly extracted. Also, the cleavage end face 11d on the rear output side of the bar 11b
Similarly, the reflectance control film 18b is formed in the same manner. The structure of the reflectance control film 18a is adjusted so that laser light used for an optical output monitor or the like can be extracted, or the laser light is not output when the optical output monitor is not required.

After the reflectance control films 18a and 18b are formed, the space between the electrodes 17a of the bar 11b is cleaved such that the stripe 14a is located substantially at the center. Thus, the semiconductor laser 10 as shown in FIG. 13 is formed.

Since the semiconductor laser 10 uses the off-angle substrate 11, the end faces 10a and 10b in the direction perpendicular to the stripe 14a are perpendicular to the top and bottom faces, but the end faces in the direction parallel to the stripe 14a. 10c, 1
0d is inclined by the off angle θ with respect to the top and bottom surfaces.
That is, the shapes of the end faces 10a and 10b are parallelograms inclined by the off angle θ. The laser light is emitted as a front output from the end face 10a in parallel with the stripe 14a. The front output side of the laser light is indicated by the arrow of the electrode 17a.

As described above, according to the semiconductor laser manufacturing method of the present embodiment, the planar shape of the electrode 17a is set to <01.
-1> It is formed so as to be asymmetrical in the direction, and the side on the front output side of the laser beam is indicated by a mark by the electrode 17a, so that the shape of the electrode 17a is confirmed by an optical microscope or image recognition. It is possible to easily determine which side is set as the front output side of the laser beam.
Therefore, when forming the reflectance control films 18a and 18b,
It is possible to reliably form the reflectance control film 18a on the front output side with respect to the one set as the front output side and the reflectance control film 18a on the rear output side with respect to the one set as the rear output side. Therefore, the front output side of the laser beam can be set to one extension direction side of the stripe 14a, and
It is possible to avoid the formation of different types of semiconductor lasers 10.

That is, when the semiconductor laser 10 is mounted on the package, there is no shift in the mounting position, so that the yield can be improved and the size of the package can be reduced. Further, the distance between other elements can be reduced, and high-density mounting can be achieved. Further, since there is no deviation in the relative positional relationship with other elements, for example, the sensitivity of the photodetector can be improved. In addition, since the near-field image and the far-field image can be limited to one type, it is possible to improve the performance such as read / write characteristics of an optical disk system using the same.

Further, according to the method of manufacturing a semiconductor laser according to the present embodiment, the shape of the electrode 17a is asymmetrical so as to indicate the forward output side. The direction can be specified without any hindrance for the purpose. Therefore, only by appropriately designing a lithography mask for forming an electrode,
The object can be achieved without increasing the number of manufacturing steps.

FIGS. 14 to 16 show a method of manufacturing a semiconductor laser according to a second embodiment of the present invention.
This semiconductor laser manufacturing method is the same as that of the first embodiment except that the shape of the isolation groove for inspection is asymmetrical instead of the electrode so as to indicate the front output side of the laser beam. . Therefore, here, the same portions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

The separation groove is defined as the off-angle substrate 11
This is for cutting off the electrical connection between the semiconductor lasers when the characteristic inspection of each semiconductor laser formed on the bar 11b is performed at the stage of cleaving the plurality of bars 11b.

In the present embodiment, first, a first cladding layer 12, an active layer 13, a second cladding layer 14, and a buried layer 15 are formed on an off-angle substrate 11 in the same manner as in the first embodiment. And a contact layer 16 are formed. Next, before forming the electrode, as shown in FIG. 14, the contact layer 16, the buried layer 15, the second clad layer 14, and a part of the active layer 13 are selectively removed by etching.
Separation grooves 29 are formed between the respective stripes 14a. However, the formation position of each separation groove 29 should not overlap the formation position of the electrode 27a shown by the broken line in FIG.

As shown in FIG. 15, a part of the separation groove 29 has an asymmetrical plane shape in the <01-1> direction (that is, the extension direction of the stripe 14a) when viewed from above. (Sawtooth shape). In other words, it is set here which side in the extension direction of the stripe 14a with the separation groove 29 as a mark is to be the front output side of the laser beam. Incidentally, here, the right side as viewed from the front is set as the front output side, and this is shown as a sawtooth shape. It should be noted that this mark will be used in a later step for the off-angle substrate 11.
Even if the semiconductor laser is cleaved and divided into a plurality of semiconductor lasers, the <01-1> direction is adjusted according to the size of the semiconductor laser so that at least one semiconductor laser is present in each semiconductor laser or for each minimum unit during mounting. Is formed repeatedly.

The plane shape of the separation groove 29 may be asymmetric so that the front output side of the laser beam can be identified.
Instead of the saw-tooth shape shown in FIG. 15, an arrow shape as described in the first embodiment may be used.

After forming the separation grooves 29, the electrodes 27a and 17b are formed in the same manner as in the first embodiment. However, unlike the first embodiment, the electrode 27a has a simple band shape. Subsequently, in the same manner as in the first embodiment, the off-angle substrate 11 is cleaved into a plurality of bars 11b, and it is determined based on the shape of the separation groove 29 that the laser beam is to be the front output side of the laser beam. The reflectance control film 18 is formed on the output side cleavage end face 11c.
a on the rear output side cleavage end face 11d.
Are formed respectively.

After forming the reflectance control films 18a and 18b, each semiconductor laser formed on the bar 11b is inspected. Thereafter, the bar 11b is cleaved into a plurality to form the semiconductor laser 20 as shown in FIG. Therefore, the front output side of the semiconductor laser 20 is indicated by the sawtooth shape of the separation groove 29.

As described above, according to the method of manufacturing the semiconductor laser according to the present embodiment, the planar shape of the separation groove 29 is set to <01.
-1>, the laser beam is formed to be asymmetrical in the direction, and the laser beam front output side is indicated by a mark formed by the separation groove 29. Therefore, similarly to the first embodiment, the laser beam front output side is used. Can be easily determined. Therefore, the sides on which the reflectance control films 18a and 18b are formed can be specified, and the formation of two types of semiconductor lasers 20 can be avoided.

Further, according to the method of manufacturing a semiconductor laser according to the present embodiment, since the separation groove 29 has an asymmetrical planar shape so as to indicate the front output side, each semiconductor laser is electrically separated. The direction can be specified without any trouble to the original purpose of the separation groove. Therefore, the object can be achieved without increasing the number of manufacturing steps only by appropriately designing the lithography mask for forming the separation groove.

In this embodiment, the separation groove 2
9 was formed to be asymmetrical in the <01-1> direction, but as shown in FIG.
In the case where the opening of FIG.
The planar shape of a may be a simple band shape, and the planar shape of the insulating film 39b may be asymmetric (for example, sawtooth shape or arrow shape) in the <01-1> direction. In that case, for example, after forming the separation groove 39a and before forming the electrode 27a,
Insulating film 3 made of silicon dioxide or silicon nitride by CVD
9, or an insulating film 39 made of silicon dioxide or aluminum oxide is formed by vapor deposition.

FIGS. 18 and 19 show a method of manufacturing a semiconductor laser according to the third embodiment of the present invention. The manufacturing method of this semiconductor laser is the same as that of the first embodiment except that a new mark is formed so as to indicate the front output side of the laser beam without deforming the shape of the electrode which is an existing component. This is the same as the embodiment. Therefore, here, the same portions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

In the present embodiment, first, the first clad layer 12, the active layer 13, the second clad layer 14, and the buried layer 15 are formed on the off-angle substrate 11 in the same manner as in the first embodiment. And a contact layer 16 are formed. Next, before the electrodes 47a are formed, marks 49 are formed between the stripes 14a as shown in FIG.
However, the formation position of each mark 49 should not overlap the formation position of the electrode 47a shown by the broken line in FIG.

The plane shape of the mark 49 is <01-
In the 1> direction (that is, the extension direction of the stripe 14a), the stripes 14a are formed to be asymmetric (for example, a line perpendicular to the base from the vertex is a triangle parallel to the stripe 14a). That is, it is set here which side in the extending direction of the stripe 14a to be the front output side of the laser beam by forming the mark. Incidentally, here, the right side is set as the front output side, and this is indicated by the vertex of the triangle. Note that, even when the off-angle substrate 11 is cleaved in a later step and divided into a plurality of semiconductor lasers, at least one mark is present in each semiconductor laser or in each minimum unit at the time of mounting. It is repeatedly formed in the <01-1> direction according to the size of the semiconductor laser.

The mark 49 is formed by, for example, an appropriate metal film, an insulating film of silicon dioxide, silicon nitride, or aluminum oxide, or a step formed by etching. At this time, the metal film can be formed by vapor deposition, the insulating film of silicon dioxide or silicon nitride can be formed by CVD, and the insulating film of silicon dioxide or aluminum oxide can be formed by vapor deposition. It can be used as it is. When the mark 49 is formed of a metal film, it is preferable that the mark 49 be formed of a metal different from that of the electrode 47a. For example, when the electrode 47a is formed of gold, the mark 49 is formed of aluminum (Al). As a result, the color and reflectance differ between the mark 49 and the electrode 47a.
Can be easily confirmed, and the front output side of the laser beam can be easily determined.

After each mark 49 is formed in this manner, the electrodes 47a and 17b are formed in the same manner as in the first embodiment.
To form However, unlike the first embodiment, the electrode 47a has a simple band shape. Subsequently, as in the first embodiment, the off-angle substrate 11 is cleaved into a plurality of bars 11b,
After determining which side is the front output side of the laser beam based on the shape of the mark 49, the reflectance control film 18a is provided on the cleavage end face 11c on the front output side, and the reflectance control film 18b is provided on the cleavage end face 11d on the rear output side. Form.

Thereafter, the bar 11b is cleaved into a plurality to form a semiconductor laser 40 as shown in FIG.
Therefore, the front output side of the semiconductor laser 40 is indicated by the apex of the triangular mark 49.

As described above, according to the method of manufacturing a semiconductor laser according to the present embodiment, the mark on the front output side of the laser light is indicated by the mark 49. It is easy to determine which side is set to the front output side of light. Therefore, the reflectance control films 18a, 1
8b can be specified, and the formation of two types of semiconductor lasers 40 can be avoided.

Further, by forming the mark 49 with a metal different from that of the electrode 47a, the mark 49 can be easily visually confirmed from the difference in color and reflectance, and the front output side can be easily identified. it can.

As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and can be variously modified within an equivalent range. For example, in each of the above embodiments, the marks 16, 29,
Although 39b and 49 are formed on the upper surface of the semiconductor laser, they may be formed on the bottom surface. That is, the planar shape of the electrode 17b instead of the electrode 17a in the first embodiment may be asymmetric, and the separation groove 29 is formed from the first cladding layer 12 to the active layer 13 in the second embodiment. You may.

In each of the above embodiments, the plane shapes of the marks 17a, 29, 39b, and 49 are asymmetric in the extending direction of the stripe 14a, but are asymmetric in the vertical direction of the stripe 14a. You may do so. That is, the mark 17
It suffices if the front output side of the laser beam can be specified by the planar shapes of a, 29, 39b, and 49.

Further, in the third embodiment,
Although the plane shape of the mark 49 is asymmetrical and the front output side of the laser beam is specified by the shape, the plane shape of the mark is not asymmetrical but the position of the mark on the top or bottom surface of the semiconductor laser. The output side may be specified.

[0052]

As described above, according to the method of manufacturing a semiconductor laser according to the present invention, the mark indicating the forward output side of the laser beam is formed. The one set as the output side can be easily determined, and the formation of two types of semiconductor lasers can be avoided. Therefore, it is possible to improve the yield, reduce the size of the package, achieve high-density mounting, improve the sensitivity of the photodetector, and improve the performance of the optical disk system, such as the read / write characteristics.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating one step in a method for manufacturing a semiconductor laser according to a first embodiment of the present invention.

FIG. 2 is a sectional view illustrating a step following FIG.

FIG. 3 is a cross-sectional view illustrating a step following FIG.

FIG. 4 is a cross-sectional view illustrating a part along the line AA of FIG. 3;

FIG. 5 is a sectional view illustrating a step following FIG.

FIG. 6 is a plan view illustrating one process shown in FIG.

FIG. 7 is a plan view illustrating the shape of the electrode shown in FIG.

8 is a plan view illustrating another shape of the electrode illustrated in FIG.

9 is a plan view illustrating another shape of the electrode illustrated in FIG.

FIG. 10 is a plan view illustrating another shape of the electrode illustrated in FIG.

FIG. 11 is a cross-sectional view illustrating a step following FIG. 5.

FIG. 12 is a sectional view illustrating a step following FIG.

FIG. 13 is a sectional view illustrating a step following FIG.

FIG. 14 is a cross-sectional view illustrating one step in a method for manufacturing a semiconductor laser according to the second embodiment of the present invention.

15 is a plan view illustrating a shape of a separation groove illustrated in FIG.

16 is a plan view illustrating another step in the method for manufacturing the semiconductor laser illustrated in FIG.

FIG. 17 is a cross-sectional view for explaining a modification of the method for manufacturing the semiconductor laser according to the second embodiment of the present invention.

FIG. 18 is a sectional view illustrating a step in a method for manufacturing a semiconductor laser according to a third embodiment of the present invention.

FIG. 19 is a plan view illustrating another step in the method for manufacturing the semiconductor laser illustrated in FIG.

FIG. 20 is a plan view illustrating a semiconductor laser manufactured by a conventional semiconductor laser manufacturing method.

FIG. 21 is a plan view illustrating a semiconductor laser manufactured by a conventional semiconductor laser manufacturing method.

FIG. 22 is a perspective view illustrating a semiconductor laser manufactured by a conventional method of manufacturing a semiconductor laser.

FIG. 23 is a perspective view illustrating a semiconductor laser manufactured by a conventional method of manufacturing a semiconductor laser.

FIG. 24 is a cross-sectional view illustrating a semiconductor laser manufactured by a conventional semiconductor laser manufacturing method.

FIG. 25 is a cross-sectional view illustrating a semiconductor laser manufactured by a conventional semiconductor laser manufacturing method.

[Explanation of symbols]

10, 20, 40, 50, 60 ... semiconductor laser, 10
a, 10b, 10c, 10d, 50a, 50b, 60
a, 60b: end face, 11: off-angle substrate, 11a: orientation flat, 11b: bar, 11c, 11d
... Cleaved end face, 12 ... First cladding layer, 13 ... Active layer,
14 ... second cladding layer, 14a, 54a, 64a ... stripe, 15 ... buried layer, 16 ... contact layer, 1
7a, 17b, 27a, 47a ... electrodes, 18a, 18b
... Reflectance control film, 29, 39a ... separation groove, 39b ... insulating film, 49 ... mark

Claims (5)

[Claims] 1. A method of manufacturing a semiconductor laser, comprising manufacturing a semiconductor laser by growing a plurality of crystal layers on an off-angle substrate, comprising: forming a mark indicating a forward output side of the laser light; A method for manufacturing a semiconductor laser, comprising: setting a front output side of a semiconductor laser. 2. The method according to claim 1, wherein the mark is formed by making the planar shape of the electrode asymmetric. 3. After growing a plurality of crystal layers, the off-angle substrate is separated into a plurality of pieces to produce a plurality of semiconductor lasers. A method of manufacturing a semiconductor laser for inspecting each semiconductor laser by forming a separation groove for interrupting connection, wherein the mark is formed by making the planar shape of the separation groove asymmetric. 2. A method for manufacturing a semiconductor laser according to item 1. 4. After growing a plurality of crystal layers, the off-angle substrate is separated into a plurality of semiconductor lasers to produce a plurality of semiconductor lasers. A method of manufacturing a semiconductor laser, wherein a separation groove for interrupting connection is formed, each semiconductor laser is inspected, and an insulating film covering the separation groove is formed, wherein the mark has an asymmetric planar shape of the insulating film. 2. The method of manufacturing a semiconductor laser according to claim 1, wherein the semiconductor laser is formed. 5. The method according to claim 1, wherein the mark is formed of a metal different from an electrode.