Semiconductor laser element and method for manufacturing the same, and semiconductor laser device

Abstract

The invention comprises: a semiconductor layer, which is composed of an n-type cladding layer (102) formed on the surface of an n-type GaAs substrate (101), an active layer (103) formed on the surface of the n-type cladding layer (102), a p-type cladding layer (104) having a ridge (104a, 105a) formed on the surface of the active layer (103), and a p-type contact layer (105) formed on the surface of the p-type cladding layer (104); an insulating film (150a, 150b) covering the surface of the semiconductor layer and having an opening on the surface of the p-type contact layer (105a); and a conductive layer, which is connected to the p-type contact layer (105a) via the opening and is formed on the surface of the insulating layer (150b) until a flat portion of the semiconductor layer adjacent to the ridge is provided, wherein a convex side wall is provided on the flat portion of the conductive layer near the ridge, and the side wall limits the expansion of solder to the vicinity of a non-luminous region, thereby preventing electrical short circuits between elements.

Description

Technical Field

[0001] The present application relates to a semiconductor laser element and a method for manufacturing the same, and a semiconductor laser device. Background Art

[0002] Semiconductor laser elements are mounted on a submount via solder in a junction-up or junction-down manner. When the purpose is to improve the characteristics during high-output and high-temperature operation, heat dissipation is generally ensured by using a junction-down arrangement.

[0003] In a multi-emitter semiconductor laser element having a plurality of light-emitting points, it is difficult to increase the size (width) of the semiconductor laser element as the number of light-emitting points increases from the viewpoints of high output, high performance, and cost reduction. Therefore, as the number of light-emitting points of a multi-emitter semiconductor laser element increases, the intervals between the light-emitting points become narrower, and thus when the multi-emitter semiconductor laser element is mounted on a submount in a junction-down manner, there is a problem that the solder flowing out during bonding with the submount is likely to come into contact with the adjacent light-emitting portion and electrode.

[0004] In contrast, for example, the following technology is disclosed in Patent Document 1: a conductive layer is provided between the surface of a semiconductor laser element and a submount to ensure spacing, and a recess is formed in the conductive layer and a space is provided to accommodate a solder layer formed on the surface of a submount electrode to prevent solder from flowing out when mounting on the submount.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-4064 (Paragraph 0024, Figure 2 )

[0006] However, the semiconductor laser element described in Patent Document 1 requires that the conductive layer be subjected to shape processing to form the recessed portion after the conductive layer is formed, which causes a problem of further increasing the manufacturing cost. Summary of the invention

[0007] The present application discloses a technology for solving the above-mentioned problems, and aims to provide a semiconductor laser element and a method for manufacturing the same, and a semiconductor laser device that can prevent electrical short circuits caused by solder flowing out when bonding to a submount and achieve reduced manufacturing costs.

[0008] The semiconductor laser element disclosed in the present application is characterized in that it comprises: a semiconductor layer composed of a first cladding layer formed on the surface of a semiconductor substrate, an active layer formed on the surface of the above-mentioned first cladding layer, a second cladding layer having a ridge formed on the surface of the above-mentioned active layer, and a contact layer formed on the surface of the above-mentioned second cladding layer; an insulating film covering the surface of the above-mentioned semiconductor layer and having an opening on the surface of the above-mentioned contact layer; and a conductive layer connected to the above-mentioned contact layer via the above-mentioned opening and formed on the surface of the above-mentioned insulating film until a flat portion of the above-mentioned semiconductor layer adjacent to the above-mentioned ridge is provided, and in the above-mentioned conductive layer, a side wall is provided on the above-mentioned flat portion close to the above-mentioned ridge.

[0009] The method for manufacturing a semiconductor laser element disclosed in the present application is characterized in that it includes the following steps: a step of forming an insulating film covering the surface of a semiconductor layer and having an opening on the surface of a contact layer, wherein the semiconductor layer is composed of a first cladding layer formed on the surface of a semiconductor substrate, an active layer formed on the surface of the first cladding layer, a second cladding layer having a ridge formed on the surface of the active layer, and a contact layer formed on the surface of the second cladding layer; a step of separating a base electrode into a first base electrode and a second base electrode having a pattern shape as a side wall on the surface of the insulating film, wherein the first base electrode is provided at a position close to the ridge on a flat portion provided in the semiconductor layer next to the ridge, and the second base electrode is provided on the surfaces of the contact layer and the insulating film, connected to the contact layer via the opening, surrounding the first base electrode, and covering the surface of the insulating film covering the flat portion; and a step of performing plating so that the current value supplied to the first base electrode is larger than the current value supplied to the second base electrode.

[0010] According to the present application, the side wall can limit the expansion of solder to the vicinity of the non-light emitting region, thereby preventing electrical short circuits between elements. In addition, since it can be easily formed, the manufacturing cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a plan view from the bonding side showing the structure of the semiconductor laser element according to the first embodiment.

[0012] Figure 2 This is a cross-sectional view showing the structure of the semiconductor laser element according to the first embodiment.

[0013] Figure 3 This is a cross-sectional view showing the structure of the semiconductor laser element according to the first embodiment.

[0014] Figure 4 It is a cross-sectional view showing the structure of a conventional semiconductor laser element.

[0015] Figure 5 It is a plan view on the bonding side showing another structure of the semiconductor laser element according to the first embodiment.

[0016] Figure 6 It is a plan view on the bonding side showing another structure of the semiconductor laser element according to the first embodiment.

[0017] Figure 7 It is a plan view on the bonding side showing another structure of the semiconductor laser element according to the first embodiment.

[0018] Figure 8 It is a cross-sectional view showing the structure of a semiconductor laser element according to the second embodiment.

[0019] Fig. 9 It is a cross-sectional view showing the structure of a semiconductor laser element according to a third embodiment.

[0020] Fig.10 This is a cross-sectional view for explaining a method for manufacturing a semiconductor laser element according to a fourth embodiment.

[0021] Fig.11 This is a flowchart showing the procedure of a method for manufacturing a semiconductor laser element according to a fourth embodiment. DETAILED DESCRIPTION

[0022] Implementation Method 1

[0023] Figure 1 It is a bonding-side plan view showing the structure of the semiconductor laser element 201 according to the first embodiment of the present application. Figure 2 yes Figure 1 AA section view, Figure 3 yes Figure 1 The BB cross-sectional views all show the installed state. Figures 1 to 3 As shown, the semiconductor laser element 201 includes a semiconductor layer, which is composed of an n-type GaAs substrate 101, an n-type cladding layer 102 as a first cladding layer, an active layer 103, a p-type cladding layer 104 as a second cladding layer, and a p-type contact layer 105 (105a, 105b). The n-type cladding layer 102, the active layer 103, the p-type cladding layer 104, and the p-type contact layer 105 are sequentially stacked on the main surface of the n-type GaAs substrate 101. The semiconductor laser device 301 is composed of a submount 110 and the semiconductor laser element 201.

[0024] In the light emitting region 190, a convex portion 104a is formed on the p-type cladding layer 104 stacked on the active layer 103 that becomes the light emitting point, and a ridge portion is formed by the p-type contact layer 105a stacked on the convex portion 104a. The surface of the semiconductor layer other than the surface of the p-type contact layer 105a is covered by an insulating film 150 (150a, 150b). On the surface of the p-type contact layer 105a, an electrode 120 that is a conductive layer in contact with the p-type contact layer 105a and a first gold plating layer 131 that is a conductive layer covering the electrode 120 are formed. The electrode 120 and the first gold plating layer 131 extend to a non-light emitting region 191 separated from the light emitting region 190. The semiconductor laser element 201 is provided with an isolation groove 151 whose bottom reaches the inside of the n-type cladding layer 102 between the light emitting regions 190, and the electrode 120 has a structure that is separated and electrically insulated for each light emitting region 190 by the isolation groove 151 and the insulating film 150a.

[0025] The non-light emitting region 191 is provided by covering the side of the light emitting region 190 with the insulating film 150b. In the first embodiment, the non-light emitting region 191 has the same structure as the semiconductor layer of the light emitting region 190, a flat portion 104b is formed on the p-type cladding layer 104, and the surface of the p-type contact layer 105b stacked on the flat portion 104b is covered by the insulating film 150b.

[0026] In the flat part of the non-luminous area 191, near the luminous area 190, a convex portion serving as a side wall, namely the second gold-plated layer 132 (132a, 132b), is formed in a C-shaped pattern on the first gold-plated layer 131. By adopting a two-layer gold-plated structure, the first gold-plated layer 131 and the second gold-plated layer 132 serving as a conductive layer are joined to the electrode 111 on the sub-base 110 via the solder 140.

[0027] Figure 4 FIG. 1 is a cross-sectional view showing a conventional semiconductor laser element mounted in a state. Figure 4As shown, in the conventional semiconductor laser element, the second gold-plated layer 532 is disposed on the first gold-plated layer 131, thereby ensuring the interval between the surface of the semiconductor laser element and the submount 110. Therefore, when the semiconductor laser element is mounted on the submount 110, even if the solder 140 flows out and spreads in the lateral direction, it is difficult to contact the light-emitting regions 190-1 and 190-2 located above. However, in the conventional semiconductor laser element, there is no way to limit the range of the solder 140 spreading in the lateral direction to the vicinity of the non-light-emitting region 191-1. Therefore, when mounted on the submount 110, if the solder 140 contacts the electrode connected to the adjacent light-emitting region 190-2 and becomes an electrical short circuit, the problem of not being able to operate the multiple light-emitting points of the semiconductor laser element independently arises. In order to prevent the above-mentioned electrical short circuit without increasing the interval between the light emitting areas 190-1 and 190-2 of the semiconductor laser element, narrowing the width of the electrode 111 of the submount to ensure sufficient interval for the lateral expansion of the solder 140 is one strategy. However, if the width of the electrode 111 of the submount is narrowed, high precision is required in the alignment when mounting the semiconductor laser element on the submount 110, which creates new problems.

[0028] In the first embodiment, when the semiconductor laser element 201 is mounted on the submount 110, a second gold-plated layer 132 (132a, 132b) formed in a C-shaped pattern in the non-luminous region 191 is used to join the solder 140 on the electrode 111 of the submount 110 in a manner that surrounds the solder 140. This allows the middle portion 132a of the C-shaped portion of the second gold-plated layer 132 to function as a wall that prevents the solder 140 from flowing out of the luminous region 190, and allows the two end portions 132b of the C-shaped portion of the second gold-plated layer 132 to function as walls that prevent the solder 140 from flowing out of the end face of the semiconductor laser element 201. This allows the range to which the solder 140 extends to be limited to the central portion of the C-shaped portion of the second gold-plated layer 132, i.e., the non-luminous region 191.

[0029] In addition, since the semiconductor laser element 201 and the submount 110 are joined in the non-light-emitting region 191, even if the second gold plating layer 132 (132a, 132b) is thickened, the stress caused thereby will not be applied or will be slightly applied to the light-emitting region 190, and thus the light-emitting characteristics of the semiconductor laser element 201 will not be damaged.

[0030] As described above, the semiconductor laser element 201 according to the first embodiment includes: a semiconductor layer including an n-type cladding layer 102 formed on the surface of an n-type GaAs substrate 101, an active layer 103 formed on the surface of the n-type cladding layer 102, a p-type cladding layer 104 having ridges 104a and 105a formed on the surface of the active layer 103, and a p-type contact layer 105 formed on the surface of the p-type cladding layer 104; and an insulating film 150 (150a, 150b) covering the surface of the semiconductor layer and provided on the p-type contact layer 105. The surface of the p-type contact layer 105a has an opening; and a conductive layer (electrode 120, first gold-plated layer 131), connected to the p-type contact layer 105a through the opening, is formed on the surface of the insulating film 150b until the flat portion provided on the semiconductor layer adjacent to the ridge, and a convex portion (second gold-plated layer 132) serving as a side wall is provided on the flat portion of the conductive layer near the ridge, so that the convex portion as the side wall can limit the expansion of the solder to the vicinity of the non-luminous region, thereby preventing electrical short circuits between elements. In addition, since it can be easily formed, the manufacturing cost can be suppressed.

[0031] In addition, although the convex portion as the side wall is formed into the C-shaped second gold plating layer 132 in the first embodiment, the present invention is not limited to this. Figure 5 1 is a plan view of the bonding side showing other structures of the semiconductor laser element of embodiment 1. Figure 5 As shown, the convex portion as the side wall may also be provided as a comb-shaped second gold-plated layer 232. In this case, when the semiconductor laser element is joined to the submount, not only can the range where the solder spreads be limited to the vicinity of the non-luminous region, but also, since the range where the solder spreads is divided into small regions by the comb-shaped shape, the solder can be prevented from spreading in a biased manner. In addition, since the contact area between the solder and the first gold-plated layer and the second gold-plated layer increases, it is expected that the contact resistance will be reduced and the joining will be stabilized.

[0032] in addition, Figure 6 as well as Figure 7 1 is a plan view of the bonding side showing another structure of the semiconductor laser element of the first embodiment. As in the second gold-plated layers 332 and 432, the convex portion as the side wall is formed in the Figure 6 In the case of making the wall thickness of the end thinner than the center, Figure 7In the case of the above, the center wall thickness is formed thinner than the end portion, so that not only the range of solder expansion is limited to the vicinity of the non-light-emitting area, but also the offset position of the solder 140 can be controlled. When the semiconductor laser element 201 and the submount 110 are mounted, the expansion of the solder 140 is biased toward the thin-walled area of ​​the second gold-plated layer 432 because the second gold-plated layer 432 serves as a barrier. In this way, by changing the wall thickness of the second gold-plated layer 432 in a manner that the solder 140 is offset relative to the resonator direction, the position where the stress caused by the solder 140 is concentrated can be controlled. In addition, since the contact area between the solder 140 and the first gold-plated layer 131 and the second gold-plated layer 432 increases, it can be expected that the contact resistance will be reduced and the bonding will be stabilized.

[0033] Implementation Method 2

[0034] In the first embodiment, the convex portion as the side wall is formed in the shape of the second gold plating layer 132 , but in the second embodiment, a case where it is formed in the shape of the underlying insulating film will be described.

[0035] Figure 8 FIG. 2 is a cross-sectional view showing the structure of a semiconductor laser element 202 according to Embodiment 2 of the present application, and shows a mounted state. Figure 8 As shown, in the semiconductor laser element 202 of the second embodiment, instead of the second gold plating layer 132 of the first embodiment, a convex portion 150c formed of an insulating film is provided as a side wall in a C-shaped pattern at a position close to the light emitting region 190 of the insulating film 150b covering the flat portion of the semiconductor layer, that is, the p-type contact layer 105b in the non-light emitting region 191. The convex portion 150c formed of the insulating film is covered by the electrode 120 so as to include the insulating film 150b on the flat portion of the p-type contact layer 105b in the non-light emitting region 191, and the electrode 120 is covered by the first gold plating layer 131. The other structures of the semiconductor laser element 202 of the second embodiment are the same as those of the semiconductor laser element 201 of the first embodiment, and the same reference numerals are given to corresponding parts and their description is omitted.

[0036] In the second embodiment, when the semiconductor laser element 202 is mounted on the submount 110, a convex portion 150c of an insulating film formed in a C-shaped pattern on the non-luminous region 191 is used to join the solder 140 on the electrode 111 of the submount 110 in a manner that surrounds the solder 140. The convex portion 150c thereby functions as a wall that prevents the solder 140 from flowing out toward the luminous region 190 and the side end surface of the luminous portion of the semiconductor laser element 202, thereby limiting the range to which the solder 140 extends to the central portion of the C-shape of the convex portion 150c, i.e., the non-luminous region 191.

[0037] In addition, after the solder 140 is preferably arranged on the electrode 111 of the submount 110 in a manner such that the convex portion 150c of the insulating film is located on the outside (i.e., the convex portion 150c of the insulating film is located in a direction to prevent the solder 140 from flowing out), the semiconductor laser element 202 is connected to the electrode 111 of the submount 110 using the solder 140.

[0038] As described above, according to the semiconductor laser element 202 involved in the second embodiment, the convex portion 150c formed of the insulating film is provided at a position close to the light emitting region 190 of the insulating film 150b covering the flat portion of the non-light emitting region 191, and is covered by the electrode 120 and the first gold plating layer 131. Therefore, the convex portion as the side wall can limit the spread of the solder to the vicinity of the non-light emitting region, thereby preventing electrical short circuits between elements. In addition, since it can be easily formed, the manufacturing cost can be suppressed.

[0039] Implementation 3

[0040] Although the convex portion as the side wall is formed of an insulating film in the second embodiment, a case where it is formed of a semiconductor layer will be described in the third embodiment.

[0041] Fig. 9 FIG. 2 is a cross-sectional view showing the structure of the semiconductor laser element 203 according to the third embodiment of the present application, and shows the mounted state. Fig. 9 As shown, in the semiconductor laser element 203 of the third embodiment, instead of the second gold plating layer 132 of the first embodiment and the convex portion 150c of the insulating film of the second embodiment, convex portions 104b and 105b formed of a semiconductor layer are formed in a C-shaped pattern as a side wall at a position close to the light emitting region 190, and are hollowed out so as to form a flat portion of the p-type cladding layer 104 as a semiconductor layer on the end side. The surface of the semiconductor layer is covered with the insulating film 150 (150a, 150b) including the surface of the convex portions 104b and 105b in addition to the surface of the p-type contact layer 105a. The convex portions 104b and 105b formed of the semiconductor layer are covered with the electrode 120 so as to include the surface of the p-type contact layer 105a to the end of the flat portion of the p-type cladding layer 104, and the electrode 120 is covered with the first gold plating layer 131. The other structures of the semiconductor laser element 203 according to the third embodiment are the same as those of the semiconductor laser element 201 according to the first embodiment, and corresponding parts are denoted by the same reference numerals and their description is omitted.

[0042] In the third embodiment, when the semiconductor laser element 203 is mounted on the submount 110, the convex portions 104b and 105b of the semiconductor layer formed in a C-shaped pattern in the non-luminous region 191 are used to join the solder 140 on the submount 110 in a manner of surrounding the solder 140. The convex portions 104b and 105b thereby function as walls to prevent the solder 140 from flowing out toward the luminous region 190 and the side end faces of the luminous portion of the semiconductor laser element 203, thereby limiting the range to which the solder 140 extends to the central portion of the C-shape of the convex portions 104b and 105b, i.e., the non-luminous region 191.

[0043] In addition, after the solder 140 is preferably arranged on the electrode 111 of the submount 110 in a manner such that the convex portions 104b, 105b of the semiconductor layer are located on the outside (i.e., the convex portions 104b, 105b of the semiconductor layer are located in a direction that prevents the solder 140 from flowing out), the semiconductor laser element 203 is joined to the submount 110 using the solder 140.

[0044] As described above, according to the semiconductor laser element 203 involved in the third embodiment, the convex portions 104b and 105b formed of the semiconductor layer are provided near the light emitting region 190 and covered by the insulating film 150b, the electrode 120 and the first gold plating layer 131. Therefore, the convex portions as the side walls can limit the expansion of the solder to the vicinity of the non-light emitting region, thereby preventing electrical short circuits between elements. In addition, since it can be easily formed, the manufacturing cost can be suppressed.

[0045] Implementation 4

[0046] In the fourth embodiment, a manufacturing method for forming the first gold-plated layer 131 and the second gold-plated layer 132 of the first embodiment through a single plating process will be described.

[0047] Fig.10 It is a cross-sectional view for explaining a method for manufacturing the semiconductor laser element 204 according to the fourth embodiment of the present application, and shows a mounted state. Fig.11 This is a flowchart showing the procedure of the plating process of the semiconductor laser element 204 according to the fourth embodiment.

[0048] First, initially, on a semiconductor layer consisting of an n-type cladding layer 102 formed on the surface of an n-type GaAs substrate 101, an active layer 103 formed on the surface of the n-type cladding layer 102, a p-type cladding layer 104 having ridges 104a, 105a formed on the surface of the active layer 103, and a p-type contact layer 105a formed on the surface of the p-type cladding layer 104, an insulating film 150 (150a, 150b) is formed that covers the surface of the above-mentioned semiconductor layer and has an opening on the surface of the p-type contact layer 105a (step S1101).

[0049] Then, if Fig.10 As shown, on the p-type contact layer 105a and the insulating film 150 (150a, 150b), the electrode 120 serving as the base is separated into the electrode 120a serving as the first base electrode and the electrode 120b serving as the second base electrode, wherein the electrode 120a is formed at a position close to the ridges 104a, 105 on the flat portion of the semiconductor layer provided next to the ridges 104a, 105a, and a second gold-plated layer 132 having a pattern such as a C-shape is to be stacked, and the electrode 120b is connected to the p-type contact layer 105a via an opening, surrounds the electrode 120a, and covers the surface of the insulating film 150b covering the flat portion of the semiconductor layer provided next to the ridges 104a, 105a (step S1102).

[0050] Next, the electrodes 120a and 120b formed separately are powered with different current values, and the second gold-plated layer 132 and the first gold-plated layer 131 are formed at the same time (step S1103). In order to make the second gold-plated layer 132 thicker than the first gold-plated layer 131, the current value powered to the electrode 120a is greater than that to the electrode 120b. In addition, at this time, the plating of the first gold-plated layer 131 and the second gold-plated layer 132 is developed not only in the thickness direction but also in the lateral direction.

[0051] Finally, since the first gold-plated layer 131 and the second gold-plated layer 132 also develop in the lateral direction, the first gold-plated layer 131 and the second gold-plated layer 132 are connected and conducted (step S1104 ), and each reaches a predetermined thickness.

[0052] As described above, the method for manufacturing a semiconductor laser element according to the fourth embodiment includes the following steps: a step of forming an insulating film 150 (150a, 150b) covering the surface of a semiconductor layer and having an opening on the surface of a p-type contact layer 105a, the semiconductor layer being composed of an n-type cladding layer 102 formed on the surface of an n-type GaAs substrate 101, an active layer 103 formed on the surface of the n-type cladding layer 102, a p-type cladding layer 104 having ridges 104a and 105a formed on the surface of the active layer 103, and a p-type contact layer 105a formed on the surface of the p-type cladding layer 104; and a step of separating a base electrode 120 into an electrode 120a and an electrode 120b on the insulating film 150b, the electrode 120a being formed beside the ridges 104a and 105a. A second gold-plated layer 132 having a C-shaped pattern, for example, is stacked on the flat portion of the semiconductor layer near the ridges 104a and 105a. The electrode 120b is formed on the p-type contact layer 105a and the insulating film 150b, connected to the p-type contact layer 105a via the opening, surrounds the electrode 120a, and covers the surface of the insulating film 150b covering the flat portion of the semiconductor layer next to the ridges 104a and 105a. The plating process is performed by making the current value supplied to the electrode 120a greater than the current value supplied to the electrode 120b. Therefore, the first gold-plated layer 131 and the second gold-plated layer can be easily formed. The convex portion as the side wall limits the expansion of the solder to the vicinity of the non-luminous area, which can not only prevent electrical short circuits between components but also suppress manufacturing costs.

[0053] This application describes various illustrative embodiments and examples, but the various features, forms and functions described in one or more embodiments are not limited to the application of a specific embodiment, and can also be applied to the embodiments alone or in various combinations. Therefore, countless unillustrated variations can be imagined within the technical scope disclosed in the specification of this application. For example, it includes the case where at least one constituent element is deformed, added or omitted, and also includes the case where at least one constituent element is extracted and combined with constituent elements of other embodiments.

[0054] Description of Reference Numerals

[0055] 102...n-type cladding layer (first cladding layer); 103...active layer; 104...p-type cladding layer (second cladding layer); 104a...p-type cladding layer (ridge); 105...p-type contact layer; 105a...p-type contact layer (ridge); 120...electrode; 120a...electrode; 131...first gold-plated layer; 132...second gold-plated layer; 150, 150a, 150b...insulating film; 201, 202, 203...semiconductor laser element; 301...semiconductor laser device.

Claims

1. A semiconductor laser element, wherein a semiconductor laser element formed on a surface of a semiconductor substrate is bonded to a submount in a junction-down manner, characterized in that: have: A semiconductor layer, comprising a first cladding layer formed on a surface of the semiconductor substrate, an active layer formed on a surface of the first cladding layer, a second cladding layer having a ridge formed on a surface of the active layer, and a contact layer formed on a surface of the second cladding layer; an insulating film covering the surface of the semiconductor layer and having an opening on the surface of the contact layer; a conductive layer connected to the contact layer via the opening and formed on the surface of the insulating film up to the flat portion of the semiconductor layer adjacent to the ridge; as well as The convex portion as the side wall is formed on the flat portion near the ridge portion so as to surround the solder, The protrusion limits the range where the solder spreads to the non-light emitting area, and The protrusion and the flat portion are bonded to electrodes on the submount via the solder.

2. The semiconductor laser element according to claim 1, wherein The convex portion is formed in a C-shape.

3. The semiconductor laser element according to claim 1, wherein The convex portion is formed in a comb shape.

4. The semiconductor laser element according to claim 1, wherein The protrusion changes the wall thickness in the plan view direction.

5. The semiconductor laser device according to any one of claims 1 to 4, wherein: The protrusion is formed by the conductive layer.

6. The semiconductor laser device according to any one of claims 1 to 4, wherein: The protrusion is formed by the insulating film, and a surface of the protrusion is covered by the conductive layer.

7. The semiconductor laser device according to any one of claims 1 to 4, wherein: The protrusion is formed of the semiconductor layer and is covered by the insulating film and the conductive layer.

8. A semiconductor laser device, characterized in that: The semiconductor laser element according to any one of claims 1 to 7 is bonded to an electrode provided on the surface of a submount via solder and through the conductive layer corresponding to the flat portion of the semiconductor laser element and the conductive layer corresponding to the wall surface of the side wall opposite to the ridge portion.

9. A method for manufacturing a semiconductor laser element, characterized in that: The process includes the following: A step of forming an insulating film covering the surface of a semiconductor layer and having an opening on the surface of a contact layer, wherein the semiconductor layer is composed of a first cladding layer formed on the surface of a semiconductor substrate, an active layer formed on the surface of the first cladding layer, a second cladding layer having a ridge formed on the surface of the active layer, and the contact layer formed on the surface of the second cladding layer; A step of separating a base electrode into a first base electrode and a second base electrode in a top view shape of a side wall on the surface of the insulating film, wherein the first base electrode is formed at a position close to the ridge portion of a flat portion provided in the semiconductor layer next to the ridge portion, and the second base electrode is formed on the surfaces of the contact layer and the insulating film, connected to the contact layer via the opening, surrounding the first base electrode, and covering the surface of the insulating film covering the flat portion; and A step of performing plating by making the current value supplied to the first base electrode larger than the current value supplied to the second base electrode.

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