JP2019129219A - Semiconductor laser element and semiconductor laser device - Google Patents

Abstract

To provide a semiconductor laser element, and the like, capable of restraining warpage incident to temperature change, while securing bond strength with a support substrate.SOLUTION: A semiconductor laser element 1 includes a board 10, and a laminate structure 20 consisting of a first conductivity type layer, an active layer and a second conductivity type layer, the second conductivity type layer includes multiple first ridges (light emission ridge R) becoming a current injection path to the active layer, and a second ridge (dummy ridge S) provided at a position adjacent to at least one first ridge out of the multiple first ridges, and does not become the current injection path to the active layer. A second metal layer (pad electrode 50) formed continuously above the multiple first ridge and the second ridge is thicker than a first metal layer formed on the underside of the board 10, and on the end side ridge located at the end out of the multiple second ridges, a first portion separated from the first ridge has an area smaller than that of a second portion close to the first ridge.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a semiconductor laser device and a semiconductor laser device.

  Since semiconductor laser elements have advantages such as long life, high efficiency, and small size, they are used as light sources for various applications including image display devices such as projectors and displays. In recent years, research and development of a high-power semiconductor laser element of a watt class exceeding 1 watt as a light source of a laser processing apparatus has been performed.

  In the semiconductor laser device, laser light is generated by injecting current into the emitter (light emitting portion), but the upper limit of the emitter width is about several tens of μm from the viewpoint of uniformity of current distribution and control of light distribution. is there. On the other hand, when high-power laser light is emitted from one emitter, the optical density of the front end surface from which the laser light is emitted becomes too high, and there is a possibility that COD (Catalytic Optical Damage) occurs on the front end surface. Therefore, a semiconductor laser device having a laser array (multi-emitter) structure in which a plurality of emitters are integrated has been proposed in order to emit laser light with high output.

  Patent Document 1 discloses a conventional semiconductor laser device having such a laser array structure. FIG. 13 shows a cross-sectional structure of a conventional semiconductor laser device 100 disclosed in Patent Document 1.

  In the conventional semiconductor laser device 100 shown in FIG. 13, a laminated structure 120 composed of a plurality of semiconductor layers is formed on a substrate 110, and a voltage is applied to the p-side electrode 141 and the n-side electrode 142. Current flows in the stacked structure 120. At this time, electrons and holes supplied from the n-type cladding layer 121 and the p-type cladding layer 126 in the stacked structure 120 are recombined in the active layer 123, and are amplified by stimulated emission and reflected by both end faces of the device. The laser is oscillated by (resonance) and emitted as laser light. Since the semiconductor laser device 100 has the ridge portion R, the supply of electrons and holes is performed directly below the ridge portion R. In the ridge stripe semiconductor laser device 100 having the ridge portion R, electrons, holes, and light are confined immediately below the ridge portion R, so that the threshold value of the laser oscillation is lowered and the transverse mode control of the laser beam is performed. Can.

  In the semiconductor laser device 100 having the laser array structure, a plurality of ridge portions R are arranged corresponding to a plurality of emitters. In the semiconductor laser device 100 shown in FIG. 13, a dummy ridge portion S is provided between adjacent ridge portions R. Since the insulating film 130 exists in the dummy ridge portion S, the current from the p-side electrode 141 is not injected into the active layer 123. Therefore, the active layer 123 immediately below the dummy ridge portion S does not emit light.

  Thus, light emission is achieved by providing the dummy ridge portion S not having the current injection function to the active layer 123 between the original ridge portions R (light emission ridge portion R) having the current injection function to the active layer 123. The ridge spacing can be narrowed for all the ridges including the ridges R and the dummy ridges S. Thereby, when the semiconductor laser element 100 is mounted on a support base such as a submount by the face-down method, the contact area between the semiconductor laser element 100 and the support base can be increased. As a result, it is possible to disperse the stress caused by the distortion remaining in the semiconductor laser device 100 after mounting on the submount.

Japanese Patent Application Laid-Open No. 2007-073669

  The p-side electrode 141 of the semiconductor laser device 100 disclosed in Patent Document 1 is formed continuously to the ridge portion R which is a light emitting ridge portion and the dummy ridge portion S. For this reason, when the semiconductor laser element 100 is mounted on the submount by the face-down method, the p-side electrode 141 functions as a pad electrode connected to the submount.

  Since the p-side electrode and the pad electrode are made of a metal material, the linear expansion coefficient is different from that of a semiconductor layer made of a semiconductor material. Further, the thickness of the p-side electrode, the thickness of the pad electrode, or the thickness of the electrode including the p-side electrode and the pad electrode is often different from the thickness of the n-side electrode, specifically, n It is thicker than the side electrode.

  For this reason, when the p-side electrode and / or the pad electrode and the semiconductor layer are thermally expanded as the temperature rises, the entire semiconductor laser element is warped. When the semiconductor laser element is warped, the emitters (light emitting points) of the respective light emitting ridge portions are not aligned on a straight line according to the warped shape. As a result, in the semiconductor laser element having the laser array structure, a plurality of laser beams are not aligned on a straight line.

  Here, the plurality of laser beams emitted from the semiconductor laser elements having the laser array structure are condensed and combined using an optical element such as a cylindrical lens. Such an optical element is generally configured to collect a plurality of laser beams arranged in a straight line.

  Therefore, when the semiconductor laser element is warped and the plurality of laser beams are not aligned on a straight line, the coupling efficiency between the plurality of laser beams and the optical element is lowered.

  On the other hand, if the pad electrode (or p-side electrode) continuously formed on the ridge portion R and the dummy ridge portion S which are the light emitting ridge portion is separated or the area is made too small, the semiconductor laser device When mounted on the support base, the bonding strength between the pad electrode of the semiconductor laser element and the support base may be reduced.

  The present disclosure has been made to solve such a problem, and a semiconductor laser device and a semiconductor capable of suppressing warpage due to temperature change while securing the bonding strength with a support base such as a submount. It aims at providing a laser device.

  In order to achieve the above object, one aspect of a semiconductor laser device according to the present disclosure includes a first conductive type substrate, a first conductive type layer formed on the first conductive type substrate, and the first conductive type An active layer formed on the layer, and a second conductive type layer formed on the active layer, wherein the first conductive type substrate, the first conductive type layer, the active layer, and the second conductive type The laminated structure formed of the mold layer has a pair of opposing end faces to be resonator end faces, and the second conductivity type layer has a longitudinal direction in a direction orthogonal to the pair of end faces, and to the active layer A plurality of first ridges serving as a current injection path, and a plurality of second ridges having a longitudinal direction in a direction orthogonal to the pair of end faces and not serving as a current injection path to the active layer; The plurality of second ridge portions are provided at least at both ends of the plurality of first ridge portions. And a first metal layer is formed on the lower surface of the first conductive type substrate, and the plurality of first ridge portions and the plurality of second ridge portions are formed on the lower surface of the first conductivity type substrate. A second metal layer is continuously formed, and the second metal layer is thicker than the first metal layer, and on the end side ridge portion, a first portion separated from the first ridge portion is The area is smaller than that of the second portion close to the first ridge portion.

  Further, one aspect of a semiconductor laser device according to the present disclosure includes the above-described semiconductor laser device and a submount, and the semiconductor laser device is configured such that the first ridge portion side and the second ridge portion side are the submount Bonded to.

  It is possible to realize a semiconductor laser element and a semiconductor laser device that can suppress warping due to a temperature change while securing a bonding strength with a support base such as a submount.

1 is a perspective view of a semiconductor laser device according to an embodiment. FIG. 2 is a perspective view of the semiconductor laser device with the pad electrode omitted in FIG. It is a top view of the semiconductor laser device according to the embodiment. It is sectional drawing of the semiconductor laser element which concerns on embodiment in the IV-IV line of FIG. (A) of FIG. 5 is an enlarged top view of the semiconductor laser device according to the embodiment, and (b) of FIG. 5 is an enlarged cross-sectional view of the same semiconductor laser device. FIG. 1 is a cross-sectional view of a semiconductor laser device according to an embodiment. It is an enlarged top view of the periphery of the end side ridge portion of the semiconductor laser device in the embodiment. It is an enlarged top view of the periphery of the end side ridge part of the semiconductor laser device of the comparative example. 6 is a perspective view of a semiconductor laser device according to Modification 1. FIG. 10 is a perspective view of a semiconductor laser device according to Modification 2. FIG. 10 is a perspective view of a semiconductor laser element according to Modification 3. FIG. 10 is a perspective view of a semiconductor laser device according to Modification 4. FIG. FIG. 1 is a cross-sectional view of a conventional semiconductor laser device disclosed in Patent Document 1;

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Each embodiment described below shows one specific example of the present disclosure. Accordingly, the numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps (steps) and order of steps, etc. shown in the following embodiments are merely examples and limit the present disclosure. It is not the main point to do. Therefore, among the components in the following embodiments, components that are not described in the independent claims indicating the highest concept of the present disclosure are described as optional components.

  Each figure is a mimetic diagram and is not necessarily illustrated strictly. Therefore, the scale and the like do not necessarily match in each figure. In the drawings, substantially the same components are denoted by the same reference numerals, and redundant description will be omitted or simplified.

Embodiment
First, the configuration of the semiconductor laser device 1 according to the embodiment will be described with reference to FIGS. FIG. 1 is a perspective view of a semiconductor laser device 1 according to an embodiment. FIG. 2 is a perspective view of the semiconductor laser device 1 with the pad electrode 50 omitted in FIG. FIG. 3 is a top view of the semiconductor laser device 1. 4 is a cross-sectional view of the semiconductor laser device taken along line IV-IV in FIG.

  As shown in FIGS. 1 to 4, the semiconductor laser device 1 includes a substrate 10, a stacked structure 20 formed on the substrate 10, an insulating layer 30 covering the stacked structure 20, and the stacked structure 20. A first electrode 41 and a second electrode 42 for injecting a current, and a pad electrode 50 are provided. In the present embodiment, the semiconductor laser element 1 is a nitride semiconductor laser element made of a nitride semiconductor material.

  The substrate 10 is, for example, a semiconductor substrate such as GaN or SiC or a sapphire substrate. The thickness of the substrate 10 is, for example, 50 μm to 120 μm. In the present embodiment, the substrate 10 is a first conductivity type substrate. Specifically, a single crystal n-type GaN substrate with a thickness of 100 μm is used as the substrate 10.

  The laminated structure 20 has a pair of first end face 20 a and second end face 20 b opposed in the cavity length direction of the semiconductor laser device 1. The pair of first end faces 20 a and the second end face 20 b are device end faces of the semiconductor laser device 1. The pair of first end faces 20a and the second end face 20b are resonator end faces of the laser light, and play a role of a reflection surface (mirror) in laser oscillation. In the present embodiment, the first end face 20a is a front end face from which laser light is emitted, and the second end face 20b is a rear end face which is an element end face on the opposite side to the first end face 20a. The first end surface 20a and the second end surface 20b are cleavage surfaces formed by cleavage, for example. The length in the cavity length direction of the multilayer structure 20 (that is, the length of the semiconductor laser 1) is, for example, 0.8 to 4 mm, and is 2 mm in the present embodiment.

  Although not shown, a reflective film made of a dielectric multilayer film is formed on the first end face 20a and the second end face 20b as an end face coat film for controlling the reflectance. Specifically, a reflective film having a low reflectivity is formed on the first end face 20a, and a reflective film having a high reflectivity is formed on the second end face 20b.

  The stacked structure 20 is a semiconductor stacked body made of a semiconductor material, and includes a first conductivity type first cladding layer 21, an active layer 23 formed on the first cladding layer 21, and an active layer 23. And a second cladding layer 26 of the second conductivity type formed. The first cladding layer 21, the active layer 23, and the second cladding layer 26 are made of, for example, a nitride semiconductor.

  In the present embodiment, the laminated structure 20 further includes a first guide layer 22, a second guide layer 24, an electron barrier layer 25, and a contact layer 27. Specifically, the stacked structure 20 includes a first cladding layer 21, a first guide layer 22, an active layer 23, a second guide layer 24, an electron barrier layer 25, The second clad layer 26 and the contact layer 27 are stacked in this order. In addition, the layer which comprises the layer structure of the laminated structure 20 is not limited to said layer, In addition to said layer, the strain relief layer etc. may be formed.

The first cladding layer 21 is formed on the substrate 10. The first cladding layer 21 is a first conductivity type layer made of a semiconductor material of a first conductivity type. For example, the first cladding layer 21 is an n-type cladding layer made of a nitride semiconductor material such as n-type Al _x GaN (0 <x <1) doped with an impurity. In the present embodiment, the first cladding layer 21 is composed of n-AlGaN. The thickness of the first cladding layer 21 is preferably 0.5 μm or more.

The first guide layer 22 is formed on the first cladding layer 21. The first guide layer 22 is an n-side guide layer formed on the n-side. For example, the first guide layer 22 is made of a nitride semiconductor material such as n-type In _x GaN (0 ≦ x <1) or the like which is not intentionally doped with an impurity or undoped. In the present embodiment, the first guide layer 22 is made of n-GaN. The first guide layer 22 may be either a single layer or a plurality of layers, but the total thickness of the first guide layer 22 is preferably 0.2 μm or more.

The active layer 23 (light emitting layer) is formed on the first guide layer 22. The active layer 23 is made of, for example, a single layer or multiple layers of nitride semiconductor material. Specifically, the active layer 23 is a quantum well structure formed of In _x GaN (0 <x <1) and / or Al _x In _y GaN (x, y 1 1). In the present embodiment, the active layer 23 is an InGaN quantum well structure.

The second guide layer 24 is formed on the active layer 23. The second guide layer 24 is a p-side guide layer formed on the p side. For example, the second guide layer 24 is made of a nitride semiconductor material such as undoped or n-type In _x GaN (0 ≦ x <1). In the present embodiment, the second guide layer 24 is made of u-GaN. The second guide layer 24 may be either a single layer or a plurality of layers, but the total thickness of the second guide layer 24 is preferably 0.05 μm or more.

  The electron barrier layer 25, the second cladding layer 26, and the contact layer 27 are second conductivity type layers made of a second conductivity type semiconductor material having a conductivity type different from the first conductivity type. In the present embodiment, the second conductivity type is p-type.

The electron barrier layer 25 is formed on the second guide layer 24. For example, the electron barrier layer 25 is a p-type electron barrier layer made of a nitride semiconductor material such as p-type Al _x GaN (0 ≦ x <1) doped with an impurity. In the present embodiment, the electron barrier layer 25 is made of p-AlGaN. The thickness of the electron barrier layer 25 is preferably 1 to 50 μm.

The second cladding layer 26 is formed on the electron barrier layer 25. For example, the second cladding layer 26 is a p-type cladding layer made of a nitride semiconductor material such as p-type Al _x GaN (0 ≦ x <1). In the present embodiment, the second cladding layer 26 is made of p-AlGaN. The thickness of the second cladding layer 26 may be 0.3 to 1 μm.

  The contact layer 27 is formed on the second cladding layer 26. For example, the contact layer 27 is a p-type contact layer formed of a p-type nitride semiconductor material. In the present embodiment, the contact layer 27 is made of p-type GaN.

  The laminated structure 20 configured as described above has a ridge waveguide structure having a light emitting ridge portion R as a ridge portion. In the present embodiment, the multilayer structure 20 has a laser array structure constituted by a plurality of light emitting ridge portions R.

  Each of the plurality of light emitting ridge portions R is a first ridge portion serving as an original ridge portion serving as a current injection path to the active layer 23. The current is injected into the active layer 23 by each light emitting ridge portion R so that the active layer 23 emits light. Each of the plurality of light emitting ridge portions R has an elongated shape having a longitudinal direction in a direction orthogonal to the pair of first end surface 20a and second end surface 20b. Specifically, each light emitting ridge portion R extends linearly along the laser resonator length direction (laser light oscillation direction).

The plurality of light emitting ridges R is a light emitting ridge R ₁ and a light emitting ridge from the one end side to the other end side in the width direction (the direction orthogonal to the laser resonator length direction) of the semiconductor laser device 1. part _{R 2,} emitting ridges _R 3, ···, emitting ridge _R i, · · ·, emitting ridge _{R n-2,} the light emitting ridge _{R n-1,} in the order of the light emitting ridge _{R n,} n This is formed (i = 1 to n). The number of light emitting ridges R is, for example, 2 to 50. In the present embodiment, 20 light emitting ridge portions R are formed at equal intervals.

  Furthermore, the stacked structure 20 has a plurality of dummy ridges S as another ridge. Each of the plurality of dummy ridge portions S is a second ridge portion which does not serve as a current injection path to the active layer 23. That is, the dummy ridge portion S has no current injection function. Like the light emitting ridge portion R, each of the plurality of dummy ridge portions S has a long shape having a longitudinal direction in a direction perpendicular to the pair of first end surfaces 20a and second end surfaces 20b. Specifically, each dummy ridge portion S extends linearly along the laser resonator length direction. Therefore, the dummy ridge portion S is formed in parallel with the light emitting ridge portion R.

  Further, the dummy ridge portion S is provided at a position adjacent to at least one light emitting ridge portion R of the plurality of light emitting ridge portions R. The dummy ridge portions S are provided between at least two light emitting ridge portions R of the plurality of light emitting ridge portions R, except for the dummy ridge portions S located at both ends in the width direction of the semiconductor laser element 1. Specifically, the dummy ridge portions S other than the both ends are formed between two adjacent light emitting ridge portions R. In the present embodiment, the dummy ridge portions S other than the both ends are formed one by one between the two adjacent light emitting ridge portions R adjacent to the light emitting ridge portion R.

The plurality of dummy ridges S are arranged from one end in the width direction of the semiconductor laser device 1 toward the other end, such as a dummy ridge S ₀ , a dummy ridge S ₁ , a dummy ridge S ₂ ,. , Dummy ridges S _i ,..., Dummy ridges S _n−2 , dummy ridges S _n−1 , and dummy ridges S _n are formed in this order (i = 0 to n). ). The dummy ridge portion S is formed on each of both ends of the laminated structure 20, and is formed by one more than the light emitting ridge portion R. In the present embodiment, since 20 light emitting ridge portions R are formed, 21 dummy ridge portions S are formed.

  Although the details will be described later, the dummy ridge portions S located at both ends in the width direction of the semiconductor laser device 1 are divided into a plurality. In the present embodiment, the dummy ridge portions S located at both ends are each divided into three. Therefore, when each of the three divided dummy ridges is counted as one, 25 dummy ridges S are formed as a whole.

  Thus, by providing the dummy ridge portion S in addition to the light emitting ridge portion R, when the semiconductor laser device 1 is mounted on a support base such as a submount by the face-down method, the semiconductor laser device 1 and the support base The contact area can be increased. As a result, it is possible to disperse the stress caused by the distortion remaining in the semiconductor laser device 1 after mounting on the support base. Thereby, concentration of stress on the light emitting ridge portion R can be suppressed. Further, by providing the dummy ridge portion S, the heat generated in the light emitting ridge portion R can be dissipated to the support base via the dummy ridge portion S.

  The light emitting ridge portion R and the dummy ridge portion S are formed on the top of the laminated structure 20. In the present embodiment, the light emitting ridge portion R and the dummy ridge portion S are formed in the second conductivity type layer of the laminated structure 20.

  Specifically, the light emitting ridge portion R and the dummy ridge portion S are formed by digging the second cladding layer 26 and the contact layer 27 to form the grooves M and M ′ in the laminated structure 20. The groove M (first groove) is formed between the light emitting ridge portion R and the dummy ridge portion S on one side (left side in the drawing) of the light emitting ridge portion R. On the other hand, the groove M ′ (second groove) is formed between the light emitting ridge portion R and the dummy ridge portion S on the other side (right side in the drawing) of the light emitting ridge portion R. That is, the light emitting ridge portion R and the two dummy ridge portions S adjacent to the light emitting ridge portion R are separated by the grooves M and M ′. In the present embodiment, the light emitting ridge portion R and the dummy ridge portion S are formed in the middle of the second cladding layer 26. That is, the bottoms of the grooves M and M ′ provided between the light emitting ridge portion R and the dummy ridge portion S exceed the contact layer 27 and reach the second cladding layer 26, and the grooves M and M ′ The bottom surface of each of the layers is located in the second cladding layer 26. Each of the light emitting ridge portion R and the dummy ridge portion S formed in this manner has a convex portion of the second cladding layer 26 whose cross section is formed in a convex shape, and is formed on the convex portion with the same width as the convex portion. Contact layer 27 formed.

  In the present embodiment, the height of the light emitting ridge portion R and the height of the dummy ridge portion S are equal. That is, the distance from the upper surface of the active layer 23 to the upper surface of the light emitting ridge portion R is equal to the distance from the upper surface of the active layer 23 to the upper surface of the dummy ridge portion S. The upper surface of the part S is at the same height. The depth of the groove M and the depth of the groove M 'are the same. That is, the position of the bottom of the groove M and the position of the bottom of the groove M ′ are the same.

  In the laminated structure 20 configured as described above, when a current is injected into the laminated structure 20, laser light is emitted from an emitter E (light emitting point) below each light emitting ridge portion R as shown in FIG. Do. In the present embodiment, laser light is emitted from each of the plurality of emitters E. That is, the semiconductor laser element 1 in the present embodiment is a multi-emitter laser including a plurality of emitters E. The plurality of emitters E are arranged in a line on the straight line in the lateral direction, and a plurality of laser beams arranged in a line on the line in the horizontal direction are emitted from the laminated structure 20.

  Each of the plurality of emitters E corresponds to each of the plurality of light emitting ridges R. That is, the emitter E and the light emitting ridge portion R correspond to each other in a one-to-one manner. Therefore, the number of emitters E is the same as the number of light emitting ridge portions R.

  In addition, the laminated structure 20 is covered by the insulating layer 30. In the present embodiment, the insulating layer 30 is formed so as to cover all the ridge portions of the multilayer structure 20 including all the light emitting ridge portions R and all the dummy ridge portions S. Specifically, so as to cover the side surfaces of the light emitting ridge portion R and the dummy ridge portion S and the flat portion (the bottom surfaces of the grooves M and M ′) between the light emitting ridge portion R and the dummy ridge portion S, It is formed along the surface of the laminated structure 20.

  Furthermore, the insulating layer 30 covers the entire upper surface of the dummy ridge portion S in the dummy ridge portion S, but covers a part of the upper surface of the light emitting ridge portion R in the light emitting ridge portion R. Specifically, a part of the insulating layer 30 on the light emitting ridge portion R is opened. A current is injected into the stacked structure 20 through the opening of the insulating layer 30. In this embodiment, the insulating layer 30 covers a part of the upper surface of the light emitting ridge portion R, but does not cover the upper surface of the light emitting ridge portion R at all, and passes through the entire upper surface of the light emitting ridge portion R. A configuration in which a current is injected into the laminated structure 20 may also be employed.

  Further, by covering the side surface of the light emitting ridge portion R with the insulating layer 30, the current injected from the first electrode 41 through the opening of the insulating layer 30 can be narrowed. That is, by covering the side surface of the light emitting ridge portion R with the insulating layer 30, it is possible to suppress the current injected from the first electrode 41 from flowing into the region between the two adjacent light emitting ridge portions R.

The insulating layer 30 is made of an insulating material. For example, the insulating layer 30 is made of a dielectric material such as SiO ₂ . In the present embodiment, the insulating layer 30 is a SiO ₂ film. The thickness of the insulating layer 30 is, for example, 100 to 500 nm.

  The first electrode 41 is a p-side electrode, and is formed on each light emitting ridge portion R. Specifically, the first electrode 41 is formed so as to fill the opening provided in the insulating layer 30, and is in contact with the contact layer 27 on the contact layer 27 which is the uppermost layer of the light emitting ridge portion R. It is formed. The first electrode 41 is an ohmic electrode in ohmic contact with the contact layer 27. Although the first electrode 41 is formed at the same height as the insulating layer 30 so as to fill only the opening of the insulating layer 30, it is not limited thereto.

  The first electrode 41 is composed of a single layer or a plurality of layers formed using at least one metal material such as Cr, Ti, Ni, Pd, Pt, and Au. In the present embodiment, the first electrode 41 has a two-layer structure of Pd / Pt. The width of the first electrode 41 is narrower than the width of the light emitting ridge portion R, but may be the same as the width of the light emitting ridge portion R.

  As shown in FIG. 2, the first electrode 41 is formed on the light emitting ridge portion R, but is not formed on the dummy ridge portion S. That is, the first electrode 41 is formed only on the light emitting ridge portion R for each light emitting ridge portion R. Therefore, a plurality of first electrodes 41 are formed in parallel to one another. That is, the plurality of first electrodes 41 are not connected to each other but are formed separately.

  The second electrode 42 is an n-side electrode. The second electrode 42 is a metal layer (first metal layer) formed on the lower surface (back surface) of the substrate 10. The second electrode 42 is an ohmic electrode that is in ohmic contact with the substrate 10 that is a semiconductor substrate. The second electrode 42 is one electrode common to the plurality of light emitting ridges R, and is formed on substantially the entire lower surface of the substrate 10.

  The second electrode 42 is composed of a single layer or a plurality of layers formed using at least one metal material such as Cr, Ti, Ni, Pd, Pt, and Au. The second electrode 42 may be made of an Au-based material containing Au. The second electrode 42 may be composed of a plurality of layers such as Ti / Au and Ti / Pt / Au. In the present embodiment, the second electrode 42 has a three-layer structure of Ti (15 nm) / Pt (40 nm) / Au (200 nm).

  The pad electrodes 50 are formed on the respective first electrodes 41 and the insulating layer 30 so as to be in contact with the plurality of first electrodes 41. The pad electrode 50 is a metal layer (second metal layer) made of a metal material. The pad electrode 50 may be made of an Au-based material containing Au. In addition, the pad electrode 50 may be configured of a plurality of layers such as Ti / Au, Ti / Pt / Au, and the like. Furthermore, the pad electrode 50 is thicker than the second electrode 42 (first metal layer) which is an n-side electrode. In the present embodiment, the pad electrode 50 has a three-layer structure of Ti (20 nm) / Pt (50 nm) / Au (1500 nm) and has a thickness twice or more that of the second electrode 42.

  In the present embodiment, the pad electrode 50 is made of a material different from that of the first electrode 41 (p-side electrode), but may be made of the same material as the first electrode 41. In this case, a combination of the pad electrode 50 and the first electrode 41 may be called a p-side electrode or a pad electrode. The pad electrode 50 is made of the same material as the second electrode 42 (n-side electrode), but may be made of a material different from the second electrode 42.

  The pad electrode 50 is formed continuously on the plurality of light emitting ridges R and at least one dummy ridge S. In the present embodiment, the pad electrode 50 is continuously formed on all the light emitting ridge portions R and all the dummy ridge portions S. That is, the pad electrode 50 is formed in a wide range on the upper surface of the multilayer structure 20 so as to cover all the ridge portions of the multilayer structure 20 including all the light emitting ridge portions R and all the dummy ridge portions S. .

  Thus, the pad electrode 50 is not formed for each of the light emitting ridge portion R and the dummy ridge portion S, but is formed over the entire ridge portion including the light emitting ridge portion R and the dummy ridge portion S. As compared with the case where each ridge portion is formed, the complexity of the configuration of the semiconductor laser device 1 can be suppressed. That is, if pad electrodes 50 are formed for each light emitting ridge portion R and each dummy ridge portion S, a plurality of pad electrodes 50 will be present, and wires need to be connected for each pad electrode 50, The electrical connection to each pad electrode 50 is complicated.

  Moreover, by forming the pad electrode 50 continuously on the plurality of light emitting ridge portions R and the plurality of dummy ridge portions S, the pad electrode 50 and the sub electrode are mounted when the semiconductor laser device 1 is mounted on the submount. Since the contact area with the mount can be gained, the bonding strength between the semiconductor laser device 1 and the submount can be increased.

  In the semiconductor laser device 1 configured as above, when a voltage is applied to the first electrode 41 and the second electrode 42, a current flows between the first electrode 41 and the second electrode 42. That is, current is injected into the laminated structure 20. The current injected into the stacked structure 20 is narrowed and flows only under the light emitting ridge portion R. As a result, the narrowed current is injected into the active layer 23 below the light emitting ridge portion R, and electrons and holes recombine in the active layer 23 to emit light.

  The light generated in the active layer 23 is, in the substrate vertical direction (longitudinal direction), the first cladding layer 21, the first guide layer 22, the active layer 23, the second guide layer 24, the electron barrier layer 25, and the second cladding layer. 26 and the refractive index difference between the layers of the contact layer 27, and in the substrate horizontal direction (lateral direction), the inside of the light emitting ridge portion R (the second cladding layer 26, the contact layer 27) and the outside of the light emitting ridge portion R It is confined by the refractive index difference with (insulation layer 30).

  Then, the light generated in the active layer 23 reciprocates between the first end face 20a and the second end face 20b, resonates and amplifies it, and gain is obtained by the injection current to obtain a high-intensity laser whose phases are aligned. The light is emitted from the first end face 20 a of the emitter E. In the present embodiment, since 20 light emitting ridge portions R are formed, laser light is emitted from each of 20 emitters E. That is, twenty laser beams are emitted from the laminated structure 20.

  Next, a detailed configuration of the semiconductor laser element 1 in the present embodiment will be described below with reference to FIGS.

  First, the detailed configuration of the pad electrode 50 will be described with reference to FIG. FIG. 5A is an enlarged top view of the semiconductor laser device 1 according to the embodiment, and FIG. 5B is an enlarged cross-sectional view of the semiconductor laser device 1.

In FIG 5, among the plurality of light emitting ridges R and a plurality of dummy ridge portions S, and the dummy ridge portions S _i, and the light emitting ridge R _i adjacent to the left side of the dummy ridge portions S _i, the dummy ridge portions S _i and the light emitting ridge R _{i + 1} adjacent to the right side of the light-emitting ridge R and part of the dummy ridge portions S _i-1 adjacent to the left side of _i, the light emitting ridge R _{i + 1} of the dummy ridge portions S _i adjacent to right _-1 is shown in part.

  As shown in FIG. 5A, when the semiconductor laser device 1 is viewed from above, the pad electrode 50 is separated from the pair of first end surface 20a and second end surface 20b by a first distance d1 on the light emitting ridge portion R. It has a part that is. Further, in the top view of the semiconductor laser device 1, the pad electrode 50 has a portion separated from the first end face 20 a and the second end face 20 b by the second distance d 2 on the dummy ridge portion S. The second distance d2 in the dummy ridge portion S is larger than the first distance d1 in the light emitting ridge portion R. As an example, the first distance d1 is 4 to 8 μm, and the second distance d2 is 15 to 25 μm.

  Specifically, in the top view of the semiconductor laser device 1, the pad electrode 50 has recesses 51 on both sides of the pair of the first end face 20 a and the second end face 20 b on the dummy ridge portion S. The recess 51 of the pad electrode 50 is a portion on the dummy ridge portion S that is separated from the pair of first end surface 20a and second end surface 20b by a second distance d2. The recessed portion 51 of the pad electrode 50 is not formed on the light emitting ridge portion R.

  In the present embodiment, the recess 51 is formed in the pad electrode 50 on the dummy ridge portion S for all of the plurality of dummy ridge portions S. By forming the recess 51 in the pad electrode 50 in this manner, on the dummy ridge portion S, a part of the side on the first end face 20 a side of the pad electrode 50 is retracted toward the second end face 20 b, A part of the side of the electrode 50 on the second end face 20b side is set back to the first end face 20a side.

  The top view shape of the recess 51 is, for example, a rectangle. In the present embodiment, the top view shape of the recess 51 is trapezoidal. Specifically, the top view shape of the recess 51 is a trapezoidal shape in which the side on the bottom of the recess 51 is shorter than the side on the opening of the recess 51. The inclination angle of the side of the trapezoid forming the recess 51 is, for example, about 45 °, but is not limited thereto.

Further, as shown in FIG. 3, the recess 51 located outermost on the dummy ridge S positioned at both ends (first dividing ridge S _0a and recesses 51 on the S _na described later), the dummy ridge portions On S, the outer side of the two sides of the trapezoid does not exist, and the recess 51 is cut out to the outer end on the dummy ridge S.

  Specifically, on the dummy ridge portion S located at an end portion of the plurality of dummy ridge portions S, the pad electrode 50 has a first portion separated from the light emission ridge portion R in the light emission ridge portion R. The area is smaller than that of the second portion close to. That is, for the pad electrode 50 on the dummy ridge portion S located at the end portion, the first end surface separated from the light emitting ridge portion R is closer to the first end face 20a and the second end portion than the second portion closer to the light emitting ridge portion R. The distance from the 2 end surface 20b is large.

  Next, a detailed configuration of the dummy ridge portion S will be described with reference to FIGS.

As shown in FIGS. 2 and 3, the plurality of dummy ridges S formed in the stacked structure 20 includes at least the dummy ridges S provided on both ends in the arrangement direction of the plurality of light emitting ridges R. _{i (i} = 0, n) a is the end-side ridge, the dummy ridge portions provided between every two light-emitting ridge portion R adjacent the plurality of light emitting ridges R S _{i (i} = 1~n- 1) and an intermediate ridge portion.

Specifically, an end-side ridge dummy ridge portions _{S i (i = 0, n} ) is an end-side ridge portion _{S 0} and _{S n.} Further, an intermediate ridge dummy ridge portions _{S i (i = 1~n-1} ) is an end-side ridge portion _{S 0} and _{S n} than the dummy ridge portions S, the dummy ridge portions _{S 1, S} 2, S ₃ ,..., S _n-3 , S _n-2 and S _n−1 . In the present embodiment, the dummy ridge portions S that are intermediate ridge portions have the same shape and the same width, and are formed at equal intervals. The widths of the light emitting ridge portion R and the dummy ridge portion S are the lengths in the direction perpendicular to the longitudinal direction of the light emitting ridge portion R (the dummy ridge portion S).

Among all the dummy ridge portions S, each of the end side ridge portions S ₀ and S _n is the dummy ridge portion located on the outermost side in each of the left and right direction (direction orthogonal to the cavity length direction) of the semiconductor laser device 1 S. 2 and 3, the end-side ridge portion S _{0 (first} end side ridge portion) is located at the left end of the laminated structure 20, the end-side ridge portion S _{n (second} end side ridge Part) is located at the right end of the laminated structure 20. Therefore, for the dummy ridge portions S (S ₁ , S ₂ ,..., S _n−2 , S _n−1 ) that are intermediate ridge portions, the light emitting ridge portions R are present on both sides, but the end The light emitting ridges R are present only on one side of the side ridges S ₀ and S _n .

The left end ridge S ₀ and the right end ridge S _n are separated into a plurality of divided ridges by a groove m. In other words, by forming the groove m in the end side ridge portion S ₀ and S _n, each of the end-side ridge portion S ₀ and S _n are divided into a plurality of divided ridges (sub dummy ridge portions). As a result, when each of the plurality of divided ridge portions is counted as one dummy ridge portion S, each of the both end portions in the width direction of the stacked structure 20 has a plurality of dummy ridge portions with the divided ridge portion as a dummy ridge portion. It is formed continuously. In the present embodiment, each of the end side ridge portions S ₀ and S _n is separated into three or more divided ridge portions, and three or more divided ridge portions are continuously arranged.

Specifically, the end-side ridge portion S ₀ of the left, by two grooves m, the first dividing ridge S _0a, is separated into three second dividing ridge S _0b and third dividing ridge S _0c ing. Among these, the second divided ridge portion _S0b is located at the center, the first divided ridge portion _S0a is located on the left side of the second divided ridge portion _S0b , and the third divided ridge portion _S0c is the second divided ridge portion _S0c . It is located on the right side of the split ridge portion S 0 _b . In the present embodiment, the first divided ridge portion S _{0 a} and the third divided ridge portion S _{0 c} are located at both ends of the end ridge portion S ₀ . The first divided ridge portion S _{0 a} is located at the leftmost end portion of the left end side ridge portion S ₀ .

Similarly, the right end ridge portion _Sn is separated by the two grooves m into a first divided ridge portion S _na , a second divided ridge portion S _nb, and a third divided ridge portion S _nc . . Specifically, the second divided ridge portion S _nb is located at the center, the first divided ridge portion S _na is located on the right side of the second divided ridge portion S _nb , and the third divided ridge portion S _nc is It is located on the left side of the second divided ridge portion _Snb . Right end side ridge portion even S _n, first dividing ridge S _na and third dividing ridge S _nc is located at both ends of the end ridge portion S _n. The first dividing ridge S _0a, in the right end side ridge portion S _n, are positioned at the rightmost end.

In the present embodiment, the end side ridge portions S ₀ and S _n are formed in symmetrical shapes. That is, the grooves m for _dividing each of the end side ridge portions S ₀ and S _n into a plurality are formed at symmetrical positions.

Groove m to separate each of the end-side ridge portion S ₀ and S _n in plurality, like the grooves M and M 'for separating the light emitting ridge R and the dummy ridge portions S, the second cladding of the laminated structure 20 It is formed by digging the layer 26 and the contact layer 27. In the present embodiment, the depth of the groove m is the same as the depth of the grooves M and M ′. That is, the position of the bottom of the groove m and the position of the bottom of the grooves M and M ′ are the same.

  The dummy ridge portion S which is an intermediate ridge portion is a non-divided ridge portion which is not divided by the groove m.

  Next, regarding the stacked structure 20 in which the light emitting ridge portion R and the dummy ridge portion S are formed, the width of the light emitting ridge portion R and the dummy ridge portion S, the width and depth of the grooves M and M ′, and the light emitting ridge portion. An example of the width WA (interval) between R ridges is shown in Table 1.

As shown in Table 1, in any light emitting ridge portion R _i (i = 1 to n), the width (ridge width) WR _i of the light emitting ridge portion is, for example, 5 μm or more and 35 μm or less. By setting 5 μm ≦ WR _i , it is possible to suppress the generation of COD on the first end face 20a that is the laser light emission end face. In addition, by setting WR _i ≦ 35 μm, a gain for causing laser oscillation can be easily obtained.

In the present embodiment, the widths WR _i of all the light emitting ridge portions R are equal. That is, the width WR _i of all the light emitting ridge portions R is uniform. Thus, by making the widths WR _i of all the light emitting ridge portions R uniform, it is possible to inject current uniformly into all the light emitting ridge portions R. As a result, laser beams having a uniform beam diameter are output from all the emitters E. Thereby, a plurality of laser beams emitted from the semiconductor laser device 1 can be condensed on an optical component such as a lens or a fiber with high efficiency. The width WR _i of the light emitting ridge R is if not uniform, with the difference in light output occurs for each emitter E, partially difference in degradation occurs in the laminated structure 20. In particular, the emitter E with a large light output is deteriorated more. On the other hand, by making the widths WR _i of all the light emitting ridge portions R uniform, it is possible to suppress the occurrence of a difference in deterioration in the stacked structure 20 due to the light output difference of the emitter E. In the present embodiment, the width WR _i of all the light emitting ridge portions R is set to 30 μm.

Further, in any dummy ridge portion S _i (i = 0 to n), the width WS _i of the dummy ridge portion S is, for example, not less than 25 μm and not more than 500 μm.

Specifically, the width WS _i of an intermediate ridge existing between the light emitting ridge R dummy ridge portions _{S i (i = 1~n-1} ) is, for example, 25μm or more 500μm or less. In the present embodiment, it has a width WS _i of all intermediate ridge portion other than the end-side ridge portion _{S 0} and _{S n} to 370 .mu.m.

On the other hand, in the end-side ridge portions S ₀ and S _n divided into a plurality, the widths of the first divided ridge portions S _0a and S _na are, for example, 25 μm or more and 300 μm or less (in this embodiment, 180 μm), The widths of the two divided ridges S _0b and S _nb are, for example, 5 μm or more and 35 μm or less (30 μm in the present embodiment), and the widths of the third divided ridges S _0c and S _nc are, for example, 25 μm or more and 500 μm or less ( In this embodiment, it is 370 μm).

  In addition, the width WM of the groove M and the width WM ′ of the groove M ′ are, for example, 5 μm or more and 30 μm or less for the optional grooves M and M ′ separating the light emitting ridge portion R and the dummy ridge portion S. The depth of the groove M and the depth of the groove M ′ are, for example, 0.1 μm or more and 0.6 μm or less (all 0.5 μm in the present embodiment). By setting 5 μm ≦ WM and WM ′, it is possible to suppress the occurrence of voids without the solder getting wet when the semiconductor laser device 1 is mounted on the submount by the face-down method. Further, by setting WM and WM ′ ≦ 30 μm, the heat generated in the emitter E corresponding to the light emitting ridge portion R can be efficiently exhausted through the dummy ridge portion S.

For the groove m that separates the end-side ridge portions S ₀ and _Sn into a plurality, the width of the groove m is, for example, 5 μm or more and 15 μm or less (all 10 μm in this embodiment), and the depth of the groove m However, it is, for example, 0.1 μm or more and 0.6 μm or less (all 0.5 μm in this embodiment).

Further, a width WA (= WS _i + WR _i ) between the ridges of two adjacent light emitting ridge portions R is, for example, 35 μm or more and 560 μm or less. In the present embodiment, the width WA between the ridges of the light emitting ridge portion R is all 390 μm.

  The ratio (WA / WR) of the width WA between the two adjacent light emitting ridges R to the width WR of the light emitting ridges R preferably satisfies WA / WR ≧ 7. By satisfying the relationship of WA / WR ≧ 7, it is possible to suppress thermal saturation due to thermal interference in high power operation in two adjacent light emitting ridges R, and light necessary for high power laser oscillation of watt class Output characteristics can be easily obtained.

Here, with respect to the end side ridge portions S ₀ and S _n , Table 2 shows a pattern example of the combination of the widths of the divided ridge portions.

As shown in Table 2, in the pattern 1, for each has been end-side ridge portion S ₀ and S _n divided three or more, a ridge width of the divided ridge of the center side, the ridge of the division ridge portion at both ends It is larger than the width. That is, in each of the end side ridge portions S ₀ and S _n , the ridge widths of the plurality of divided ridge portions are wider toward the center. In this embodiment, the ridge width of the end-side ridge portion _{S 0} and _S the second dividing ridge portion of the center of _{n S} 0b _{(S nb)} is first divided ridge outer side in the end-side ridge portion _{S 0} and _{S n} The ridge width of the portion S _0a (S _na ) is larger than the ridge width of the third divided ridge portion S _0c (S _nc ) at the end side ridge portions S ₀ and S _n . Yes. In the pattern 1, the ridge width of the first divided ridge portion S _0a (S _na ) and the ridge width of the third divided ridge portion S _0c (S _nc ) are the same, but the present invention is not limited thereto.

In pattern 2, the plurality of divided the end side ridge portion S ₀ and S _n, the ridge width of the plurality of divided ridges are equal all. Specifically, the widths of the first divided ridge portion S _0a (S _na ), the second divided ridge portion S _0b (S _nb ), and the third divided ridge portion S _0c (S _nc ) are all equal.

In pattern 3, the ridge width of the split ridge portion on the center side is smaller than the ridge width of the split ridge portions on both ends of the end ridge portions S ₀ and S _n divided into three or more. . That is, in each of the end side ridge portions S ₀ and S _n , the ridge widths of the plurality of divided ridge portions are narrower toward the center. Specifically, the ridge width of the end-side ridge portion _{S 0} and _S the second dividing ridge portion of the center of _{n S} 0b _{(S nb)} is first divided ridge portion of the outer side in the end-side ridge portion _{S 0} and _{S n} S _0a is smaller than the ridge width of the _{(S na),} and is smaller than the ridge width of the third split ridge _S 0c inside the end-side ridge portion _{S 0} and _{S n (S nc)} . In the pattern 3, the ridge width of the third divided ridge portion S _0c (S _nc ) on the inner side is larger than the ridge width of the first divided ridge portion S _0a (S _na ) on the outer side. Not limited to.

Further, the pattern 3, the ridge width of the end-side ridge portion _{S 0} and _S third dividing ridge portion of the inner side of _{n S} 0c _{(S nc)} comprises a ridge width of the intermediate ridge _S i (i = _1~n) The ridge width of the second divided ridge portion S _0b (S _nb ) at the center in the end side ridge portions S ₀ and S _n is the same as the ridge width of the light emitting ridge portion R. With this configuration, it is possible to mass-produce a plurality of types of semiconductor laser devices 1 having different numbers of light emitting ridges R (number of emitters) at low cost.

Specifically, the ridge width of the third divided ridge portion S _0c (S _nc ) and the ridge width of the intermediate ridge portion S _i (i = 1 to n) are made the same, and the second divided ridge portion S _0b ( When the ridge width of S _nb ) and the ridge width of the light emitting ridge portion R are the same, in the state where the step of forming the insulating layer 30 is completed, the plurality of light emitting ridge portions R having the same width on the wafer have the same width. Since a plurality of dummy ridge portions S are periodically and alternately arranged one by one, depending on which light emitting ridge portion R the first electrode 41 (p-side electrode) is formed in the next step The dummy ridge portion S corresponding to the second divided ridge portion S _0b (S _nb ) may also be a light emitting ridge portion R. As a result, even if the reliability is somewhat inferior due to the user's request, if it is desired to increase the number of emitters to achieve a higher output, the second ridge portion S _0b (S _nb ) is placed on the ridge portion corresponding to the second divided ridge portion S _0b (S _nb ). By forming the one electrode 41, the ridge portion can be made to function not as the dummy ridge portion S but as the light emitting ridge portion R, so that the semiconductor laser device 1 with higher output can be realized. Conversely, by not forming the first electrode 41 in the ridge corresponding to the light emitting ridge R, the ridge where the first electrode 41 is not formed becomes a dummy ridge that is the second divided ridge S _0b (S _nb ). It can function as the part S. For example, a first electrode is formed on M (N> M) ridge portions out of N ridge portions having the same width as the light emission ridge portion R to function as the light emission ridge portion R, and (N−M) The ridge portion can function as the dummy ridge portion S. Thus, the stress can be relaxed by the groove of the adjacent dummy ridge portion S, so that the semiconductor laser device 1 with higher reliability can be realized. In this way, after the process of forming the insulating layer 30 is completed, a large number of wafers in which a plurality of light emitting ridge portions R having the same width and a plurality of dummy ridge portions S having the same width are arranged alternately one by one are arranged. The number of light emitting ridges R (the number of emitters) and the dummy ridges serving as support parts at the time of mounting are adjusted by adjusting the presence / absence of the first electrode 41 and the cleaving position according to the user's request. The number of S can be arbitrarily changed. Thereby, productivity improvement and cost reduction can be expected by process commonization.

In the pattern 4, the ridge widths of the plurality of divided ridge portions increase with distance from the light emitting ridge portion R in the plurality of divided end side ridge portions S ₀ and S _n . That is, the ridge width of the divided ridge portion increases as it is farther from the light emitting ridge portion R (as the end of the semiconductor laser device 1), and conversely, the ridge width of the divided ridge portion decreases as it is closer to the light emitting ridge portion R. Yes. Specifically, the distance from the light emitting ridge R adjacent to the end side ridge portion _{S 0} and _{S n,} third dividing ridge _S 0c _{(S nc),} second dividing ridge _S 0b _{(S nb)} and the The ridge width is gradually increased in the order of the one-part ridge portion S _0a (S _na ).

In the pattern 5, the ridge widths of the plurality of divided ridge portions decrease with increasing distance from the light emitting ridge portion R with respect to the end side ridge portions S ₀ and S _n divided into a plurality. In other words, the ridge width of the divided ridge portion becomes smaller as it is farther from the light emitting ridge portion R (as the end of the semiconductor laser device 1), and conversely, the ridge width of the divided ridge portion becomes larger as it is closer to the light emitting ridge portion R. Yes. Specifically, the distance from the light emitting ridge R adjacent to the end side ridge portion _{S 0} and _{S n,} third dividing ridge _S 0c _{(S nc),} second dividing ridge _S 0b _{(S nb)} and the The ridge width is gradually narrowed in the order of the one-divided ridge portion S _0a (S _na ).

Further, in the present embodiment, the sum of the ridge widths of the plurality of divided ridge portions in each of the end side ridge portions S ₀ and S _n is an intermediate ridge portion S _i (i = 1 to n) which is a non-divided ridge portion. It is larger than the width of. Specifically, in this embodiment, since the ridge width of the intermediate ridge portion S _i (i = 1 to n) is 370 μm, the patterns 1 to 3 correspond to this. In this case, the sum of the ridge width of a plurality of divided ridges at each end-side ridge portion S ₀ and S _n is about 210μm larger than the ridge width of the intermediate ridge. Thus, by the end-side ridge portion S ₀ and S _n wider than the intermediate ridge portion, the semiconductor laser element 1 and the submount when mounting the semiconductor laser element 1 to the submount by the face-down method Since the contact area (junction area) can be increased, the junction strength between the semiconductor laser device 1 and the submount can be increased. The semiconductor laser device 1 shown in FIG. 1 is illustrated as an example of the pattern 3.

The total ridge width of a plurality of divided ridges at each end-side ridge portion S ₀ and S _n may be equal to the width of the intermediate ridge portions to be not dividing ridge. In this case, in the present embodiment, since the ridge width of the middle ridge portion S _i (i = 1 to n) is 370 μm, the pattern 4 corresponds.

The total ridge width of a plurality of divided ridges at each end-side ridge portion S ₀ and S _n may be less than the width of the intermediate ridge is not divided ridge. In this case, in the present embodiment, since the ridge width of the intermediate ridge portion S _i (i = 1 to n) is 370 μm, the pattern 5 corresponds.

  When the semiconductor laser device 1 configured as described above is incorporated into a device such as a laser processing apparatus, the semiconductor laser device 2 is in the form of a module as shown in FIG. FIG. 6 is a cross-sectional view of the semiconductor laser device 2 according to the embodiment.

  As shown in FIG. 6, the semiconductor laser device 2 includes the semiconductor laser element 1 described above and a submount 60. The semiconductor laser element 1 is mounted on the submount 60 by a face down method (junction down method). That is, in the semiconductor laser device 1, the ridge portion side (light emitting ridge portion R side, dummy ridge portion S) is joined to the submount 60. Specifically, the pad electrode 50 of the semiconductor laser device 1 is connected to a bonding layer (not shown) stacked on the submount 60.

  Submount 60 includes a base made of, for example, a semiconductor material such as SiC, a ceramic material such as AlN, a high thermal conductive material such as diamond or a diamond composite material, and a metal layer formed on the surface of the base. . The semiconductor laser device 1 and the metal layer of the submount 60 are bonded via a bonding layer made of a solder layer such as AuSn.

  In order to strengthen the bonding between the semiconductor laser device 1 and the submount 60, that is, to reduce the contact thermal resistance and the contact electrical resistance between the pad electrode 50 and the submount 60, the pad electrode 50 can be made as close as possible. It is good to enlarge.

  As shown in FIG. 6, the semiconductor laser device 2 according to the present embodiment further includes a first heat radiating member 71 and a second heat radiating member 72, and a joined body of the semiconductor laser element 1 and the submount 60 is It is sandwiched between the first heat radiating member 71 and the second heat radiating member 72. The first heat radiating member 71 and the second heat radiating member 72 are heat sinks for radiating heat generated by the semiconductor laser device 1. The first heat radiation member 71 and the second heat radiation member 72 may be conductors for supplying a current to the semiconductor laser device 1. Therefore, as the first heat radiating member 71 and the second heat radiating member 72, it is preferable to use a metal block or the like made of a metal material such as copper which is excellent in electrical conductivity and thermal conductivity.

  Thus, by sandwiching the joined body of the semiconductor laser element 1 and the submount 60 between the first heat radiating member 71 and the second heat radiating member 72, the heat conducted from the light emitting ridge portion R to the pad electrode 50 is It spreads at 50 and is transmitted to the first heat dissipation member 71 via the submount 60. Thereby, the heat dissipation of the heat generated in the semiconductor laser device 1 can be improved, and the highly reliable semiconductor laser device 2 can be realized.

  Further, in the semiconductor laser device 1 according to the present embodiment, the height of the light emitting ridge portion R and the height of the dummy ridge portion S are equal, and the upper surface of the light emitting ridge portion R and the upper surface of the dummy ridge portion S have the same height. Position.

  With this configuration, when the semiconductor laser element 1 is mounted on the submount 60 by the face-down method, the mounting surface of the semiconductor laser element 1 is flat, so that the semiconductor laser element 1 can be easily mounted on the submount 60. be able to. Further, since the height of the light emitting ridge portion R and the height of the dummy ridge portion S are equal to each other, the light emitting ridge portion R and the dummy ridge portion S can be easily formed in the laminated structure 20.

  Next, the effects of the semiconductor laser device 1 according to the present embodiment will be described including the background to the present disclosure.

  The warp S of the semiconductor laser device 1 is determined by the metal material of the pad electrode 50 formed continuously on the plurality of light emitting ridges R and the plurality of dummy ridges S, and the semiconductor material of the laminated structure 20. Is a relational expression of S = α × Δκ × L, where Δk is a linear expansion coefficient and L is a deposition distance between the pad electrode 50 and the laminated structure 20. Α is a proportionality constant determined by the shape of the pad electrode 50 and the like.

  Here, the pad electrode 50 (i) flows the electrode to each light emitting ridge R, (ii) flows a current between two adjacent light emitting ridges R, (iii) the semiconductor laser device 1 is submounted, etc. When mounted on the supporting substrate, the supporting substrate and the semiconductor laser element 1 are joined.

(I), in terms of (ii), the upper end side ridge portion S ₀ and S _n is the outermost of the plurality of dummy ridge portions S, there is no need to form a pad electrode 50. Accordingly, by not forming the pad electrode 50 on the end side ridge portion S ₀ and S _n, the deposition distance L between the pad electrode 50 and the layered structure 20 is shortened, the warping S of the semiconductor laser element 1 It can be made smaller.

On the other hand, from the viewpoint of (iii), in order to increase the bonding strength between the semiconductor laser element 1 and the submount 60, the pad electrode 50 is formed on the end side ridge portion S ₀ and S _n is better present. For example, when the semiconductor laser element 1 is used in the apparatus used in the vibration is large environment, it is necessary to improve the bonding strength between the semiconductor laser element 1 and the submount 60, an end-side ridge portion S ₀ and S A pad electrode 50 having as large an area as possible may be formed on _n .

The present disclosure has been conceived from such a viewpoint. Specifically, in the semiconductor laser device 1 in the present embodiment, the pad electrode 50 (second metal layer) continuously formed on the plurality of light emitting ridge portions R and the plurality of dummy ridge portions S includes: the second electrode 42 (first metal layer) thicker than that formed on the lower surface of the substrate 10, and, at the end side ridge portion S ₀ and the S _n among the plurality of dummy ridge portions S, away from the light emitting ridge R The first portion is smaller in area than the second portion close to the light emitting ridge portion R. That is to say, the pad electrode 50, the end side ridge portion S ₀ and the S _n of dummy ridge portions S are deposited area of the pad electrode 50 and the layered structure 20 is reduced as it goes outward.

For example, as shown in FIG. 7, in the semiconductor laser device 1 of the present embodiment, first away from the light emitting ridge R of the first dividing ridge pad electrode 50 on the S _na end side ridge portion S _n 1 portion (first right-side portion on the division ridge S _na in FIG. 7), a second portion (Fig closer to the light-emitting ridge portion R of the first dividing ridge S pad electrode 50 on _na end side ridge portion S _n The distance from the first end face 20a and the second end face 20b is larger than the left side portion on the first divided ridge portion _Sna .

Figure 7 is an enlarged top view of the end-side ridge portion S _n around the semiconductor laser device 1 in the embodiment. In FIG. 7, only the end-side ridge portion S _n periphery of the end-side ridge portion S ₀ and S _n is not shown, the opposite end side ridge portion S ₀ around the same configuration of.

More specifically, as shown in FIG. 7, the pad electrode 50, the ridge end of the outer on first dividing ridge S _na (right side in FIG. 7), the inner side of the first dividing ridge S _na ( The distance from the first end surface 20a and the second end surface 20b is larger than the ridge end on the left side in FIG. In this embodiment, the recess 51 on the first divided ridge S _na has become notched shape to the outer end of the first dividing ridge S _na.

Here, when the pad electrode 50 of the semiconductor laser device 1 in the present embodiment shown in FIG. 7 and the pad electrode 250 of the semiconductor laser device 200 of the comparative example shown in FIG. 8 are compared, the pad electrode 50 and the pad electrode are compared. The area difference ΔS with respect to 150 is represented by ΔS = {(L2 + 3) × Z1 / 2 + L4 × Z1} × 2 = (L2 + L3 + 2 × L4) × Z1. In this embodiment, since L2 = 10 μm, L3 = 24 μm, L2 = 50 μm, and Z1 = 14 μm, ΔS = 2352 μm ² . That is, in the semiconductor laser device 1 according to the present embodiment, the deposition area between the pad electrode 50 and the laminated structure 20 can be reduced by about 2300 μm ² compared to the semiconductor laser device 100 of the comparative example.

In the semiconductor laser device 200 of the comparative example shown in FIG. 8, the recess 251 of the first divided ridge _{S na} on the pad electrode 250 at the end-side ridge portion _{S n} is the outer end of the first dividing ridge _{S na} The pad electrode 250 on the first divided ridge portion _Sna is not cut out to the first end surface 20a side and the second end surface 20b side. Further, also in FIG. 8, only the end-side ridge portion S _n periphery of the end-side ridge portion S ₀ and S _n is not shown, the opposite end side ridge portion S ₀ around the same configuration of.

Thus, on the end side ridge portion S ₀ and S _n, the first portion away from the light emitting ridge R of the pad electrode 50, the area than near the second portion to the light-emitting ridge R of the pad electrode 50 by being smaller, while still forming a pad electrode 50 on the end side ridge portion S ₀ and S _n, the proportional constant α for small and pad electrode 50 is a semiconductor laser element which is determined by the shape of the pad electrode 50 1 Can weaken the power of As a result, it is possible to suppress the warpage of the semiconductor laser device 1 caused by the temperature change while securing the bonding strength between the semiconductor laser device 1 and the support base such as the submount 60 and the like.

In the above embodiment, although leaving the pad electrode 50 on the end side ridge portion S ₀ and S _n, sub without the presence of the pad electrode 50 on the end side ridge portion S ₀ and S _n if possible bonding strength to secure the support substrate and the semiconductor laser element 1 of the mount 60 such as shown in FIG. 9, the pad electrode 50 is not formed on the end side ridge portion S ₀ and S _n May be

  With this configuration, the adhesion area of the pad electrode 50 and the laminated structure 20 can be further reduced as compared with the semiconductor laser device 1 shown in FIG. 1, so that warpage of the semiconductor laser device 1 can be further suppressed. Can.

In FIG. 9, for simplification, the number of light emitting ridges R and dummy ridges S is reduced. Further, in FIG. 9, the end ridge portions S ₀ and _Sn are not divided. Thus, the end-side ridge portion S ₀ and S _n may not be divided.

Also, when leaving the pad electrode 50 on the end side ridge portion S ₀ and S _n, as shown in FIG. 10, away from the light emitting ridge R of the pad electrode 50 at the end-side ridge portion S ₀ and the S _n The corner portion of the first portion may be inclined in a direction in which the distance from the first end surface 20a and the second end surface 20b increases as the distance from the light emitting ridge portion R increases. Specifically, in FIG. 10, the pad electrode 50, first according to the corner portion of the first portion away from the light emitting ridge R of the end-side ridge portion S ₀ and the S _n, away from the light-emitting ridge R It has the inclination part 52 which inclines in the direction where the distance from the end surface 20a and the 2nd end surface 20b becomes large.

  The semiconductor laser element shown in FIG. 10 can increase the bonding strength with the submount as compared with the semiconductor laser element shown in FIG. In FIG. 10, the inclined portion 52 may be formed only on one of the first end surface 20a side and the second end surface 20b side.

Another example of when to leave the pad electrode 50 on the end side ridge portion S ₀ and S _n, as shown in FIG. 11, the pad electrode 50 at the end side ridge portion S ₀ and the S _n, On the side away from the light emitting ridge portion R, a cutout portion 53 may be provided. Notch 53 is, for example, is formed so as cutting away toward the portion in the lateral direction of the sides of the end-side ridge portion S ₀ and the pad electrode 50 on the S _n inward.

The semiconductor laser element shown in FIG. 11 can increase the bonding strength with the submount as compared with the semiconductor laser element shown in FIG. Further, the semiconductor laser device, longitudinal ends on the end side ridge portion S ₀ and S deposition portion of the pad electrode 50 on the _n is the end-side ridge portion S ₀ and S _n (first shown in FIG. 11 The end surface 20a side and the second end surface 20b side) are larger than the center portion. As a result, the semiconductor laser device shown in FIG. 11 can increase the bonding strength with the submount at the corner of the pad electrode 50 and generate heat as compared with the semiconductor laser device shown in FIGS. The heat at the first end face 20a and the second end face 20b that can be easily released can be released more efficiently.

In FIG. 10 and FIG. 11, the sloped portion 52 and the cutout portion 53 may be formed only in any one of the end side ridge portions S ₀ and S _n .

In the semiconductor laser device shown in FIGS. 9-11, the end-side ridge portion S ₀ and S _n, when it is separated into a plurality of divided ridge by a groove m is characterized in FIGS. 9 to 11 May be applied to any split ridge portion.

  Further, in the semiconductor laser device 1 according to the present embodiment, as shown in FIG. 5, the pad electrode 50 formed continuously on the plurality of light emitting ridges R and the dummy ridges S is a light emitting ridge R On the dummy ridge portion S, a portion separated from the first end face 20a and the second end face 20b by the first distance d1 is provided, and the dummy ridge portion S is separated from the first end face 20a and the second end face 20b by the second distance d2 In addition, the second distance d2 is larger than the first distance d1.

  In this manner, by making the second distance d2 on the dummy ridge portion S larger than the first distance d1 on the light emitting ridge portion R, the vicinity of the element end surface (on the first end surface 20a side and the second end surface) in the dummy ridge portion S. The pad electrode 50 in the vicinity of the 20 b side can be recessed more than the pad electrode 50 in the vicinity of the element end face in the light emitting ridge portion R. That is, in plan view, part of the side on the first end face 20 a side of the pad electrode 50 and part of the side on the second end face 20 b side of the pad electrode 50 are respectively retracted to the opposite side.

  As a result, even if heat is generated at the element end face of the emitter E corresponding to the light emitting ridge part R due to dangling bonds existing in the vicinity of the element end face of the light emitting ridge part R, it is generated between the element end faces of two adjacent emitters E. It is possible to suppress the propagation of the generated heat to the dummy ridge portion S adjacent to the light emitting ridge portion R via the pad electrode 50. Therefore, it is possible to suppress that the heat generated at the element end faces of two adjacent emitters E interfere with each other through the pad electrode 50.

  Further, the second distance d2 on the dummy ridge portion S is made larger than the first distance d1 on the light emitting ridge portion R so that the pad electrode 50 in the vicinity of the element end surface in the dummy ridge portion S is located in the vicinity of the element end surface in the light emitting ridge portion R. Even if heat generated at the element end face of the emitter E corresponding to the light emitting ridge portion R propagates to the dummy ridge portion S by being recessed from the pad electrode 50, the pad near the element end face in the dummy ridge portion S The thermal expansion of the electrode 50 can be suppressed. That is, by providing a region (concave portion 51) where the pad electrode 50 does not exist on the dummy ridge portion S, thermal expansion of the pad electrode 50 in this region can be eliminated. As a result, it is possible to suppress the light emitting ridge portion R from being compressed from both sides due to thermal expansion by the pad electrode 50 existing in the vicinity of the element end face in the dummy ridge portion S. Therefore, the generation of crystal defects in the light emitting ridge portion R can be suppressed by the compressive stress of the light emitting ridge portion R.

  As described above, according to the semiconductor laser device 1 of the present embodiment, it is possible to suppress the thermal interference between two adjacent emitters E via the pad electrode 50, and the crystal of the light emitting ridge portion R due to the thermal expansion of the pad electrode 50. Defects can be suppressed. Therefore, the semiconductor laser device 1 with high reliability can be realized.

  In the region inside (inside) the pad electrode 50 that is separated from the first end surface 20a and the second end surface 20b, the light propagates from the light emitting ridge portion R to the dummy ridge portion S adjacent to the light emitting ridge portion R through the pad electrode 50. Although there is heat, this heat is diffused widely by a region inside the pad electrode 50 that is widely formed across the light emitting ridge portion R and the dummy ridge portion S, so that the heat density is low and the temperature rise is small. For this reason, since the thermal expansion of the pad electrode 50 due to the diffused heat is small, the compressive stress received by the light emitting ridge portion R is also small. Further, in the light emitting ridge portion R and the dummy ridge portion S in the region inside the pad electrode 50, there are not many dangling bonds in the first place. For this reason, in the region inside the pad electrode 50, crystal defects do not occur in the light emitting ridge portion R very much.

  Further, in the present embodiment, the pad electrode 50 has the recess 51 on the side of the first end face 20a and the second end face 20b on the dummy ridge portion S, and this recess 51 is the first end face. This is a portion that is separated from 20a and the second end face 20b by a second distance d2.

Specifically, as shown in FIG. 5 (a), the first end face 20a side of the pad electrode 50 on the light emitting ridge R _i sides, the left light emitting ridge R _i groove M _i and right After extending to the left dummy ridge portion S _i-1 and the right dummy ridge portion S _{i in} a horizontal direction beyond the groove M ′ _i , the inclination is about 45 ° on the dummy ridge portions S _i-1 and S _i. The recess 51 is formed in the pad electrode 50 on the dummy ridges S _i-1 and S _{i by} moving away from the first end surface 20a.

  As described above, by forming the recess 51 in the pad electrode 50 on the dummy ridge portion S, the second distance d2 on the dummy ridge portion S can be easily made larger than the first distance d1 on the light emitting ridge portion R. Can. Then, in the semiconductor laser device 1 according to the present embodiment, the heat interference between two adjacent emitters E via the pad electrode 50 and the crystal defects of the light emitting ridge portion R due to the thermal expansion of the pad electrode 50 are caused by the recess 51. It can be suppressed.

  In the present embodiment, the recess 51 of the pad electrode 50 is not formed on the light emitting ridge portion R. Therefore, even if the recess 51 is formed in the pad electrode 50, it does not hinder the injection of the current into the light emitting ridge portion R.

Further, in the semiconductor laser device 1 according to the present embodiment shown in FIG. 1, as shown in FIGS. 2 and 3, the end ridge portion S ₀ (S _n ) of the plurality of dummy ridge portions S has a groove A plurality of divided ridges are separated by m.

As described above, the end-side ridge portion S ₀ (S _n ) is separated into a plurality of pieces, whereby the strain m caused by the stress can be relieved by the grooves m between the plurality of divided ridge portions. With this configuration, a difference in thermal expansion occurs with a difference in linear expansion coefficient between the laminated structure 20 of the semiconductor laser device 1 and the submount 60 due to a temperature difference etc. during mounting, and the width of the laminated structure 20 of the semiconductor laser device 1 Even if stress is generated at the end of the direction, the stress can be absorbed by the groove m between the plurality of split ridges. As a result, the strain caused in the dummy ridge portion S due to the stress due to the thermal expansion difference can be alleviated, so that the generation of crystal defects in the dummy ridge portion S can be suppressed. As a result, it is possible to suppress the occurrence of crystal defects in the light emitting ridge portion R by propagating crystal defects in the dummy ridge portion S to the light emitting ridge portion R adjacent to the dummy ridge portion S. Therefore, the semiconductor laser device 1 with high reliability can be realized.

In the present embodiment, both end-side ridge portion S ₀ and S _n is the plurality of separated, only one end side ridge portion S ₀ and S _n may be the plurality of separated.

(Modification)
As described above, the semiconductor laser element 1 and the semiconductor laser device 2 according to the present disclosure have been described based on the embodiments, but the present disclosure is not limited to the above embodiments.

  For example, in the above embodiment, the portion of the pad electrode 50 which is separated from the element end face (the first end face 20a and the second end face 20b) on the light emitting ridge R by the first distance d1 is the first end face 20a side and Although it formed in both the 2nd end surface 20b side, it is not restricted to this, You may form in the at least one element end surface side of the 1st end surface 20a and the 2nd end surface 20b.

  Similarly, the portions of the pad electrode 50 that are separated from the element end surfaces (first end surface 20a, second end surface 20b) on the dummy ridge portion S by the second distance d2 are the first end surface 20a side and the second end surface 20b side. However, the present invention is not limited to this, and may be formed on at least one of the first end surface 20a and the second end surface 20b. That is, in the above embodiment, the recessed portion 51 which constitutes the amount of retraction (the amount of recess) from the side of the pad electrode 50 which is the second distance d2 in the dummy ridge portion S is the side on the first end face 20a side and the second end face It may be formed on at least one of the sides on the 20b side.

  Specifically, in the above embodiment, the recess 51 of the pad electrode 50 is formed on both sides of the first end face 20a and the second end face 20b, either of the first end face 20a and the second end face 20b. It may be formed only on one side. As described above, by forming the recess 51 of the pad electrode 50 only on one side of the first end surface 20a side and the second end surface 20b side, the area of the pad electrode 50 can be increased compared to the above embodiment. can do. Thus, the contact area with the submount 60 can be increased, so that a semiconductor laser device with higher reliability can be realized.

  When the second distance d2 in the dummy ridge portion S is increased by, for example, increasing the amount of retraction of the recess 51, the length in the cavity length direction of the pad electrode 50 connecting adjacent light emitting ridge portions R is shortened. As a result, the resistance of the pad electrode 50 partially rises to generate ineffective power and heat is generated by the ineffective power. Therefore, the amount of retraction of the recess 51 should not be too large, and may be set to an optimum value.

  In the above embodiment, the first end surface 20a and the second end surface 20b are flat surfaces. However, the present invention is not limited to this, and in the dummy ridge portion S, the pad electrode 50 is separated by the second distance d2. The end face on the side having the portion may have a groove 20 c extending downward from the upper surface of the dummy ridge portion S. For example, as shown in FIG. 12, grooves 20 c may be formed extending downward from the upper surface of the dummy ridge portion S on both the first end surface 20 a and the second end surface 20 b of the dummy ridge portion S. In this way, by forming the groove 20c, it is possible to further suppress the thermal interference between two adjacent emitters E via the pad electrode 50.

  The depth of the groove 20c is a length that reaches the substrate 10 from the upper surface of the dummy ridge S toward the substrate 10, but the groove 20c reaches the substrate 10 from the upper surface of the dummy ridge S. It is possible to form only up to the middle layer (for example, the first cladding layer 21) of the stacked structure 20 without doing so. In FIG. 12, the surface of the groove 20 c is exposed, but the surface of the groove 20 c may be covered with the insulating layer 30.

  Further, in the above embodiment, the first electrode 41 (p-side electrode) is formed in the light emitting ridge portion R and not formed on the dummy ridge portion S, but the present invention is not limited to this. For example, the first electrode 41 may be formed on both the light emitting ridge portion R and the dummy ridge portion S. However, in this case, an insulating film is formed between the dummy ridge portion S and the first electrode 41 or an insulating layer is formed in the dummy ridge portion S, and the active layer 23 below the dummy ridge portion S is formed. It is necessary to form in the dummy ridge portion S a current injection blocking structure in which no current is injected. When the first electrode 41 is also formed on the dummy ridge portion S, a plurality of first electrodes 41 may be formed for each ridge portion R and each dummy ridge portion S, or all the ridge portions may be formed. One first electrode 41 may be formed so as to cover R and all the dummy ridge portions S. In the latter case, the first electrode 41 may be used as the pad electrode without providing the pad electrode 50 separately.

  In the above embodiment, the width WR of the light emitting ridge portion R and the width WS of the dummy ridge portion S are different from each other. However, the present invention is not limited to this. That is, the width WR of the light emitting ridge portion R and the width WS of the dummy ridge portion S may be the same.

  Further, in the above embodiment, the semiconductor laser device 1 is mounted on the submount 60 by the face down method, but the present invention is not limited to this. For example, the semiconductor laser element 1 may be mounted on a support base such as the submount 60 by a face-up method.

  In addition, modes obtained by applying various modifications that those skilled in the art may think on the above embodiment and modifications, and components and functions in the embodiments and modifications without departing from the spirit of the present disclosure. An embodiment realized by arbitrarily combining is also included in the present disclosure.

  The semiconductor laser device and the semiconductor laser device according to the present disclosure can be used as a light source of various devices such as a laser processing device or an image display device, and in particular, as a light source of a device requiring a relatively high light output. It is useful.

DESCRIPTION OF SYMBOLS 1 Semiconductor laser element 2 Semiconductor laser apparatus 10 Substrate 20 Laminated structure 20a 1st end surface 20b 2nd end surface 20c Groove part 21 1st cladding layer 22 1st guide layer 23 Active layer 24 2nd guide layer 25 Electronic barrier layer 26 2nd cladding Layer 27 Contact layer 30 Insulating layer 41 First electrode 42 Second electrode 50 Pad electrode 51 Recessed portion 52 Inclined portion 53 Notched portion 60 Submount 71 First heat radiating member 72 Second heat radiating member R Light emitting ridge portion S Dummy ridge portion M, M ', M groove E emitter

Claims (8)

A first conductive substrate,
A first conductivity type layer formed on the first conductivity type substrate;
An active layer formed on the first conductivity type layer;
A second conductivity type layer formed on the active layer,
The laminated structure including the first conductivity type substrate, the first conductivity type layer, the active layer, and the second conductivity type layer includes a pair of opposed end surfaces that serve as resonator end surfaces,
The second conductivity type layer is
A plurality of first ridge portions having a longitudinal direction in a direction orthogonal to the pair of end faces and serving as a current injection path to the active layer;
And a plurality of second ridges having a longitudinal direction in a direction orthogonal to the pair of end faces and not serving as a current injection path to the active layer,
The plurality of second ridges includes at least end ridges provided on both ends of the plurality of first ridges,
A first metal layer is formed on the lower surface of the first conductivity type substrate,
A second metal layer is continuously formed on the plurality of first ridges and the plurality of second ridges,
The second metal layer is thicker than the first metal layer, and on the end side ridge portion, a first portion separated from the first ridge portion is closer than the second portion closer to the first ridge portion. Semiconductor laser device with a small area. The semiconductor laser device according to claim 1, wherein a height of the first ridge portion is equal to a height of the second ridge portion. The first portion of the second metal layer on the end ridge portion is at least one end surface of the pair of end surfaces from the second portion of the second metal layer on the end ridge portion. The semiconductor laser device according to claim 1, wherein the distance is large. The corner of the first portion of the second metal layer on the end-side ridge portion is inclined in a direction in which the distance from one end surface of the pair of end surfaces increases as the distance from the first ridge portion increases. The semiconductor laser device according to claim 1. 3. The semiconductor laser device according to claim 1, wherein the second metal layer has a cutout portion on a side of the end ridge portion that is away from the first ridge portion. A first conductive substrate,
A first conductivity type layer formed on the first conductivity type substrate;
An active layer formed on the first conductivity type layer;
A second conductivity type layer formed on the active layer,
The laminated structure including the first conductivity type substrate, the first conductivity type layer, the active layer, and the second conductivity type layer includes a pair of opposed end surfaces that serve as resonator end surfaces,
The second conductivity type layer is
A plurality of first ridge portions having a longitudinal direction in a direction orthogonal to the pair of end faces and serving as a current injection path to the active layer;
And a plurality of second ridges having a longitudinal direction in a direction orthogonal to the pair of end faces and not serving as a current injection path to the active layer,
Each of the plurality of second ridges includes an end-side ridge provided at each of both ends of the plurality of first ridges in the arrangement direction,
A first metal layer is formed on the lower surface of the first conductivity type substrate,
A second metal layer is continuously formed on the plurality of first ridge portions and the second ridge portion,
A semiconductor laser device, wherein the second metal layer is thicker than the first metal layer and is not formed on the end side ridge portion. The semiconductor laser device according to any one of claims 1 to 6,
A submount, and
The semiconductor laser device is such that the first ridge portion side and the second ridge portion side are joined to the submount. And a first heat radiation member and a second heat radiation member,
The semiconductor laser device according to claim 7, wherein a bonded body of the semiconductor laser element and the submount is sandwiched between the first heat radiating member and the second heat radiating member.

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