Semiconductor laser device

Abstract

A semiconductor laser device (100) comprises: a submount (30) having a bottom plate (45) and a convex portion (46) protruding from the surface of the bottom plate (45); and a semiconductor laser (1) bonded to the submount (30). The semiconductor laser (1) comprises: a semiconductor substrate (2); a semiconductor structure (3) formed on the surface of the semiconductor substrate (2) and including an active layer (5); a first electrode (8); and a second electrode (9). The side surface of the semiconductor laser (1) opposite to the convex portion (46) and the second electrode (9) are bonded to the side surface of the convex portion (46) opposite to the semiconductor laser (1) and the surface of the bottom plate (45) respectively through a bonding member (40). The end of the bonding member (40) bonding the side surface of the convex portion (46) to the side surface of the semiconductor laser (1) in the direction in which the convex portion (46) protrudes, i.e., in the z direction, is located farther in the z direction than the surface of the semiconductor substrate (2) of the semiconductor laser (1).

Description

Technical Field

[0001] The present application relates to a semiconductor laser device. Background Art

[0002] Usually, in a semiconductor laser device, a chip-shaped semiconductor laser is bonded to a submount. Semiconductor laser devices are sometimes required to operate within a wide temperature range of, for example, -40°C to 95°C. In order to operate within a wide temperature range of -40°C to 95°C, a conventional semiconductor laser device is mounted in a package such as a can package together with a temperature adjustment mechanism such as a Peltier cooler that cools the semiconductor laser device in operation, or is mounted in a modular optical module together with other optical components. In order to make a packaged semiconductor laser device or an optical module equipped with a semiconductor laser device small, etc., it is sometimes required to be able to perform so-called non-cooling operations, that is, a semiconductor laser device that does not require temperature adjustment by a temperature adjustment mechanism.

[0003] In order to realize a semiconductor laser device capable of performing non-cooling operation within a wide temperature range, it is necessary to fully release the heat generated by the semiconductor laser even without a temperature adjustment mechanism, and it is necessary to improve the heat dissipation. Patent document 1 discloses a semiconductor laser device, which, in order to improve the heat dissipation, inserts a nitride semiconductor laser formed on an insulating substrate into a recessed portion of a support body (sub-mount) having a metal formed on the inner surface. Patent document 2 discloses a semiconductor laser device having a secondary base portion bonded to the primary base portion by epoxy resin, and a semiconductor laser is mounted on a sub-mount having an L-shaped cross-sectional shape in such a manner that a printed wiring formed on the side of the secondary base portion and a printed wiring formed on the surface of the primary base portion are connected to a first electrode and a second electrode respectively via a solder pattern.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 10-22570 ( Figure 3 )

[0005] Patent Document 2: Japanese Patent Application Publication No. 2019-212859 (FIG. 14)

[0006] The semiconductor laser device of Patent Document 1 has semiconductor lasers connected to the bottom surface and the bottom surface side of the side surface in the concave portion of the submount, and cannot fully dissipate heat from the side surface of the semiconductor laser to the side surface of the concave portion of the submount. Therefore, the semiconductor laser device of Patent Document 1 is difficult to perform non-cooling operation in a wide temperature range.

[0007] The semiconductor laser in the semiconductor laser device of Patent Document 2 comprises: a first electrode connected to the topmost layer of the ridge including the active layer, i.e., the contact layer, and arranged to extend along the side and back of the semiconductor substrate; and a second electrode formed on the back of the semiconductor substrate, and the semiconductor laser is a wire-free bonding semiconductor laser in which the first electrode connected to the contact layer of the ridge and the sub-mount are connected without using a lead. The second electrode formed on the back of the semiconductor substrate is insulated from the first electrode extending from the side by a convex portion covered by an insulating film. In the semiconductor laser device of Patent Document 2, the heat dissipation from the back of the semiconductor laser is mainly carried out through a path from the second electrode narrowed to about 1 / 3 by being sandwiched by the convex portion to the first submount portion via the solder pattern. In addition, the heat dissipation from the side of the semiconductor laser is mainly carried out through a path from the first electrode arranged in the concave narrowed to about 1 / 3 to the second submount portion via the solder pattern. In addition, the first submount portion and the second submount portion are insulated by epoxy resin. Therefore, the semiconductor laser device of Patent Document 2 cannot fully dissipate heat from the side of the semiconductor laser to the first submount portion with a large volume via the second submount portion. Therefore, it is difficult for the semiconductor laser device of Patent Document 2 to perform an uncooled operation in a wide temperature range. Summary of the invention

[0008] An object of the technology disclosed in this specification is to realize a semiconductor laser device capable of performing an uncooled operation in a wide temperature range.

[0009] A semiconductor laser device of an example disclosed in the present application specification comprises: a submount having a bottom plate portion and a convex portion protruding from the surface of the bottom plate portion; and a semiconductor laser bonded to the submount. The semiconductor laser comprises: a semiconductor substrate; a semiconductor structure portion formed on the surface of the semiconductor substrate and including an active layer that generates light emitted from an emission end face; a first electrode formed on the surface of the semiconductor structure portion opposite to the semiconductor substrate; and a second electrode formed on the back of the semiconductor substrate. The side surface of the semiconductor laser opposite to the convex portion and the second electrode are bonded to the side surface of the convex portion opposite to the semiconductor laser and the surface of the bottom plate portion, respectively, through a bonding component. The end of the bonding component that bonds the side surface of the convex portion to the side surface of the semiconductor laser in the direction in which the convex portion protrudes, i.e., in the z direction, is located farther in the z direction than the surface of the semiconductor substrate of the semiconductor laser.

[0010] In a semiconductor laser device of an example disclosed in the present application specification, since the second electrodes on the side and back sides of the semiconductor laser are joined to the side faces of the protrusions of the sub-base opposite to them and the surface of the bottom plate portion via a joining component, and the end of the joining component in the z direction that joins the side faces of the protrusions to the side faces of the semiconductor laser is located farther away from the surface of the semiconductor substrate, non-cooling operation can be performed within a wide temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a perspective view showing the semiconductor laser device according to the first embodiment.

[0012] Figure 2 yes Figure 1 A cross-sectional view of a semiconductor laser device.

[0013] Figure 3 Yes means Figure 1 A cross-sectional view of a main portion of a semiconductor structure portion in a semiconductor laser.

[0014] Figure 4 This is a cross-sectional view showing another example of the submount according to the first embodiment.

[0015] Figure 5 It is a perspective view showing a semiconductor laser device according to the second embodiment.

[0016] Figure 6 Yes means Figure 5 A three-dimensional diagram of a semiconductor laser.

[0017] Figure 7 yes Figure 5 A first cross-sectional view of a semiconductor laser device.

[0018] Figure 8 yes Figure 5 A second cross-sectional view of a semiconductor laser device.

[0019] Fig. 9 Yes means Figure 5 A cross-sectional view of the main body of the sub-abutment.

[0020] Fig.10 Yes means Figure 5 A stereoscopic view of the cover of the sub-base.

[0021] Fig.11 yes Fig.10 A first cross-sectional view of a cover of a secondary base.

[0022] Fig.12 yes Fig.10 A second cross-sectional view of the cover of the secondary platform.

[0023] Fig.13 Yes means Figure 5 Surface view of the other covers of the sub-base. DETAILED DESCRIPTION

[0024] Implementation Method 1

[0025] Figure 1 is a perspective view showing a semiconductor laser device according to Embodiment 1, Figure 2 yes Figure 1 A cross-sectional view of a semiconductor laser device. Figure 3 Yes means Figure 1 A cross-sectional view of a main part of a semiconductor structure portion in a semiconductor laser, Figure 4 This is a cross-sectional view showing another example of the submount according to the first embodiment. Figure 2 yes Figure 1 The cross section includes the dotted line 49 and is cut parallel to the z direction. The semiconductor laser device 100 involved in the first embodiment includes a semiconductor laser 1 and a submount 30 on which the semiconductor laser 1 is mounted. The semiconductor laser 1 includes: a semiconductor substrate 2; a semiconductor structure 3 formed on the surface of the semiconductor substrate 2 and including an active layer 5 that generates light; a first electrode 8 as a surface electrode formed on the surface of the semiconductor structure 3 on the opposite side of the semiconductor substrate 2; and a second electrode 9 as a back electrode formed on the back side of the semiconductor substrate 2. The submount 30 includes a base 31 and a metal layer 32, and the metal layer 32 is formed on the side of the base 31 on which the semiconductor laser 1 is mounted. The semiconductor laser 1 emits light from the emission end face 21 along the optical axis 20. In addition, the semiconductor laser 1 may also emit light from the emission end face 21 along the optical axis 20, and emit light from the end face on the opposite side to the emission end face 21 along the optical axis 20. The direction of light emitted from the emission end face 21 in the optical axis 20 is marked with an arrow. In the figure, a direction perpendicular to the semiconductor substrate 2 is a z direction, a direction parallel to the extending direction of the active layer 5 is an x ​​direction, and a direction perpendicular to the x direction and the z direction is a y direction.

[0026] The sub-mount 30 includes a bottom plate 45 and a convex portion 46 protruding from the bottom plate 45 in the z direction, and the cross-sectional shape of the sub-mount 30 perpendicular to the x-axis is an L-shaped shape. The convex portion 46 of the sub-mount 30 extends from the surface of the bottom plate 45 in the z direction. The sub-mount 30 is an L-shaped sub-mount. The bottom plate 45 is a range from the dotted line 47a to the dotted line 48, and the convex portion 46 is a range from the dotted line 48 to the dotted line 47b. The dotted line 47a is a dotted line extending along the surface of the sub-mount 30 opposite to the metal layer 32, that is, the back side, and the dotted line 47b is a dotted line connected to the farthest part of the sub-mount 30 that is farthest from the back side in the z direction. The dotted line 48 is a dotted line extending along the surface of the sub-mount 30 opposite to the back side of the semiconductor laser 1. The metal layer 32 is formed on the surface of the submount 30 that faces the semiconductor laser 1, that is, the surface of the base 31 at the bottom plate portion 45, the surface in the y direction at the convex portion 46 of the base 31, and the surface in the z direction. The metal layer 32 may also be formed on the surface of the submount 30 that faces the semiconductor laser 1, that is, the surface of the bottom plate portion 45, and the surface in the y direction of the convex portion 46. In addition, the surface in the y direction is appropriately referred to as a side surface.

[0027] exist Figure 1 , Figure 2 , an example is shown in which the metal layer 32 is also formed on the surface of the base 31 in the z direction at the protrusion 46, and the metal layer 32 is formed on the entire surface of the positive side in the z direction and the positive side in the y direction of the base 31 in the submount 30. In the semiconductor laser 1, the second electrode 9 and the surface on the negative side in the y direction, that is, the side opposite to the submount 30, are joined to the metal layer 32 of the submount 30 by a joining member 40 such as a welding material. Figure 1 The lead 41a connected to the first electrode 8 of the semiconductor laser 1 and the lead 41b connected to the metal layer 32 of the submount 30 are also described. The semiconductor laser device 100 is connected to an external circuit or the like through the leads 41a and 41b. In addition, when the surface of the convex portion 46 in the z direction is not connected to the external circuit or the like, the metal layer 32 may not be formed on the surface of the convex portion 46 in the z direction.

[0028] The semiconductor laser device 100 of the first embodiment is an example in which the two surfaces of the semiconductor laser 1 are bonded to the submount 30. The submount 30 is different from the submount in which the first and second submount portions are insulated by epoxy resin in the patent document 2. In order not to hinder the heat conduction between the bottom plate portion 45 and the protrusion 46, the submount 30 has an integrally formed base portion 31 or a base portion 32 formed by the bottom plate portion 45 or a base portion 33 formed by the bottom plate portion 45 or a base portion 34 formed by the bottom plate portion 45 or a base portion 35 formed by the bottom plate portion 45 or a base portion 36 formed by the bottom plate portion 45 or a base portion 31 ... Figure 4 The base 31 is formed by joining the two base blocks 33a and 33b via a conductive joining member 34 such as a welding material. Figure 4 In another example of the submount 30 shown, the base block 33 a is a base at the bottom plate portion 45 , and the base block 33 b is a base at the protrusion 46 .

[0029] In order to improve the heat dissipation of heat generated by light generation to the submount 30, the semiconductor laser device 100 of the first embodiment arranges the active layer 5 at a position close to the convex portion 46 side of the submount 30, that is, at an offset position, so that the thermal resistance from the active layer 5 to the side of the convex portion 46 of the submount 30 does not become extremely smaller than the thermal resistance from the active layer 5 to the surface of the bottom plate portion 45 of the submount 30, or is as equal as possible. The active layer 5 is arranged at a position closer to the convex portion 46 side than the center 18 between the side surfaces, which is the center between the two side surfaces of the semiconductor laser 1 in the y direction. The dotted line 17 is a dotted line that includes the center 18 between the side surfaces and extends in the z direction. More specifically, the distance d1 from the central axis 22 of the active layer 5 parallel to the x-direction to the surface in the y-direction opposite to the protrusion 46 of the submount 30, that is, the side surface of the semiconductor structure 3 in the semiconductor laser 1 and the side surface of the semiconductor substrate 2 is designed to be shorter than the distance d2 from the central axis 22 of the active layer 5 to the back surface of the semiconductor substrate 2 in the semiconductor laser 1 opposite to the bottom plate 45 of the submount 30. The dotted line 51a is a dotted line including the central axis 22 and extending in the z-direction, and the dotted line 51c is a dotted line including the central axis 22 and extending in the y-direction. The dotted line 51b is a dotted line extending along the side surface of the semiconductor structure 3 and the semiconductor substrate 2 in the semiconductor laser 1 opposite to the protrusion 46 of the submount 30, and the dotted line 51d is a dotted line extending along the back surface of the semiconductor substrate 2 in the semiconductor laser 1 opposite to the bottom plate 45 of the submount 30. The distance d1 is the distance from the dotted line 51a to the dotted line 51b, and the distance d2 is the distance from the dotted line 51c to the dotted line 51d.

[0030] The length l1 of the joining member 40 joining the side surface of the protrusion 46 of the submount 30 to the side surface of the semiconductor laser 1 in the z direction is approximately the same as the length L1 of the side surface of the semiconductor laser 1, and is at least longer than the length from the surface of the bottom plate 45 to the surface of the semiconductor substrate 2 of the semiconductor laser 1. Figure 2, an example is shown in which the positive side end in the z direction of the bonding member 40 arranged on the side of the protrusion 46 of the submount 30 is located between the surface of the semiconductor substrate 2 and the surface of the semiconductor structure 3. That is, the end (the portion of the dotted line 55c) in the direction in which the protrusion 46 protrudes, i.e., in the z direction, of the bonding member 40 that bonds the side of the protrusion 46 to the side of the semiconductor laser 1 is located farther in the z direction than the surface of the semiconductor substrate 2 of the semiconductor laser 1. In addition, in the submount 30, the end (the portion of the dotted line 47b) of the protruding z direction of the protrusion 46 is located farther in the z direction than the surface of the first electrode 8 of the semiconductor laser 1. The dotted line 55a is a dotted line extending along the surface of the semiconductor structure 3 in the semiconductor laser 1, and the dotted line 55b is a dotted line extending along the surface of the negative side in the z direction, i.e., the back surface, of the second electrode 9 in the semiconductor laser 1. The dotted line 55c is a dotted line connected to the positive side end of the bonding component 40 in the z direction which is farthest from the bottom plate portion 45 of the submount 30 in the z direction. As described above, the dotted line 48 is a dotted line extending along the surface of the submount 30 opposite to the back surface of the semiconductor laser 1. More specifically, the dotted line 48 is also a dotted line connected to the negative side end of the bonding component 40 in the z direction, and is a dotted line extending along the surface of the metal layer 32 formed on the bottom plate portion 45 of the submount 30 opposite to the semiconductor laser 1. The length L1 is the length from the dotted line 55a to the dotted line 55b, and the length l1 is the length from the dotted line 55c to the dotted line 48.

[0031] The structural example of the semiconductor laser 1 is described in detail. The semiconductor substrate 2 is, for example, an InP substrate of the first conductivity type. The semiconductor structure 3 of the semiconductor laser 1 is formed on the surface of the InP semiconductor substrate 2 of the first conductivity type. The semiconductor structure 3 of the semiconductor laser 1 includes an InP cladding layer 4 of the first conductivity type, an active layer 5, an InP cladding layer 6 of the second conductivity type, an InP buried layer 12, an InGaAs contact layer 7 of the second conductivity type, and an insulating film 11 such as SiO2. The first electrode 8 as a surface electrode formed on the surface of the semiconductor structure 3 opposite to the semiconductor substrate 2 is connected to the contact layer 7 through an opening 15 formed in the insulating film 11. The semiconductor structure 3 is between the dotted line 52c and the dotted line 52d. The dotted line 52c is a dotted line extending along the boundary between the semiconductor substrate 2 and the buried layer 12, and the dotted line 52d is a dotted line extending along the surface of the insulating film 11. The second electrode 9 as a back electrode and the first electrode 8 as a surface electrode are, for example, TiAu, AuZn, etc. The active layer 5 is composed of a multi-quantum well including InGaAsP, AlGaInAs, AlInAs, etc. When the first conductivity type is n-type and the second conductivity type is p-type, the first electrode 8 is an anode electrode and the second electrode 9 is a cathode electrode. When the first conductivity type is p-type and the second conductivity type is n-type, the first electrode 8 is a cathode electrode and the second electrode 9 is an anode electrode. The cladding layer 4, the active layer 5 and a part of the cladding layer 6 constitute a mesa extending in the x direction, that is, a mesa strip 13. The mesa strip 13 is between the dotted line 52a and the dotted line 52b. The buried layer 12 is formed on both sides of the mesa strip 13 in the y direction, and grooves 10a and 10b are formed that penetrate the semiconductor structure 3 and reach the semiconductor substrate 2.

[0032] The outline of the manufacturing method of the semiconductor structure portion 3 is described. The mesa strips 13 are formed by dry etching using a SiO2 mask to form the cladding layer 4, the active layer 5, and a part of the cladding layer 6 formed in sequence on the semiconductor substrate 2. The buried layer 12 is formed on both sides of the mesa strips 13 in the y direction, and the semiconductor substrate 2 is exposed by dry etching. The cladding layer 6 and the contact layer 7 are formed on the surface of the buried layer 12 and the surface of the mesa strips 13, and the grooves 10a and 10b are formed by wet etching using a photoresist mask. The photoresist mask is removed, and the insulating film 11 is formed on the surface of the contact layer 7 and the grooves 10a and 10b. The opening 15 of the insulating film 11 is formed using the photoresist mask. Thereafter, the photoresist mask is removed, and a metal layer of an electrode material is formed on the surface and back of the semiconductor laser 1, thereby forming the first electrode 8 and the second electrode 9.

[0033] The material of the base portion 31 of the submount 30 is, for example, AlN. The material of the metal layer 32 is, for example, Au. The bonding member 40 is a solder such as AuSn, a conductive resin paste, or the like.

[0034] The semiconductor laser device 100 of the first embodiment is different from a general semiconductor laser device in which a semiconductor laser is mounted on one surface of a simple hexahedral submount. The submount 30 includes a bottom plate 45 and a convex portion 46 protruding from the bottom plate 45 in the z direction. The second electrode 9 on the back side and the side surface of the semiconductor laser 1 are bonded to the surface of the bottom plate 45 and the side surface of the convex portion 46 of the submount 30, so that heat can be dissipated from the back side and the side surface of the semiconductor laser 1 to the submount 30. In addition, in the semiconductor laser device 100 of the first embodiment, almost all of the side surface of the semiconductor laser 1 facing the submount 30, for example, all of the side surface of the semiconductor substrate 2 of the semiconductor laser 1, are bonded to the convex portion 46 of the submount 30. Therefore, the heat dissipation from the side surface of the semiconductor laser 1 to the submount 30 can be improved compared with the semiconductor laser devices of Patent Document 1 and Patent Document 2, and non-cooling operation can be performed in a wide temperature range of -40°C to 95°C. Furthermore, in the semiconductor laser device 100 of embodiment 1, by making the distance d1 from the central axis 22 of the active layer 5 to the side surface opposite to the protrusion 46 of the sub-mount 30 shorter than the distance d2 from the central axis 22 of the active layer 5 to the back surface of the semiconductor substrate 2 opposite to the bottom plate portion 45 of the sub-mount 30, that is, the position of the active layer 5 is shifted from the center in the y direction to the side of the protrusion 46 of the sub-mount 30, compared with the case where the position of the active layer 5 is not shifted in the y direction, even a semiconductor laser 1 with a large output of the output light and a large power consumption can achieve non-cooling operation within a wide temperature range of -40°C to 95°C.

[0035] As described above, the semiconductor laser device 100 of the first embodiment includes: the submount 30 including the bottom plate portion 45 and the protrusion 46 protruding from the surface of the bottom plate portion 45; and the semiconductor laser 1 bonded to the submount 30. The semiconductor laser 1 includes: the semiconductor substrate 2; the semiconductor structure portion 3 formed on the surface of the semiconductor substrate 2 and including the active layer 5 for generating light emitted from the emission end face 21; the first electrode 8 formed on the surface of the semiconductor structure portion 3 on the opposite side to the semiconductor substrate 2; and the second electrode 9 formed on the back surface of the semiconductor substrate 2. The side surface of the semiconductor laser 1 facing the protrusion 46 and the second electrode 9 are bonded to the side surface of the protrusion 46 facing the semiconductor laser 1 and the surface of the bottom plate portion 45, respectively, through the bonding member 40. The end of the bonding member 40 in the direction in which the protrusion 46 protrudes, that is, the z direction, which bonds the side surface of the protrusion 46 to the side surface of the semiconductor laser 1, is located farther in the z direction than the surface of the semiconductor substrate 2 of the semiconductor laser 1. The semiconductor laser device 100 of embodiment 1 is structured such that the second electrode 9 on the side and back sides of the semiconductor laser 1 and the side of the protrusion 46 in the sub-base 30 opposite to them and the surface of the bottom plate 45 are joined by a joining component 40, and the end in the z-direction of the joining component 40 for joining the side of the protrusion 46 to the side of the semiconductor laser 1 is located farther away from the surface of the semiconductor substrate 2, thereby enabling non-cooling operation to be performed within a wide temperature range.

[0036] Implementation Method 2

[0037] Figure 5 is a perspective view showing a semiconductor laser device according to Embodiment 2, Figure 6 Yes means Figure 5 A three-dimensional diagram of a semiconductor laser. Figure 7 yes Figure 5 A first cross-sectional view of a semiconductor laser device, Figure 8 yes Figure 5 A second cross-sectional view of a semiconductor laser device. Fig. 9 Yes means Figure 5 A cross-sectional view of the main body of the sub-abutment, Fig.10 Yes means Figure 5 A stereoscopic view of the cover of the sub-base. Fig.11 yes Fig.10 A first cross-sectional view of the cover of the submount, Fig.12 yes Fig.10 A second cross-sectional view of the cover of the secondary platform. Fig.13 Yes means Figure 5 Surface view of the other covers of the sub-base. Figure 7 is included Figure 5 A cross section cut along the dotted line 54a and parallel to the z direction, Figure 8 is included Figure 5 A cross section cut along the dotted line 54b and parallel to the z direction. Fig.11 is included Fig.10 A cross section cut along the dotted line 57a and parallel to the z direction, Fig.12 is included Fig.10 The cross section is cut along the dotted line 57b and parallel to the z direction. Figure 5 In FIG. 4 , the pattern of the metal layer 32a on the positive side in the z direction of the convex portion 46b is omitted. Fig.10 , the patterns of the metal layer 32b and the bonding member 40b on the positive side in the z direction are omitted. The semiconductor laser device 100 of the second embodiment is an example in which the submount 30 is bonded to the semiconductor laser 1 on four surfaces of the semiconductor laser 1, namely, the surface in the z direction and the surface in the y direction except the emission end face 21 and the end face on the opposite side of the emission end face 21. The semiconductor laser device 100 of the second embodiment is different from the semiconductor laser device 100 of the first embodiment in that the submount 30 is bonded to the semiconductor laser 1 on the inner surface of the submount 30 having the main body 38 and the cover 39, namely, the inner surface in the z direction and the inner surface in the y direction of the submount 30. The following mainly describes the parts that are different from the semiconductor laser device 100 of the first embodiment.

[0038] The semiconductor laser 1 of the second embodiment includes: a semiconductor substrate 2; a semiconductor structure 3 formed on the surface of the semiconductor substrate 2 and including an active layer 5 that generates light; a first electrode 8 as a surface electrode formed on the surface of the semiconductor structure 3 on the opposite side of the semiconductor substrate 2; a second electrode 9 as a back electrode formed on the back side of the semiconductor substrate 2; and a protective film 14 formed on the surface of the semiconductor structure 3 on the positive side in the z direction, the surface of the first electrode 8 on the positive side in the z direction, and the surface in the y direction. An opening 16 is formed in the protective film 14 to expose a part of the first electrode 8. The protective film 14 is a resin film such as polyimide, and is formed in the wafer manufacturing process of the semiconductor laser 1. The protective film 14 is formed by spin coating a liquid resin material, and the opening 16 is formed by wet etching using a photoresist mask. The submount 30 of the second embodiment includes a main body 38 and a cover 39. The main body 38 includes a base 31 and a metal layer 32a formed on the side of the base 31 on which the semiconductor laser 1 is mounted. The cover 39 includes a base 35 and a metal layer 32b formed on the side of the base 35 opposite to the semiconductor laser 1 and the side opposite to the main body 38. The cover 39 is provided with an opening 36, which is a through hole for passing the lead 41a connected to the first electrode 8 of the semiconductor laser 1. The opening 36 penetrates the cover surface 63 from the cover back surface 62 of the cover 39. The first electrode 8 is exposed through the opening 16 of the protective film 14 and the opening 36 of the cover 39.

[0039] The main body 38 includes a bottom plate 45 and two convex portions 46a and 46b protruding from the bottom plate 45 in the z direction. The cross-sectional shape of the main body 38 perpendicular to the x-axis is a U-shape or a shape having a concave portion. The bottom plate 45 is a range from the dotted line 47a to the dotted line 48, the convex portion 46a on the negative side in the y direction is a range from the dotted line 48 to the dotted line 47b, and the convex portion 46b on the positive side in the y direction is a range from the dotted line 48 to the dotted line 47c. The dotted line 47b is a dotted line connected to the farthest portion on the positive side in the z direction located at the position farthest from the back side of the main body 38 on the positive side in the z direction, and is a dotted line connected to the farthest portion on the positive side in the z direction of the convex portion 46a on the negative side in the y direction. The dotted line 47c is a dotted line connected to the farthest portion on the z direction of the convex portion 46b on the positive side in the y direction. The metal layer 32a is formed on the inner surface of the main body 38 which is the surface opposite to the semiconductor laser 1, that is, the surface of the base 31 at the bottom plate portion 45, the surface of the base 31 at the positive side in the y direction at the convex portion 46a, and the surface of the base 31 at the negative side in the y direction at the convex portion 46b. In addition, the metal layer 32a is also formed on the surface of the base 31 at the convex portion 46a in the z direction. It can also be said that the metal layer 32a is formed on the inner surface of the main body 38 which is the surface opposite to the semiconductor laser 1, that is, the surface of the bottom plate portion 45, the surface of the convex portion 46a on the positive side in the y direction, and the surface of the convex portion 46b on the negative side in the y direction.

[0040] exist Figure 5 , Figure 7 , Figure 8 , an example is shown in which the metal layer 32a is also formed on the surface of the base 31 on the positive side in the z direction at the convex portion 46a, and the metal layer 32a is formed on the inner surface of the base 31 at the main body 38 and on the surface of the convex portion 46a of one of the two convex portions 46a and 46b on the positive side in the z direction. The second electrode 9 of the semiconductor laser 1 and the surfaces on both sides in the y direction, that is, the two side surfaces opposite to the main body 38, are joined to the metal layer 32a of the main body 38 by a joining member 40a such as a welding material. In addition, the surface of the semiconductor laser 1 on the opposite side to the semiconductor substrate 2, that is, the surface of the protective film 14, is joined to the metal layer 32b of the cover 39 by a joining member 40b such as a welding material. The surfaces on both sides of the metal layer 32b of the cover 39 in the y direction are joined to the metal layers 32a of the convex portions 46a and 46b of the opposite main body 38 by a joining member 40b such as a welding material. That is, the first cover side surface 61a of the cover 39 opposite to the side surface of the protrusion 46a, the second cover side surface 61b opposite to the side surface of the other protrusion 46b, and the cover back surface 62 opposite to the surface of the protective film 14 of the semiconductor laser 1 are respectively bonded to the side surface of the opposite protrusion 46a, the side surface of the other protrusion 46b, and the surface of the protective film 14 by another bonding member 40b. Figure 5 , Figure 7 , Figure 81 and 2 also describe a lead 41a connected to the first electrode 8 of the semiconductor laser 1 and a lead 41b connected to the metal layer 32a of the main body 38 of the submount 30. The semiconductor laser device 100 is connected to an external circuit or the like via the leads 41a and 41b.

[0041] The length l2 in the z direction of the joining member 40a that joins the side surfaces of the protrusions 46a, 46b of the main body 38 of the submount 30 to the side surfaces of the semiconductor laser 1 is approximately the same as the length L2 of the side surfaces of the semiconductor laser 1, and is at least longer than the length from the surface of the bottom plate 45 to the surface of the semiconductor structure 3 of the semiconductor laser 1. Figure 7 , Figure 8 , an example is shown in which the positive side end in the z direction of the bonding member 40a disposed on the side of the protrusions 46a, 46b of the main body 38 of the submount 30 is at the same position in the z direction as the surface of the protective film 14. That is, the end (the portion of the dotted line 56a) in the direction in which the protrusions 46a, 46b protrude, i.e., in the z direction, of the bonding member 40a that bonds the side of the protrusions 46a, 46b to the side of the semiconductor laser 1 is located farther in the z direction than the surface of the semiconductor substrate 2 of the semiconductor laser 1. The dotted line 56a is a dotted line extending along the surface of the protective film 14 in the semiconductor laser 1, and the dotted line 56b is a dotted line extending along the negative side surface in the z direction, i.e., the back surface of the second electrode 9 in the semiconductor laser 1. In addition, the dotted line 56a is also a dotted line that is connected to the positive side end in the z direction of the bonding member 40a that is farthest from the bottom plate portion 45 of the main body 38 of the submount 30 in the z direction. The dotted line 48 is a dotted line extending along the surface of the main body 38 of the submount 30 that is opposite to the back surface of the semiconductor laser 1. More specifically, the dotted line 48 is also a dotted line connected to the negative end of the bonding member 40a in the z direction, and is a dotted line extending along the surface of the metal layer 32a formed on the bottom plate portion 45 of the main body 38 that is opposite to the semiconductor laser 1. The length L2 is the length from the dotted line 56a to the dotted line 56b, and the length l2 is the length from the dotted line 56a to the dotted line 48.

[0042] A method for manufacturing the semiconductor laser device 100 according to the second embodiment will be described. Fig. 9 As shown in FIG. 1 , a bonding member 40a is formed on the inner surface of the main body 38 of the submount 30, i.e., the surface of the metal layer 32a, and the semiconductor laser 1 is placed on the inner surface of the main body 38 of the submount 30, and the semiconductor laser 1 is bonded to the main body 38 of the submount 30 by the bonding member 40a (first step). Figure 10 to Figure 12As shown, a bonding member 40b is formed on the surface of the metal layer 32b formed on the surface of the cover 39 opposite to the semiconductor laser 1 and the surface opposite to the body 38, and the cover 39 is placed on the surface of the semiconductor laser 1 mounted on the body 38, and the semiconductor laser 1 and the body 38 are bonded to the cover 39 by the bonding member 40b (second step). In the case where the bonding members 40a and 40b are welding materials, the semiconductor laser 1 and the body 38 may not be completely bonded in the first step, and the bonding members 40a and 40b may be melted in the second step to bond the semiconductor laser 1, the body 38, and the cover 39 to each other at the same time.

[0043] In the semiconductor laser device 100 of the second embodiment, the main body 38 of the submount 30 includes the bottom plate 45 and the two protrusions 46a and 46b protruding from the bottom plate 45 in the z direction. The second electrode 9 on the back side and the two side surfaces of the semiconductor laser 1 are bonded to the surface of the bottom plate 45 and the inner surfaces of the protrusions 46a and 46b, that is, the side surfaces of the protrusions 46a and 46b on the side opposite to the semiconductor laser 1 in the main body 38 of the submount 30. Therefore, heat can be dissipated from the back side and the two side surfaces of the semiconductor laser 1 to the submount 30. In addition, in the semiconductor laser device 100 of the second embodiment, the cover 39 of the submount 30 is bonded to the protective film 14 formed on the surface of the semiconductor laser 1 and the inner surfaces of the protrusions 46a and 46b of the main body 38. Therefore, heat can be dissipated from the four surfaces of the semiconductor laser 1, that is, the back side, the two side surfaces, and the surface opposite to the back side to the submount 30. Therefore, the semiconductor laser device 100 according to the second embodiment can improve the heat dissipation to the submount 30 compared with the semiconductor laser device 100 according to the first embodiment, and can perform an uncooled operation in a wide temperature range of -40°C to 95°C.

[0044] Since the protective film 14 is insulating, the thermal conductivity of the protective film 14 is lower than that of the semiconductor substrate 2 and the semiconductor structure 3, but the heat dissipation can be improved compared with the semiconductor laser device in which the protective film 14 is partially void. In the semiconductor laser device 100 of the second embodiment, the inner surface of the submount 30 except the opening 36 of the cover 39 is joined to the four opposite surfaces of the semiconductor laser 1, that is, the back surface, two side surfaces, and the front surface, by the joining members 40a and 40b, so that the heat dissipation to the submount 30 can be improved compared with the semiconductor laser device 100 of the first embodiment, and the non-cooling operation can be performed in a wide temperature range of -40°C to 95°C. In addition, an example is shown in which a void exists between the second electrode 9 and the main body 38 of the submount 30 because the side surface of the second electrode 9 in the y direction is retreated from the side surface of the semiconductor substrate 2 in the y direction. Since the heat conductivity of the second electrode 9 and the semiconductor substrate 2 is greater than the void, there is no problem even if there is a small void between the second electrode 9 and the main body 38 of the submount 30. In addition, the side surface of the second electrode 9 in the y direction may be substantially the same as the side surface of the semiconductor substrate 2 in the y direction. In this case, the inner surface of the submount 30 except the opening 36 of the cover 39 and the four opposite surfaces of the semiconductor laser 1, namely, the back surface, two side surfaces, and the front surface, are seamlessly bonded by the bonding members 40a and 40b.

[0045] With respect to the semiconductor laser device 100 of the second embodiment, an example is shown in which the position of the active layer 5 of the semiconductor laser 1 in the y direction is different from that of the semiconductor laser 1 of the first embodiment but is not offset. The position of the active layer 5 of the semiconductor laser 1 in the y direction is preferably such that the thermal resistance from the active layer 5 to the protrusion 46b of the main body 38 on the positive side in the y direction is substantially equal to the thermal resistance from the active layer 5 to the protrusion 46a of the main body 38 on the negative side in the y direction. In addition, with respect to the opening 36, an example of a through hole penetrating from the back side 62 of the cover 39 through the cover surface 63 is shown, but the invention is not limited thereto. The opening 36 may penetrate from the back side 62 of the cover 39 through the cover surface 63 in such a manner as to expose at least a portion of the first electrode 8 connected to the lead 41a. For example, as Fig.13 As shown, the opening 36 may be connected to the surface (side surface) of the cover 39 in the x direction.

[0046] As described above, the semiconductor laser device 100 of the second embodiment includes: the submount 30 including the main body 38 and the cover 39, the main body 38 including the bottom plate 45, the convex portion 46a protruding from the surface of the bottom plate 45, and the other convex portion 46b protruding from the surface of the bottom plate 45, and the cover 39 bonded to the convex portion 46a and the other convex portion 46b; and the semiconductor laser 1 bonded to the submount 30. The semiconductor laser 1 includes: the semiconductor substrate 2; the semiconductor structure 3 formed on the surface of the semiconductor substrate 2 and including the active layer 5 for generating light emitted from the emission end face 21; the first electrode 8 formed on the surface of the semiconductor structure 3 opposite to the semiconductor substrate 2; the second electrode 9 formed on the back surface of the semiconductor substrate 2; and the protective film 14 formed on the surface of the semiconductor structure 3 and the surface of the first electrode 8. The side surface of the semiconductor laser 1 facing the convex portion 46a and the second electrode 9 are bonded to the side surface of the convex portion 46a facing the semiconductor laser 1 and the surface of the bottom plate 45 through the bonding member 40a. The side surface of the semiconductor laser 1 opposite to the other protrusion 46b is joined to the side surface of the other protrusion 46b opposite to the semiconductor laser 1 through the joining component 40a. The end of the joining component 40a in the direction in which the protrusion 46a protrudes, i.e., in the z direction, that joins the side surface of the protrusion 46a to the side surface of the semiconductor laser 1 is located farther in the z direction than the surface of the semiconductor substrate 2 of the semiconductor laser 1. The other end of the joining component 40a in the direction in which the other protrusion 46b protrudes, i.e., in the z direction, that joins the side surface of the other protrusion 46b to the side surface of the semiconductor laser 1 is located farther in the z direction than the surface of the semiconductor substrate 2 of the semiconductor laser 1. The first cover side 61a of the cover 39 opposite to the side of the protrusion 46a, the second cover side 61b opposite to the side of the other protrusion 46b, and the cover back side 62 opposite to the surface of the protective film 14 of the semiconductor laser 1 are respectively joined to the side of the opposite protrusion 46a, the side of the other protrusion 46b, and the surface of the protective film 14 through another joining component 40b. The semiconductor laser device 100 of embodiment 2 is structured such that the two side surfaces of the semiconductor laser 1 and the second electrode 9 on the back side are joined to the side surfaces of the protrusions 46a and 46b opposite to them in the sub-base 30 and the surface of the bottom plate portion 45 by a joining component 40a, so that the end in the z-direction of the joining component 40a for joining the side surfaces of the protrusions 46a and 46b to the side surfaces of the semiconductor laser 1 is located farther away from the surface of the semiconductor substrate 2, and the cover 39 is joined to the side surfaces of the protrusions 46a and 46b and the surface of the protective film 14 by another joining component 40b, thereby enabling non-cooling operation to be performed within a wide temperature range.

[0047] In addition, although various illustrative embodiments and examples are described in this application, the various features, forms and functions described in one or more embodiments are not limited to the application of a specific embodiment, and can also be applied to the embodiment alone or in various combinations. Therefore, countless unillustrated variations can be imagined within the technical scope disclosed in the specification of this application. For example, it includes the case where at least one constituent element is deformed, added or omitted, and also includes the case where at least one constituent element is extracted and combined with constituent elements of other embodiments.

[0048] Description of Reference Numerals

[0049] 1...semiconductor laser; 2...semiconductor substrate; 3...semiconductor structure; 5...active layer; 8...first electrode; 9...second electrode; 14...protective film; 16...opening; 18...center between side faces; 21...emitting end face; 22...central axis; 30...submount; 36...opening; 38...main body; 39...cover; 40, 40a, 40b...joining part; 45...bottom plate; 46, 46a, 46b...convex part; 61a, 61b...side face of cover; 62...back face of cover; 63...surface of cover; 100...semiconductor laser device; d1...distance; d2...distance.

Claims

1. A semiconductor laser device, The semiconductor laser device comprises: a submount having a bottom plate portion and a convex portion protruding from a surface of the bottom plate portion; and a semiconductor laser bonded to the submount. in, The semiconductor laser comprises: a semiconductor substrate; a semiconductor structure formed on a surface of the semiconductor substrate and including an active layer for generating light emitted from an emission end surface; a first electrode formed on a surface of the semiconductor structure opposite to the semiconductor substrate; and a second electrode formed on the back side of the semiconductor substrate, The side surface of the semiconductor laser facing the convex portion and the second electrode are bonded to the side surface of the convex portion facing the semiconductor laser and the surface of the bottom plate portion respectively through bonding members. The direction in which the convex portion protrudes from the surface of the bottom plate portion is defined as the z direction, The side surface of the semiconductor laser opposite to the convex portion is a surface of the semiconductor laser perpendicular to the direction in which the active layer extends and the z direction. The end portion of the joining member where the side surface of the protrusion is joined to the side surface of the semiconductor laser in the z direction is located farther in the z direction than the surface of the semiconductor substrate of the semiconductor laser. An end portion of the protrusion of the submount in the z direction is located farther in the z direction than a surface of the first electrode of the semiconductor laser.

2. The semiconductor laser device according to claim 1, wherein The direction in which the active layer of the semiconductor laser extends is defined as an x ​​direction, and the direction perpendicular to the x direction and the z direction is defined as a y direction. The active layer is arranged on a side closer to the convex portion than a center between two side surfaces of the semiconductor laser in the y direction.

3. The semiconductor laser device according to claim 1 or 2, wherein: A distance from a central axis of the active layer in a direction in which the active layer extends to a side surface of the semiconductor laser facing the protrusion is shorter than a distance from the central axis of the active layer to a back surface of the semiconductor substrate.

4. A semiconductor laser device, wherein: A semiconductor laser device is provided which is connected to the submount and the semiconductor laser device is connected to the submount. The submount comprises: a main body including a bottom plate, a convex portion protruding from the surface of the bottom plate, and another convex portion protruding from the surface of the bottom plate; and a cover joined to the convex portion and the other convex portion. The semiconductor laser comprises: a semiconductor substrate; a semiconductor structure formed on a surface of the semiconductor substrate and including an active layer for generating light emitted from an emission end surface; a first electrode formed on a surface of the semiconductor structure opposite to the semiconductor substrate; A second electrode formed on the back side of the semiconductor substrate; and a protective film formed on the surface of the semiconductor structure and the surface of the first electrode, The side surface of the semiconductor laser facing the convex portion and the second electrode are bonded to the side surface of the convex portion facing the semiconductor laser and the surface of the bottom plate portion respectively through bonding members. The side surface of the semiconductor laser opposite to the other protrusion is bonded to the side surface of the other protrusion opposite to the semiconductor laser by the bonding member. The direction in which the convex portion and the other convex portion protrude from the surface of the bottom plate portion is defined as a z direction, The end portion of the joining member where the side surface of the protrusion is joined to the side surface of the semiconductor laser in the z direction is located farther in the z direction than the surface of the semiconductor substrate of the semiconductor laser. The other end in the z direction of the portion of the joining member that joins the side surface of the other protrusion to the side surface of the semiconductor laser is located farther in the z direction than the surface of the semiconductor substrate of the semiconductor laser. A first cover side surface of the cover opposite to the side surface of the protrusion, a second cover side surface opposite to the side surface of the other protrusion, and a cover back surface opposite to the surface of the protective film of the semiconductor laser are respectively joined to the opposite side surface of the protrusion, the side surface of the other protrusion, and the surface of the protective film through another joining component.

5. The semiconductor laser device according to claim 4, wherein: A first opening is formed in the protective film of the semiconductor laser, The cover of the submount has a second opening formed therein that passes through from the back side of the cover to the cover surface on the opposite side to the back side of the cover. The first electrode is exposed through the first opening and the second opening.

6. A semiconductor laser device, wherein: A semiconductor laser device is provided which is connected to the submount and the semiconductor laser device is connected to the submount. The submount comprises: a main body including a bottom plate, a convex portion protruding from the surface of the bottom plate, and another convex portion protruding from the surface of the bottom plate; and a cover joined to the convex portion and the other convex portion. The semiconductor laser comprises: a semiconductor substrate; a semiconductor structure formed on a surface of the semiconductor substrate and including an active layer for generating light emitted from an emission end surface; a first electrode formed on a surface of the semiconductor structure opposite to the semiconductor substrate; A second electrode formed on the back side of the semiconductor substrate; and a protective film formed on the surface of the semiconductor structure and the surface of the first electrode, The side surface of the semiconductor laser facing the convex portion and the second electrode are bonded to the side surface of the convex portion facing the semiconductor laser and the surface of the bottom plate portion respectively through bonding members. The side surface of the semiconductor laser opposite to the other protrusion is bonded to the side surface of the other protrusion opposite to the semiconductor laser by the bonding member. The direction in which the convex portion and the other convex portion protrude from the surface of the bottom plate portion is defined as a z direction, The end portion of the joining member where the side surface of the protrusion is joined to the side surface of the semiconductor laser in the z direction is located farther in the z direction than the surface of the semiconductor substrate of the semiconductor laser. The other end in the z direction of the portion of the joining member that joins the side surface of the other protrusion to the side surface of the semiconductor laser is located farther in the z direction than the surface of the semiconductor substrate of the semiconductor laser. The end of the convex portion of the submount in the z direction and the other end of the other convex portion in the z direction are located farther in the z direction than the surface of the first electrode of the semiconductor laser. A first cover side surface of the cover opposite to the side surface of the protrusion, a second cover side surface opposite to the side surface of the other protrusion, and a cover back surface opposite to the surface of the protective film of the semiconductor laser are respectively joined to the opposite side surface of the protrusion, the side surface of the other protrusion, and the surface of the protective film through another joining component.

7. The semiconductor laser device according to claim 6, wherein A first opening is formed in the protective film of the semiconductor laser, The cover of the submount has a second opening formed therein that passes through from the back side of the cover to the cover surface on the opposite side to the back side of the cover. The first electrode is exposed through the first opening and the second opening.

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