Semiconductor laser device

Abstract

A semiconductor laser device (1) comprises a sub-mount (40), a semiconductor laser element (10), and a bonding material (30), the semiconductor laser element (10) including a substrate (11) and a stack (SL) and being disposed with the stack (SL) opposing the sub-mount. The stack (SL) has formed thereon a waveguide extending in a first direction (D1) parallel to a major surface (11s) of the substrate (11). The bonding material (30) includes an inner region (30M) bonded to the semiconductor laser element (10), and one outer region (30B) and another outer region (30C) disposed outside the inner region (30M). The one outer region (30B) is spaced apart from one side surface (10B) of the semiconductor laser element (10), and the other outer region (30C) is spaced apart from another side surface (10C) of the semiconductor laser element (10). In a second direction (D2) perpendicular to the first direction (D1) and parallel to the major surface (11s) of the substrate (11), the width A of the semiconductor laser element (10) and each of the width B of the outer region (30B) and the width C of the other outer region (30C) respectively satisfy the relationships B ≥ A / 4 and C ≥ A / 4.

Description

Technical Field

[0001] The present disclosure relates to a semiconductor laser device and a method for manufacturing the semiconductor laser device.

Background Art

[0002] In recent years, semiconductor laser elements have attracted attention as light sources for various applications, such as light sources for image display devices such as displays and projectors, light sources for in-vehicle headlamps, light sources for industrial and household lighting, or light sources for industrial equipment such as laser welding devices, thin film annealing devices, and laser processing devices. Further, for semiconductor laser elements used as light sources for the above applications, higher output exceeding 1 watt and high beam quality are desired.

[0003] As the heat generation amount increases with the increase in the output of the semiconductor laser element, a configuration in which the semiconductor laser element is mounted on a heat dissipation member such as a submount having a high thermal conductivity is adopted (see Patent Document 1, etc.). In the semiconductor laser element described in Patent Document 1, junction-down mounting in which the p-type semiconductor layer side among the n-type semiconductor layer laminated at a position close to the substrate of the semiconductor laser element and the p-type semiconductor layer laminated at a position far from the substrate is mounted on the submount is adopted. Thereby, since the active layer and the submount can be brought closer to each other than in the case where the substrate side of the semiconductor laser element is mounted on the submount, the heat dissipation characteristics can be improved.

[0004] When the semiconductor laser element is junction-down mounted on a heat dissipation member such as a submount, a bonding material such as solder for bonding the semiconductor laser element and the submount may adhere to the side surface of the semiconductor laser element, resulting in a short circuit between the p-type semiconductor layer and the n-type semiconductor layer. In the semiconductor laser device described in Patent Document 1, the end portion of the p-side electrode of the semiconductor laser element is positioned inside by a predetermined distance from the side surface of the semiconductor laser element, so as to suppress the adhesion of the bonding material to the side surface of the semiconductor laser element.

Prior Art Documents

Patent Documents

[0005] Japanese Patent Document 1 Japanese Unexamined Patent Application Publication No. 2010-171047 Summary of the Invention Problems to be Solved by the Invention

[0006] However, with the increase in the output of semiconductor laser elements, the elements are becoming larger. In order to secure the bonding area between the electrodes of the enlarged semiconductor laser element and the bonding material, the bonding material tends to be thickened. Also in the semiconductor laser device described in Patent Document 1, due to the thickening of the bonding material, there is a risk that the bonding material leaks out near the side surface of the semiconductor laser element and adheres to the side surface of the semiconductor laser element.

[0007] The present disclosure addresses such problems, and an object thereof is to provide a semiconductor laser device and the like that can suppress the adhesion of the bonding material to the side surface of the semiconductor laser element. Means for Solving the Problems

[0008] In order to solve the above problems, one aspect of the semiconductor laser device according to the present disclosure includes a submount, a semiconductor laser element, and a bonding material that bonds the submount and the semiconductor laser element. The semiconductor laser element has a substrate and a laminate stacked on a main surface of the substrate, and the laminate is arranged so as to face the submount. The laminate has a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer stacked in order on the substrate. A waveguide extending in a first direction parallel to the main surface of the substrate is formed in the laminate. In a cross section perpendicular to the first direction, the bonding material has an internal region bonded to the semiconductor laser element, and one external region and the other external region respectively arranged on one side surface side and the other side surface side of the internal region with respect to the semiconductor laser element among the regions arranged outside the internal region. The one external region includes a region arranged outside the one side surface, and the other external region includes a region arranged outside the other side surface. The one external region is separated from the one side surface of the semiconductor laser element, and in a second direction perpendicular to the first direction and parallel to the main surface of the substrate, the width A of the semiconductor laser element, the width B of the one external region, and the width C of the other external region satisfy the relationships of B≧A / 4 and C≧A / 4.

[0009] Also, in one aspect of the semiconductor laser device according to the present disclosure, the width A of the semiconductor laser element, the width B of the one external region, and the width C of the other external region may satisfy at least one of the relationships of B≧A / 2 and C≧A / 2.

[0010] Also, in one aspect of the semiconductor laser device according to the present disclosure, the width B of the one external region may be equal to the width C of the other external region.

[0011] Also, in one aspect of the semiconductor laser device according to the present disclosure, the average thickness of the bonding material may be smaller than 3.5 μm.

[0012] Also, in one aspect of the semiconductor laser device according to the present disclosure, the bonding material in the internal region has a maximum thickness at a position closer to the other side surface than the one side surface, and the maximum thickness t3 of the internal region and the thickness t4 of the flat portion of the bonding material in the other external region may satisfy the relationship of t4 ≦ t3.

[0013] Also, in one aspect of the semiconductor laser device according to the present disclosure, the bonding material in the internal region has a minimum thickness at a position closer to the one side surface than the other side surface, and the minimum thickness t1 of the bonding material in the internal region and the thickness t2 of the flat portion of the bonding material in the one external region may satisfy the relationship of t2 ≦ t1.

[0014] Also, in one aspect of the semiconductor laser device according to the present disclosure, the surface of at least one of the one external region and the other external region, which is disposed between the semiconductor laser element and the submount, may be a concave surface or a flat surface.

[0015] Also, in one aspect of the semiconductor laser device according to the present disclosure, the semiconductor laser element has a step portion formed at an end closer to the submount on at least one of the one side surface and the other side surface, and at the step portion, the semiconductor laser element and the bonding material may be separated from each other.

[0016] Also, in one aspect of the semiconductor laser device according to the present disclosure, the semiconductor laser element has a first step portion formed at an end portion of the one side surface closer to the submount, and a second step portion formed at an end portion of the other side surface closer to the submount. In the first step portion and the second step portion, the semiconductor laser element and the bonding material are separated from each other. The maximum thickness t13 of the bonding material in the one external region and the distance t12 between the first step portion and the surface of the bonding material on the submount side satisfy the relationship of t13 ≤ t12. The maximum thickness t17 of the bonding material in the other external region and the distance t16 between the second step portion and the surface of the bonding material on the submount side may satisfy the relationship of t17 ≤ t16.

[0017] Also, in one aspect of the semiconductor laser device according to the present disclosure, the maximum thickness t15 of the bonding material in the internal region, the minimum thickness t11 of the bonding material in the internal region, the maximum thickness t13 of the bonding material in the one external region, and the maximum thickness t17 of the bonding material in the other external region may satisfy at least one of the relationships of t13 ≤ t11 × 4 and t17 ≤ t15 × 4.

[0018] Also, in one aspect of the semiconductor laser device according to the present disclosure, the maximum thickness t15 of the bonding material in the internal region, the minimum thickness t11 of the bonding material in the internal region, the maximum thickness t13 of the bonding material in the one external region, and the maximum thickness t17 of the bonding material in the other external region may satisfy at least one of the relationships of t13 ≤ t11 × 2 and t17 ≤ t15 × 2.

[0019] Further, in one aspect of the semiconductor laser device according to the present disclosure, the semiconductor laser element has a first stepped portion formed at an end portion closer to the submount on the one side surface, and a second stepped portion formed at an end portion closer to the submount on the other side surface. In the first stepped portion and the second stepped portion, the semiconductor laser element and the bonding material are separated from each other. The bonding material in the internal region has a maximum thickness at a position closer to the other side surface than the one side surface, and has a minimum thickness at a position closer to the one side surface than the other side surface. The maximum thickness t15 of the bonding material in the internal region, the minimum thickness t11 of the bonding material in the internal region, the thickness t14 of the bonding material at the outer edge portion in the one external region, and the thickness t18 of the bonding material at the outer edge portion in the other external region may satisfy at least one of the relationships of t11 ≧ t14 / 1.5 and t15 ≧ t18 / 1.5.

[0020] Further, in one aspect of the semiconductor laser device according to the present disclosure, the semiconductor laser element has an insulating layer disposed between the laminate and the bonding material, and the insulating layer may be separated from the bonding material at both end portions of the semiconductor laser element in the second direction.

[0021] Further, in one aspect of the semiconductor laser device according to the present disclosure, the semiconductor laser element has a front end face that emits laser light in the first direction and a rear end face that faces the front end face. The front end face may be disposed outside the submount than the outer edge portion of the submount in the first direction.

[0022] Further, in one aspect of the semiconductor laser device according to the present disclosure, the rear end face is disposed inside the submount than the outer edge portion of the submount in the first direction, and the bonding material is disposed between the rear end face and the outer edge portion of the submount, and the bonding material may be separated from the rear end face.

[0023] In one aspect of the semiconductor laser device according to the present disclosure, the thickness t5 of the flat portion of the bonding material disposed between the rear end surface and the outer edge portion of the submount, and the bonding material located inside from the rear end surface by a distance equal to the width A of the semiconductor laser element thickness The thickness t6 may satisfy the relationship of t5 ≤ t6.

[0024] In one aspect of the semiconductor laser device according to the present disclosure, the distance t22 between the rear end surface and the surface of the bonding material on the submount side, and the maximum thickness t23 of the bonding material disposed between the rear end surface and the outer edge portion of the submount may satisfy the relationship of t23 ≤ t22.

[0025] In one aspect of the semiconductor laser device according to the present disclosure, in the first direction, the maximum thickness t21 of the bonding material located inside from the rear end surface by a distance equal to the width A of the semiconductor laser element, and the maximum thickness t23 of the bonding material disposed between the rear end surface and the outer edge portion of the submount may satisfy the relationship of t23 ≤ t21 × 4.

[0026] In one aspect of the semiconductor laser device according to the present disclosure, in the first direction, the maximum thickness t21 of the bonding material located inside from the rear end surface by a distance equal to the width A of the semiconductor laser element, and the maximum thickness t23 of the bonding material disposed between the rear end surface and the outer edge portion of the submount may satisfy the relationship of t23 ≤ t21 × 2.

[0027] In one aspect of the semiconductor laser device according to the present disclosure, in the first direction, the maximum thickness t21 of the bonding material located inside from the rear end surface by a distance equal to the width A of the semiconductor laser element, and the thickness t24 of the outer edge portion of the bonding material disposed between the rear end surface and the outer edge portion of the submount may satisfy the relationship of t21 ≥ t24 / 1.5.

[0028] Also, in one aspect of the semiconductor laser device according to the present disclosure, the distance D in the first direction between the rear end face and the outer edge of the bonding material disposed between the rear end face and the outer edge of the submount, and the width A of the semiconductor laser element may satisfy the relationship D≧A / 4.

[0029] Also, in one aspect of the semiconductor laser device according to the present disclosure, the distance D in the first direction between the rear end face and the outer edge of the bonding material disposed between the rear end face and the outer edge of the submount, and the width A of the semiconductor laser element may satisfy the relationship D≧A / 2.

[0030] Also, in one aspect of the semiconductor laser device according to the present disclosure, the semiconductor laser element has an insulating layer disposed between the laminate and the bonding material, and the insulating layer may be separated from the bonding material at an end closer to the rear end face of the semiconductor laser element in the first direction.

[0031] Also, in one aspect of the semiconductor laser device according to the present disclosure, the submount may have a metal electrode film electrically connected to the bonding material and a barrier layer disposed between the electrode film and the bonding material.

[0032] Also, in one aspect of the semiconductor laser device according to the present disclosure, the area S1 of the barrier layer and the area S2 of the bonding material in contact with the submount may satisfy the relationship S1≧S2.

[0033] Also, in one aspect of the semiconductor laser device according to the present disclosure, the submount may have a first base and an adhesion layer disposed between the first base and the electrode film.

[0034] Also, one aspect of the method for manufacturing a semiconductor laser device according to the present disclosure includes a step of preparing a submount having an electrode film and with a bonding material laminated above the electrode film, a step of disposing a semiconductor laser element on the bonding material, a first heating step of heating the submount to melt the bonding material after the step of disposing the semiconductor laser element, a first temperature lowering step of lowering the temperature of the submount after the first heating step, a second heating step of heating the submount after the first temperature lowering step, and a second temperature lowering step of lowering the temperature of the submount after the second heating step.

[0035] Further, in one aspect of the method for manufacturing a semiconductor laser device according to the present disclosure, when the melting point of the bonding material is Tm, the peak temperature in the first heating step is the first peak temperature T1, and the peak temperature in the second heating step is the second peak temperature T2, the relationship Tm < T1 < T2 may be satisfied.

Advantages of the Invention

[0036] According to the present disclosure, it is possible to provide a semiconductor laser device or the like that can suppress the adhesion of a bonding material to the side surface of a semiconductor laser element.

Brief Description of the Drawings

[0037]

Figure 1

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Embodiments for Carrying Out the Invention

[0038] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, and the arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0039] Also, each figure is a schematic diagram and is not necessarily drawn precisely. Therefore, the scales etc. in each figure do not necessarily match. In each figure, the same reference numerals are given to substantially the same configurations, and duplicate explanations are omitted or simplified.

[0040] In this specification, the terms "upper" and "lower" do not refer to the upward (vertically upward) and downward (vertically downward) directions in absolute spatial recognition, but are used as terms defined by the relative positional relationship based on the stacking order in the stacked structure. Further, the terms "upper" and "lower" are applicable not only when two components are arranged at intervals and another component exists between the two components, but also when the two components are arranged in contact with each other.

[0041] (Embodiment 1) The semiconductor laser device and its manufacturing method according to Embodiment 1 will be described.

[0042] [1-1. Overall Configuration] First, the overall configuration of the semiconductor laser device according to the present embodiment will be described with reference to FIGS. 1 and 2. FIGS. 1 and 2 are schematic cross-sectional views showing cross-sections perpendicular to the first direction D1 and the second direction D2 of the semiconductor laser device 1 according to the present embodiment, respectively. FIG. 2 shows the cross-section taken along the line II-II of FIG. 1.

[0043] As shown in FIGS. 1 and 2, the semiconductor laser device 1 includes a submount 40, a semiconductor laser element 10, and a bonding material 30 that bonds the submount 40 and the semiconductor laser element 10.

[0044] The semiconductor laser element 10 is bonded to the main surface of the submount 40 and is an element that emits laser light. Hereinafter, the overall configuration of the semiconductor laser element 10 will be described with reference to FIG. 3. FIG. 3 is a schematic cross-sectional view showing the overall configuration of the semiconductor laser element 10 according to the present embodiment. FIG. 3 shows a cross-section perpendicular to the first direction D1 of the semiconductor laser element 10.

[0045] As shown in FIG. 3, the semiconductor laser element 10 includes a substrate 11 and a laminate SL. In the present embodiment, the semiconductor laser element 10 further includes an insulating layer 15, a p-side contact electrode 16, a p-side electrode 17, and an n-side electrode 19. As shown in FIGS. 1 and 2, the semiconductor laser element 10 is arranged such that the laminate SL faces the submount 40, and the p-side electrode 17 is electrically connected to the submount 40. That is, the semiconductor laser element 10 is junction-down mounted on the submount 40.

[0046] In the laminate SL, a waveguide extending in a first direction D1 parallel to the main surface 11s of the substrate 11 is formed. As shown in FIG. 2, the semiconductor laser element 10 has a front end face 10F that emits laser light in the first direction D1 and a rear end face 10R that faces the front end face 10F. The front end face 10F and the rear end face 10R constitute a resonator of the semiconductor laser element 10. The dimension of the semiconductor laser element 10 in the first direction D1 corresponds to the resonator length L. The resonator length L is, for example, about 1 mm or more and 10 mm or less. In the present embodiment, the resonator length L is 1.2 mm. The front end face 10F of the semiconductor laser element 10 is arranged outside the submount 40 from the outer edge portion of the submount 40 in the first direction D1. In other words, the front end face 10F of the semiconductor laser element 10 protrudes from the edge of the submount 40 toward the outside of the submount 40 in the first direction D1. Thereby, it is possible to suppress the laser light emitted from the front end face 10F from interfering with the submount 40.

[0047] The width A of the semiconductor laser element 10 shown in FIG. 1 represents the dimension of the semiconductor laser element 10 in a second direction D2 that is perpendicular to the first direction D1 and parallel to the main surface 11s of the substrate 11. The third direction D3 shown in FIGS. 1 to 3 is a direction perpendicular to the first direction D1 and the second direction D2. The width A of the semiconductor laser element 10 is, for example, about 0.1 mm or more and 3 mm or less. In the present embodiment, the width A of the semiconductor laser element 10 is 0.15 mm.

[0048] Further, as shown in FIG. 3, step portions 11b and 11c are formed on side surfaces 10B and 10C of the semiconductor laser element 10 according to the present embodiment, respectively. The step portion 11b is an example of a first step portion formed at an end closer to the submount 40 on one side surface 10B of the semiconductor laser element 10. The step portion 11c is an example of a second step portion formed at an end closer to the submount 40 on the other side surface 10C of the semiconductor laser element 10. The step portions 11b and 11c are part of separation grooves extending in a first direction D1 formed when the semiconductor laser element 10 is singulated. Each step portion is a portion recessed from each side surface in a second direction D2.

[0049] Hereinafter, each component of the semiconductor laser element 10 will be described with reference to FIG. 3.

[0050] The substrate 11 is a plate-like member serving as a base of the semiconductor laser element 10. In the present embodiment, the substrate 11 is a semiconductor substrate made of n-type GaN.

[0051] The laminate SL is a semiconductor laminate structure laminated on the main surface 11s of the substrate 11. In the present embodiment, the laminate SL includes an n-type semiconductor layer 12, an active layer 13, and a p-type semiconductor layer 14 laminated in this order on the substrate 11. Note that the laminate SL may further include layers other than these layers. Two groove portions 10t extending in the first direction D1 are formed in the laminate SL. The groove portions 10t reach at least from the p-type semiconductor layer 14 to the n-type semiconductor layer 12 of the laminate SL. By forming the two groove portions 10t, a ridge portion 10s is formed between the two groove portions 10t. Current is supplied to the ridge portion 10s, and light is emitted from the active layer 13 in the ridge portion 10s. Also, a region including the ridge portion 10s forms a waveguide.

[0052] The n-type semiconductor layer 12 is an example of a first-conductivity-type semiconductor layer laminated above the main surface 11s of the substrate 11. In the present embodiment, the n-type semiconductor layer 12 includes at least an n-type cladding layer. Note that the n-type semiconductor layer 12 may include a buffer layer disposed between the substrate 11 and the n-type cladding layer, an n-side guide layer disposed between the n-type cladding layer and the active layer 13, and the like. In the present embodiment, the n-type semiconductor layer 12 is formed of an n-type nitride semiconductor such as n-type AlGaN.

[0053] The active layer 13 is a light-emitting layer laminated above the n-type semiconductor layer 12. In the present embodiment, the active layer 13 is a quantum well active layer formed of a nitride semiconductor.

[0054] The p-type semiconductor layer 14 is an example of a second-conductivity-type semiconductor layer disposed above the active layer 13. In the present embodiment, the p-type semiconductor layer 14 includes at least a p-type cladding layer. Note that the p-type semiconductor layer 14 may include a contact layer disposed between the p-type cladding layer and the p-side contact electrode 16, a p-side guide layer disposed between the p-type cladding layer and the active layer 13, and the like. In the present embodiment, the p-type semiconductor layer 14 is formed of a p-type nitride semiconductor such as p-type AlGaN.

[0055] The insulating layer 15 is a layer that electrically insulates between the p-side electrode 17 and the laminate SL. The insulating layer 15 may have a function of confining light in the ridge portion 10s. In the present embodiment, the insulating layer 15 is disposed between the laminate SL and the p-side electrode 17. The insulating layer 15 continuously covers the surface of the laminate SL from the side surface of the ridge portion 10s to the stepped portions 11b and 11c. An opening is provided in the insulating layer 15 at the upper part of the ridge portion 10s, and the ridge portion 10s and the p-side electrode 17 are to be connected via the p-side contact electrode 16 disposed in the opening of the insulating layer 15. As shown in FIG. 1, the insulating layer 15 is spaced apart from the bonding material 30 at both ends in the second direction D2 of the semiconductor laser element 10. Also, as shown in FIG. 2, the outer edge portions on the front end face 10F side and the rear end face 10R side of the ridge portion 10s are covered by the insulating layer 15. At the outer edge portions on the front end face 10F side and the rear end face 10R side, the insulating layer 15 is exposed from the p-side contact electrode 16 and the p-side electrode 17, and the end portions of the p-side contact electrode 16 and the end portions of the p-side electrode 17 are disposed so as to ride above the insulating layer 15. The end portions of the p-side contact electrode 16 and the end portions of the p-side electrode 17 are spaced apart from the front end face 10F and the rear end face 10R. Also, the insulating layer 15 is exposed from the p-side contact electrode 16 and the p-side electrode 17 at the outer edge portions on the front end face 10F side and the rear end face 10R side of the semiconductor laser element 10, and is exposed from the p-side electrode 17 at the stepped portions 11b and 11c. Also, the insulating layer 15 is spaced apart from the bonding material 30 at the end portion closer to the rear end face 10R in the first direction D1 of the semiconductor laser element 10. As the insulating layer 15, for example, a SiO2 film, a SiN film, or the like can be used.

[0056] The p-side contact electrode 16 is an example of a second-conductivity-type semiconductor layer and a second-conductivity-side contact electrode that makes an ohmic contact. In the present embodiment, the p-side contact electrode 16 is an electrode that makes an ohmic contact with the p-type semiconductor layer 14. The p-side contact electrode 16 is disposed within the opening of the insulating layer 15 and contacts the upper portion of the ridge portion 10s. As the p-side contact electrode 16, for example, a laminated film of Pd and Pt sequentially laminated on the p-type semiconductor layer 14, a laminated film of Pd, Ti, and Pt, etc. can be used.

[0057] The p-side electrode 17 is an electrode that is electrically connected to the p-type semiconductor layer 14 via the p-side contact electrode 16. The p-side electrode 17 covers the upper surface of the insulating layer 15 except for the outer edge portion of the insulating layer 15. In other words, the p-side electrode 17 is not disposed at the outer edge portions on the front end face 10F side and the rear end face 10R side of the ridge portion 10s. Also, it is not disposed at the step portions 11b and 11c of the semiconductor laser element 10. In the present embodiment, as the p-side electrode 17, for example, a single-layer film such as a Ti film, or a laminated film of Ti and Pt, a laminated film of Ti, Pt, Au, and Pt sequentially laminated on the p-side contact electrode 16, etc. can be used. Note that an Au film may be further formed on the outermost layer of the p-side electrode 17. The Au film formed on the outermost layer may be integrated with a bonding material 30 made of AuSn or the like that bonds the p-side electrode 17. In such a case, the Au film integrated with the bonding material 30 may be regarded as a part of the bonding material 30.

[0058] The n-side electrode 19 is an electrode formed on the back main surface of the main surface on which the laminate SL of the substrate 11 is laminated. As the n-side electrode 19, for example, a laminated film of Ti and Au sequentially laminated on the substrate 11 can be used.

[0059] Note that the configurations of the electrodes of the p-side contact electrode 16, the p-side electrode 17, and the n-side electrode 19 are not limited to the above configurations. For example, as each electrode, a laminated film or an alloy film containing at least one of C, N, Co, Cu, Ag, Ir, Sc, Au, Cr, Mo, La, W, Al, Tl, Y, La, Ce, Pr, Nd, Sm, Eu, Tb, Ti, Zr, Hf, V, Nb, Ta, Pt, and Ni may be used.

[0060] The submount 40 is a base to which the semiconductor laser element 10 is bonded. The submount 40 functions as a heat sink for discharging the heat generated by the semiconductor laser element 10. In the present embodiment, the submount 40 has a plate-like shape. As shown in FIGS. 1 and 2, the submount 40 includes a first base 41, an adhesion layer 42, an electrode film 43, and a barrier layer 44.

[0061] The first base 41 is a main member of the submount 40. In the present embodiment, the first base 41 has a rectangular plate-like shape. As the first base 41, for example, a ceramic substrate, a polycrystalline substrate, a single crystal substrate, etc. made of materials such as alumina, AlN, SiC, and diamond can be used.

[0062] The adhesion layer 42 is a layer disposed between the first base 41 and the electrode film 43. As the adhesion layer 42, for example, a single layer film such as a Ti film, a laminated film of Ti and Pt laminated in order on the first base 41, etc. can be used. Note that the configuration of the adhesion layer 42 is not limited to this, and it may be a laminated film or an alloy film similar to the above-described p-side contact electrode 16, etc.

[0063] The electrode film 43 is a metal film electrically connected to the bonding material 30. The electrode film 43 functions as an electrode of the submount 40. As the electrode film 43, for example, Au or the like can be used. Thereby, a wire made of Au can be easily connected to the electrode film 43.

[0064] The barrier layer 44 is a metal layer disposed between the electrode film 43 and the bonding material 30. The barrier layer 44 is connected to the bonding material 30. The barrier layer 44 is made of a material with low wettability to the bonding material 30 composed of solder or the like, and has a function of suppressing the molten bonding material 30 due to heating from contacting the electrode film 43. The area S1 of the barrier layer 44 and the area S2 in contact with the submount 40 of the bonding material 30 satisfy the relationship of S1≧S2. Thereby, it is possible to suppress the molten bonding material 30 due to heating from contacting the electrode film 43.

[0065] For example, Pt can be used as the barrier layer 44. Note that the configuration of the barrier layer 44 is not limited thereto, and for example, it may be a laminated film or an alloy film containing at least one of Ti, Pt, Ni, Cr, Co, Ru, and W.

[0066] The bonding material 30 is a member that bonds the submount 40 and the semiconductor laser element 10. As shown in FIG. 1, in a cross section perpendicular to the first direction D1, the bonding material 30 includes an internal region 30M bonded to the semiconductor laser element 10, and among the regions arranged outside the internal region 30M, one external region 30B and the other external region 30C that are respectively arranged on one side surface 10B side and the other side surface 10C side of the semiconductor laser element 10 with respect to the internal region 30M. In other words, the external region 30B is a region on the side close to the side surface 10B of the semiconductor laser element 10 among the regions arranged outside the internal region 30M, and the external region 30C is a region on the side close to the side surface 10C of the semiconductor laser element 10 among the regions arranged outside the internal region 30M. One external region 30B of the bonding material 30 includes a region arranged outside one side surface 10B of the semiconductor laser element 10 and a region arranged between the semiconductor laser element 10 and the submount 40 inside one side surface 10B of the semiconductor laser element 10 in the second direction D2, and the other external region 30C includes a region arranged outside the other side surface 10C of the semiconductor laser element 10 and a region arranged between the semiconductor laser element 10 and the submount 40 inside the other side surface 10C of the semiconductor laser element 10 in the second direction D2. The region where the bonding material 30 bonds to the semiconductor laser element 10 substantially coincides with the region where the p-side electrode 17 is formed. The bonding material 30 is separated from the insulating layer 15 exposed from the p-side electrode 17 on the front end face 10F side and the rear end face 10R side of the semiconductor laser element 10, and is also separated from the insulating layer 15 exposed from the p-side electrode 17 at the step portions 11b and 11c of the semiconductor laser element 10. The bonding material 30 is made of, for example, AuSn solder. Note that the bonding material 30 is not limited to AuSn solder, and may be solder such as AgSn solder or SAC solder, or may be a conductive paste other than solder such as Au nanoparticles or Ag nanoparticles. The detailed configuration of the bonding material 30 will be described later.

[0067] [1-2. Operation and Effect] Next, the operation and effect of the semiconductor laser device 1 according to the present embodiment will be described with reference to FIGS. 1 to 4 while comparing with a comparative example.

[0068] In the semiconductor laser device 1 according to the present embodiment, in the second direction D2, the width A of the semiconductor laser element 10, the width B of one external region 30B of the bonding material 30, and the width C of the other external region 30C satisfy the relationships B≧A / 4 and C≧A / 4.

[0069] Here, the relationship between the widths of the external regions 30B and 30C of the bonding material 30 of the semiconductor laser device 1 and the shape of the bonding material 30 will be described with reference to FIG. 4. FIG. 4 is a schematic diagram showing the relationship between the width B of one external region 30B of the bonding material 30 according to the comparative example and the present embodiment and the maximum thickness of the bonding material 30 in the one external region 30B. Cross-sectional view (a) of FIG. 4 shows the comparative example, and cross-sectional views (b) and (c) show an example and another example of the present embodiment. In the comparative example shown in cross-sectional view (a) of FIG. 4, since the entire lower surface of the semiconductor laser element 10 (that is, the surface facing the submount 40) is bonded to the bonding material 30, the external region 30B is defined as the region outside the side surface of the semiconductor laser element 10. However, for comparison with the width B of the external region 30B according to the present embodiment shown in cross-sectional views (b) and (c) of FIG. 4, the width B in the comparative example of FIG. 4(a) is regarded as the region outside the step portion 11b of the semiconductor laser element 10. Hereinafter, assuming that the width B and the width C are of the same degree, only the relationship between the width B and the maximum thickness of the bonding material 30 in the one external region 30B will be described.

[0070] Cross-sectional view (a) of FIG. 4 shows the shape of the external region 30B when B<A / 4 holds for the width B of the external region 30B. Cross-sectional view (b) of FIG. 4 shows the shape of the external region 30B when B≧A / 4 holds for the width B of the external region 30B. Cross-sectional view (c) of FIG. 4 shows the shape of the external region 30B when the width B of the external region 30B is larger than the width B shown in cross-sectional view (b).

[0071] The bonding material 30 shown in each cross-sectional view of FIG. 4 is melted by heating when bonding the semiconductor laser element 10. Further, in order to increase the contact area between the semiconductor laser element 10 and the bonding material 30, a load is applied to the semiconductor laser element 10. As a result, the semiconductor laser element 10 is pressed against the submount 40. At this time, a part of the bonding material 30 disposed between the semiconductor laser element 10 and the submount 40 is pushed out to the external region 30B (and the external region 30C). Assuming that the thickness of the bonding material 30 before bonding the semiconductor laser element 10 in each cross-sectional view of FIG. 4 is the same, the bonding material 30 of the same amount is pushed out to the external region 30B in each cross-sectional view. For this reason, the narrower the width of the external region 30B, the greater the maximum thickness of the bonding material 30 in the external region 30B. As shown in the cross-sectional view (a) of FIG. 4, when the width B is narrow, the maximum thickness of the bonding material 30 in the external region 30B becomes larger than the distance from the submount 40 to the side surface 10B of the semiconductor laser element 10, and the bonding material 30 can adhere to the side surface 10B. Note that since the bonding material 30 is formed in direct contact with the barrier layer 44 only in the region where the barrier layer 44 is formed, the outer edge portion of the external region 30B in the second direction D2 substantially coincides with the outer edge portion of the barrier layer 44. The bonding material 30 does not directly contact the electrode film 43.

[0072] On the other hand, as shown in the cross-sectional view (b) of FIG. 4, when B≧A / 4 is satisfied with respect to the width B, the bonding material 30 pushed out to the external region 30B is dispersed in the width direction (that is, the second direction D2). Therefore, the maximum thickness of the bonding material 30 in the external region 30B becomes smaller than the distance from the submount 40 to the side surface 10B of the semiconductor laser element 10. Along with this, the external region 30B is separated from the side surface 10B of the semiconductor laser element 10. That is, a gap gB is formed between the side surface 10B and the external region 30B of the bonding material 30. Thereby, it is possible to suppress the bonding material 30 from adhering to the side surface 10B of the semiconductor laser element 10.

[0073] In cross-sectional view (c) of FIG. 4, since the width B is larger than in the case of cross-sectional view (b), the maximum thickness of the bonding material 30 in the outer region 30B is further reduced. Thereby, it is possible to further suppress the bonding material 30 from adhering to the side surface 10B of the semiconductor laser element 10.

[0074] As shown in FIG. 1, the outer region 30C also has the same configuration as the outer region 30B. That is, the other outer region 30C is separated from the other side surface 10C of the semiconductor laser element 10. That is, a gap gC is formed between the other side surface 10C and the other outer region 30C of the bonding material 30. Thereby, it is possible to suppress the bonding material 30 from adhering to the other side surface 10C of the semiconductor laser element 10.

[0075] As described above, in the present embodiment, since it is possible to suppress the bonding material 30 from adhering to the side surfaces 10B and 10C of the semiconductor laser element 10, it is possible to suppress a short circuit between the p-type semiconductor layer 14 and the n-type semiconductor layer 12 due to the bonding material 30.

[0076] Further, the width A of the semiconductor laser element 10, the width B of one outer region 30B, and the width C of the other outer region 30C may satisfy at least one of the relationships B≥A / 2 and C≥A / 2. Thereby, since the maximum thickness of the bonding material 30 in each outer region can be further reduced, it is possible to further suppress the bonding material 30 from adhering to the side surface 10B of the semiconductor laser element 10.

[0077] Further, the width A of the semiconductor laser element 10, the width B of one outer region 30B, and the width C of the other outer region 30C may satisfy the relationships B≤2A and C≤2A. Thereby, an increase in the size of the semiconductor laser device 1 can be suppressed. Also, the width A of the semiconductor laser element 10, the width B of one outer region 30B, and the width C of the other outer region 30C may satisfy the relationships B≤A and C≤A. Thereby, an increase in the size of the semiconductor laser device 1 can be further suppressed.

[0078] Also, the width B of one of the external regions 30B may be equal to the width C of the other external region 30C. Here, the width B being equal to the width C means not only the case where the width B exactly matches the width C, but also the case where the width B is substantially equal to the width C. For example, the width B being equal to the width C means the case where the difference between the width B and the width C is 10% or less of the width B. In this way, by making the width B equal to the width C, the maximum thickness of the bonding material 30 in the external regions 30B and 30C can be made approximately the same. Therefore, since the bonding material 30 can be prevented from becoming thick in either the external region 30B or 30C, the bonding material 30 can be prevented from adhering to either the side surfaces 10B and 10C of the semiconductor laser element 10.

[0079] Also, the surface of at least one of one external region 30B and the other external region 30C of the bonding material 30, which is disposed between the semiconductor laser element 10 and the submount 40, may be a concave surface or a flat surface. In the present embodiment, as shown in FIG. 1, the surfaces of one external region 30B and the other external region 30C of the bonding material 30, which are disposed between the semiconductor laser element 10 and the submount 40, are both concave surfaces.

[0080] Also, in the present embodiment, the average thickness of the bonding material 30 may be less than 3.5 μm. The average thickness of the bonding material 30 is equal to the thickness of the bonding material 30 before the semiconductor laser element 10 is disposed thereon. In this way, by reducing the average thickness of the bonding material 30, the thermal resistance in the bonding material 30 can be reduced, so that the heat dissipation characteristics from the semiconductor laser element 10 to the submount 40 can be enhanced. Also, by reducing the average thickness of the bonding material 30, the bonding material 30 can be prevented from adhering to each side surface of the semiconductor laser element 10. Also, the average thickness of the bonding material 30 may be less than 0.3% of the resonator length L of the semiconductor laser element 10. Also, the average thickness of the bonding material 30 may be less than 3% of the width A of the semiconductor laser element 10.

[0081] In addition, in the present embodiment, the average thickness of the bonding material 30 may be greater than 2.0 μm. If the thickness of the bonding material 30 is too small, the bonding material 30 may not sufficiently spread over the bonding surface of the semiconductor laser element 10, and the bonding area between the bonding material 30 and the semiconductor laser element 10 may become small. However, by making the average thickness of the bonding material 30 greater than 2.0 μm, it is possible to suppress a decrease in the bonding area between the bonding material 30 and the semiconductor laser element 10. Therefore, it is possible to suppress an increase in the thermal resistance between the semiconductor laser element 10 and the bonding material 30 due to a decrease in the bonding area. Also, the average thickness of the bonding material 30 may be greater than 0.05% of the resonator length L of the semiconductor laser element 10. Further, the average thickness of the bonding material 30 may be greater than 0.4% of the width A of the semiconductor laser element 10.

[0082] Also, the average thickness of the bonding material 30 may be adjusted according to the dimensions of the semiconductor laser element 10. For example, the resonator length L [μm] of the semiconductor laser element 10 and the average thickness ts of the bonding material 30 may satisfy ts < 2.0 + 0.5×(L / 800). Thereby, the thickness of the bonding material 30 can be optimized according to the dimensions of the semiconductor laser element 10.

[0083] In addition, in the present embodiment, as shown in FIG. 1, the thickness t2 of the flat portion in one external region 30B and the thickness t4 of the flat portion in the other external region 30C may be equal to or less than the maximum thickness t3 of the bonding material 30 in the internal region 30M. Here, the flat portion means a portion where the surface of each external region (that is, the back side of the surface of the bonding material 30 facing the submount 40) is parallel to the main surface of the submount 40. Note that parallel means not only a state where the main surface of the submount 40 and the surface of the bonding material 30 are completely parallel, but also a state where they are substantially parallel. For example, parallel means a state where the angle formed by the main surface of the submount 40 and the surface of the bonding material 30 is 2° or less. Note that the thickness of the flat portion of each external region may be defined as the thickness of the central portion in the second direction D2 of each external region.

[0084] In this way, by making the thickness of the flat portion in each external region equal to or less than the maximum thickness of the internal region 30M, it is possible to reduce the thickness of the bonding material 30 in each external region while ensuring a sufficient thickness of the bonding material 30 in the internal region 30M. Therefore, while securing the bonding area between the semiconductor laser element 10 and the bonding material 30, it is possible to suppress the bonding material 30 from adhering to each side surface of the semiconductor laser element 10.

[0085] Further, the semiconductor laser element 10 may be disposed inclined with respect to the main surface of the submount 40. For example, the bonding material 30 in the internal region 30M may have a maximum thickness at a position closer to the other side surface 10C than to one side surface 10B of the semiconductor laser element 10. In this case, the maximum thickness t3 of the internal region 30M and the thickness t4 of the flat portion of the bonding material 30 in the other external region 30C may satisfy the relationship t4 ≦ t3. Even in such a configuration, by making the thickness t4 of the flat portion in the external region 30C equal to or less than the maximum thickness t3 of the internal region 30M, while securing the bonding area between the semiconductor laser element 10 and the bonding material 30, it is possible to suppress the bonding material 30 in the external region 30C from adhering to the side surface 10C of the semiconductor laser element 10.

[0086] Also, the bonding material 30 in the internal region 30M may have a minimum thickness at a position closer to one side surface 10B than to the other side surface 10C of the semiconductor laser element 10. In this case, the minimum thickness t1 of the bonding material 30 in the internal region 30M and the thickness t2 of the flat portion of the bonding material 30 in the one external region 30B may satisfy the relationship t2 ≦ t1. Even in such a configuration, by making the thickness t2 of the flat portion in the external region 30B equal to or less than the minimum thickness t1 of the internal region 30M, while securing the bonding area between the semiconductor laser element 10 and the bonding material 30, it is possible to suppress the bonding material 30 in the external region 30B from adhering to the side surface 10B of the semiconductor laser element 10.

[0087] Further, as shown in FIG. 3, the semiconductor laser element 10 has a stepped portion formed at least at one of one side surface 10B and the other side surface 10C, at an end portion closer to the submount 40. In the stepped portion, the semiconductor laser element 10 and the bonding material 30 may be separated. In the stepped portion, a part of the insulating layer 15 continuously arranged from the side surface of the ridge portion 10s is exposed from the p-side electrode 17, and the bonding material 30 is separated from the insulating layer 15 arranged in the stepped portion. In the present embodiment, the p-side electrode 17 is formed only on the upper surface of the laminate SL and is not formed on the side surface of the laminate SL, that is, on the stepped portion.

[0088] In the present embodiment, stepped portions 11b and 11c are formed on one side surface 10B and the other side surface 10C, respectively. By forming the stepped portions 11b and 11c on the semiconductor laser element 10, the distance from the surface of the bonding material 30 to each side surface of the semiconductor laser element 10 can be increased, so that the bonding material 30 can be prevented from adhering to each side surface of the semiconductor laser element 10.

[0089] Also, as shown in FIG. 2, the rear end surface 10R of the semiconductor laser element 10 is arranged inside the submount 40 in the first direction D1, from the outer edge portion of the submount 40 (the right end of the submount 40 shown in FIG. 2), and the bonding material 30 is arranged between the rear end surface 10R and the outer edge portion of the submount 40. The insulating layer 15 is exposed from the p-side contact electrode 16 and the p-side electrode 17 at the outer edge portion on the rear end surface 10R side of the semiconductor laser element 10. The p-side electrode 17 is arranged over the entire upper surface of the laminate SL, excluding the stepped portions 11b, 11c, the outer edge portion on the front end surface 10F side, and the outer edge portion on the rear end surface 10R side of the semiconductor laser element 10. The bonding material 30 is joined to the p-side electrode 17 and is not joined to the insulating layer 15. Therefore, the bonding material 30 is separated from the insulating layer 15 at the outer edge portion on the rear end surface 10R side, and the bonding material 30 is separated from the rear end surface 10R of the semiconductor laser element 10. That is, a gap gR is formed between the rear end surface 10R and the bonding material 30. Thereby, it is possible to prevent the bonding material 30 located outside the rear end surface 10R of the semiconductor laser element 10 from adhering to the rear end surface 10R of the semiconductor laser element 10.

[0090] Also, the thickness t5 of the flat portion of the bonding material 30 disposed between the rear end face 10R of the semiconductor laser element 10 and the outer edge portion of the submount 40, and the thickness t6 of the bonding material 30 located inside the semiconductor laser element 10 from the rear end face 10R by the same distance as the width A of the semiconductor laser element 10 satisfy the relationship of t5 ≤ t6. Here, the flat portion means a portion where the surface of the bonding material 30 (that is, the back side of the surface of the bonding material 30 facing the submount 40) is parallel to the main surface of the submount 40. Note that parallel means not only a state where the main surface of the submount 40 and the surface of the bonding material 30 are completely parallel, but also a state where they are substantially parallel. For example, parallel means a state where the angle formed by the main surface of the submount 40 and the surface of the bonding material 30 is 2° or less. Note that the thickness of the flat portion may be defined as the thickness at the intermediate position between the position of the rear end face 10R in the second direction D2 and the outer edge portion of the bonding material 30.

[0091] As described above, by satisfying the relationship of t5 ≤ t6, it is possible to suppress the adhesion of the bonding material 30 located outside the rear end face 10R of the semiconductor laser element 10 to the rear end face 10R of the semiconductor laser element 10.

[0092] Also, the distance D in the first direction D1 between the rear end face 10R of the semiconductor laser element 10 and the outer edge portion of the bonding material 30 disposed between the rear end face 10R and the outer edge portion of the submount 40, and the width A of the semiconductor laser element 10 satisfy the relationship of D ≥ A / 4. Thereby, similar to the external regions 30B and 30C of the bonding material 30 described above, the maximum thickness of the bonding material 30 located outside the rear end face 10R can be reduced. Therefore, it is possible to suppress the adhesion of the bonding material 30 located outside the rear end face 10R of the semiconductor laser element 10 to the rear end face 10R of the semiconductor laser element 10.

[0093] Also, the distance D and the width A of the semiconductor laser element 10 may satisfy the relationship of D ≥ A / 2. Thereby, it is possible to further suppress the adhesion of the bonding material 30 located outside the rear end face 10R of the semiconductor laser element 10 to the rear end face 10R of the semiconductor laser element 10.

[0094] Further, the distance D and the width A of the semiconductor laser element 10 may satisfy the relationship D ≤ 2A. Thereby, an increase in the size of the semiconductor laser device 1 can be suppressed. Also, the distance D and the width A of the semiconductor laser element 10 may satisfy the relationship D ≤ A. Thereby, an increase in the size of the semiconductor laser device 1 can be further suppressed.

[0095] In addition, in a cross section perpendicular to the second direction D2 as shown in FIG. 2, the semiconductor laser element 10 may be joined while being inclined with respect to the main surface of the submount 40. For example, when the semiconductor laser element 10 is joined while being inclined with respect to the main surface of the submount 40, the thickness of the bonding material 30 may increase as it approaches the rear end surface 10R from the front end surface 10F of the semiconductor laser element 10. Even in such a case, the adhesion of the bonding material 30 to the rear end surface 10R of the semiconductor laser element 10 can be suppressed by each of the above configurations.

[0096] [1-3. Manufacturing method] Next, a manufacturing method of the semiconductor laser device 1 according to the present embodiment will be described with reference to FIGS. 5 to 8. FIG. 5 is a flowchart showing the flow of the manufacturing method of the semiconductor laser device 1 according to the present embodiment. FIGS. 6 to 8 are schematic cross-sectional views showing each step of the manufacturing method of the semiconductor laser device 1 according to the present embodiment. In FIGS. 6 to 8, cross sections perpendicular to the second direction D2 of the semiconductor laser element 10, the submount 40, and the bonding material 30 are shown.

[0097] First, as shown in FIG. 5, a semiconductor laser element 10 is prepared (S10).

[0098] Subsequently, a submount 40 in which a bonding material 30 is laminated above the electrode film 43 is prepared (S20). In the present embodiment, a bonding material 30 having a thickness ts is laminated on the barrier layer 44 of the submount 40.

[0099] Subsequently, as shown in FIG. 6, the semiconductor laser element 10 is placed on the bonding material 30 (S30 in FIG. 5). Here, the semiconductor laser element 10 is placed on the bonding material 30 such that the laminate SL of the semiconductor laser element 10 faces the bonding material 30. At this time, the front end face 10F of the semiconductor laser element 10 is disposed outside the outer edge of the submount 40.

[0100] As shown in FIG. 5, after the step S30 of placing the semiconductor laser element 10, the submount 40 is heated to a first peak temperature T1 higher than the melting point Tm of the bonding material 30 to melt the bonding material 30 (first heating step S40). Specifically, as shown in FIG. 6, the submount 40 is placed on the heater 990, and the submount 40 is heated by raising the temperature of the heater 990. In this first heating step S40, before the temperature of the submount 40 reaches the melting point Tm of the bonding material 30, as shown in FIG. 7, by starting to apply a load to the semiconductor laser element 10, the semiconductor laser element 10 is pressed against the submount 40. Thereby, after the bonding material 30 is melted, the contact area between the surface of the semiconductor laser element 10 facing the bonding material 30 and the bonding material 30 can be increased. In other words, it is possible to suppress the formation of voids between the semiconductor laser element 10 and the bonding material 30. By applying a load to the semiconductor laser element 10, the bonding material 30 is extruded from the internal region 30M between the semiconductor laser element 10 and the submount 40 to the external regions 30B and 30C, and the region outside the rear end face 10R of the semiconductor laser element 10. For this reason, the maximum thickness of the bonding material 30 in the external regions 30B and 30C increases.

[0101] As shown in FIG. 5, after the first heating step S40, the temperature of the submount 40 is lowered to a switching temperature Tv which is lower than the melting point Tm of the bonding material 30 (first cooling step S50). In this first cooling step S50, before the temperature of the submount 40 reaches the melting point Tm of the bonding material 30, the application of the load to the semiconductor laser element 10 is stopped. The temperature at which the application of the load is stopped does not necessarily have to be higher than the melting point Tm, and may be a temperature lower than the melting point Tm.

[0102] After the first temperature reduction step S50, the submount 40 is heated to a second peak temperature T2 that is higher than the melting point Tm of the bonding material 30 to remelt the bonding material 30 (second heating step S60). Here, the first peak temperature T1, the second peak temperature T2, and the melting point Tm of the bonding material 30 satisfy the relationship Tm < T1 < T2.

[0103] After the second heating step S60, the temperature of the submount 40 is lowered to a temperature below the melting point Tm of the bonding material 30 (second temperature reduction step S70). Here, the temperature of the submount 40 is lowered to the temperature before the first heating step S40 (i.e., the standby temperature).

[0104] In the second heating step S60 and the second temperature reduction step S70, a load may or may not be applied to the semiconductor laser element 10. By not applying a load to the semiconductor laser element 10, the bonding material 30 extruded from the internal region 30M between the semiconductor laser element 10 and the submount 40 to the external regions 30B and 30C can be moved back to the internal region 30M by surface tension. Thereby, the maximum thickness of the bonding material 30 in the external regions 30B and 30C can be reduced.

[0105] Through the above steps, the semiconductor laser device 1 as shown in FIG. 8 can be manufactured.

[0106] (Embodiment 2) The semiconductor laser device according to Embodiment 2 will be described. The semiconductor laser device according to the present embodiment mainly differs from the semiconductor laser device 1 according to Embodiment 1 in the shape of the bonding material. Hereinafter, the semiconductor laser device according to the present embodiment will be described mainly focusing on the differences from the semiconductor laser device 1 according to Embodiment 1.

[0107] [2-1. Overall Configuration] First, the overall configuration of the semiconductor laser device according to the present embodiment will be described with reference to FIGS. 9 and 10. FIGS. 9 and 10 are schematic cross-sectional views showing cross-sections perpendicular to the first direction D1 and the second direction D2 of the semiconductor laser device 101 according to the present embodiment, respectively. FIG. 10 shows a cross-section taken along the line X-X in FIG. 9.

[0108] As shown in FIGS. 9 and 10, the semiconductor laser device 101 includes a submount 40, a semiconductor laser element 10, and a bonding material 130 that bonds the submount 40 and the semiconductor laser element 10. The semiconductor laser element 10 and the submount 40 according to the present embodiment have the same configuration as the semiconductor laser element 10 and the submount 40 according to Embodiment 1.

[0109] The bonding material 130 according to the present embodiment is a member that bonds the submount 40 and the semiconductor laser element 10. As shown in FIG. 9, the bonding material 1 30 has, in a cross-section perpendicular to the first direction D1, an internal region 130M bonded to the semiconductor laser element 10, and one external region 130B and the other external region 130C that are respectively disposed on one side surface 10B side and the other side surface 10C side of the semiconductor laser element 10 with respect to the internal region 130M among the regions disposed outside the internal region 130M. In other words, the external region 130B is the region closer to the side surface 10B of the semiconductor laser element 10 among the regions disposed outside the internal region 130M, and the external region 130C is the region closer to the side surface 10C of the semiconductor laser element 10 among the regions disposed outside the internal region 130M.

[0110] In this embodiment, the surfaces of the respective outer regions are convex. The bonding material 130 having such a shape can be realized, for example, by reducing the width of each outer region from the semiconductor laser device 1 according to Embodiment 1 or by changing a part of the manufacturing method. For example, the bonding material 130 according to this embodiment can be realized by shortening the time of the second heating step or increasing the load applied to the semiconductor laser element 10 as compared with the case of Embodiment 1. The detailed configuration of the bonding material 130 will be described later.

[0111] [2-2. Operation and Effect] Next, the operation and effect of the semiconductor laser device 101 according to this embodiment will be described with reference to FIGS. 9 and 10.

[0112] In the semiconductor laser device 101 shown in FIG. 9, similar to the semiconductor laser device 1 according to Embodiment 1, in the second direction D2, the width A of the semiconductor laser element 10, the width B of one outer region 130B of the bonding material 130, and the width C of the other outer region 130C satisfy the relationships of B≧A / 4 and C≧A / 4. Thereby, similar to the semiconductor laser device 1 according to Embodiment 1, since the bonding material 130 can be prevented from adhering to the side surfaces 10B and 10C of the semiconductor laser element 10, a short circuit between the p-type semiconductor layer 14 and the n-type semiconductor layer 12 due to the bonding material 130 can be suppressed.

[0113] Further, the width A of the semiconductor laser element 10, the width B of one outer region 130B, and the width C of the other outer region 130C may satisfy at least one of the relationships of B≧A / 2 and C≧A / 2.

[0114] Further, the width A of the semiconductor laser element 10, the width B of one outer region 130B, and the width C of the other outer region 130C may satisfy the relationships of B≦2A and C≦2A. Also, the width A of the semiconductor laser element 10, the width B of one outer region 130B, and the width C of the other outer region 130C may satisfy the relationships of B≦A and C≦A.

[0115] As described in Embodiment 1, the semiconductor laser element 10 has a stepped portion 11b formed at the end of one side surface 10B closer to the submount 40, and a stepped portion 11c formed at the end of the other side surface 10C closer to the submount 40. As shown in FIG. 9, in the stepped portion 11b and the stepped portion 11c, the semiconductor laser element 10 and the bonding material 130 are separated. That is, a gap gB is formed between one side surface 10B and one external region 130B of the bonding material 130, and a gap gC is formed between the other side surface 10C and the other external region 130C of the bonding material 130. Thereby, adhesion of the bonding material 130 to the side surfaces 10B and 10C of the semiconductor laser element 10 can be suppressed.

[0116] Also, the maximum thickness t13 of the bonding material 130 in one external region 130B and the distance t12 between the stepped portion 11b and the surface of the bonding material 130 on the submount 40 side (that is, the distance between the side surface 10B and the submount 40) satisfy the relationship t13 ≦ t12. Further, the maximum thickness t17 of the bonding material 130 in the other external region 130C and the distance t16 between the stepped portion 11c and the surface of the bonding material 130 on the submount 40 side (that is, the distance between the side surface 10C and the submount 40) satisfy the relationship t17 ≦ t16. Thereby, adhesion of the bonding material 130 to the side surfaces 10B and 10C of the semiconductor laser element 10 can be suppressed.

[0117] Also, the maximum thickness t15 of the bonding material 130 in the internal region 130M, the minimum thickness t11 of the bonding material 130 in the internal region 130M, the maximum thickness t13 of the bonding material 130 in one external region 130B, and the maximum thickness t17 of the bonding material 130 in the other external region 130C satisfy at least one of the relationships t13 ≦ t11 × 4 and t17 ≦ t15 × 4. Thereby, since the thickness of the bonding material 130 in each external region can be reduced, adhesion of the bonding material 130 to the side surfaces 10B and 10C of the semiconductor laser element 10 can be suppressed.

[0118] Further, the above-described maximum thickness t15, minimum thickness t11, maximum thickness t13, and maximum thickness t17 may satisfy at least one of the relationships of t13 ≤ t11×2 and t17 ≤ t15×2. Thereby, since the thickness of the bonding material 130 in each outer region of the bonding material 130 can be further reduced, it is possible to suppress the bonding material 130 from adhering to the side surfaces 10B and 10C of the semiconductor laser element 10.

[0119] Further, the semiconductor laser element 10 may be disposed inclined with respect to the main surface of the submount 40. For example, the bonding material 130 in the inner region 130M of the bonding material 130 may have a maximum thickness at a position closer to the other side surface 10C than the one side surface 10B, and a minimum thickness at a position closer to the one side surface 10B than the other side surface 10C. In this case, the maximum thickness t15 of the bonding material 130 in the inner region 130M, the minimum thickness t11 of the bonding material 130 in the inner region 130M, the thickness t14 of the bonding material 130 at the outer edge in one outer region 130B, and the thickness t18 of the bonding material 130 at the outer edge in the other outer region 130C may satisfy at least one of the relationships of t11 ≥ t14 / 1.5 and t15 ≥ t18 / 1.5. Thereby, while sufficiently securing the thickness of the bonding material 130 in the inner region 130M, the thickness of the bonding material 130 in each outer region can be reduced. Therefore, while securing the bonding area between the semiconductor laser element 10 and the bonding material 130, it is possible to suppress the bonding material 130 from adhering to each side surface of the semiconductor laser element 10.

[0120] Further, as shown in FIG. 10, the distance t22 between the rear end surface 10R of the semiconductor laser element 10 and the surface of the bonding material 130 on the submount 40 side (that is, the distance between the rear end surface 10R and the submount 40), and the maximum thickness t23 of the bonding material 130 disposed between the rear end surface 10R and the outer edge of the submount 40 satisfy the relationship of t23 ≤ t22. Thereby, it is possible to suppress the bonding material 130 from adhering to the rear end surface 10R of the semiconductor laser element 10.

[0121] Also, in the first direction D1, the maximum thickness t21 of the bonding material 130 located inside from the rear end face 10R by the same distance as the width A of the semiconductor laser element 10, and the maximum thickness t23 of the bonding material 130 disposed between the rear end face 10R and the outer edge portion of the submount 40 satisfy the relationship of t23 ≤ t21 × 4. Thereby, while sufficiently ensuring the thickness of the bonding material 130 between the semiconductor laser element 10 and the submount 40, the thickness of the bonding material 130 outside the rear end face 10R of the semiconductor laser element 10 can be reduced. Therefore, while securing the bonding area between the semiconductor laser element 10 and the bonding material 130, adhesion of the bonding material 130 to the rear end face 10R of the semiconductor laser element 10 can be suppressed.

[0122] Also, the maximum thickness t21 and the maximum thickness t23 may satisfy the relationship of t23 ≤ t21 × 2. Thereby, adhesion of the bonding material 130 to the rear end face 10R of the semiconductor laser element 10 can be further suppressed.

[0123] Also, in the first direction D1, the maximum thickness t21 of the bonding material 130 located inside from the rear end face 10R by the same distance as the width A of the semiconductor laser element 10, and the thickness t24 of the outer edge portion of the bonding material 130 disposed between the rear end face 10R and the outer edge portion of the submount 40 satisfy the relationship of t21 ≥ t24 / 1.5. Thereby, adhesion of the bonding material 130 to the rear end face 10R of the semiconductor laser element 10 can be suppressed.

[0124] (Embodiment 3) The semiconductor laser device according to Embodiment 3 will be described. The semiconductor laser device according to the present embodiment is mainly different from the semiconductor laser device 1 according to Embodiment 1 in that no step portion is formed in the semiconductor laser element. Hereinafter, the semiconductor laser device according to the present embodiment will be described with reference to FIGS. 11 and 12, centering on the differences from the semiconductor laser device 1 according to Embodiment 1.

[0125] FIG. 11 is a schematic cross-sectional view showing a cross-section perpendicular to the first direction D1 of the semiconductor laser device 201 according to the present embodiment. As shown in FIG. 11, the semiconductor laser device 201 includes a submount 40, a semiconductor laser element 210, and a bonding material 30 that bonds the submount 40 and the semiconductor laser element 210. The submount 40 and the bonding material 30 according to the present embodiment have the same configuration as the submount 40 and the bonding material 30 according to the first embodiment.

[0126] The semiconductor laser element 210 according to the present embodiment will be described with reference to FIG. 12. FIG. 12 is a schematic cross-sectional view showing the overall configuration of the semiconductor laser element 210 according to the present embodiment. As shown in FIG. 12, the semiconductor laser element 210 includes a substrate 211, a laminate SL, an insulating layer 15, a p-side contact electrode 16, a p-side electrode 17, and an n-side electrode 19. In the semiconductor laser element 210 according to the present embodiment, the step portions 11b and 11c are not formed. Accordingly, the shape of the substrate 211 and the like is different from the shape of the substrate 11 and the like according to the first embodiment.

[0127] Also in the semiconductor laser device 201 using the semiconductor laser element 210 having such a configuration, similar to the semiconductor laser device 1 according to the first embodiment, it is possible to suppress the bonding material 30 from adhering to one side surface 210B, the other side surface 210C, and the rear end surface (not shown in FIGS. 11 and 12) of the semiconductor laser element 210. Specifically, as shown in FIGS. 11 and 12, the p-side electrode 17 of the semiconductor laser element 210 is not formed on each side surface. Such a p-side electrode 17 and the bonding material 30 are bonded. In the present embodiment, the bonding material 30 is not bonded to the insulating layer 15 of the semiconductor laser element 10. Thereby, as shown in FIG. 11, the bonding material 30 includes an internal region 30M bonded to the p-side electrode 17 of the semiconductor laser element 210, and one external region 30B and the other external region 30C that are respectively disposed on one side surface 210B side and the other side surface 210C side of the semiconductor laser element 210 with respect to the internal region 30M among the regions disposed outside the internal region 30M.

[0128] Therefore, as shown in FIG. 11, the outer region 30B of the bonding material 30 can be separated from one side surface 210B of the semiconductor laser element 210. That is, a gap gB is formed between one side surface 210B and the outer region 30B of the bonding material 30. Also, the outer region 30C of the bonding material 30 can be separated from the other side surface 210C of the semiconductor laser element 210. That is, a gap gC is formed between the other side surface 210C and the outer region 30C of the bonding material 30.

[0129] Thus, even when using the semiconductor laser element 210 without a step portion formed thereon, a semiconductor laser device 201 can be realized that can suppress the bonding material 30 from adhering to each side surface and the rear end surface of the semiconductor laser element 210.

[0130] (Modification examples, etc.) As described above, the semiconductor laser device according to the present disclosure has been described based on each embodiment, but the present disclosure is not limited to the above-described embodiments.

[0131] For example, in each of the above embodiments, the semiconductor laser element is an element using a nitride-based semiconductor material, but the semiconductor laser element is not limited thereto. For example, the semiconductor laser element may be an element using a GaAs-based material. In this case, the resonator length L may be about 4 mm and the width A may be about 0.5 mm.

[0132] Also, in the semiconductor laser element 10 according to each of the above embodiments, the waveguide is formed by the ridge portion 10s, but the configuration of the waveguide is not limited thereto. For example, the waveguide may be formed using an electrode stripe structure, an embedded type structure, or the like.

[0133] Also, forms obtained by applying various modifications that those skilled in the art can conceive to each of the above embodiments, and forms realized by arbitrarily combining the components and functions in each of the above embodiments without departing from the spirit of the present disclosure are also included in the present disclosure.

Industrial Applicability

[0134] The semiconductor laser device of the present disclosure can be applied, for example, as a high-power and high-efficiency light source to a laser processing machine, a projector, an in-vehicle headlamp, etc.

Explanation of Reference Numerals

[0135] 1, 101, 201 Semiconductor laser device 10, 210 Semiconductor laser element 10B, 10C, 210B, 210C Side surface 10F Front end face 10R Rear end face 10s Ridge portion 10t Groove portion 11, 211 Substrate 11b, 11c Step portion 11s Main surface 12 n-type semiconductor layer 13 Active layer 14 p-type semiconductor layer 15 Insulating layer 16 p-side contact electrode 17 p-side electrode 19 n-side electrode 30, 130 Bonding material 30B, 30C, 130B, 130C External region 30M, 130M Internal region 40 Submount 41 First base 42 Adhesive layer 43 Electrode film 44 Barrier layer 990 Heater gB, gC, gR Gap SL Laminate

Claims

1. a submount; a semiconductor laser element; a bonding material for bonding the submount and the semiconductor laser element, wherein the semiconductor laser element has a substrate and a laminate stacked on a main surface of the substrate, and the laminate is arranged so as to face the submount, wherein the laminate has a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer stacked in this order on the substrate, a waveguide extending in a first direction parallel to the main surface of the substrate is formed in the laminate, wherein the bonding material, in a cross section perpendicular to the first direction, has an internal region bonded to the semiconductor laser element, and, among regions arranged outside the internal region, has one external region and the other external region respectively arranged on one side surface side and the other side surface side of the semiconductor laser element with respect to the internal region, wherein the one external region includes a region arranged outside the one side surface, the other external region includes a region arranged outside the other side surface, the one external region is spaced apart from the one side surface of the semiconductor laser element, the semiconductor laser element has a first step portion formed at an end portion of the one side surface closer to the submount, and a second step portion formed at an end portion of the other side surface closer to the submount, at the first step portion and the second step portion, the semiconductor laser element and the bonding material are spaced apart from each other, a maximum thickness t13 of the bonding material in the one external region and a distance t12 between the first step portion and a surface of the bonding material on the submount side satisfy a relationship of t13 ≤ t12, a maximum thickness t17 of the bonding material in the other external region and a distance t16 between the second step portion and a surface of the bonding material on the submount side satisfy a relationship of t17 ≤ t16, a width A of the semiconductor laser element, a width B of the one external region, and a width C of the other external region in a second direction perpendicular to the first direction and parallel to the main surface of the substrate satisfy relationships of B ≥ A / 4 and C ≥ A / 4 a semiconductor laser device.

2. The maximum thickness t15 of the bonding material in the internal region, the minimum thickness t11 of the bonding material in the internal region, the maximum thickness t13 of the bonding material in one of the external regions, and the maximum thickness t17 of the bonding material in the other external region satisfy at least one of the relationships: t13 ≤ t11 × 4 and t17 ≤ t15 × 4 The semiconductor laser device according to claim 1.

3. The maximum thickness t15 of the bonding material in the internal region, the minimum thickness t11 of the bonding material in the internal region, the maximum thickness t13 of the bonding material in one of the external regions, and the maximum thickness t17 of the bonding material in the other external region satisfy at least one of the relationships: t13 ≤ t11 × 2 and t17 ≤ t15 × 2 The semiconductor laser device according to claim 2.

4. A submount, A semiconductor laser element, A bonding material for bonding the submount and the semiconductor laser element, The semiconductor laser element has a substrate and a stacked body laminated on the main surface of the substrate, and the stacked body is arranged so as to face the submount, The stacked body, Has a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer laminated in order on the substrate, A waveguide extending in a first direction parallel to the main surface of the substrate is formed in the stacked body, The bonding material, in a cross-section perpendicular to the first direction, An internal region bonded to the semiconductor laser element, Among the regions arranged outside the internal region, one external region and the other external region respectively arranged on one side surface side and the other side surface side of the semiconductor laser element with respect to the internal region, The one external region includes a region arranged outside the one side surface, The other external region includes a region arranged outside the other side surface, The one external region is spaced apart from the one side surface of the semiconductor laser element, The semiconductor laser element has a first step portion formed at an end portion closer to the submount on the one side surface, and a second step portion formed at an end portion closer to the submount on the other side surface. In the first step portion and the second step portion, the semiconductor laser element and the bonding material are spaced apart, The bonding material in the internal region has a maximum thickness at a position closer to the other side surface than the one side surface, and has a minimum thickness at a position closer to the one side surface than the other side surface. The maximum thickness t15 of the bonding material in the internal region, the minimum thickness t11 of the bonding material in the internal region, the thickness t14 of the bonding material at the outer edge in the one external region, and the thickness t18 of the bonding material at the outer edge in the other external region satisfy at least one of the relationships t11 ≥ t14 / 1.5 and t15 ≥ t18 / 1.

5. In a second direction perpendicular to the first direction and parallel to the main surface of the substrate, the width A of the semiconductor laser element, the width B of the one external region, and the width C of the other external region satisfy the relationships B ≥ A / 4 and C ≥ A / 4. Semiconductor laser device.

5. A submount; A semiconductor laser element; A bonding material for bonding the submount and the semiconductor laser element; The semiconductor laser element has a substrate and a laminate laminated on the main surface of the substrate, and the laminate is arranged so as to face the submount. The laminate Has a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer laminated in order on the substrate. A waveguide extending in a first direction parallel to the main surface of the substrate is formed in the laminate. In a cross section perpendicular to the first direction, the bonding material An internal region bonded to the semiconductor laser element; Among the regions arranged outside the internal region, an external region on one side surface side and an external region on the other side surface side of the semiconductor laser element with respect to the internal region, respectively. The one external region includes a region arranged outside the one side surface. The other external region includes a region arranged outside the other side surface. The one external region is separated from the one side surface of the semiconductor laser element. In a second direction perpendicular to the first direction and parallel to the main surface of the substrate, the width A of the semiconductor laser element, the width B of the one external region, and the width C of the other external region satisfy the relationships B ≥ A / 4 and C ≥ A / 4. The semiconductor laser element has an insulating layer arranged between the laminate and the bonding material. The insulating layer is in contact with the laminate. The insulating layer is separated from the bonding material at both ends of the semiconductor laser element in the second direction. Semiconductor laser device. **Claim 6** A submount, A semiconductor laser element, A bonding material for bonding the submount and the semiconductor laser element, The semiconductor laser element has a substrate and a laminate laminated on the main surface of the substrate, and the laminate is arranged so as to face the submount. The laminate, Has a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer laminated in order on the substrate. A waveguide extending in a first direction parallel to the main surface of the substrate is formed in the laminate. The bonding material, in a cross section perpendicular to the first direction, An internal region bonded to the semiconductor laser element, Among the regions arranged outside the internal region, one external region and the other external region respectively arranged on one side surface side and the other side surface side of the semiconductor laser element with respect to the internal region. The one external region includes a region arranged outside the one side surface. The other external region includes a region arranged outside the other side surface. The one external region is separated from the one side surface of the semiconductor laser element. The semiconductor laser element has a front end face that emits laser light in the first direction and a rear end face that faces the front end face. The front end face is arranged outside the submount with respect to the outer edge of the submount in the first direction. The rear end face is arranged inside the submount with respect to the outer edge of the submount in the first direction. The bonding material is arranged between the rear end face and the outer edge of the submount. The bonding material is separated from the rear end face. In a second direction perpendicular to the first direction and parallel to the main surface of the substrate, the width A of the semiconductor laser element, the width B of the one external region, and the width C of the other external region satisfy the relationships B≥A / 4 and C≥A / 4. Semiconductor laser device. **Claim 7** The thickness t5 of the flat portion of the bonding material arranged between the rear end face and the outer edge of the submount and the thickness t6 of the bonding material located inside from the rear end face by the same distance as the width A of the semiconductor laser element satisfy the relationship t5≤t6. The semiconductor laser device according to claim 6. **Claim 8** The distance t22 between the rear end face and the surface of the bonding material on the submount side, and the maximum thickness t23 of the bonding material disposed between the rear end face and the outer edge of the submount satisfy the relationship t23 ≦ t22. The semiconductor laser device according to claim 6.

9. In the first direction, the maximum thickness t21 of the bonding material located inside from the rear end face by the same distance as the width A of the semiconductor laser element, and the maximum thickness t23 of the bonding material disposed between the rear end face and the outer edge of the submount satisfy the relationship t23 ≦ t21 × 4. The semiconductor laser device according to claim 8.

10. In the first direction, the maximum thickness t21 of the bonding material located inside from the rear end face by the same distance as the width A of the semiconductor laser element, and the maximum thickness t23 of the bonding material disposed between the rear end face and the outer edge of the submount satisfy the relationship t23 ≦ t21 × 2. The semiconductor laser device according to claim 9.

11. In the first direction, the maximum thickness t21 of the bonding material located inside from the rear end face by the same distance as the width A of the semiconductor laser element, and the thickness t24 of the outer edge of the bonding material disposed between the rear end face and the outer edge of the submount satisfy the relationship t21 ≧ t24 / 1.

5. The semiconductor laser device according to any one of claims 8 to 10.

12. The distance D in the first direction between the rear end face and the outer edge of the bonding material disposed between the rear end face and the outer edge of the submount, and the width A of the semiconductor laser element satisfy the relationship D ≧ A / 4. The semiconductor laser device according to any one of claims 8 to 11.

13. The distance D in the first direction between the rear end face and the outer edge of the bonding material disposed between the rear end face and the outer edge of the submount, and the width A of the semiconductor laser element satisfy the relationship D ≧ A / 2. The semiconductor laser device according to claim 12.

14. The semiconductor laser element has an insulating layer disposed between the laminate and the bonding material. The insulating layer is separated from the bonding material at an end portion closer to the rear end face of the semiconductor laser element in the first direction. The semiconductor laser device according to any one of claims 6 to 13.

15. The submount has a metal electrode film electrically connected to the bonding material, and a barrier layer disposed between the electrode film and the bonding material. The semiconductor laser device according to any one of claims 1 to 14.

16. The area S1 of the barrier layer and the area S2 of the bonding material in contact with the submount satisfy the relationship S1 ≥ S2. The semiconductor laser device according to claim 15.

17. The submount has a first base and an adhesion layer disposed between the first base and the electrode film. The semiconductor laser device according to claim 15 or 16.

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