JP5280119B2 - Semiconductor laser device - Google Patents

Description

  The present invention relates to a semiconductor laser device, and more particularly to a technique effective when applied to a multi-beam semiconductor laser device.

  A multi-beam semiconductor laser device used as a light source for information processing equipment such as a laser printer has a plurality of light emitting units arranged one-dimensionally or two-dimensionally. Therefore, there is an advantage that the number of scanning beams can be increased and high-speed printing is possible, so that the demand is rapidly increasing.

  The multi-beam semiconductor laser device includes a laser chip in which a semiconductor layer having a plurality of light emitting portions is stacked on a main surface of a semiconductor substrate made of GaAs or the like (hereinafter simply referred to as a substrate). A p-type electrode is formed on the main surface of the laser chip, and an n-type electrode is formed on the back surface. Further, a heat-dissipating Au plating layer is formed on the p-type electrode. The main surface of the laser chip is connected to one surface of the submount (support substrate) via solder made of Au—Sn alloy or the like. A heat sink made of Cu or the like is connected to the other surface of the submount by solder. The submount has a role of relieving thermal stress due to a difference in linear expansion coefficient between the heat sink and the laser chip and improving heat dissipation. Therefore, as the material for the submount, a material having good thermal conductivity and a thermal expansion coefficient close to that of the substrate, for example, SiC, Si, CuW, AlN, or the like is used.

  The above-described method for mounting the main surface of the laser chip toward the submount side is called a junction down method, and has an advantage that the heat generated in the light emitting part can be efficiently released to the submount. However, it is known that in this junction down method, stress is easily applied to the joint between the laser chip and the submount, so that the light emitting portion is distorted by the thermal stress during mounting, resulting in variations in optical characteristics. In particular, in the case of a multi-beam semiconductor laser device, it is required to suppress a difference in polarization angle between beams and to realize a laser element with uniform optical characteristics. It is an important issue to reduce the difference between applied distortion beams.

  However, for example, when a multi-beam semiconductor laser device arranged one-dimensionally is manufactured, the polarization direction of each beam varies, and the polarization angle (the deviation of the polarization direction of the laser beam from the direction parallel to the active layer in the semiconductor layer) is generated. There is a problem that a difference between beams is generated. It is known that when shear strain is applied to a semiconductor layer, the polarization direction of the beam rotates in proportion to the shear strain (MAFritz, IEEE Trans.Comp.Package.Technol., 27 (2004) p147 ), It is considered that the difference in polarization angle between the beams is caused by the difference in shear strain between the light emitting portions.

  The relative difference in shear strain described above will be described with reference to FIGS. 13 and 14. Here, a case where the linear expansion coefficient of the substrate is larger than that of the submount will be considered.

  The laser chip 1 is bonded to the submount with solder such as Au—Sn at a temperature of 200 ° C. to 300 ° C. When the temperature drops to room temperature after solder bonding (after mounting), the submount is less likely to shrink than the substrate 3 (the coefficient of linear expansion is small), so the side closer to the submount (the p-type electrode 8 and the Au plating layer 9 are Although the semiconductor layer 5 is pulled outward in the horizontal direction on the main surface side formed, the semiconductor layer 5 is compressed inward in the horizontal direction on the back side where the n-type electrode 2 is formed (see FIG. 13). ). Here, the horizontal direction is a direction parallel to the bonding surface between the semiconductor layer 5 and the substrate 3, and the vertical direction is a direction perpendicular to the bonding surface between the semiconductor layer 5 and the substrate 3, that is, the laser chip 1. It is defined as the direction perpendicular to the resonator direction.

  The parallelograms indicated by the diagonal lines in FIG. 13 represent the state of shear deformation in each light emitting unit 6, and the shear strain in each light emitting unit 6 is plotted as shown in FIG. In FIG. 13 and FIG. 14, the numbers LD1, LD2,. As can be seen from FIG. 13, the vertical / horizontal shear strain after mounting differs in direction and magnitude for each light-emitting portion 6, and it can be seen that there is a difference between shear strain beams. When the linear expansion coefficient of the substrate 3 is smaller than that of the submount, the sign of the shear strain in the light emitting unit 6 in FIG. 14 is reversed. As described above, since different shear strains are applied to the respective light emitting units 6 after mounting, in the multi-beam semiconductor laser device, the polarization angle for each beam is different, and a difference in polarization angle between beams occurs.

  As a method for suppressing the rotation of the polarization angle and a method for reducing distortion applied to the light emitting part after mounting, for example, Japanese Patent Laid-Open No. 2002-246696 (Patent Document 1) discloses a direction parallel to the active layer of a laser chip. Means for improving the deviation of the polarization direction of the laser beam with respect to the laser beam have been proposed. This proposal improves the deviation of the polarization direction by arranging the light emission point at a position intentionally displaced from the center position in the width direction of the chip.

Japanese Patent Application Laid-Open No. 07-202323 (Patent Document 2) discloses that a pseudo laser element that does not emit light during use is formed outside a region where a plurality of semiconductor laser elements are formed, and thermal stress is applied to the pseudo laser element. Means have been proposed for obtaining a multi-beam semiconductor laser device having uniform optical characteristics by absorption.
JP 2002-246696 A Japanese Patent Application Laid-Open No. 07-202323

  According to the study of the present inventor, the proposal described in Patent Document 1 is a multi-beam semiconductor having a plurality of light emitting points arranged at equal intervals on one semiconductor substrate and having different polarization angles for each beam. It cannot be applied to a laser device. Further, according to the research of the present inventors, the method of forming a pseudo laser element as described in Patent Document 2 can reduce the difference between direct distortion beams, but is shown in FIG. 13 and FIG. With respect to the difference in shear strain between beams, a sufficient reduction effect cannot be obtained.

  Further, according to the study of the present inventor, when the laser chip is mounted on the submount via the solder, the variation in the polarization angle for each beam is the amount of solder wetting at the interface between the Au plating layer of the laser chip and the solder. It has been found that it is also caused by non-uniformity of

  An object of the present invention is to provide a multi-beam semiconductor laser device that suppresses a difference in shear strain between beams applied to a light emitting portion after mounting and has a small difference in polarization angle between beams.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

A semiconductor laser device according to an invention of the present application is formed on a semiconductor substrate, a first conductivity type cathode electrode formed on a first surface of the semiconductor substrate, a second surface of the semiconductor substrate, and A semiconductor layer having a plurality of light emitting portions therein, a second conductivity type anode electrode formed above each of the plurality of light emitting portions, and a heat dissipation plating formed on each surface of the anode electrode A multi-beam semiconductor chip having a layer,
Each of the plated layers is bonded to the first surface of the support substrate via solder, whereby the semiconductor chip is mounted on the support substrate,
A metal layer made of a material having wettability with respect to the solder is interposed in part of the interface between the plating layer and the solder, and wettability with respect to the solder is interposed in the other part of the interface. A barrier metal layer made of a material that does not have a gap is interposed.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  By controlling [the ratio of the contact area between the metal layer and the solder: the contact area between the barrier metal layer and the solder] for each light emitting portion, the beam position dependency of the polarization angle is canceled out, so the difference between the polarization angle beams is small. A multi-beam semiconductor laser device can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted. Also, in the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

(Embodiment 1)
In this embodiment, an example in which the present invention is applied to a multi-beam semiconductor laser device having a convex ridge portion will be described.

FIG. 1 is a cross-sectional view of the main part of the multi-beam semiconductor laser device of the present embodiment. As shown in FIG. 1, a plurality of laser chips 1 (in this embodiment, in the present embodiment) are formed on a main surface of a substrate 3 made of GaAs (linear expansion coefficient = 6.4 × 10 ⁻⁶ / K). A semiconductor layer 5 having two (2) convex ridges 4 is laminated, and a light emitting part 6 is formed in the semiconductor layer 5 below each of the two ridges 4. The two ridge portions 4 extend in the direction of the resonator of the laser chip 1 and serve as a power feeding portion to which a current is constricted and supplied.

  An insulating layer 7 is formed on both side surfaces of the ridge portion 4 and on the semiconductor layer 5 in the vicinity thereof. A p-type electrode (anode electrode) 8 which is an independent electrode is formed on the ridge portion 4 on the insulating layer 7. It is formed so as to be in contact with the upper surface. Further, a heat radiating Au plating layer 9 is formed on the surface of the p-type electrode 8. On the other hand, an n-type electrode (cathode electrode) 2 that is a common electrode is formed on the back surface of the substrate 3. The n-type electrode 2 is made of, for example, a Ti layer and a metal film in which a Pt layer and an Au layer are sequentially stacked on the Ti layer.

The laser chip 1 has a submount (support substrate) 13 made of SiC (linear expansion coefficient = 4.0 × 10 ⁻⁶ / K) or AlN (linear expansion coefficient = 4.8 × 10 ⁻⁶ / K). It is mounted on the lower surface with solder 10. The solder 10 is made of, for example, an Au—Sn alloy. Although not shown, a heat sink made of Cu is connected to the upper surface of the submount 13 by solder.

  In the semiconductor laser device of the present embodiment, the connection portion between the laser chip 1 and the submount 13 has the following structure. That is, a barrier metal layer 11 made of a material that does not wet the solder 10 is formed on the surface of the Au plating layer 9 of the laser chip 1. A metal layer 12 made of a material having wettability with respect to the solder 10 is laminated on the part. The barrier metal layer 11 that has no wettability with respect to the solder 10 is composed of, for example, a Ti layer and a Pt layer laminated on the Ti layer. The metal layer 12 having wettability with respect to the solder 10 is made of Au.

  Therefore, a part of the solder 10 interposed between the laser chip 1 and the submount 13 is in contact with the barrier metal layer 11 and the other part is in contact with the metal layer 12. Here, since the barrier metal layer 11 does not have wettability with respect to the solder 10, the barrier metal layer 11 and the solder 10 are in contact with each other but are not joined. On the other hand, in the region where the metal layer 12 and the solder 10 are in contact, the metal layer 12 (= Au) has wettability with respect to the solder 10 (= Au—Sn). 10 are joined together by Au—Sn alloy bonding. In FIG. 1, the metal layer 12 and the solder 10 are illustrated as being separated from each other. However, since the metal layer 12 is actually melted in the solder 10, the boundary between the two is not good. It is clear.

  On the other hand, two submount electrodes 14 are formed on the lower surface of the submount 13 so as to face the two ridge portions 4 of the laser chip 1, and these submount electrodes 14 and the solder 10 are in contact with each other. doing. The submount electrode 14 includes, for example, a Ti layer, a Pt layer stacked on the Ti layer, and an Au layer stacked on the Pt layer. That is, since the surface of the submount electrode 14 is made of a material (= Au) having wettability with respect to the solder 10 (= Au—Sn), the submount electrode 14 and the solder 10 are made of an Au—Sn alloy. They are joined together by a bond.

  As described above, in the region where the laser chip 1 and the solder 10 are in contact with each other, only the contact surfaces of the metal layer 12 and the solder 10 are bonded to each other, and the contact surfaces of the barrier metal layer 11 and the solder 10 are They conduct electricity but are not joined together.

  As described above, when the laser chip 1 is mounted on the submount 13 via the solder 10, the reason why the polarization angle of the beam varies for each light emitting part 6 is that the Au plating layer 9 formed in each light emitting part 6 The amount of wetting of the solder 10 at the interface with the solder 10 is not uniform.

  Therefore, in the present embodiment, the direction and magnitude of the shear strain in each light emitting section 6 shown in FIG. 13 is considered, and [the contact area between the metal layer 12 and the solder 10: the contact between the barrier metal layer 11 and the solder 10] The ratio of the area] is controlled for each light emitting unit 6. As a result, the beam position dependency of the polarization angle is canceled out, so that a multi-beam semiconductor laser device with a small difference between the polarization angle beams can be realized.

  Next, the detailed structure of the semiconductor layer 5 of the laser chip 1 will be described with reference to FIG. FIG. 2 is an enlarged cross-sectional view showing a region corresponding to one element of the laser chip 1.

  The laser chip 1 has a substrate 3 made of, for example, n-type GaAs, and a semiconductor layer 5 is formed on the main surface thereof. The semiconductor layer 5 includes an n-type cladding layer 15 sequentially stacked along a direction perpendicular to the main surface, an active layer 16 having a multi-quantum well structure, a p-type first cladding layer 17, A mold etching stop layer 18 is used. The ridge portion 4 on the upper side of the semiconductor layer 5 is constituted by a p-type second cladding layer 19 and a p-type contact layer 20.

  Here, an example of the material and thickness of the semiconductor layer 5 is shown. The n-type cladding layer 15 is made of AlGaInP having a thickness of 2.0 μm. The active layer 16 is made of an AlGaInP layer having a barrier layer thickness of 5 nm, and the well layer is made of a GaInP layer having a thickness of 6 nm, and has a multi-quantum well structure having three layers. The p-type first cladding layer 17, the p-type etching stop layer 18 and the p-type second cladding layer 19 are all made of AlGaInP. The p-type first cladding layer 17 has a thickness of 0.3 μm, the p-type etching stop layer 18 has a thickness of 20 nm, and the p-type second cladding layer 19 has a thickness of 1.2 μm. The p-type contact layer 20 is made of GaAs having a thickness of 0.4 μm.

  An insulating layer 7 is formed on the main surface side of the substrate 3 except for the surface (upper surface) of the ridge portion 4. The insulating layer 7 is composed of, for example, a silicon oxide film and a PSG film formed on the silicon oxide film. The insulating layer 7 includes each side surface (both side surfaces) of the ridge portion 4 and has a structure covering a part of the upper surface of the substrate 3, but the upper surface of the substrate 3 except for the surface (upper surface) of the ridge portion 4. It may cover the whole.

  A p-type electrode 8 is formed on the ridge 4 and the insulating layer 7. A part of the p-type electrode 8 is connected to the p-type contact layer 20 of the ridge portion 4. Further, the end portion of the p-type electrode 8 is terminated on the insulating layer 7 so as not to reach both side edges of the substrate 3. That is, the p-type electrode 8 is an independent electrode separated on the insulating layer 7 so that a voltage can be individually applied to the ridge portion 4 of each semiconductor laser element. The p-type electrode 8 is made of, for example, a Ti layer and a metal film in which a Pt layer and an Au layer are sequentially laminated on the Ti layer, and the overall thickness is 0.5 μm.

  An Au plating layer 9 having a higher thermal conductivity than that of the substrate 3 is formed on the p-type electrode 8. The Au plating layer 9 is formed as thick as 3 μm to 7 μm. On the other hand, an n-type electrode 2 is formed on the back surface of the substrate 3. The n-type electrode 2 is made of, for example, a metal multilayer film in which Ti, Pt, and Au are sequentially laminated, and the overall thickness is 0.5 μm.

  Next, a method for mounting the laser chip 1 on the submount 13 will be described with reference to FIGS. Here, FIG. 3 to FIG. 8 are cross-sectional views showing a region for one laser element of the substrate 3 in a wafer state.

  First, as shown in FIG. 3, a semiconductor layer 5 having a convex ridge portion 4 is formed on the main surface of the substrate 3 in accordance with a well-known wafer process, and then the upper portion of the semiconductor layer 5 excluding the upper surface of the ridge portion 4 is formed. The insulating layer 7 is formed, and then the p-type electrode 8 is formed on the insulating layer 7.

  Next, as shown in FIG. 4, after a photoresist film 22 having an opening in the region where the Au plating layer 9 is to be formed is formed on the p-type electrode 8, an electrolytic plating method is used as shown in FIG. An Au plating layer 9 is formed on the p-type electrode 8. At this time, the Au plating layer 9 is formed on the p-type electrode 8 in a region not covered with the photoresist film 22.

  Next, as shown in FIG. 6, a barrier metal layer 11 composed of a Ti layer and a Pt layer is deposited on the Au plating layer 9, and then a metal layer composed of an Au layer is formed on the barrier metal layer 11. 12 is formed by vapor deposition.

  Next, after removing the photoresist film 22, as shown in FIG. 7, a photoresist film 23 in which a part of the metal layer 12 is exposed is formed on the substrate 3, and the metal exposed at the bottom of the photoresist film 23 is formed. Layer 12 is removed by wet etching.

  Next, after removing the photoresist film 23, as shown in FIG. 8, the p-type electrode 8 is patterned to separate each element, and the n-type electrode 2 is formed on the back surface of the substrate 3. Thereafter, the substrate 3 in the wafer state is cleaved to be separated into laser chips 1 and the laser chip 1 is mounted on the lower surface of the submount 13 with the solder 10 to obtain the semiconductor laser device shown in FIG. .

  FIG. 9 is a fragmentary perspective view showing the overall configuration of the multi-beam semiconductor laser device of the present embodiment, and FIG. 10 is an enlarged perspective view showing a part of FIG.

  The multi-beam semiconductor laser device has a package (sealing container) including a disc-shaped stem 30 and a cap 31 covering the upper surface of the stem 30, and the laser chip 1 is sealed inside the cap 31. It has been stopped. The stem 30 is made of an Fe alloy having a diameter of about 5.6 mm and a thickness of about 1.2 mm. A flange portion 32 provided on the outer periphery of the bottom portion of the cap 31 is fixed to the upper surface of the stem 30. In addition, a round hole 34 to which a transparent glass plate 33 is bonded is provided at the center portion of the upper surface of the cap 31.

  Near the center of the upper surface of the stem 30, a heat sink 35 made of a metal having good thermal conductivity, such as Cu, is mounted. The heat sink 35 is joined to the upper surface of the stem 30 via a brazing material (not shown). The submount 13 is fixed to one side of the heat sink 35 via solder (not shown), and the laser chip 1 is mounted on one side of the submount 13.

  An n-type electrode 2 not shown in FIGS. 9 and 10 is formed on one surface of the laser chip 1, and the n-type electrode 2 and the heat sink 35 are electrically connected by an Au wire 36. That is, the laser chip is mounted on the surface of the submount 13 by a junction down system in which the main surface side on which the light emitting unit 6 is formed is opposed to the submount 13.

  The laser chip 1 emits laser light from its both ends (upper end and lower end in FIG. 1). Therefore, the submount 13 that supports the laser chip 1 is fixed to the heat sink 35 so that the chip mounting surface faces a direction perpendicular to the upper surface of the stem 30. Laser light emitted from the upper end of the laser chip 1 is emitted to the outside through the round hole 34 of the cap 31.

  Six leads 37a, 37b, 37c, 37d, 37e, and 37f are attached to the lower surface of the stem 30. The upper ends of the leads 37a, 37b, 37e, and 37f protruding to the upper surface side of the stem 30 and the heat sink 35 are electrically connected by Au wires 38. The lead 37 c is fixed to the lower surface of the stem 30 and is in an electrically equipotential state with the stem 30.

(Embodiment 2)
FIG. 11 is a cross-sectional view of a main part of the multi-beam semiconductor laser device according to the present embodiment. In the multi-beam semiconductor laser device of the present embodiment, a part of the solder 10 interposed between the laser chip 1 and the submount 13 is in contact with the barrier metal layer 11 as in the first embodiment. The portion is in contact with the metal layer 12. That is, since the metal layer 12 is made of a material having wettability to the solder 10, the contact surfaces of the metal layer 12 and the solder 10 are joined to each other. On the other hand, since the barrier metal layer 11 is made of a material that does not have wettability with respect to the solder 10, the contact surface between the barrier metal layer 11 and the solder 10 conducts heat and electricity but is not joined to each other.

  Further, in the multi-beam semiconductor laser device of the present embodiment, in addition to the above configuration, the center position of the Au plating layer 9 in each ridge portion 4 is intentionally displaced with respect to the center position of the light emitting portion 6 therebelow. Has been. That is, in each ridge portion 4, the Au plating layer 9 is formed asymmetrically with respect to the center position of the ridge portion 4.

  In this way, in the stage before the laser chip 1 is mounted on the submount 13, it is possible to apply a shear strain in the direction opposite to the shear strain applied after mounting to the light emitting portion 6, so that the laser chip 1 is mounted on the submount 13. It is possible to reduce the shearing strain applied to the light emitting portion 6 after being mounted on. Thereby, it is possible to realize a multi-beam semiconductor laser device in which the difference between polarization angle beams is further small.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  In the above-described embodiment, an example in which the present invention is applied to a multi-beam semiconductor laser device having a laser chip 1 having a convex ridge portion 4 has been described. However, as shown in FIG. The present invention can also be applied to a multi-beam semiconductor laser device having the laser chip 1 in which the p-type second cladding layer 19 and the p-type contact layer 20 exist on the p-type etching stop layer 18.

  In the above embodiment, the Au plating layer 9 is formed on the surface of the p-type electrode 8 of the laser chip 1, and the surface of the Au plating layer 9 has wettability with respect to the solder 10 made of an Au—Sn alloy. A barrier metal layer 11 composed of a Ti layer / Pt layer that does not have is formed, and a metal layer 12 made of Au having wettability to the solder 10 is formed on a part of the surface of the barrier metal layer 11. However, the plating layer, the solder, the metal layer, and the barrier metal layer are not limited to the above materials.

  In the above embodiment, an example in which the present invention is applied to a two-beam semiconductor laser device including two light emitting units has been described. However, the present invention is a multi-beam including three or more light emitting units. Of course, it can be applied to a semiconductor laser device.

In the above embodiment, the example in which the linear expansion coefficient of the substrate 3 is applied to the multi-beam semiconductor laser device is smaller than that of the submount 13. However, the linear expansion coefficient of the substrate 3 is larger than that of the submount 13. Of course, the present invention can be applied to a large multi-beam semiconductor laser device. As such multi-beam semiconductor laser device, the multi-mounting the laser chip made of GaAs on the sub-mount made of CuW (linear expansion coefficient ^{= 6.5 × 10 -6 /K~8.3×10 -6 /} K) A beam semiconductor laser device can be exemplified.

  In the above-described embodiment, an example in which the present invention is applied to a multi-beam semiconductor laser device having a plurality of light-emitting portions has been described. However, the present invention is applied to a single-beam semiconductor laser device having a single light-emitting portion. It can also be applied. That is, in the single beam semiconductor laser device, the problem of the difference in polarization angle between the beams does not occur, but as a correction means when the center value of the manufacturing variation of the polarization angle is deviated from 0 (zero), [metal layer and solder It is possible to apply the configuration of the present invention in which the ratio of the contact area of the barrier metal layer to the solder] is controlled.

  The present invention is effective when applied to a multi-beam semiconductor laser device.

It is principal part sectional drawing which shows the multi-beam semiconductor laser apparatus which is one embodiment of this invention. FIG. 2 is a partial enlarged cross-sectional view of a semiconductor chip mounted on the multi-beam semiconductor laser device shown in FIG. 1. FIG. 2 is a cross-sectional view of a principal part of a semiconductor substrate (wafer) showing a mounting method of the multi-beam semiconductor laser device shown in FIG. FIG. 4 is a fragmentary cross-sectional view of the semiconductor substrate illustrating the mounting method of the multi-beam semiconductor laser device following FIG. 3. FIG. 5 is a main-portion cross-sectional view of the semiconductor substrate showing the mounting method of the multi-beam semiconductor laser device following FIG. 4; FIG. 6 is a cross-sectional view of the principal part of the semiconductor substrate showing the mounting method of the multi-beam semiconductor laser device following FIG. 5. FIG. 7 is a fragmentary cross-sectional view of a semiconductor substrate showing a method for mounting the multi-beam semiconductor laser device following FIG. 6. FIG. 8 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for mounting the multi-beam semiconductor laser device following FIG. 7. 1 is a fragmentary perspective view showing an overall configuration of a multi-beam semiconductor laser device according to an embodiment of the present invention. It is a perspective view which expands and shows a part of FIG. It is principal part sectional drawing which shows the multi-beam semiconductor laser apparatus which is other embodiment of this invention. It is principal part sectional drawing which shows another example of the semiconductor chip mounted in the multi-beam semiconductor laser apparatus of this invention. It is a schematic diagram which shows the shear deformation of the light emission part in the laser chip after mounting in the support substrate. It is the graph which plotted the shear distortion of the light emission part shown in FIG.

Explanation of symbols

1 Laser chip 2 n-type electrode (cathode electrode)
3 Semiconductor substrate 4 Ridge part 5 Semiconductor layer 6 Light emitting part 7 Insulating layer 8 p-type electrode (anode electrode)
9 Au plating layer 10 Solder 11 Barrier metal layer 12 Metal layer 13 Submount (support substrate)
14 submount electrode 15 n-type cladding layer 16 active layer 17 p-type first cladding layer 18 p-type etching stop layer 19 p-type second cladding layer 20 p-type contact layers 22 and 23 photoresist film 30 stem 31 cap 32 flange portion 33 Glass plate 34 Round hole 35 Heat sink 36 Au wire 37a, 37b, 37c, 37d, 37e, 37f Lead 38 Au wire

Claims (6)

A semiconductor substrate, a first conductivity type cathode electrode formed on the first surface of the semiconductor substrate, and a semiconductor formed on the second surface of the semiconductor substrate and having a plurality of light emitting portions therein A region, a plurality of ridge portions formed above each of the plurality of light emitting portions and having a first ridge portion and a second ridge portion adjacent to each other, and an upper portion of each of the plurality of ridge portions A multi-beam semiconductor chip having a plurality of anode electrodes of the second conductivity type formed on the surface and a plurality of heat-dissipating plating layers formed on the respective surfaces of the anode electrodes;
Each of the plurality of plating layers is bonded to the first surface of the support substrate via solder, whereby the semiconductor chip is mounted on the support substrate,
A metal layer made of a material having wettability with respect to the solder is interposed in a part of each interface between the plurality of plating layers and the solder, and the other part of the interface is connected to the solder. On the other hand, a barrier metal layer composed of a material that does not have wettability is interposed,
The linear expansion coefficient of the semiconductor substrate is larger than the linear expansion coefficient of the support substrate,
The metal layer on the first ridge portion is disposed at a position close to the second ridge portion side,
The semiconductor laser device according to claim 1, wherein the metal layer on the second ridge portion is disposed at a position close to the first ridge portion side .   2. The semiconductor laser device according to claim 1, wherein the plurality of plating layers are made of Au, the solder is made of an Au-Sn alloy, and the material having wettability to the solder is Au.   3. The semiconductor laser device according to claim 2, wherein the material having no wettability with respect to the solder is Pt.   2. The semiconductor laser device according to claim 1, wherein the semiconductor substrate is made of GaAs, and the support substrate is made of SiC or AlN.   2. The semiconductor laser device according to claim 1, wherein a heat sink is bonded to the second surface of the support substrate.   2. The semiconductor laser device according to claim 1, wherein the barrier metal layer is formed on a part of each upper portion of the plurality of ridge portions.

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