JP2007013002A - Semiconductor laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently reduce a stress caused in a light emitting region in a semiconductor laser device wherein a semiconductor laser element is fixed by soldering to a heatsink with a junction-down structure. <P>SOLUTION: A semiconductor laser device 10 comprises a semiconductor laser element 1 having a plurality of semiconductor layers 1c formed on a substrate 1s and having an electrode 1d formed on a surface of the substrate opposed to the layers 1c, and a heatsink 2 joined to the semiconductor laser element 1 with a solder 7 from the side of the surface of the element provided with the electrode 1d. Under a condition that the laser element 1 is joined to the heatsink 2 with the solder 7 after being melted and solidified, a distance between the solder 7 and the optical waveguide Q of the laser element 1 is set at 20 μm or more. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device including a semiconductor laser element and a heat sink in which the semiconductor laser element is fixed with a junction down structure.

  Conventionally, as described in Patent Document 1, for example, in a nitride semiconductor laser element or the like, a structure in which a P electrode and an N electrode are formed on the same side with respect to a substrate is employed. When mounting this type of semiconductor laser device, a so-called junction-down structure is used in which the surface of the device on which the P and N electrodes are formed is joined to a heat sink in order to improve heat dissipation from the device. Often done. The heat sink often takes the form of a submount interposed between the two when a semiconductor laser is mounted on a large heat dissipation block.

  In this cited reference 1, when the element surface on which the P electrode and the N electrode are formed as described above is bonded to a heat sink, the solder used for the bonding is not used in the portion directly below the optical waveguide portion of the semiconductor laser element. It is also described that it is divided into two so as to be continuous, and the P electrode portion and the N electrode portion are joined to the heat sink by the two solders, respectively.

  In the above-described fixing structure using solder, it is important to prevent large stress caused by solder bonding from occurring in the optical waveguide portion that is the light emitting region so as not to impair the static characteristics of the semiconductor laser element. is there.

  As described above, in the structure in which the semiconductor laser element is bonded and fixed to a heat sink or the like, the structures shown in Patent Document 1 and Patent Document 2 are conventionally known as structures for reducing the stress generated in the semiconductor laser element. .

  The structure shown in Patent Document 1 is a structure in which a semiconductor laser element is fixed on a pedestal of a copper-based material, and the width dimension of the semiconductor laser element and the total thickness dimension of the semiconductor laser chip and the submount are optimized. This is to reduce the stress applied to the light emitting region of the semiconductor laser element.

The structure disclosed in Patent Document 2 is a structure in which a semiconductor laser element is fixed on a pedestal with solder, and the ratio between the width dimension and thickness of the submount is optimized to reduce the stress applied to the light emitting region of the semiconductor laser element. It is something to try.
JP 2004-96062 A Japanese Patent Laid-Open No. 2001-168445 JP 2004-349294 A

  As shown in Cited Document 1, a semiconductor laser device in which a semiconductor laser element is mounted on a heat sink with a junction-down structure using two divided solders can reduce mounting stress and improve mounting accuracy. There is room for improvement in improving the static characteristics of the laser element.

  On the other hand, it is difficult to sufficiently reduce the stress generated in the semiconductor laser element in the structures shown in the cited document 2 and the cited document 3, and when a semiconductor laser device adopting these structures is subjected to a thermal cycle test, it has a high probability. It has been confirmed that defective products are generated.

  Further, even when the structures shown in the cited document 2 and the cited document 3 are applied to the semiconductor laser device having the junction-down structure described above, it is not clear whether the effect of reducing the stress generated in the semiconductor laser element can be obtained.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to sufficiently reduce stress generated in a light emitting region in a semiconductor laser device in which a semiconductor laser element is fixed to a heat sink with a junction down structure by solder. To do.

A semiconductor laser device according to the present invention comprises:
A semiconductor laser device in which a plurality of semiconductor layers are formed on a substrate and an electrode is formed on the surface of the layer opposite to the substrate;
In this semiconductor laser device, comprising a heat sink joined with solder from the surface side on which the electrodes are formed (that is, with a junction-down structure),
In the state where the semiconductor laser element is bonded to the heat sink by the solder solidified after melting, the distance between the solder and the optical waveguide of the semiconductor laser element is 20 μm or more.

  The above-mentioned distance is the distance between the solder end of the optical waveguide from the solder side end and the surface that is lowered perpendicularly to the plane parallel to the solder layer (hereinafter the same).

  The pattern before melting of the solder is preferably smaller than the electrode of the semiconductor laser element and has a discrete or constricted shape. Further, it is desirable that the pattern before melting of the solder has a shape protruding from the P electrode of the semiconductor laser element to the side opposite to the optical waveguide.

  On the other hand, it is desirable that the uppermost electrode layer in the light emitting region of the semiconductor laser element is formed using a barrier metal such as Pt, Mo, Ti or Pd.

  Conventionally, when a semiconductor laser element is bonded to a heat sink that takes the form of a submount or the like, the optical waveguide part of the element generates heat and tends to deteriorate as the operating temperature rises. Adhesion directly improves heat dissipation. On the other hand, the structure shown in Patent Document 1 is such that the optical waveguide portion is not directly bonded to the submount for the purpose of improving the mounting position accuracy of the semiconductor laser element. It has been newly found that this occurs. Hereinafter, this point will be described in detail.

  The semiconductor laser device described in the cited document 1, that is, a GaN-based semiconductor laser element in which a P electrode and an N electrode are formed on the same side with respect to a substrate is joined to a heat sink by soldering, and the solder is a semiconductor laser. A semiconductor laser device is divided into two so as to be discontinuous in a portion immediately below the optical waveguide portion of the element, and the P electrode portion and the N electrode portion are joined to the heat sink by the two solders for several hundred hours. When the static characteristics of the semiconductor laser element were evaluated by conducting a temperature cycle test in which the ambient temperature was changed between −40 ° C. and 85 ° C., the static characteristics were defective. As a result of studying the test results, the present inventor has found that the failure rate of static characteristics increases as the solder melted at the time of joining approaches the light emitting region, as shown in FIG. More specifically, when the distance between the solder and the optical waveguide is less than 20 μm, the defect rate is significantly increased.

  The present inventor speculated that the solder spreads to the optical waveguide portion, and stress is applied to the optical waveguide portion, thereby causing the occurrence of poor static characteristics. Therefore, when the relationship between the distance between the solder and the optical waveguide and the stress applied to the optical waveguide of the semiconductor laser element was simulated by a computer, the result shown in FIG. 9 was obtained. This simulation was performed in each case with the thickness of the heat sink being 0.25 mm and the thermal expansion coefficient (linear expansion coefficient) of the material being five as shown in the figure.

  As shown in FIG. 9, when the distance between the solder solidified after melting and the optical waveguide is less than 20 μm, the stress rapidly increases. Based on this and the test result shown in FIG. 8, it is estimated that the above-described static characteristic failure is caused by the stress applied to the optical waveguide by the solder. Therefore, when the distance is set to 20 μm or more in each embodiment described later, the yield of manufacturing the semiconductor laser device is 95% or more in any case. As a result, it was confirmed that the stress generated in the optical waveguide as the light emitting region can be sufficiently reduced by setting the distance between the solder and the optical waveguide to 20 μm in the present invention.

  In addition, when the pattern before melting of the solder is smaller than the electrode of the semiconductor laser element and has a discrete or constricted shape, when the solder is melted, adjacent portions (discrete shapes) In the case of a constricted shape, the portions larger than the constriction are fused to reach the PN junction and the P-type epitaxial layer. Is prevented.

  In addition, when the pattern before melting of the solder has a shape protruding from the P electrode of the semiconductor laser element to the side opposite to the optical waveguide, the solder tends to flow to the side opposite to the optical waveguide when melting. Therefore, in this case as well, it is possible to prevent the solder from reaching the PN junction and the P-type epitaxial layer and causing a short circuit.

  On the other hand, when the uppermost electrode layer of the light emitting region of the semiconductor laser element is formed using a barrier metal such as Pt, Mo, Ti, or Pd, the molten solder flows on the barrier metal to the light emitting region side. That is, since it is prevented from proceeding to the optical waveguide side, it is effective to keep the distance between the solder and the optical waveguide of the semiconductor laser element at 20 μm or more.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic front shape of a semiconductor laser device 10 according to a first embodiment of the present invention. As shown in the figure, in this semiconductor laser device 10, a semiconductor laser element 1 in a chip state, which is a GaN-based semiconductor laser element, is mounted on an AlN heat dissipation block 3 via an AlN (aluminum nitride) submount 2 as a heat sink. It will be. In this embodiment, as shown in FIG. 2, a plurality of (for example, seven) semiconductor laser elements 1 are mounted side by side on the AlN heat dissipation block 3, thereby forming a laser light source device that emits a plurality of laser beams. ing.

  In addition, on the upper surface of the AlN heat dissipation block 3, one N-pole electric wiring layer 18 that is common to the plurality of semiconductor laser elements 1, and P electrode electricity formed individually for each semiconductor laser element 1. A wiring layer 19 and an alignment mark 20 for positioning the semiconductor laser element 1 are formed.

  In the semiconductor laser device 1, a GaN layer (not shown), a contact layer 1a made of an N-type semiconductor, and the like are sequentially formed on a sapphire substrate 1s (below in FIG. 1), and a part of the contact layer 1a An N electrode 1b is formed on the region, and a lower clad layer made of an N-type semiconductor, an upper light guide layer, an active layer, and an upper light guide layer made of a P-type semiconductor on the other region of the contact layer 1a. In addition, a semiconductor layer 1c is formed by sequentially laminating a cladding layer, a contact layer, and the like, and a P electrode 1d is formed on the semiconductor layer 1c (directly on a contact layer made of a P-type semiconductor). It will be.

  The semiconductor laser element 1 is mounted as follows. In the present embodiment, the surface of the AlN substrate 2s that is cut as described later and constitutes the AlN submount 2 is polished, for example, the substrate thickness is 0.25 mm, and the surface roughness Ra is 0.05 μm or less. Finished to be. A Ti / Pt / Au metallized layer 4 is formed on the lower surface of the AlN substrate 2s. As the AlN substrate 2s, a substrate having a thermal conductivity of 170 W / mK or more is used, thereby ensuring good heat dissipation.

  A pair of Ti / Pt / Au metallization layers 5 and 15 as electrode wiring functional layers are formed on the upper surface of the AlN substrate 2s. These metallized layers 5 and 15 are formed, for example, by forming a Ti / Pt / Au film on the entire upper surface of the AlN substrate 2s by sputtering, patterning a resist having a predetermined shape on the Ti / Pt / Au film, and forming a resist-free portion by ion milling. The Ti / Pt / Au film is removed.

  Next, metallized layers 6 and 16 made of Au thick films having different thicknesses are formed on the metallized layers 5 and 15 and function as a wetting improving layer and a height adjusting layer, respectively. The difference in thickness between the Au metallized layers 6 and 16 is, for example, 0.3 μm. The metallized layers 6 and 16 having different thicknesses can be formed by vapor deposition using, for example, a lift-off method.

  Next, Pt films 26 and 36 as wettability improving layers are formed in regions where the solder on the metallized layers 6 and 16 is formed. The Pt films 26 and 36 are formed by patterning by sputtering using, for example, a lift-off method.

  Next, AuSn solder (hereinafter simply referred to as solder) 7 and 17 are formed on the Pt films 26 and 36, respectively. The solder 7 that joins the P electrode 1d has, for example, four circular dots having a diameter of 30 μm and a thickness of 1.75 ± 0.25 μm, and the direction of the resonator axis of the semiconductor laser element 1 (the P electrode 1d and the N electrode 1b The pattern is formed in parallel at a pitch of 90 μm in a direction orthogonal to the arrangement direction. On the other hand, the solder 17 to which the N electrode 1b is bonded has a rectangular pattern in which the length of the semiconductor laser element 1 in the resonator axial direction is 700 μm and the width in the direction perpendicular thereto is 350 μm, for example. It is formed so as to cover the entire surface area of 36. The solders 7 and 17 are formed to have a target composition ratio (for example, the Au composition is 73 ± 10 wt%) by, for example, a binary evaporation method of Au and Sn.

  Thereafter, the AlN substrate 2s is cut to form a plurality of AlN submounts 2. In this embodiment, the AlN submount 2 basically includes an AlN substrate 2s, a Ti / Pt / Au metallized layer 4, a Ti / Pt / Au metallized layer 5, 15, an Au metallized layer 6, 16 and a Pt film 26, 36. It is configured.

  Next, the chip-shaped semiconductor laser device 1 whose outer shape is formed in a size of about 350 × 700 × 100 μm on the AlN submount 2 cut one by one as described above is the P electrode 1d. Is positioned on the solder 7, and the N electrode 1 b is positioned and disposed on the solder 17. Then, by applying a predetermined load, the semiconductor laser element 1 is pressed against the AlN submount 2 and the whole is heated to 310 ° C. in this state. As a result, the solders 7 and 17 are melted, and the semiconductor laser element 1 is joined to the AlN submount 2 from the P electrode 1d and N electrode 1b sides. The P electrode 1d and the N electrode 1b are formed on the same surface, and the size is 150 × 600 μm for the former and 100 × 600 μm for the latter.

  When the semiconductor laser device 1 is positioned and arranged, a ridge-shaped optical waveguide (light emitting region) Q extending in a direction perpendicular to the paper surface in FIG. 1 is formed between the metallized layers 5 and 6 and the metallized layers 15 and 16. The dot-shaped solder 7 is located within the groove-shaped portion and is lowered from the side end (right end in FIG. 1) of the optical waveguide Q toward the plane parallel to the layer of the solder 7. The element 1 is positioned in the P electrode width direction so that the distance to the center of the electrode becomes 75 μm. By positioning in this way, the distance L between the optical waveguide Q and the dot-like solder 7 is 30 μm or more in a state where the dot-like solder 7 is melted and solidified. The distance L is the distance between the surface of the optical waveguide Q that is lowered from the side end of the optical waveguide Q at a right angle toward the surface parallel to the layer of the solder 7 and the end of the dot-like solder 7 as described above. .

  As described above, in the present embodiment, the distance L between the optical waveguide Q and the dot-like solder 7 is 30 μm or more, which exceeds 20 μm described above, and thereby the stress generated in the optical waveguide Q can be kept small. Actually, the production yield of the semiconductor laser device 10 was 95% or more.

  Further, since the pattern before melting of the solder 7 is smaller than the P electrode 1d of the semiconductor laser element 1 and has a discrete shape, adjacent portions are merged, and a PN junction portion or a P-type epitaxial layer is fused. It is prevented that a short circuit is caused by reaching up to.

  The semiconductor laser element 1 is positioned in the waveguide length direction so that its light emitting end face protrudes 100 ± 30 μm from the end face of the AlN submount 2 (see FIG. 2). Further, since the AlN submount 2 is formed with a step portion by the Au metallization layers 6 and 16 having different thicknesses, the step between the P electrode 1d and the N electrode 1b of the semiconductor laser element 1 is determined by this step portion. Absorbed.

  Next, as shown in FIG. 1, the AlN heat dissipating block 3 in which the Ti / Pt / Au metallized layer 8 and the Pt layer 9 as the wettability improving layer are formed on the upper surface is heated to 150 ° C., and the solder 11 is placed thereon. The AlN submount 2 is placed with the Ti / Pt / Au metallized layer 4 on the top, and the two are pressed to 200 ° C. with a force of 200 to 500 gf (≈1.96 to 4.9 N). The AlN submount 2 is joined to the AlN heat dissipation block 3 by heating and melting the solder 11. Thereafter, the metallized layer 5 that can be electrically connected to the P electrode 1d is connected to the P electrode electrical wiring layer 19, and the metallized layer 15 that can be electrically connected to the N electrode 1b is connected to the N electrode electrical circuit. Each is connected to the wiring layer 18 by wire bonding.

  As described above, the semiconductor laser element 1 is mounted on the AlN heat dissipation block 3 via the AlN submount 2. As apparent from the above description, in the present embodiment, the semiconductor laser device 1 is arranged in a direction in which the sapphire substrate 1s side is positioned upward, and the device formation surface side (PN junction side) is fixed to the AlN heat dissipation block 3 side. The so-called junction down structure is used for mounting.

  When the AlN submount 2 is joined to the AlN heat dissipation block 3 as described above, it is necessary to place the AlN submount 2 at a predetermined position with high positioning accuracy with respect to the AlN heat dissipation block 3. In this case, the alignment mark 20 described above is used as a positioning reference. For this positioning, for example, after setting the AlN heat dissipation block 3 on a mounting machine having an image recognition function, the portion of the AlN submount 2 where the semiconductor laser element 1 is not fixed is sucked and held by a collet, and the AlN submount is mounted. 2 can be supplied to a mounting machine and the image recognition function can be used. More specifically, this image recognition function captures a surface image of a workpiece, searches the surface image of the captured workpiece for a mark that matches the feature of the mark image registered in advance in the storage means, and detects and detects it. This is a function for obtaining the position from the specified specific position for the mark.

  Next, the formation of the AlN heat dissipation block 3 will be described in detail. First, the surface of the AlN substrate that forms the AlN heat dissipation block 3 by cutting as described later is finished by polishing so that the thickness is, for example, 8 mm and the surface roughness Ra is 0.05 μm or less. A Ti / Pt / Au layer is formed on the upper surface of the AlN substrate by sputtering. The thermal conductivity of the AlN substrate is 140 W / mK or more, and good heat dissipation is ensured.

  Next, a predetermined resist pattern is formed on the Ti / Pt / Au layer, and the Ti / Pt / Au film having no resist is removed by ion milling, whereby the Ti / Pt / Au shown in FIG. The metallized layer 8, the electric wiring layers 18 and 19 and the alignment mark 20 shown in FIG. 2 are formed. A Pt layer 9 is formed on the Ti / Pt / Au metallized layer 8 by lift-off. Further, the above-mentioned solder 11 is formed thereon by, for example, a binary vapor deposition method of Au and Sn so as to have a target composition ratio (for example, Au composition is 73 ± 10 wt%). Thereafter, the AlN substrate is cut to form a plurality of AlN heat dissipation blocks 3.

  In the present embodiment, a glass lens holder 25 is bonded and fixed to the front surface 3a of the AlN heat dissipation block 3 as shown in FIG. The lens holder 25 is for adhering and fixing a collimating lens array in which a plurality of collimating lenses for collimating laser beams emitted from a plurality of semiconductor laser elements 1 are arranged in parallel on the upper surface thereof. The AlN substrate is first cut at the portion to be the front surface 3a, and the cut surface is polished so as to have a surface roughness: Ra = 0.1 to 0.2 μm, and then a plurality of cross sections orthogonal to the cut surface. A plurality of AlN heat dissipation blocks 3 are formed by cutting on the surface.

  The solder for the P electrode is not limited to the above-described plurality of dot-shaped patterns, and as in the second embodiment shown in FIG. 4, a plurality of dot-shaped polygonal shapes (in this case, quadrangular shapes). It is also possible to employ a solder 7 ′ having a pattern composed of a part and a part having a narrower width connecting those parts. The semiconductor laser device of this embodiment is basically formed in the same manner as the device of the first embodiment described above except that the pattern of the solder 7 'is different. In FIG. 4, elements that are the same as those in FIGS. 1 to 3 are given the same reference numerals, and redundant descriptions thereof are omitted (hereinafter the same).

  As described above, even when the solder pattern partially constricted is adopted, when the semiconductor laser element is mounted, the surface lowered from the side end portion of the optical waveguide Q toward the plane parallel to the layer of the solder 7 '. The element is positioned in a state where the distance from the long axis of the solder 7 'having a pattern of quadrangular squares is 75 μm. As a result, in the state where the solder 7 'is melted and solidified, the distance between the optical waveguide Q and the solder 7' becomes 30 μm or more, which exceeds 20 μm, and the stress generated in the optical waveguide Q is kept small. It is done. Also in this case, the production yield of the semiconductor laser device was 95% or more.

  Further, the pattern before melting of the solder 7 'is smaller than the P electrode 1d of the semiconductor laser element 1 and has a shape having a constriction, so that large portions on both sides of the constriction are fused, and a PN junction portion or A short circuit is prevented from reaching the P-type epitaxial layer.

  Incidentally, as the solder for the P electrode, as in the third embodiment shown in FIG. 5, it is also possible to employ a solder 7 ″ having an overall rectangular pattern. The semiconductor laser device of this embodiment However, it is basically formed in the same manner as the apparatus of the first embodiment except that the pattern of the solder 7 ″ is different.

  When such a solder pattern is employed, when the semiconductor laser element is mounted, a surface lowered from the side end portion of the optical waveguide Q toward a plane parallel to the layer of the solder 7 "and a side end portion of the solder 7". The element is positioned in a state where the distance to the (side end portion on the solder 17 side) is 30 μm or more. As a result, in the state where the solder 7 ″ is melted and solidified, the distance between the optical waveguide Q and the solder 7 ″ is 25 μm or more, which exceeds 20 μm, and the stress generated in the optical waveguide Q is kept small. It is done. Also in this case, the production yield of the semiconductor laser device was 95% or more.

  Further, since the pattern before melting of the solder 7 ″ protrudes from the P electrode 1d of the semiconductor laser element 1 to the side opposite to the optical waveguide Q, when the solder 7 ″ melts, the pattern of the optical waveguide Q It tends to flow to the other side. Therefore, in this case as well, it is possible to prevent the solder 7 ″ from reaching the PN junction and the P-type epitaxial layer and causing a short circuit.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. The semiconductor laser device of the present embodiment is partially different from the first embodiment shown in FIGS. 1 to 3 in the configuration of the GaN-based semiconductor laser device 1 in a chip state, and the other points are basically the same. It is formed similarly to the apparatus of the first embodiment.

  That is, as shown in these figures, the uppermost layer of the P electrode is formed from the Pt metallized layer 1e from the side end portion (left end portion in FIG. 6) of the optical waveguide Q to a position at a predetermined distance. The outer portion is formed of an Au metallized layer 1f. As for the wettability with solder, Au is better than Pt. Therefore, when the solder 7 for joining the P electrode 1d in such a configuration melts, the solder 7 flows easily in the portion where the uppermost layer is the Au metallized layer 1f, but the uppermost layer is Pt metallized. It does not easily flow out to the portion that is the layer 1e.

  Therefore, by setting the distance from the side end portion of the optical waveguide Q to the end portion of the Pt metallized layer 1e to a predetermined value, the end portion of the solder 7 solidified after melting and the side end portion of the optical waveguide Q Can be controlled to a desired value of 20 μm or more. The same effect can be obtained by providing a metallized layer made of Mo, Pd or the like instead of the Pt metallized layer 1e.

1 is a schematic front view showing a semiconductor laser device according to a first embodiment of the present invention. Perspective view showing the semiconductor laser device A perspective view showing a part of the semiconductor laser device The perspective view which shows the principal part of the semiconductor laser apparatus by the 2nd Embodiment of this invention. The perspective view which shows the principal part of the semiconductor laser apparatus by the 3rd Embodiment of this invention. Schematic front view showing a semiconductor laser device according to a fourth embodiment of the present invention The perspective view which shows the principal part of the semiconductor laser apparatus of FIG. The graph which shows the relationship between the distance between the optical waveguide of a semiconductor laser element and the solder which fixes this element to a heat sink, and element yield Graph showing the relationship between the distance between the optical waveguide of the semiconductor laser element and the solder that fixes the element to the heat sink, and the stress applied to the optical waveguide

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor laser element 1b N electrode 1d P electrode 2 AlN submount 3 AlN heat dissipation block 7, 7 ', 7 "Solder for P electrode
17 N electrode solder Q Optical waveguide

Claims (5)

A semiconductor laser device in which a plurality of semiconductor layers are formed on a substrate and an electrode is formed on the surface of the layer opposite to the substrate;
In this semiconductor laser device, comprising a heat sink joined with solder from the surface side on which the electrodes are formed,
A semiconductor laser device, wherein a distance between the solder and the optical waveguide of the semiconductor laser element is 20 μm or more in a state where the semiconductor laser element is bonded to a heat sink by the solder solidified after melting.   2. The semiconductor laser device according to claim 1, wherein the semiconductor laser element is a nitride semiconductor laser element, and the solder is divided immediately below the light emitting portion.   3. The semiconductor laser device according to claim 1, wherein a pattern of the solder before melting is smaller than the electrode of the semiconductor laser element and has a discrete or constricted shape.   4. The semiconductor laser device according to claim 1, wherein the pattern before melting of the solder has a shape protruding from the P electrode of the semiconductor laser element to the side opposite to the optical waveguide. .   5. The semiconductor laser device according to claim 1, wherein the uppermost electrode layer in the light emitting region of the semiconductor laser element is formed using a barrier metal such as Pt, Mo, Ti, or Pd.

Images