JP4342495B2 - Semiconductor laser device - Google Patents

Description

  The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device having a plurality of semiconductor laser element portions.

  2. Description of the Related Art Conventionally, monolithic semiconductor laser elements that can independently extract a plurality of laser beams from one chip are known. Further, as such a monolithic semiconductor laser element, an element portion emitting red laser light of 650 nm band for reproducing a DVD (digital versatile disk) and an infrared laser beam of 780 nm band for reproducing a CD (compact disk). There is known a semiconductor laser in which an element portion emitting light is integrated on the same substrate (for example, see Patent Document 1).

  FIG. 17 is a simplified cross-sectional view of the conventional semiconductor laser device disclosed in Patent Document 1. The structure of a conventional semiconductor laser element will be described with reference to FIG.

  As shown in FIG. 17, the conventional semiconductor laser device includes a first semiconductor laser element portion 150 having an AlGaInP-based semiconductor layer and a second semiconductor laser element portion 160 having an AlGaAs-based semiconductor layer. The first semiconductor laser element unit 150 has a function of emitting red laser light in the 650 nm band. The second semiconductor laser element unit 160 has a function of emitting infrared laser light in the 780 nm band. The first semiconductor laser element unit 150 and the second semiconductor laser element unit 160 are formed on the same n-type GaAs substrate 101.

  The first semiconductor laser element portion 150 and the second semiconductor laser element portion 160 are formed with a first waveguide 102 and a second waveguide 103 for emitting laser light. Further, p-side electrodes 104 and 105 are formed on the first semiconductor laser element portion 150 and the second semiconductor laser element portion 160.

  In addition, the first semiconductor laser element unit 150 and the second semiconductor laser element unit 160 formed on the same n-type GaAs substrate 101 radiate heat generated in the first waveguide 102 and the second waveguide 103. The first waveguide 102 and the second waveguide 103 are attached on the upper surface of the heat sink 106 made of AlN in a junction down manner with the first waveguide 102 and the second waveguide 103 facing downward. Specifically, the p-side electrode 104 of the first semiconductor laser element unit 150 and the p-side electrode 105 of the second semiconductor laser element unit 160 are respectively connected via solder layers 107 and 108 made of AuSn having a thickness of about 3 μm. The electrodes 109 and 110 formed on the upper surface of the heat sink 106 are fused.

Further, in the conventional semiconductor laser device, heat generated in the first waveguide 102 of the first semiconductor laser element unit 150 and the second waveguide 103 of the second semiconductor laser element unit 160 is easily radiated to the heat sink 106 side. In addition, the solder layers 107 and 108 are bonded to the electrodes 109 and 110 formed on the upper surface of the heat sink 106 by being fused so as to be in contact with almost the entire surface of the p-side electrodes 104 and 105, respectively. That is, in the conventional semiconductor laser device shown in FIG. 17, the first semiconductor laser element portion 150 is formed below the first waveguide 102 formation region and the second semiconductor laser element portion 160 second waveguide 103 formation region. The fusion is performed with the solder layers 107 and 108 disposed below. Here, when laser light is emitted to a common optical system using a semiconductor laser element in which a plurality of semiconductor laser element units emitting different wavelengths are emitted on one substrate, the common optical system is a laser having a different wavelength. Since light passes, the polarization characteristics (polarization ratio, polarization angle) of laser light of each wavelength are important.
Japanese Patent Laid-Open No. 2004-193302

  However, in the conventional semiconductor laser device shown in FIG. 17, the region below the formation region of the first waveguide 102 of the first semiconductor laser element portion 150 and the formation region of the second waveguide 103 of the second semiconductor laser element portion 160. With the solder layers 107 and 108 disposed below, the p-side electrodes 104 and 105 are soldered to the electrodes 109 and 110 formed on the upper surface of the heat sink 106 by the solder layers 107 and 108, respectively. Since the layers 107 and 108 are fixed to each other, the first semiconductor laser element portion 150 has a thermal expansion coefficient difference between the first semiconductor laser element portion 150 and the second semiconductor laser element portion 160 and the heat sink 106. A tensile stress is applied to the first waveguide 102 and the second waveguide 103 of the second semiconductor laser element unit 160. As a result, tensile strain occurs in the first waveguide 102 of the first semiconductor laser element unit 150 and the second waveguide 103 of the second semiconductor laser element unit 160. With regard to this point, as a result of various studies by the inventor of the present application, due to the tensile strain of the first waveguide 102 of the first semiconductor laser element unit 150 and the second waveguide 103 of the second semiconductor laser element unit 160 described above, It has been found that the polarization characteristics of the first semiconductor laser element section 150 that emits red laser light is degraded, while the polarization characteristics of the second semiconductor laser element section 160 that emits infrared laser light in the 780 nm band is not degraded. For this reason, the inventor of the present application has a region below the formation region of the first waveguide 102 of the first semiconductor laser element unit 150 and a formation region of the second waveguide 103 of the second semiconductor laser element unit 160 as shown in FIG. In the structure in which the solder layers 107 and 108 are disposed below, it is difficult to suppress a decrease in polarization characteristics of the first semiconductor laser element unit 150 that emits red laser light in the 650 nm band (problem). I found that there is.

  The present invention has been made in order to solve the above-described problems, and one object of the present invention is to emit a plurality of different oscillation wavelengths and to obtain polarization characteristics of each semiconductor laser element portion. It is an object of the present invention to provide a semiconductor laser device capable of suppressing a decrease in the above.

Means for Solving the Problems and Effects of the Invention

  To achieve the above object, a semiconductor laser device according to a first aspect of the present invention includes a light emitting layer formed on a first substrate, including a first waveguide, and containing at least Ga, In, and P. The first semiconductor laser element portion, the second semiconductor laser element portion formed on the first substrate and including the second waveguide, and the first waveguide and the second waveguide are disposed on the lower side. The first semiconductor laser element portion and the second semiconductor laser element portion each include a base attached using the first fusion layer and the second fusion layer, and the first semiconductor laser element portion is viewed in plan view. Thus, the first fusion layer is attached to the base side in at least a part of the region located below the formation region of the first waveguide.

  In the semiconductor laser device according to the first aspect, as described above, the first semiconductor laser element portion including the first waveguide and the light emitting layer containing at least Ga, In and P, and the second waveguide are provided. The second semiconductor laser element portion including the first semiconductor substrate is formed on the first substrate, and the first and second waveguides are mounted on the base so that the first and second waveguides are disposed on the lower side. The first semiconductor in a state where there is no fusion layer in at least a part of the region located below the formation region of the first waveguide of the first semiconductor laser element portion including the light emitting layer containing at least Ga, In, and P By attaching the laser element part to the base side, the bonding area between the first semiconductor laser element part and the base in the region located below the formation region of the first waveguide can be reduced. Tensile stress of the first waveguide vicinity caused by the difference in thermal expansion coefficient between the first semiconductor laser element portion can be reduced. Thereby, since it can suppress that an excessive tensile distortion generate | occur | produces in the 1st waveguide vicinity of a 1st semiconductor laser element part, it can suppress that a polarization characteristic falls. That is, the quantum well layer of the first semiconductor laser element portion including the light emitting layer containing at least Ga, In, and P is usually introduced with compressive strain during the growth of the quantum well layer, and the compressive strain is favorable due to the compressive strain. Polarization characteristics are maintained. In this case, when the first semiconductor laser element portion and the base are joined, the first semiconductor laser element is caused by a tensile stress generated due to a difference in thermal expansion coefficient between the first semiconductor laser element portion and the base. Since a tensile strain is newly generated in the vicinity of the first waveguide of the portion, the compressive strain of the quantum well layer is canceled and reduced, and as a result, the polarization characteristics are considered to deteriorate. In the present invention, as described above, the tensile strain generated in the vicinity of the first waveguide can be reduced, so that the compressive strain introduced into the quantum well layer of the first semiconductor laser element portion is canceled and reduced. As a result, it is considered that the deterioration of the polarization characteristics of the first semiconductor laser element portion can be suppressed.

  In the semiconductor laser device according to the first aspect described above, preferably, the first semiconductor laser element portion is on the base side in a state where the first fusion layer is not present in a region located below the formation region of the first waveguide. It is attached. With this configuration, the junction area between the first semiconductor laser element portion and the base in the region located below the formation region of the first waveguide can be reduced to zero, so the base and the first semiconductor laser It is possible to further suppress the generation of tensile stress in the vicinity of the first waveguide due to the difference in thermal expansion coefficient with the element portion. For this reason, it is possible to further suppress the occurrence of excessive tensile strain in the vicinity of the first waveguide of the first semiconductor laser element portion, and thus it is more effective that the polarization characteristics of the first semiconductor laser element portion are deteriorated. Can be suppressed.

  In the semiconductor laser device according to the first aspect described above, preferably, the first semiconductor laser element portion is bonded to a part of a region located below the formation region of the first waveguide in a plan view. It is attached to the base side with no layer. According to this structure, when the contact area between the first semiconductor laser element portion and the fusion layer is fused in a state where the fusion layer does not exist in a region located below the formation region of the first waveguide. Since it increases in comparison, the heat dissipation of the first semiconductor laser element portion can be improved accordingly.

  The first semiconductor laser element portion is attached to the base side in a state where the first fusion layer is not present in a part of the region located below the formation region of the first waveguide in plan view. Preferably, in the semiconductor laser device, the first fusion layer is, in a plan view, in the vicinity of the central portion in the extending direction of the first waveguide in the region located below the formation region of the first waveguide. Is formed. If comprised in this way, since a 1st semiconductor laser element part and a base can be joined by the 1st fusion layer in the central part vicinity of the 1st waveguide, the 1st semiconductor laser element part, a base, Can be improved in bonding strength between the first semiconductor laser element portion and the base as compared with the case where the first fusion layer is bonded at one end portion in the extending direction of the first waveguide.

  The first semiconductor laser element portion is attached to the base side in a state where the first fusion layer is not present in a part of the region located below the formation region of the first waveguide in plan view. Preferably, in the semiconductor laser device, the first fusion layer is spaced apart from the first waveguide formation region by a predetermined distance in a direction in which the first waveguide extends in a plan view. Are formed. With this configuration, since the fusion layer is dispersedly disposed below the formation region of the first waveguide, the vicinity of the first waveguide is caused by the junction between the first semiconductor laser element portion and the base. It is possible to disperse the generation position of the stress generated in. For this reason, in addition to the improvement in heat dissipation due to the presence of the first fusion layer in a partial region below the formation region of the first waveguide of the first semiconductor laser element portion, the first semiconductor laser element portion The tensile strain introduced in the vicinity of the first waveguide can be reduced.

  In the semiconductor laser device according to the first aspect, preferably, the second semiconductor laser element portion includes a light emitting layer containing Ga and As and is below the formation region of the second waveguide as viewed in a plan view. The second fusion layer is attached to the base side in a state where the second fusion layer exists in the located region. If comprised in this way, in the 2nd waveguide vicinity of the 2nd semiconductor laser element part containing the light emitting layer containing Ga and As by the 2nd fusion layer located under the formation field of the 2nd waveguide, Since tensile stress is applied due to the difference in thermal expansion coefficient between the base and the second semiconductor laser element portion, an appropriate tensile strain can be generated in the vicinity of the second waveguide. Thereby, the polarization characteristic of the second semiconductor laser element portion can be improved. This is because, in the quantum well layer of the second semiconductor laser element portion including the light-emitting layer containing Ga and As, normally, no compressive strain is introduced during the growth of the quantum well layer, and the second semiconductor laser element It is considered that an appropriate tensile strain can be generated in the quantum well layer of the second semiconductor laser element portion by joining the portion and the base. As a result, it is considered that the polarization characteristics of the second semiconductor laser element portion can be improved.

  In the semiconductor laser device according to the first aspect, preferably, the first semiconductor laser element portion includes the first electrode portion, and the second semiconductor laser element portion includes the second electrode portion. A third electrode portion and a fourth electrode portion are formed on the base so as to correspond to the first electrode portion and the second electrode portion, respectively, and the first electrode portion and the second electrode portion are respectively the first electrode portion and the second electrode portion. The first semiconductor laser element portion and the second semiconductor laser element portion are fixed to the base by being fused to the third electrode portion and the fourth electrode portion via the fusion layer and the second fusion layer. The first fusion layer for fusing the first electrode portion and the third electrode portion is a region located below the formation region of the first waveguide of the first semiconductor laser element portion in plan view. It is arranged so that it does not exist at least in part. If comprised in this way, the 1st electrode part and the 3rd electrode part are joined via the 1st fusion layer, and the 1st semiconductor laser element part can be easily below the formation area of the 1st waveguide. In the state where the first fusion layer does not exist in at least a part of the region located in the region, the second electrode portion and the fourth electrode portion can be bonded to each other through the second fusion layer. By doing so, the second semiconductor laser element portion can be easily fixed to the base.

  In the semiconductor laser device including the electrode part, preferably, the third electrode part is formed in a region other than a region located below the formation region of the first waveguide on the base. According to this structure, when the first electrode portion of the first semiconductor laser element portion and the third electrode portion formed on the base surface are joined via the fusion layer, the fusion layer becomes the third electrode. Since it is formed only on the surface of the portion, it is possible to easily make the region located below the formation region of the first waveguide in a state in which no fusion layer exists.

  In the semiconductor laser device according to the first aspect, preferably, the third semiconductor laser is formed on the second substrate and emits laser light having an oscillation wavelength different from that of the first semiconductor laser element portion and the second semiconductor laser element portion. The device further includes an element portion, and the third semiconductor laser element portion is disposed between the first semiconductor laser element portion and the second semiconductor laser element portion and the base, and the first semiconductor laser element portion is planarly arranged. As seen, the first fusion layer is not present in at least a part of the region located below the formation region of the first waveguide, and is attached to the base side via the third semiconductor laser element portion. . If comprised in this way, between the light emission points between the 1st semiconductor laser element part, the 2nd semiconductor laser element part, and the 3rd semiconductor laser element part, suppressing the fall of the polarization characteristic of the 1st semiconductor laser element part. Since the distance can be shortened, an optical member such as a lens can be effectively shared.

  In the semiconductor laser device according to the first aspect, preferably, each of the first waveguide and the second waveguide includes a convex ridge portion protruding toward the base side. In such a structure having a convex ridge portion, stress is easily applied to the convex ridge portion constituting the first waveguide. Therefore, at least of the region located below the formation region of the first waveguide of the present invention It is more effective to reduce the tensile stress applied to the convex ridge portion by a configuration in which the solder layer does not exist in part.

  In the semiconductor laser device according to the first aspect, preferably, the first substrate is an off substrate having a predetermined off angle. With this configuration, good quality crystal growth is performed on the surface of the off substrate, so that the first semiconductor laser element portion and the second semiconductor laser element portion having excellent characteristics can be easily formed on the surface of the off substrate. can do.

  In the semiconductor laser device according to the first aspect, the fusion layer is preferably a solder layer. If comprised in this way, while being able to connect between electrode parts electrically, an electrode part can be fixed easily.

  In the semiconductor laser device according to the first aspect, the base is preferably a heat dissipation base. If comprised in this way, the heat | fever produced by light emission of the laser beam of a semiconductor laser apparatus can be thermally radiated easily.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a sectional view showing a state in which the semiconductor laser device according to the first embodiment of the present invention is fused to a heat sink. FIG. 2 is a sectional view showing the semiconductor laser device according to the first embodiment shown in FIG. 3 is an enlarged cross-sectional view of the light emitting layer of the first semiconductor laser element portion of the semiconductor laser element according to the first embodiment shown in FIG. 1, and FIG. 4 is a semiconductor laser according to the first embodiment shown in FIG. It is an expanded sectional view of the light emitting layer of the 2nd semiconductor laser element part of an element. FIG. 5 is a plan view showing a state in which the semiconductor laser device according to the first embodiment shown in FIG. 1 is fused to a heat sink. The structure of the semiconductor laser device according to the first embodiment will be described with reference to FIGS.

  As shown in FIG. 2, the semiconductor laser device according to the first embodiment includes a first semiconductor laser element portion 10 having an AlGaInP-based semiconductor layer and a second semiconductor laser element portion 20 having an AlGaAs-based semiconductor layer. . The first semiconductor laser element section 10 has a function of emitting red laser light in the 650 nm band, and the second semiconductor laser element section 20 has a function of emitting infrared laser light in the 780 nm band. The first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 are formed on the upper surface of the same n-type GaAs substrate 1. The n-type GaAs substrate 1 is an example of the “first substrate” in the present invention.

  Further, a separation groove 4 for electrically separating the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 is provided between the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20. Is provided. The width W1 of the separation groove 4 is configured to be about 30 μm. The distance W2 between the central portion of the ridge portion 16 of the first semiconductor laser element portion 10 and the central portion of the ridge portion 26 of the second semiconductor laser element portion 20 is configured to be about 110 μm.

As a specific structure of the first semiconductor laser element unit 10 that emits red laser light in the 650 nm band, n-type GaAs, which is an off substrate inclined at an off angle of about 9 ° in the [011] direction from the (100) plane. An n-type cladding layer 11 made of n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P having a thickness of about 1.5 μm is formed on the upper surface of the substrate 1. A light emitting layer 12 is formed on the n-type cladding layer 11.

As shown in FIG. 3, the light emitting layer 12 has three quantum well layers 12a made of In _0.57 Ga _0.43 P having a thickness of about 8 nm, and a thickness of about 6 nm (Al _0.5 Ga). _{0.5) 0.5} an in and two quantum barrier layer 12b made of _0.5 P contains a first 1MQW active layer 12e having a multiple quantum well structure are alternately laminated. Compressive strain is introduced into the quantum well layer 12a during crystal growth of the quantum well layer 12a. In addition, an n-side light guide layer 12c made of undoped (Al _0.5 Ga _0.5 ) _0.5 In _0.5 P having a thickness of about 50 nm and a p-side light guide so as to sandwich the first MQW active layer 12e. A layer 12d is provided. The first MQW active layer 12e, the n-side light guide layer 12c, and the p-side light guide layer 12d constitute the light emitting layer 12.

As shown in FIG. 2, a p-type first cladding layer made of p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P having a thickness of about 0.2 μm is formed on the light emitting layer 12. 13 is formed. On the p-type first cladding layer 13, an etching stop layer 13a made of p-type In _0.5 Ga _0.5 P having a thickness of about 20 nm is formed. A p-type second cladding layer 14 made of p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P having a thickness of about 1 μm is formed in a predetermined region on the etching stop layer 13a. Yes. The p-type second cladding layer 14 is formed in a mesa shape (trapezoidal shape). A p-type contact layer 15 made of p-type GaInP having a thickness of about 0.1 μm is formed on the p-type second cladding layer 14. The p-type second cladding layer 14 and the p-type contact layer 15 constitute a ridge portion 16. The width of the root portion of the ridge portion 16 is about 3 μm. A first waveguide 16 a is formed in a region corresponding to the ridge portion 16 in the vicinity of the light emitting layer 12.

  Further, an n-type current blocking layer 17 made of n-type AlInP having a thickness of about 1 μm is formed in a portion of the ridge portion 16 other than on the p-type contact layer 15. On the upper surfaces of the n-type current blocking layer 17 and the p-type contact layer 15 of the ridge portion 16, a Cr layer having a thickness of about 15 nm and an Au layer having a thickness of about 1 μm from the lower layer to the upper layer. A p-side electrode 18 made of is formed. The p-side electrode 18 is an example of the “first electrode portion” in the present invention.

In addition, as a specific structure of the second semiconductor laser element unit 20 that emits infrared laser light in the 780 nm band, n having a thickness of about 1.5 μm is formed on the upper surface of the n-type GaAs substrate 1 that is an off-substrate. An n-type cladding layer 21 made of type Al _0.45 Ga _0.55 As is formed. A light emitting layer 22 is formed on the n-type cladding layer 21.

As shown in FIG. 4, the light emitting layer 22 has three quantum well layers 22a made of (Al _0.1 Ga _0.9 ) _0.5 As having a thickness of about 6 nm and a thickness of about 8 nm ( al _0.35 Ga _0.65) and the two quantum barrier layer 22b made of _0.5 as includes a first 2MQW active layer 22e having a multiple quantum well structure are alternately laminated. The quantum well layer 22a is not introduced with compressive strain during crystal growth of the quantum well layer 22a. Further, an n-side light guide layer 22c and a p-side light guide layer 22d made of undoped (Al _0.35 Ga _0.65 ) _0.5 As having a thickness of about 20 nm are provided so as to sandwich the second MQW active layer 22e. It has been. The second MQW active layer 22e, the n-side light guide layer 22c, and the p-side light guide layer 22d constitute the light emitting layer 22.

As shown in FIG. 2, a p-type first clad layer 23 made of p-type (Al _0.45 Ga _0.55 ) _0.5 As having a thickness of about 0.2 μm is formed on the light emitting layer 22. ing. On the p-type first cladding layer 23, an etching stop layer 23a made of (Al _0.7 Ga _0.3 ) _0.5 As having a thickness of about 20 nm is formed. A p-type second cladding layer 24 made of p-type (Al _0.45 Ga _0.55 ) _0.5 As having a thickness of about 1 μm is formed in a predetermined region on the etching stop layer 23a. The p-type second cladding layer 24 is formed in a mesa shape (trapezoidal shape). A p-type contact layer 25 made of p-type GaAs having a thickness of about 0.1 μm is formed on the p-type second cladding layer 24. The p-type second cladding layer 24 and the p-type contact layer 25 constitute a ridge portion 26. The ridge portion 26 has a width of about 3 μm. A second waveguide 26 a is formed in a region corresponding to the ridge portion 26 in the vicinity of the light emitting layer 22.

In addition, an n-type current blocking layer 27 made of n-type (Al _0.7 Ga _0.3 ) _0.5 As having a thickness of about 1 μm is formed in a portion of the ridge portion 26 other than on the p-type contact layer 25. Has been. A p-type cap layer 28 made of p-type GaAs having a thickness of about 1.5 μm is formed on the upper surfaces of the n-type current blocking layer 27 and the p-type contact layer 25. On the p-type cap layer 28, a p-side electrode 29 made of a Cr layer having a thickness of about 15 nm and an Au layer having a thickness of about 1 μm is formed from the lower layer to the upper layer. The p-side electrode 29 is an example of the “second electrode portion” in the present invention.

  Then, on the back surface of the n-type GaAs substrate 1, an AuGe layer having a thickness of about 0.1 μm, a Ni layer having a thickness of about 30 nm, and about 0, in order from the side close to the back surface of the n-type GaAs substrate 1. An n-side electrode 2 made of an Au layer having a thickness of .5 μm is formed.

  As shown in FIG. 1, the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 formed on the upper surface of the same n-type GaAs substrate 1 generate heat generated in the light emitting layers 12 and 22. In order to dissipate heat, the pn junction (the first waveguide 16a and the second waveguide 26a) sandwiching the light emitting layers 12 and 22 is attached to the upper surface of the heat sink 30 made of AlN by a junction down method. ing. The regions corresponding to the p-side electrodes 18 and 29 of the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 on the upper surface of the heat sink 30 have a thickness of about 0.1 μm from the lower layer to the upper layer. Electrodes 30a and 30b made of a Ti layer, a Pt layer having a thickness of about 0.2 μm, and an Au layer having a thickness of about 0.3 μm are formed at a predetermined interval. The electrodes 30a and 30b are examples of the “third electrode portion” and the “fourth electrode portion” in the present invention, respectively. The p-side electrode 18 of the first semiconductor laser element portion 10 and the p-side electrode 29 of the second semiconductor laser element portion 20 are made of solder layers 31 and 32 made of AuSn (Au: 80 wt%) having a thickness of about 3 μm. The heat sink 30 is fused on the upper surface. The heat sink 30 is an example of the “base” and “heat dissipation base” of the present invention, and the solder layer 31 is an example of the “fusion layer” and “first fusion layer” of the present invention. The solder layer 32 is an example of the “fusion layer” and the “second fusion layer” in the present invention.

  Here, in the first embodiment, as shown in FIG. 1 and FIG. 5, the p-side electrode 18 of the first semiconductor laser element unit 10 is seen as a first conductor of the first semiconductor laser element unit 10 in plan view. By soldering the solder layer 31 in a region other than the region located below the formation region of the waveguide 16a, the solder layer 31 is fixed to the electrode 30a of the heat sink 30. That is, in the region located below the formation region of the first waveguide 16a of the first semiconductor laser element part 10, the solder layer 31 is not provided but a space is provided. The distance W3 from the central portion of the first waveguide 16a of the first semiconductor laser element portion 10 to the solder layer 31 is about 10 μm. Since the width of the root portion of the ridge portion 16 is about 3 μm (about 1.5 μm on one side), only about 8.5 μm (= about 10 μm−about 1.5 μm) in the horizontal direction from the end of the region where the ridge portion 16 is formed. A solder layer 31 is provided apart. The electrode 30 a of the heat sink 30 is formed in a region other than the region located below the region where the first waveguide 16 a of the first semiconductor laser element unit 10 is formed.

  Further, in the first embodiment, as shown in FIGS. 1 and 5, the second semiconductor laser element portion 20 is fused in a state where almost the entire surface of the p-side electrode 29 is in contact with the solder layer 32. It is fixed to the electrode 30b. The distance W4 from the center of the second waveguide 26a of the second semiconductor laser element unit 20 to the end of the solder layer 32 on the second semiconductor laser element unit 20 side is about 30 μm.

  6 and 7 are graphs showing the measurement results of the polarization angle and polarization ratio of the red laser light according to the structure of the first embodiment shown in FIG. 1, respectively. 8 and 9 are graphs showing the measurement results of the polarization angle and the polarization ratio of the red laser light according to Comparative Example 1. FIG. Specifically, in FIGS. 6 and 7, the solder layer 31 does not exist in a region located below the formation region of the first waveguide 16a of the first semiconductor laser element unit 10 that emits red laser light. In addition, the first semiconductor laser device according to the first embodiment in which the solder layer 32 exists in a region located below the formation region of the second waveguide 26a of the second semiconductor laser device unit 20 that emits infrared laser light. The measurement results of the polarization angle and polarization ratio of the AlGaInP red laser of the unit 10 are shown. Further, in FIGS. 8 and 9, the solder layer 31 is present in a region located below the formation region of the first waveguide 16a of the first semiconductor laser element unit 10 that emits red laser light, and The AlGaInP of the first semiconductor laser element portion 10 according to the first comparative example in which the solder layer 32 is also present in the region located below the formation region of the second waveguide 26a of the second semiconductor laser element portion 20 that emits infrared laser light. The measurement results of the polarization angle and the polarization ratio of the system red laser are shown. In addition, the horizontal axis of the graphs of FIGS. 6 and 8 indicates the polarization angle (°), and the vertical axis of the graph indicates the frequency (the number of times each polarization angle is obtained). Moreover, the horizontal axis of the graphs of FIGS. 7 and 9 indicates the polarization ratio, and the vertical axis of the graph indicates the frequency (the number of times each polarization ratio is obtained).

  Here, the polarization angle and the polarization ratio will be described. When laser light is passed through the polarizing prism while rotating the polarizing prism, the light intensity of the laser light that has passed through the polarizing prism changes depending on the rotation angle of the polarizing prism. At this time, the rotation angle of the polarizing prism when the light intensity of the laser beam reaches the maximum (max.) Is the polarization angle. Further, when the polarizing prism is further rotated from the rotation angle of the polarizing prism when the light intensity of the laser light becomes maximum, the light intensity of the laser light becomes minimum (min.). The ratio (max./min.) Between the maximum value and the minimum value of this laser beam is the polarization ratio. The polarization characteristic is evaluated from the polarization angle and the polarization ratio. The smaller the polarization angle, the better the polarization characteristic, and the larger the polarization ratio, the better the polarization characteristic.

  As a measurement result, the solder layer 31 does not exist in a region located below the formation region of the first waveguide 16a of the first semiconductor laser element unit 10, and the second waveguide of the second semiconductor laser element unit 20 is present. In the first embodiment in which the solder layer 32 exists in a region located below the formation region 26a, the frequency when the polarization angle is −5 ° is the highest as shown in FIG. Further, in the first embodiment, the frequency at which the polarization angle is −5 ° is twice or more compared to the case where the deflection angles are 0 ° and −10 °. In the first embodiment, the frequency at which the polarization angle is −5 ° occupies most of the whole. On the other hand, the solder layer 31 is provided in a region located below the formation region of the first waveguide 16a of the first semiconductor laser element portion 10 and below the formation region of the second waveguide 26a of the second semiconductor laser element portion 20, respectively. In Comparative Example 1 in which there are 32 and 32, as shown in FIG. 8, there is no significant difference in frequency between the polarization angles of −5 °, −10 °, and −15 °, and the sum of these accounts for most of the whole. ing. Thereby, when the solder layer 31 does not exist in a region located below the formation region of the first waveguide 16a of the first semiconductor laser element unit 10, the first waveguide 16a of the first semiconductor laser element unit 10 It can be seen that the polarization angle of the red laser light becomes smaller and the variation becomes smaller than when the solder layer 31 is present in the region located below the formation region.

  The polarization ratio of the red laser light according to the first embodiment is such that the total frequency of the polarization ratios of 100, 150, 200, and 250 occupies most of the whole as shown in FIG. As shown in FIG. 9, the frequency of the red laser beam according to (1) is such that the frequency of the polarization ratio is prominently 100, and then the frequency of the polarization ratio 50 is high. In Comparative Example 1, the total frequency of the polarization ratios of 50 and 100 occupies most of the entire frequency. Thus, the polarization ratio of the red laser light according to the first embodiment is larger than the polarization ratio of the red laser light according to Comparative Example 1.

  From the measurement results of the polarization characteristics of the AlGaInP red laser shown in FIGS. 6 to 9, the solder is applied to a region located below the formation region of the first waveguide 16 a of the first semiconductor laser element unit 10 in plan view. It has been found that when the layer 31 is not present, the polarization characteristics of the laser light of the first semiconductor laser element portion 10 which is red laser light is improved.

  10 and 11 are graphs showing the measurement results of the polarization angle and polarization ratio of infrared laser light according to Comparative Example 2. FIG. 12 and 13 are graphs showing the measurement results of the polarization angle and polarization ratio of infrared laser light according to Comparative Example 3. FIG. Specifically, in FIGS. 10 and 11, the solder layer 31 exists in a region located below the formation region of the first waveguide 16 a of the first semiconductor laser element unit 10 that emits red laser light. In addition, the second semiconductor laser element portion according to the comparative example 2 in which the solder layer 32 is also present in a region located below the formation region of the second waveguide 26a of the second semiconductor laser element portion 20 that emits infrared laser light. The measurement results of the polarization angle and polarization ratio of 20 infrared lasers are shown. In FIGS. 12 and 13, the solder layer 31 is present in a region located below the formation region of the first waveguide 16 a of the first semiconductor laser element unit 10 that emits red laser light, and The infrared of the second semiconductor laser element unit 20 according to the comparative example 3 in which the solder layer 32 does not exist in a region located below the formation region of the second waveguide 26a of the second semiconductor laser element unit 20 that emits infrared laser light. The measurement results of the laser polarization angle and polarization ratio are shown. The horizontal axis of the graphs of FIGS. 10 and 12 indicates the polarization angle (°), and the vertical axis of the graph indicates the frequency (the number of times each polarization angle is obtained). Moreover, the horizontal axis of the graphs of FIGS. 11 and 13 indicates the polarization ratio, and the vertical axis of the graph indicates the frequency (the number of times each polarization ratio is obtained).

  As a measurement result, a region located below the formation region of the first waveguide 16a of the first semiconductor laser element portion 10 and a region located below the formation region of the second waveguide 26a of the second semiconductor laser element portion 20 In the case of Comparative Example 2 in which the solder layers 31 and 32 are present in any of these, as shown in FIG. 10, the frequency when the polarization angle is −5 ° is the highest. Further, in Comparative Example 2, the frequency at which the polarization angle is −5 ° is twice or more compared to the case where the deflection angles are 0 ° and −10 °. In Comparative Example 2, the frequency of the polarization angle of −5 ° occupies most of the whole. On the other hand, the solder layer 31 is present in a region located below the formation region of the first waveguide 16a of the first semiconductor laser element portion 10, and is located below the second waveguide 26a of the second semiconductor laser element portion 20. In the case of Comparative Example 3 in which the solder layer 32 does not exist in the region to be used, as shown in FIG. 12, there is no significant difference in frequency between the polarization angles of −5 °, −10 °, and −15 °. It occupies most of the whole. For this reason, when the solder layer 32 exists in a region located below the formation region of the second waveguide 26a of the second semiconductor laser element unit 20, the second waveguide 26a of the second semiconductor laser element unit 20 Compared to the case where the solder layer 32 is not present in the region located below the formation region, the polarization angle of the infrared laser light is reduced and the variation is reduced.

  In addition, in the polarization ratio of the infrared laser light according to Comparative Example 2, the total frequency of the polarization ratios of 200, 250, and 300 occupies most of the whole as shown in FIG. In the polarization ratio of the infrared laser beam 3, as shown in FIG. 13, the frequency of the polarization ratio is prominently high at 100, and then the frequency of the polarization ratio 50 is high. Further, the total frequency of the polarization ratios of 50, 100 and 150 occupies most of the entire frequency. From this, the polarization ratio of the infrared laser light in Comparative Example 2 is larger than the polarization ratio of the infrared laser light in Comparative Example 3.

  From the measurement results of the polarization characteristics of the AlGaAs infrared laser shown in FIGS. 10 to 13, the solder layer 32 exists in a region located below the formation region of the second waveguide 26 a of the second semiconductor laser element unit 20. In this case, the polarization characteristic of the laser light of the second semiconductor laser element unit 20 that is infrared laser light is improved. 10 and 11 show the measurement results of Comparative Example 2 in which the solder layer 31 is present in a region located below the formation region of the first waveguide 16a of the first semiconductor laser element portion 10. FIG. In this case, the polarization characteristic of the infrared laser light is whether or not the solder layer 31 exists in a region located below the formation region of the first waveguide 16a of the first semiconductor laser element unit 10 that emits red laser light. It is thought that it does not affect. Therefore, even in the case of the first embodiment in which the solder layer 31 does not exist in the region located below the formation region of the first waveguide 16a of the first semiconductor laser element section 10, the same result as in the comparative example 2 is obtained. Conceivable.

  The reason why these measurement results were obtained is considered as follows. That is, as described above, a compressive strain is usually introduced into the quantum well layer 12a of the first semiconductor laser element unit 10 that emits red laser light during crystal growth of the quantum well layer 12a. Good polarization characteristics are maintained. In this case, when the first semiconductor laser element portion 10 and the heat sink 30 are joined, the first semiconductor is caused by the tensile stress generated due to the difference in thermal expansion coefficient between the first semiconductor laser element portion 10 and the heat sink 30. Since tensile strain is newly generated in the vicinity of the first waveguide 16a of the laser element portion 10, it is considered that the compressive strain of the quantum well layer 12a is canceled and becomes small, and as a result, polarization characteristics are deteriorated. On the other hand, when the solder layer 31 does not exist in a region located below the formation region of the first waveguide 16a of the first semiconductor laser element unit 10, the p-side electrode 18 and the heat sink 30 of the first semiconductor laser element unit 10 are provided. Since the bonding area with the electrode 30a on the upper surface of the first semiconductor laser device becomes smaller, the tensile stress generated due to the difference in thermal expansion coefficient between the first semiconductor laser element portion 10 and the heat sink 30 is reduced. For this reason, the tensile strain newly introduced in the vicinity of the first waveguide 16a is reduced, so that an appropriate tensile strain is introduced into the quantum well layer 12a of the first semiconductor laser element section 10. As a result, it is considered that the polarization characteristic of the red laser light of the first semiconductor laser element unit 10 is improved.

  On the other hand, the quantum well layer 22a of the second semiconductor laser element unit 20 that emits infrared laser light is normally not subjected to compressive strain during crystal growth of the quantum well layer 22a. When the heat sink 30 and the heat sink 30 are joined, the vicinity of the second waveguide 26a of the second semiconductor laser element portion 20 due to the tensile stress caused by the difference in thermal expansion coefficient between the second semiconductor laser element portion 20 and the heat sink 30 Tensile strain is generated. This tensile strain is considered to cause an appropriate tensile strain in the quantum well layer 22a of the second semiconductor laser element portion 20 and improve the polarization characteristics of the infrared laser light of the second semiconductor laser element portion 20.

  In the first embodiment, as described above, the first semiconductor laser element unit 10 including the first waveguide 16a that emits red laser light and the second semiconductor including the second waveguide 26a that emits infrared laser light. In the structure in which the laser element portion 20 is formed on the GaAs substrate 1 and is attached to the heat sink 30 so that the first waveguide 16a and the second waveguide 26a are disposed on the lower side, The first semiconductor laser element portion 10 is fixed to the heat sink 30 side in a state where the solder layer 31 does not exist in a region located below the formation region of the first waveguide 16 a of the first semiconductor laser element portion 10, thereby Since the junction area between the first semiconductor laser element portion 10 and the heat sink 30 in the region located below the formation region of the waveguide 16a can be reduced to zero, the heat sink 3 Can be reduced when the tensile stress of the first waveguide 16a near caused by the difference in thermal expansion coefficient between the first semiconductor laser element portion 10. Thereby, since it can suppress that an excessive tensile distortion generate | occur | produces in the 1st waveguide 16a vicinity of the 1st semiconductor laser element part 10, it can suppress that a polarization characteristic falls.

  In the first embodiment, the second semiconductor laser element portion 20 including the second waveguide 26a that emits infrared laser light is positioned below the formation region of the second waveguide 26a in plan view. In the state where the solder layer 32 exists in the region, the second waveguide of the second semiconductor laser element unit 20 is fixed by the solder layer 32 located below the formation region of the second waveguide 26a by being fixed to the heat sink 30 side. Since a tensile stress generated due to a difference in thermal expansion coefficient between the heat sink 30 and the second semiconductor laser element portion 20 is applied in the vicinity of 26a, an appropriate tensile strain can be generated in the vicinity of the second waveguide 26a. Thereby, the polarization characteristic of the second semiconductor laser element unit 20 can be improved.

  In the first embodiment, the p-side electrode 18 is formed on the first semiconductor laser element portion 10, the p-side electrode 29 is formed on the second semiconductor laser element portion 20, and the p-side electrode 29 is formed on the heat sink 30. Electrodes 30a and 30b are formed so as to correspond to the electrodes 18 and 29, respectively, and the p-side electrodes 18 and 29 are fused to the electrodes 30a and 30b via the solder layers 31 and 32, respectively. The first semiconductor laser element 10 and the second semiconductor laser element portion 20 are fixed to the heat sink 30 and the solder layer 31 for fusing the p-side electrode 18 and the electrode 30a is viewed in plan view. The p-side electrode 18 and the electrode 30a are interposed via the solder layer 31 by disposing them so as not to exist in a region located below the formation region of the first waveguide 16a of the element unit 10. By combining, the first semiconductor laser element portion 10 can be easily fixed to the heat sink 30 in a state where the solder layer 31 does not exist in a region located below the formation region of the first waveguide 16a, By bonding the p-side electrode 29 and the electrode 30b through the solder layer 32, the second semiconductor laser element portion 20 can be easily fixed to the heat sink 30.

  In the first embodiment, the electrode 30a is formed in a region other than the region located below the region where the first waveguide 16a is formed on the heat sink 30, so that the p-side electrode of the first semiconductor laser element unit 10 is formed. Since the solder layer 31 can be easily formed only on the surface of the p-side electrode 18 when the 18 and the electrode 30a formed on the surface of the heat sink 30 are fixed through the solder layer 31, the first conductor The region located below the formation region of the waveguide 16a can be easily made so that the solder layer 31 does not exist.

  In the first embodiment, since the n-type GaAs substrate 1 is an off-substrate having a predetermined off-angle, good quality crystal growth can be performed on the n-type GaAs substrate 1 that is an off-substrate. The first semiconductor laser element portion 10 and the second semiconductor laser element portion 20 having excellent characteristics can be easily formed on the surface of the n-type GaAs substrate 1.

(Second Embodiment)
FIG. 14 is a plan view showing a semiconductor laser device according to the second embodiment of the present invention. In the second embodiment, unlike the first embodiment, the solder layer 131 is formed on a part of a region located below the formation region of the first waveguide 16a of the first semiconductor laser element portion 10 in plan view. An example in the case where there exists will be described. Other configurations of the second embodiment are the same as those of the first embodiment.

  That is, in the second embodiment, the same semiconductor laser element as that in the first embodiment is mounted on the heat sink 30. Specifically, the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 formed on the upper surface of the same n-type GaAs substrate 1 are used to dissipate heat generated in the light emitting layers 12 and 22. The pn junction (the first waveguide 16a and the second waveguide 26a) sandwiching the light emitting layers 12 and 22 is attached to the upper surface of the heat sink 30 made of AlN by a junction down method.

  Here, in the second embodiment, as shown in FIG. 14, as viewed in a plan view, the first guide in the region located below the formation region of the first waveguide 16 a of the first semiconductor laser element unit 10. A solder layer 131 exists in the vicinity of the central portion in the extending direction of the waveguide 16 a, and the first semiconductor laser element portion 10 is fixed on the heat sink 30. The solder layer 131 is an example of the “fusion layer” and the “first fusion layer” in the present invention.

  In the second embodiment, as described above, the solder layer 131 is present in at least a part of the region located below the formation region of the first waveguide 16a when the first semiconductor laser element unit 10 is viewed in plan. By fusing in a state where the first semiconductor laser element portion 10 and the solder layer 131 are bonded, the solder layer 131 is located in a region located below the formation region of the first waveguide 16a in plan view. Therefore, heat dissipation of the first semiconductor laser element portion 10 can be improved accordingly. As a result, the temperature characteristics of the first semiconductor laser element unit 10 can be improved.

  In the second embodiment, the solder layer 131 is formed in the vicinity of the central portion in the extending direction of the first waveguide 16a in the region located below the formation region of the first waveguide 16a in plan view. As a result, the first semiconductor laser element portion 10 and the heat sink 30 can be joined to each other by the solder layer 131 in the vicinity of the center portion of the first waveguide 16a. The bonding strength between the first semiconductor laser element portion 10 and the heat sink 30 can be improved as compared with the case where the bonding is performed by the solder layer 131 at one end portion in the extending direction of the one waveguide 16a.

  The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

(Third embodiment)
FIG. 15 is a plan view showing a semiconductor laser device according to the third embodiment of the present invention. In the third embodiment, unlike the first and second embodiments, a predetermined interval is provided in an area located below the formation area of the first waveguide 16a of the first semiconductor laser element portion in plan view. An example in the case where a plurality of solder layers 231 are present apart from each other will be described. Other configurations of the third embodiment are the same as those of the first and second embodiments.

  That is, in the third embodiment, the same semiconductor laser element as that in the first and second embodiments is mounted on the heat sink 30. Specifically, the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 formed on the upper surface of the same n-type GaAs substrate 1 are used to dissipate heat generated in the light emitting layers 12 and 22. In addition, the pn junction sandwiching the light emitting layers 12 and 22 is attached to the upper surface of the heat sink 30 made of AlN by a junction down method.

  Here, in the third embodiment, as shown in FIG. 15, a predetermined interval is provided in a region located below the formation region of the first waveguide 16 a of the first semiconductor laser element unit 10 in plan view. A plurality of solder layers 231 are present at a distance, and the first semiconductor laser element portion 10 is fixed on the heat sink 30. The solder layer 231 is an example of the “fusion layer” and the “first fusion layer” in the present invention.

  In the third embodiment, as described above, the solder layer 231 has a predetermined interval in the extending direction of the first waveguide 16a in a region located below the formation region of the first waveguide 16a in plan view. As a result, the solder layer 231 is dispersed and arranged below the formation region of the first waveguide 16a. Therefore, the first semiconductor laser element portion 10 and the heat sink 30 are bonded to each other. It is possible to disperse the generation position of stress generated in the vicinity of one waveguide 16a. For this reason, in addition to the improvement in heat dissipation due to the presence of the solder layer 231 in a partial region below the formation region of the first waveguide 16a of the first semiconductor laser element unit 10, the first semiconductor laser element unit 10 The tensile strain introduced in the vicinity of the first waveguide 16a can be reduced.

  The remaining effects of the third embodiment are similar to those of the aforementioned first embodiment and second embodiment.

(Fourth embodiment)
FIG. 16 is a sectional view showing a state in which the semiconductor laser device according to the fourth embodiment of the present invention is fused to a heat sink. In the fourth embodiment, unlike the first to third embodiments, a 405 nm band blue-violet laser is provided between the semiconductor laser element including the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 and the heat sink. An example in which a semiconductor laser element including the third semiconductor laser element unit 40 that emits light is formed will be described. The structure of the semiconductor laser element including the first semiconductor laser element part 10 and the second semiconductor laser element part 20 is the same as in the first to third embodiments.

First, with reference to FIG. 16, the structure of the semiconductor laser element including the third semiconductor laser element unit 40 that emits 405 nm band blue-violet laser light will be described. On the n-type GaN substrate 41 having a thickness of about 100 μm, a low-temperature buffer layer 42 made of undoped Al _0.01 Ga _0.99 N having a thickness of about 1.0 μm is formed. The n-type GaN substrate 41 is an example of the “second substrate” in the present invention. On the low-temperature buffer layer 42, an n-type cladding layer 43 made of Ge-doped n-type Al _0.07 Ga _0.93 N having a thickness of about 2.0 μm is formed. On the n-type cladding layer 43, an MQW active layer 44 having a multiple quantum well structure is formed. The MQW active layer 44 includes three quantum well layers made of undoped In _0.15 Ga _0.85 N having a thickness of about 3.5 nm, and undoped In _0.02 Ga _0.98 having a thickness of about 20 nm. Three quantum barrier layers made of N are alternately stacked.

Further, on the MQW active layer 44, a p-side light guide layer 45 made of undoped In _0.01 Ga _0.99 N having a thickness of about 80 nm is formed. A p-side carrier block layer 46 made of undoped Al _0.2 Ga _0.8 N having a thickness of about 20 nm is formed on the p-side light guide layer 45. Further, on the p-side carrier block layer 46, as shown in FIG. 16, a p-type cladding layer 47 made of Al _0.07 Ga _0.93 N doped with Mg having a flat portion and a convex portion is formed. Has been. The film thickness of the convex part of the p-type cladding layer 47 is about 0.45 μm, and the film thickness of the flat part other than the convex part of the p-type cladding layer 47 is about 0.05 μm. A p-side contact layer 48 made of undoped In _0.07 Ga _0.93 N having a thickness of about 2 nm is formed on the upper surface of the convex portion of the p-type cladding layer 47. The convex portion of the p-type cladding layer 47 and the p-side contact layer 48 constitute a ridge portion 49 serving as a current path. The ridge portion 49 is formed in a stripe shape (elongated shape) extending in the light emission direction when seen in a plan view. The ridge portion 49 has a width of about 1.5 μm.

A current blocking layer 50 made of a SiO ₂ film having a thickness of about 0.2 μm is formed on the side surface of the ridge portion 49 and on the upper surface of the flat portion of the p-type cladding layer 47. On the upper surface of the p-side contact layer 48, from the lower layer to the upper layer, a Si layer having a thickness of about 1 nm, a Pd layer having a thickness of about 20 nm, and an Au layer having a thickness of about 10 nm, A p-side ohmic electrode 51 made of is formed.

  Further, Ti having a film thickness of about 30 nm from the lower layer to the upper layer so as to be in contact with the upper surface of the p-side ohmic electrode 51 on the upper surface of the p-side ohmic electrode 51 and the upper surface of the current blocking layer 50. A p-side pad electrode 52 comprising a layer, a Pd layer having a thickness of about 150 nm, and an Au layer having a thickness of about 3000 nm is formed. Further, in the regions corresponding to the p-side electrode 18 of the first semiconductor laser element unit 10 and the p-side electrode 29 of the second semiconductor laser element unit 20 on the upper surface of the current blocking layer 50, the same as the p-side pad electrode 52 is provided. The p-side pad electrodes 52a and 52b having the composition are formed.

  Further, on the back surface of the n-type GaN substrate 41, as shown in FIG. 16, an Si layer having a film thickness of about 1 nm and a film thickness of about 6 nm are sequentially formed from the side closer to the back surface of the n-type GaN substrate 41. An n-side electrode 53 made of an Al layer, a Pd layer having a thickness of about 30 nm, and an Au layer having a thickness of about 300 nm is formed.

  Here, in the fourth embodiment, as shown in FIG. 16, the third semiconductor laser element unit 40 is disposed between the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 and the heat sink 130. Yes. Specifically, the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 formed on the upper surface of the same n-type GaAs substrate 1 are p-type semiconductor laser elements including the third semiconductor laser element unit 40. Attached on the upper surfaces of the side pad electrodes 52a and 52b in a junction down manner. That is, the p-side electrode 18 of the first semiconductor laser element unit 10 and the p-side electrode 29 of the second semiconductor laser element unit 20 are formed by solder layers 31 and 32 made of AuSn (Au: 80 wt%) having a thickness of about 3 μm. The p-side pad electrodes 52a and 52b of the semiconductor laser element including the third semiconductor laser element section 40 are fused to each other. The method for fixing the semiconductor laser element including the first semiconductor laser element part 10 and the second semiconductor laser element part 20 and the semiconductor laser element including the third semiconductor laser element part 40 is the same as that in the first embodiment. . Further, on the entire upper surface of the heat sink 130 made of AlN, a Ti layer having a thickness of about 0.1 μm, a Pt layer having a thickness of about 0.2 μm, and about 0.3 μm from the lower layer to the upper layer. An electrode 130a made of an Au layer having a thickness of 5 mm is formed, and the semiconductor laser element including the third semiconductor laser element unit 40 is interposed between the n-side electrode 53 of the semiconductor laser element and the electrode 130a of the heat sink 130. The solder layer 232 made of AuSn (Au: 80 wt%) having a thickness of about 3 μm is bonded to the heat sink 130 by fusing. That is, in the fourth embodiment, the first semiconductor laser element portion 10 is in a state in which the solder layer 31 does not exist in at least a part of the region located below the formation region of the first waveguide 16a in plan view. Thus, it is attached to the heat sink 130 side via the third semiconductor laser element portion 40.

  In the fourth embodiment, as described above, the third semiconductor laser element unit 40 that emits blue-violet laser light having an oscillation wavelength different from that of the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 is the first semiconductor laser element unit 40. The semiconductor laser element portion 10 and the second semiconductor laser element portion 20 are arranged between the heat sink 130 and the first semiconductor laser element portion 10 below the formation region of the first waveguide 16a in plan view. In the state where the solder layer 31 does not exist in at least a part of the region located in the region, the polarization characteristic of the first semiconductor laser element unit 10 is reduced by attaching the third semiconductor laser element unit 40 to the heat sink 130 side. The distance between the light emitting points among the first semiconductor laser element unit 10, the second semiconductor laser element unit 20, and the third semiconductor laser element unit 40 can be shortened while being suppressed. Since wear can effectively share an optical member such as a lens.

  Other effects of the fourth embodiment are the same as those of the first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first to fourth embodiments, at least one of the regions located below the formation region of the first waveguide of the first semiconductor laser element unit that emits red laser light in the 650 nm band in plan view. The first semiconductor laser element portion is fused with no solder layer in the portion, and the second semiconductor laser element portion that emits infrared laser light in the 780 nm band is positioned below the second waveguide formation region. Although the example in which the second semiconductor laser element portion is fused in the state where the solder layer is present in the region to be processed is shown, the present invention is not limited to this, and the red laser beam in the 650 nm band is emitted in a plan view. A region located below the formation region of the first waveguide of the first semiconductor laser element portion and a formation region of the second waveguide of the second semiconductor laser element portion that emits infrared laser light in the 780 nm band. Each region of the region At least a portion in a state in which the solder layer is not present, the first semiconductor laser element portion and the second semiconductor laser element portion may be the fusion.

  In the first to fourth embodiments, the first semiconductor laser element unit that emits 650 nm band red laser light and the second semiconductor laser element unit that emits 780 nm band infrared laser light on the same substrate. However, the present invention is not limited to this, and the first semiconductor laser element that emits red laser light of 650 nm band and wavelengths other than infrared laser light of 780 nm band on the same substrate. The present invention can also be applied to a structure in which a second semiconductor laser element section that emits the laser beam is formed.

  In the first to fourth embodiments, the substrate of the semiconductor laser element including the first semiconductor laser element part and the second semiconductor laser element part has an off angle of about 9 ° in the [011] direction from the (100) plane. Although an example using an inclined n-type GaAs substrate has been shown, the present invention is not limited to this, and a substrate other than the off-substrate may be used.

  Moreover, in the said 1st-4th embodiment, although the example which used the heat sink which consists of AlN which has insulation and favorable thermal conductivity was shown as a base of this invention, this invention is not limited to this. A heat sink made of another material may be used. For example, a heat sink made of SiC, diamond, Si, or the like may be used. Alternatively, a heat sink in which electrodes are patterned after forming an insulating film on the surface thereof using a conductive material such as Cu, Al, and CuW may be used as a base.

  In the first to fourth embodiments, the semiconductor including the heat sink or the third semiconductor laser element portion as the p-side electrode of the first semiconductor laser element portion and the second semiconductor laser element portion through the solder layer made of AuSn. Although it was made to fuse to the p-side pad electrode of the laser element, the present invention is not limited to this, and a material other than solder may be used as the fusion layer.

  In the first embodiment, the electrode portion is formed in the region corresponding to the p-side electrode of the first semiconductor laser element portion that emits red laser light of 650 nm band on the heat sink, Although the example in which the electrode portion is formed in a region other than the region located below the formation region of the first waveguide of the first semiconductor laser element portion has been shown, the present invention is not limited to this, and the first The electrode portion may also be formed in a region located below the formation region of the first waveguide of the one semiconductor laser element portion. Also in this case, the solder layer is disposed in a state where it does not exist in at least a part of a region located below the formation region of the first waveguide of the first semiconductor laser element portion.

  In the fourth embodiment, an example in which a semiconductor laser element that emits 405 nm band blue-violet laser light is used for the third semiconductor laser element unit is shown. However, the present invention is not limited to this, and a 650 nm band red laser is used. As long as it is an element other than an element that emits light and an element that emits infrared laser light in the 780 nm band, a semiconductor laser element that emits laser light other than blue-violet laser light may be used.

  In the fourth embodiment, the p-side pad electrode is formed in the region corresponding to the p-side electrode of the first semiconductor laser element portion that emits red laser light in the 650 nm band on the semiconductor laser element including the third semiconductor laser element portion. In the example shown, the p-side pad electrode is formed in a region other than the region located below the formation region of the first waveguide of the first semiconductor laser element portion. The invention is not limited to this, and the p-side pad electrode may also be formed in a region located below the formation region of the first waveguide of the first semiconductor laser element portion in plan view. Also in this case, the solder layer is disposed in a state where it does not exist in at least a part of a region located below the formation region of the first waveguide of the first semiconductor laser element portion.

It is sectional drawing which showed the state which fuse | melted the semiconductor laser element by 1st Embodiment of this invention to the heat sink. FIG. 2 is a cross-sectional view showing the semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 2 is an enlarged cross-sectional view of a light emitting layer of a first semiconductor laser element portion of the semiconductor laser element according to the first embodiment shown in FIG. 1. It is an expanded sectional view of the light emitting layer of the 2nd semiconductor laser element part of the semiconductor laser element by 1st Embodiment shown in FIG. FIG. 2 is a plan view showing a state where the semiconductor laser device according to the first embodiment shown in FIG. 1 is fused to a heat sink. It is the graph which showed the measurement result of the polarization angle of the red laser beam in 1st Embodiment shown in FIG. It is the graph which showed the measurement result of the polarization ratio of the red laser beam in 1st Embodiment shown in FIG. 5 is a graph showing the measurement result of the polarization angle of red laser light in Comparative Example 1. 6 is a graph showing measurement results of a polarization ratio of red laser light in Comparative Example 1. 5 is a graph showing measurement results of the polarization angle of infrared laser light according to Comparative Example 2. 5 is a graph showing measurement results of the polarization ratio of infrared laser light according to Comparative Example 2. 10 is a graph showing the measurement results of the polarization angle of infrared laser light according to Comparative Example 3. 10 is a graph showing measurement results of the polarization ratio of infrared laser light according to Comparative Example 3. It is the top view which showed the semiconductor laser apparatus by 2nd Embodiment of this invention. It is the top view which showed the semiconductor laser apparatus by 3rd Embodiment of this invention. It is sectional drawing which showed the state which fuse | melted the semiconductor laser element by 4th Embodiment of this invention to the heat sink. It is sectional drawing which showed the conventional semiconductor laser apparatus.

Explanation of symbols

1 n-type GaAs substrate (first substrate)
10 1st semiconductor laser element part 12, 22 Light emitting layer 18 p side electrode (1st electrode part)
20 Second semiconductor laser element portion 16, 26, 49 Ridge portion 16a First waveguide 26a Second waveguide 29 p-side electrode (second electrode portion)
30, 130 Heat sink (base, heat dissipation base)
30a, 30b Electrode 31, 131, 231 Solder layer (first fusion layer)
32 Solder layer (second fusion layer)
232 Solder layer (fusion layer)
40 Third semiconductor laser element portion 41 n-type GaN substrate (second substrate)

Claims (12)

A first semiconductor laser element portion formed on a first substrate, including a first waveguide, and including a light emitting layer containing at least Ga, In, and P;
A second semiconductor laser element portion formed on the first substrate and including a second waveguide;
The first semiconductor laser element portion and the second semiconductor laser element portion have a first fusion layer and a second fusion layer, respectively, so that the first waveguide and the second waveguide are disposed on the lower side. A base attached with a layer,
The first semiconductor laser element portion is on the base side in a state where the first fusion layer is not present in a part of a region located below the formation region of the first waveguide when seen in a plan view. Installed,
The first fusion layer is formed in the vicinity of a central portion in a direction in which the first waveguide extends in a region located below the formation region of the first waveguide as viewed in a plan view. Laser device. A first semiconductor laser element portion formed on a first substrate, including a first waveguide, and including a light emitting layer containing at least Ga, In, and P;
A second semiconductor laser element portion formed on the first substrate and including a second waveguide;
The first semiconductor laser element portion and the second semiconductor laser element portion have a first fusion layer and a second fusion layer, respectively, so that the first waveguide and the second waveguide are disposed on the lower side. A base attached with a layer,
The first semiconductor laser element portion is on the base side in a state where the first fusion layer is not present in a part of a region located below the formation region of the first waveguide when seen in a plan view. Installed,
A plurality of the first fusion layers are formed at a predetermined interval in a direction in which the first waveguide extends in a region located below the formation region of the first waveguide in plan view. Semiconductor laser device. A first semiconductor laser element portion formed on a first substrate, including a first waveguide, and including a light emitting layer containing at least Ga, In, and P;
A second semiconductor laser element portion formed on the first substrate and including a second waveguide;
The first semiconductor laser element portion and the second semiconductor laser element portion have a first fusion layer and a second fusion layer, respectively, so that the first waveguide and the second waveguide are disposed on the lower side. A base attached with a layer,
The first semiconductor laser element portion is on the base side in a state where the first fusion layer is not present in at least a part of a region located below the formation region of the first waveguide when seen in a plan view. Attached,
The second semiconductor laser element portion includes a light emitting layer containing Ga and As, and the second fusion layer is present in a region located below the formation region of the second waveguide when seen in a plan view. A semiconductor laser device attached to the base side in a state where   The second semiconductor laser element portion includes a light emitting layer containing Ga and As, and the second fusion layer is present in a region located below the formation region of the second waveguide when seen in a plan view. The semiconductor laser device according to claim 1, wherein the semiconductor laser device is attached to the base side in a state where The said 1st semiconductor laser element part is attached to the said base side in the state where the said 1st fusion | fusion layer does not exist in the area | region located under the formation area of the said 1st waveguide. Semiconductor laser device.   A first electrode portion is formed in the first semiconductor laser element portion, and a second electrode portion is formed in the second semiconductor laser element portion,
  A third electrode portion and a fourth electrode portion are formed on the base so as to correspond to the first electrode portion and the second electrode portion,
  The first electrode portion and the second electrode portion are fused to the third electrode portion and the fourth electrode portion via the first fusion layer and the second fusion layer, respectively. The first semiconductor laser element portion and the second semiconductor laser element portion are fixed to the base;
  The first fusion layer for fusing the first electrode portion and the third electrode portion is located below the first waveguide formation region of the first semiconductor laser element portion in plan view. The semiconductor laser device according to claim 1, wherein the semiconductor laser device is disposed so as not to exist in at least a part of the region.   The semiconductor laser device according to claim 6, wherein the third electrode portion is formed in a region other than a region located below the formation region of the first waveguide on the base.   A third semiconductor laser element portion that is formed on the second substrate and emits laser light having an oscillation wavelength different from that of the first semiconductor laser element portion and the second semiconductor laser element portion;
  The third semiconductor laser element portion is disposed between the first semiconductor laser element portion and the second semiconductor laser element portion and the base,
  The first semiconductor laser element portion includes the third semiconductor in a state where the first fusion layer is not present in at least a part of a region located below the formation region of the first waveguide when seen in a plan view. The semiconductor laser device according to claim 1, wherein the semiconductor laser device is attached to the base side via a laser element portion.   9. The semiconductor laser device according to claim 1, wherein each of the first waveguide and the second waveguide includes a convex ridge portion protruding toward the base.   The semiconductor laser device according to claim 1, wherein the first substrate is an off substrate having a predetermined off angle.   The semiconductor laser device according to claim 1, wherein the fusion layer is a solder layer.   The semiconductor laser device according to claim 1, wherein the base is a heat dissipation base.

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