JP2006032406A - Semiconductor laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser device which can be mounted with higher accuracy to obtain a stable characteristic. <P>SOLUTION: On a heatsink 21, a lower sub-mount 30, a bar type semiconductor laser element 10 mounting in parallel a plurality of laser diode chips, and an upper sub-mount 40 are sequentially laminated with each end surface aligned with one end surface of the heatsink 21. The lower sub-mount 30 and the upper sub-mount 40 have thermal expansion coefficients lower than that of the semiconductor laser element 10. Even when the thermal expansion coefficients of upper and lower surfaces of the semiconductor laser element 10 are balanced and the thermal expansion coefficients of the lower sub-mount 30 and the upper sub-mount 40 are low, mounting accuracy can be enhanced by controlling the generation of warp or the like and a stable characteristic can be obtained in the semiconductor laser element 10 of a red color having an oscillation wavelength particularly in a wavelength region of 630 μm or more and 690 μm or less. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor laser device in which a semiconductor laser element is mounted on a support member.

  The light emitting region of the semiconductor laser is currently expanded to a blue-violet short wavelength region, and is expected to be applied to optical communication, high density optical recording, or a display. While the light emitting area is expanded in this way, there are problems such as reduction in operating current, low noise, low cost, high output, high speed operation, and reliability during high temperature operation. There are still many issues that need to be improved in applied equipment. In particular, regarding the problems related to heat generation, the use of semiconductor lasers in various fields is limited. This problem related to heat generation is related to a large amount of heat generated per unit area of the semiconductor laser, and heat circulation causes phenomena such as an increase in junction temperature and generation of stress. As the operating temperature of the junction increases, the light emission output, the light emission efficiency, the lifetime of the semiconductor laser, and the like decrease, and there is a problem that the wavelength of light generated from the semiconductor laser is lengthened.

  As a method for controlling the heat generation of the semiconductor laser that causes these problems, for example, the semiconductor laser element is disposed on a submount (support member) such as silicon carbide (SiC), and the lower surface of the submount is further heat sinked (heat dissipation). The method of joining to (member) is used.

There is also a method in which a heat sink is bonded to each of the n-side electrode and the p-side electrode of the semiconductor laser element to release the generated heat. For example, in Patent Document 1, a gap is formed by sandwiching a spacer between two heat sinks, a bar-shaped semiconductor laser element is disposed in the gap, and then the solder that has been coated on the heat sink is melted in advance. Even if the element has a unique curved shape, the semiconductor laser element and the heat sink can be brought into close contact and bonded. Alternatively, for example, Patent Document 2 discloses a configuration in which the semiconductor laser element is cooled by being sandwiched from above and below by a metal plate.
Japanese Patent Laid-Open No. 11-340581 U.S. Pat. No. 4,454,602

  However, since these conventional structures use a metal submount or metal plate, the thermal expansion coefficient of the metal is considerably larger than that of the semiconductor laser element, which may cause cracks in the semiconductor laser element. . Further, in the configuration described in Patent Document 2, the semiconductor laser element and the metal plate are merely in contact with each other, and an adhesive layer or the like is not particularly provided, so that a sufficient cooling effect may not be obtained. It was.

  On the other hand, when a submount having a smaller thermal expansion coefficient than the semiconductor laser element is provided only on the lower side of the semiconductor laser element, the submount 130 largely warps toward the semiconductor laser element 110 as shown in FIG. As a result, the mounting accuracy on the heat sink has been reduced. Further, in the case where the warp remains in the long-term reliability test, there is a problem that the oblique crack 110A and the lateral crack 110B are likely to occur in the semiconductor laser element 110 as shown in FIG.

  Further, when mounting using a submount having the same thermal expansion coefficient as that of the semiconductor laser element in order to reduce warpage and distortion, a semiconductor laser element using a substrate made of GaAs, particularly an element having an oscillation wavelength in the red wavelength region However, there is a problem that characteristics such as light output and reliability deteriorate.

  The present invention has been made in view of such problems, and an object thereof is to provide a semiconductor laser device which can be mounted with high accuracy and can obtain stable characteristics.

The semiconductor laser device according to the present invention is improved in mounting accuracy by having the following requirements (A) to (C).
(A) A semiconductor laser device having first and second surfaces facing each other and emitting light in a direction perpendicular to the facing direction of the first and second surfaces. (B) Lower thermal expansion coefficient than that of the semiconductor laser device. A first support member (C) disposed on the first surface of the semiconductor laser element with the first weld layer interposed therebetween, and having a lower thermal expansion coefficient than the semiconductor laser element, and the second surface of the semiconductor laser element A second support member disposed with a second weld layer therebetween

  According to the semiconductor laser device of the present invention, not only the first support member having a lower thermal expansion coefficient than the semiconductor laser element is disposed on the first surface of the semiconductor laser element but also the lower thermal expansion coefficient than that of the semiconductor laser element. Since the second support member is also disposed on the second surface of the semiconductor laser element, the thermal expansion coefficient is balanced between the first surface side and the second surface side of the semiconductor laser element, so that the first support member is provided. And even if the thermal expansion coefficient of the second support member is low, their warpage can be suppressed, and the second support member can be disposed on the heat dissipation member in a horizontal state. Therefore, the mounting accuracy can be increased. In particular, stable characteristics can be obtained in a red semiconductor laser device having an oscillation wavelength in the wavelength range of 630 μm or more and 690 μm or less. In addition, since the first support member and the second support member are bonded together with the first weld layer and the second weld layer interposed therebetween, the heat generated in the semiconductor laser element is transferred to the first support member and the second support member. It is possible to efficiently dissipate the heat and improve the exhaust heat performance. Therefore, it is possible to cope with a high-power laser.

  Furthermore, since the first support member and the second support member have substantially the same thermal expansion coefficient, the semiconductor laser element is not subjected to an excessive load, and the reliability can be improved.

  In addition, by providing the second support member, it is not necessary to directly apply a bonding wire to the semiconductor laser element or to perform patterning for wire bonding on the first support member. Therefore, damage due to ultrasonic waves or heat can be reduced, and problems such as chipping of the semiconductor laser element and peeling of the p-side electrode can be avoided.

  In particular, if the second support member has a smaller dimension in the direction of light emission from the semiconductor laser element than the first support member, the mounting stability of the second support member can be enhanced.

  In particular, if the second support member is made of a material containing diamond and copper (hereinafter referred to as “diamond-copper (Cu)”), or a body portion made of aluminum nitride is provided with a through hole, If the through hole is filled with a conductive layer, the electrical conductivity can be improved.

  In addition, in particular, if one or more metal coating layers are provided on the surface of the second support member and the total thickness of the metal coating layers is 2 μm or more, the second support member may be made of a material having low conductivity. Electrical conductivity can be improved.

  Furthermore, in particular, if the second heat dissipating member is disposed on the second support member, the heat dissipation can be further improved.

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

  FIG. 1 shows a schematic configuration of a semiconductor laser element 10 included as a component in a semiconductor laser device according to an embodiment of the present invention. FIG. 2 shows the overall configuration of a semiconductor laser device provided with the semiconductor laser element 10.

  The semiconductor laser element 10 is a red laser having an oscillation wavelength in a wavelength region of, for example, 630 μm or more and 690 μm or less. The semiconductor laser element 10 is, for example, a laser diode bar in which a plurality of laser diode (LD) chips 11 are arranged side by side, and the dimensions thereof are about 10 mm in length, and the resonator length is 200 μm to 1.5 mm. Is about 700 μm and has a thickness of about 100 μm. Here, the thickness is a dimension in the opposing direction of the first surface (lower surface in FIG. 1) 10A and the second surface (upper surface in FIG. 1) 10B of the semiconductor laser element 10, and the resonator length is the semiconductor laser. It is a dimension in the emission direction of the light LB from the element 10, that is, the resonator direction, and the length is a dimension in a direction orthogonal to both the facing direction of the first surface 10A and the second surface 10B and the resonator direction.

  Each laser diode chip 11 has a semiconductor layer 13 including an active layer made of an AlGaInP-based compound semiconductor on a substrate 12 made of gallium arsenide (GaAs). Note that the AlGaInP-based compound semiconductor here refers to at least one of aluminum (Al) and gallium (Ga) among the group 3B elements in the short-period periodic table and indium (In) and phosphorus (P) among the group 5B elements. A quaternary semiconductor including at least one of the above, for example, an AlGaInP mixed crystal, a GaInP mixed crystal, an AlInP mixed crystal, or the like. These contain an n-type impurity such as silicon (Si) or selenium (Se), or a p-type impurity such as magnesium (Mg), zinc (Zn), or carbon (C) as necessary.

  On the semiconductor layer 13, for example, a p-side electrode 14 is formed corresponding to each laser diode chip 11. The p-side electrode 14 has a configuration in which, for example, a titanium (Ti) layer, a platinum (Pt) layer, and a gold (Au) layer are sequentially stacked from the semiconductor layer 13 side. In addition, an n-side electrode 15 is provided on the back surface of the substrate 12 corresponding to each laser diode chip 11, for example. The n-side electrode 15 has a configuration in which, for example, a gold (Au) layer, an alloy layer of gold (Au) and germanium (Ge), and a gold (Au) layer are sequentially stacked from the substrate 12 side.

  The semiconductor laser device provided with the semiconductor laser element is used as a light source of a laser projector. For example, the lower submount 30, the semiconductor laser element 10, and the upper submount 40 are provided on the heat sink 21, respectively. It has a configuration in which the end surface is sequentially laminated so that the end surface is aligned with the one end surface of the heat sink 21. The semiconductor laser element 10 is disposed such that the first surface 10A faces the upper submount 40 and the second surface 10B faces the lower submount 30. The light LB from the semiconductor laser element 10 is emitted mainly from the end face aligned with the end face of the heat sink 21 in a direction orthogonal to the stacking direction of the lower submount 30 and the upper submount 40.

  The heat sink 21 is made of, for example, a material having electrical and thermal conductivity such as copper (Cu), and a thin film made of gold (Au) or the like is attached to the surface. The thermal conductivity is a characteristic necessary for releasing a large amount of intense heat generated from the semiconductor laser element 10 and maintaining the semiconductor laser element 10 at an appropriate temperature. This is a characteristic necessary for efficient conduction.

  On the heat sink 21, for example, an electrode member 22 made of the same material as the heat sink 21 is fixed by screws 22A and 22B, for example. An insulating plate 23 made of, for example, a glass epoxy material is provided between the heat sink 21 and the electrode member 22, and the heat sink 21 and the electrode member 22 are electrically insulated. The electrode member 22 is provided with a step portion 22C at one corner on the semiconductor laser element 10 side. One end portion of a wire 50 made of gold (Au) having a thickness of, for example, 200 μm is formed on the step portion 22C. It is joined. The other end of the wire 50 is joined to the upper submount 40, and the electrode member 22 and the first surface 10 </ b> A of the semiconductor laser element 10 are electrically connected via the upper submount 40. A protective member 24 made of the same material as the heat sink 21 is fixed to the step 22C of the electrode member 22 with screws 24A in order to protect the wire 50, the semiconductor laser element 10, and the like.

  FIG. 3 shows a cross-sectional structure along the line III-III of the semiconductor laser device shown in FIG. The lower submount 30 has a thickness of about 3 μm to 5 μm, for example, and is disposed on the second surface 10B of the semiconductor laser element 10 with a lower welding layer 31 made of solder or the like interposed therebetween. An adhesive layer 32 made of solder or the like is provided between the lower submount 30 and the heat sink 21.

  The lower welding layer 31 and the adhesive layer 32 are preferably made of solder not containing lead (lead-free solder), but may be made of lead-based solder. Specific examples of the constituent material of the lower welding layer 31 include gold (Au) -tin (Sn) solder (eutectic) or silver (Ag) -tin (Sn) solder (eutectic). Specifically, the constituent material of the adhesive layer 32 includes a low melting point solder mainly composed of indium (In) or the like. The tin (Sn) -lead (Pb) type and the tin (Sn) -silver (Ag) -copper (Cu) type are used for both the lower welding layer 31 and the adhesive layer 32 depending on the combination. Is possible.

  The upper submount 40 has a thickness of about 3 μm to 5 μm, for example, and is disposed on the first surface 10A of the semiconductor laser element 10 with an upper welding layer 41 made of solder or the like interposed therebetween. The constituent material of the upper weld layer 41 is the same as that of the lower weld layer 31 described above, and specific constituent materials include, for example, gold (Au) -tin (Sn) solder (eutectic), silver (Ag) -tin ( Sn) Solder (eutectic).

  The lower submount 30 and the upper submount 40 have, for example, the same shape, and the dimensions thereof are, for example, a length of about 11 mm, a depth of about 2 mm, and a thickness of about 300 μm. Here, the depth is a dimension in the emission direction of the light LB from the semiconductor laser element 10, that is, in the resonator direction. In this way, when the lower submount 30 and the upper submount 40 have the same dimensions, in order to increase the mounting stability of the upper submount 40, as shown by the dotted line in FIG. It is also possible to put a spacer 42 between the mount 30 and the upper submount 40. In FIG. 4, the electrode member 22, the insulating plate 23, the protective member 24 and the wire 50 shown in FIG. 2, the lower welding layer 31, the upper welding layer 41, the adhesive layer 32, etc. shown in FIG. 3 are omitted. ing.

  The depth of the upper submount 40 is preferably smaller than that of the lower submount 30 as shown in FIG. This is because the mounting stability of the upper submount 40 can be improved. In this case, the depth of the upper submount 40 is preferably longer than the resonator length of the semiconductor laser element 30.

  The lower submount 30 and the upper submount 40 have a thermal expansion coefficient lower than that of the semiconductor laser element 10. Thus, in this semiconductor laser device, the thermal expansion coefficients are balanced between the first surface 10A side and the second surface 10B side of the semiconductor laser element 10, and the thermal expansion of the lower submount 30 and the upper submount 40 is balanced. Even if the coefficient is low, it is possible to suppress the occurrence of warp and the like to improve mounting accuracy, and in particular, it is possible to obtain stable characteristics in the red semiconductor laser device 10 having an oscillation wavelength in the wavelength range of 630 μm to 690 μm. ing.

  As a constituent material of the lower submount 30 and the upper submount 40, for example, composite diamond, diamond-copper (Cu), silicon carbide (SiC), and aluminum nitride (AlN) are preferable. This is because the coefficient of thermal expansion is lower than that of GaAs, which is the main constituent material of the semiconductor laser element 10, and the thermal conductivity is large. Table 1 shows an example of the thermal expansion coefficient and thermal conductivity of these materials.

  Lower submount 30 and upper submount 40 may be made of the same material, or may be made of different materials. For example, since the lower submount 30 also has a role as an accuracy reference in the mounting process of the semiconductor laser device 10, the constituent material of the lower submount 30 ensures high processing accuracy among the above-described materials. It is preferable to select what can be done. On the other hand, the upper submount 40 is preferably made of a highly conductive material from the viewpoint of voltage reduction. This is because by providing the upper submount 40, it is possible to suppress as much as possible the increase in voltage due to the corresponding electrical resistance. For example, diamond-copper (Cu) is preferable as a material capable of improving the electrical conductivity of the upper submount 40. Moreover, although not shown in figure, what has the main-body part which consists of aluminum nitride, the through-hole provided in the main-body part, and the conductive layer with which the through-hole was filled is also preferable. Alternatively, for example, as shown in FIG. 6, if a metal coating layer 40B is provided on the surface of the insulating main body portion 40A and the thickness of the metal coating layer 40B is 2 μm or more, the main body portion 40A is made of silicon carbide (SiC) or the like. Even if it is made of a material having low conductivity, the conductivity of the upper submount 40 can be improved. The metal coating layer 40B may be a single layer or a stacked structure of a plurality of layers. When the metal coating layer 40B has a laminated structure of a plurality of layers, the total thickness thereof is preferably 2 μm or more.

  This semiconductor laser device can be manufactured, for example, as follows.

  First, for example, on the front side of the substrate 12 made of the above-described material, for example, by MOCVD (Metal Organic Chemical Vapor Deposition) method or MBE (Molecular Beam Epitaxy) method, A semiconductor layer 13 is formed. Next, the p-side electrode 14 and the n-side electrode 15 are formed, and the substrate 12 is adjusted to a predetermined size. Thereby, the bar-shaped semiconductor laser element 10 shown in FIG. 1 is formed.

  Subsequently, a lower submount 30 made of the above-described dimensions and materials is prepared, and a gold (Au) layer and a surface of the lower submount 30 on which the semiconductor laser element 10 is provided are formed by, for example, vacuum evaporation or plating. The lower welding layer 31 is formed by sequentially stacking tin (Sn) layers.

  After the lower welding layer 31 is formed on the lower submount 30, the second surface 10B of the semiconductor laser device 10 and the lower welding layer 31 of the lower submount 30 are opposed to each other, and alignment is performed with high precision. The semiconductor laser element 10 is placed on the side submount 30. Subsequently, the lower submount 30 is subjected to heat treatment, so that the semiconductor laser element 10 is welded to the lower submount 30 as shown in FIG.

  Further, an upper submount 40 made of the above-described dimensions and materials is prepared, and a gold (Au) layer and tin (Sn) are formed on the surface of the upper submount 40 on which the semiconductor laser element 10 is provided, for example, by vacuum deposition or plating. The upper welding layer 41 is formed by sequentially laminating layers.

  After the upper welding layer 41 is formed on the upper submount 40, the first surface 10A of the semiconductor laser element 10 and the upper welding layer 41 of the upper submount 40 are opposed to each other, and alignment is performed with high precision. Mounted on the semiconductor laser element 10. Subsequently, by subjecting the upper submount 40 to heat treatment, the semiconductor laser element 10 is welded to the upper submount 40 as shown in FIG. Even when the upper welding layer 41 and the lower welding layer 31 are both made of gold (Au) -tin (Sn) solder (melting point: about 280 ° C.), the lower welding layer 31 is formed by alloying. Since the melting point has risen, there is no possibility that the position of the semiconductor laser element 10 is shifted when the upper welding layer 41 is heated and the lower welding layer 31 is also melted.

  After the semiconductor laser element 10 is welded to the upper submount 40, the lower submount 30 is placed on the heat sink 21 with an adhesive layer 32 made of, for example, lead-free solder (melting point: about 220 ° C.), and heat treatment is performed. Apply. As a result, as shown in FIG. 3, the lower submount 30, the semiconductor laser element 10, and the upper submount 40 are sequentially stacked and bonded onto the heat sink 21 with the adhesive layer 32 therebetween. Here, since the lower submount 30 and the upper submount 40 having lower thermal expansion coefficients are respectively disposed on both the first surface 10A and the second surface 10B of the semiconductor laser element 10, the semiconductor Even if the thermal expansion coefficients of the first surface 10A side and the second surface 10B side of the laser element 10 are balanced and the thermal expansion coefficients of the lower submount 30 and the upper submount 40 are low, their warpage is suppressed. It can be arranged in the heat sink 21 in a horizontal state, and the mounting accuracy can be increased.

  After bonding the lower submount 30 and the heat sink 21, the electrode member 22 is fixed on the heat sink 21 via the insulating plate 23, and one end of the wire 50 is joined to the step 22C of the electrode member 22. The other end of 50 is joined to the upper submount 40. After that, the protection member 24 is fixed to the step 22C of the electrode member 22. Thus, the semiconductor laser device shown in FIG. 2 is completed.

  In the manufacturing method described above, the upper welding layer 41 and the lower welding layer 31 are both made of gold (Au) -tin (Sn) solder, and the adhesive layer 32 is made of solder not containing lead. As described above, the lower welding layer 31 and the upper welding layer 41 may be made of different solders. For example, the lower welding layer 31 is gold (Au) -tin (Sn) solder (melting point: about 280 ° C.), the upper welding layer 41 is lead-free solder (melting point: about 220 ° C.), and the adhesive layer 32 is mainly composed of indium. The low melting point solder (melting point: about 150 ° C.) may be used.

  In this semiconductor laser device, when a predetermined voltage is applied between the n-side electrode 15 and the p-side electrode 14 of each laser diode chip 11, current is injected into the active layer of the semiconductor layer 13, and electron-hole Luminescence occurs due to recombination. Here, not only the lower submount 30 having a lower thermal expansion coefficient than the semiconductor laser 10 is disposed on the second surface 10B of the semiconductor laser element 10, but also the thermal expansion as low as the lower submount 30. Since the upper submount 40 having a coefficient is also disposed on the first surface 10A of the semiconductor laser 10, even if the thermal expansion coefficients of the lower submount 30 and the upper submount 40 are low, their warpage is suppressed, Mounting accuracy is high. Therefore, stable characteristics can be obtained particularly in a red semiconductor laser element having an oscillation wavelength in a wavelength range of 630 μm or more and 690 μm or less.

  As described above, in the semiconductor laser device of the present embodiment, the lower submount 30 having a lower thermal expansion coefficient than that of the semiconductor laser element 10 is disposed on the second surface 10B of the semiconductor laser element 10, while the semiconductor laser element 10 Since the upper submount 40 having a lower coefficient of thermal expansion than the semiconductor laser element 10 is also disposed on the first surface 10A, heat is generated between the first surface 10A side and the second surface 10B side of the semiconductor laser element 10. Even if the expansion coefficients are balanced and the thermal expansion coefficients of the lower submount 30 and the upper submount 40 are low, their warpage can be suppressed and the heat sink 21 can be disposed in a horizontal state. Therefore, the mounting accuracy can be increased. In particular, stable characteristics can be obtained in the red semiconductor laser device 10 having an oscillation wavelength in the wavelength range of 630 μm to 690 μm. Further, since the lower submount 30 and the upper submount 40 are bonded with the lower welding layer 31 and the upper welding layer 41 interposed therebetween, the heat generated in the semiconductor laser element 10 is transferred to the lower submount 30 and the upper submount 40. It is possible to dissipate efficiently through the submount 40, and to improve exhaust heat performance. Therefore, it is possible to cope with a high-power laser.

  Further, since the lower submount 30 and the upper submount 40 have substantially the same thermal expansion coefficient, the semiconductor laser element 10 is not subjected to an excessive load, and the reliability can be improved.

  In addition, by providing the upper submount 40, it is not necessary to directly hit the wire 50 on the semiconductor laser element 10. Therefore, damage due to ultrasonic waves or heat can be reduced, and problems such as chipping of the semiconductor laser element 10 and peeling of the p-side electrode 14 can be avoided.

  Hereinafter, modifications of the above embodiment will be described. In these modified examples, the heat sink is further improved by disposing an upper heat sink also on the first surface 10 </ b> A side of the semiconductor laser element 10.

[Modification 1]
For example, as shown in FIG. 8, it is preferable that a block-shaped upper heat sink 60 is disposed on the upper submount 40 with the upper adhesive layer 61 therebetween. Examples of the constituent material of the upper heat sink 60 include a material in which a thin film made of gold is formed on a copper surface, or diamond. The upper adhesive layer 61 has a thickness of 3 μm to 5 μm, for example, and is made of the same material as that of the adhesive layer 32.

[Modification 2]
Further, the upper heat sink is not limited to a block shape, and for example, a thin plate upper heat sink 70 as shown in FIGS. 9 and 10 may be provided. The upper heat sink 70 includes, for example, a joint portion 71 fixed to the upper submount 40 and a bridging portion 72 extending laterally from the joint portion 71. An end 72A of the bridging portion 72 is an electrode. The portion 22 is fixed to the step 22C. Since heat is likely to spread relatively in the lateral direction, by providing such an upper heat sink 70, the heat exhaustion not only in the upward direction but also in the lateral direction is improved, and the heat generated in the semiconductor laser element 10 is transferred to the electrode portion 22. Can be dissipated.

  The upper heat sink 70 is made of, for example, a copper plate having a thickness of about several tens of μm to several hundreds of μm, and a thin film made of gold (Au) is formed on the surface. Although not shown, the joining portion 71 and the end portion 72A of the bridging portion 72 may be respectively bonded to the upper submount 40 and the step portion 22C of the electrode portion 22 with an adhesive layer made of solder therebetween. Alternatively, the joining portion 71 and the end portion 72A of the bridging portion 72 are formed on the upper submount 40 and the step portion 22C of the electrode portion 22 by heating or ultrasonic pressure bonding using a thin film made of gold (Au) on the surface. Each may be joined.

  Further, the upper heat sink 70 preferably has a planar shape that does not hinder electrical connection by the wire 50. For example, the bridging portion 72 of the upper heat sink 70 has a comb shape and is disposed in the gap between the wires 50. By doing so, it is possible to improve the heat exhausting property without hindering the electrical connection by the wire 50, and it is possible to use a material having low conductivity as the constituent material of the upper heat sink 70, and the range of selection of the material is wide. can do.

  Furthermore, as shown in FIGS. 11 and 12, it is preferable that a height adjustment structure 72 </ b> B for absorbing a subtle difference in thickness of the semiconductor laser element 10 is formed in the bridging portion 72 of the upper heat sink 70. . This is because by providing such a height adjustment structure 72B, it is possible to prevent the semiconductor laser element 10 from being loaded, to suppress cracking and chipping, and to improve reliability. Further, it is possible to eliminate the need to strictly determine the size of the upper heat sink 70 in accordance with the thickness of the semiconductor laser element 10. As the height adjustment structure 72B, an accordion-type stretchable structure or the like is preferable.

  The planar shape of the bridging portion 72 of the upper heat sink 70 is not limited to the comb shape as shown in FIG. 10 as long as the electrical connection by the wire 50 is not hindered. For example, as shown in FIGS. 13 and 14, a connecting portion 72 </ b> C that connects the end portions of the bridging portion 72 may be formed. Further, as shown in FIGS. 15 and 16, a connecting portion 72 </ b> C for connecting the end portions of the bridging portion 72 may be formed, and a window portion 73 may be provided only at a position where the wire 50 is hit. In addition, the shape of the window part 73 is not specifically limited. Also in the modified examples shown in FIGS. 13 to 16, the bridging portion 72 may be provided with a height adjusting structure 72B as shown in FIGS.

  Furthermore, as shown in FIGS. 17 and 18, the joint portion 71 of the upper heat sink 70 may be directly fixed to the upper surface 10 </ b> B of the semiconductor laser element 10 without providing the upper submount 40. If it does in this way, although it is a simple structure, high heat exhaustion property can be obtained. Also in this case, a height adjustment structure 72B as shown in FIGS. 11 and 12 is provided, a connecting portion 72C as shown in FIGS. 13 and 14 is provided, or FIGS. It is possible to provide the window part 73 as shown.

  While the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, the case where the semiconductor laser device includes the bar-shaped semiconductor laser element 10 has been described. However, the semiconductor laser element 10 may be a laser diode chip.

  Further, for example, in the above-described embodiment, the semiconductor laser element 10 is disposed so that the first surface 10A faces the upper submount 40 and the second surface 10B faces the lower submount 30. However, the first surface 10A may be disposed so as to face the lower submount 30, and the second surface 10B may be disposed so as to face the upper submount 40.

  Furthermore, for example, the material and thickness of each layer described in the above embodiment, the film formation method and the film formation conditions are not limited, and other materials and thicknesses may be used, or other film formation methods and Film forming conditions may be used. For example, in the above-described embodiment, a red laser having the semiconductor layer 13 made of an AlGaInP-based compound semiconductor on the substrate 12 made of GaAs has been described as an example. However, the present invention is, for example, GaAs-based (infrared: 780 nm to 850 nm). Alternatively, it can be applied to other material systems such as a GaN system (oscillation wavelength of 400 nm to 500 nm).

  In addition, although the semiconductor laser has been described as an example in the above embodiment, the present invention can be applied to other semiconductor light emitting elements such as a superluminescent diode in addition to the semiconductor laser.

  The semiconductor laser device according to the present invention can be used, for example, in a laser projector.

FIG. 3 is an enlarged perspective view showing a part of the semiconductor laser element shown in FIG. 2. 1 is an exploded perspective view showing an overall configuration of a semiconductor laser device according to an embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view illustrating a structure taken along line III-III of the semiconductor laser device illustrated in FIG. 2. FIG. 3 is an enlarged cross-sectional view illustrating a structure in a light emission direction of the semiconductor laser device illustrated in FIG. 2. FIG. 6 is a cross-sectional view illustrating a modification of the semiconductor laser device illustrated in FIG. 2. FIG. 10 is a cross-sectional view illustrating another modification of the semiconductor laser device illustrated in FIG. 2. FIG. 3 is a cross-sectional view illustrating a method of manufacturing the semiconductor laser device illustrated in FIG. 2 in order of steps. FIG. 6 is a cross-sectional view illustrating a modification of the semiconductor laser device illustrated in FIG. 2. FIG. 10 is a plan view illustrating another modification of the semiconductor laser device illustrated in FIG. 2. FIG. 10 is a cross-sectional view illustrating the structure of the semiconductor laser device illustrated in FIG. 9 in the light emission direction. FIG. 10 is a plan view illustrating still another modification of the semiconductor laser device illustrated in FIG. 2. FIG. 12 is a cross-sectional view illustrating a structure in a light emission direction of the semiconductor laser device illustrated in FIG. 11. FIG. 10 is a plan view illustrating still another modification of the semiconductor laser device illustrated in FIG. 2. It is sectional drawing showing the structure in the emission direction of the light of the semiconductor laser apparatus shown in FIG. FIG. 10 is a plan view illustrating still another modification of the semiconductor laser device illustrated in FIG. 2. FIG. 16 is a cross-sectional view illustrating a structure in a light emission direction of the semiconductor laser device illustrated in FIG. 15. FIG. 10 is a plan view illustrating still another modification of the semiconductor laser device illustrated in FIG. 2. FIG. 18 is a cross-sectional view illustrating a structure in a light emission direction of the semiconductor laser device illustrated in FIG. 17. It is sectional drawing for demonstrating the problem of the conventional semiconductor laser apparatus. It is sectional drawing for demonstrating the problem of the conventional semiconductor laser apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Semiconductor laser element, 10A ... 1st surface, 10B ... 2nd surface, 11 ... Laser diode chip, 12 ... Substrate, 13 ... Semiconductor layer, 14 ... P side electrode, 15 ... N side electrode, 21 ... Heat sink, 22 DESCRIPTION OF SYMBOLS ... Electrode part, 23 ... Insulating plate, 24 ... Protection member, 30 ... Lower submount, 31 ... Lower welding layer, 32 ... Adhesion layer, 40 ... Upper submount, 41 ... Upper welding layer, 50 ... Wire, 60 , 70 ... Upper heat sink, 71 ... Joint part, 72 ... Bridge part, 72A ... End part, 72B ... Height adjustment structure, 72C ... Connection part, 73 ... Window part

Claims (9)

A semiconductor laser element having first and second surfaces facing each other and emitting light in a direction perpendicular to the facing direction of the first and second surfaces;
A first support member having a thermal expansion coefficient lower than that of the semiconductor laser element and disposed on the first surface of the semiconductor laser element with a first weld layer interposed therebetween;
And a second support member having a thermal expansion coefficient lower than that of the semiconductor laser element and disposed on the second surface of the semiconductor laser element with a second weld layer interposed therebetween. . The semiconductor laser device according to claim 1, wherein the semiconductor laser element has an oscillation wavelength in a wavelength range of 630 μm to 690 μm. The semiconductor laser element includes a substrate made of GaAs and at least one of aluminum (Al) and gallium (Ga) among group 3B elements and at least one of indium (In) and phosphorus (P) among group 5B elements. The semiconductor laser device according to claim 2, further comprising a semiconductor layer made of an AlGaInP-based compound semiconductor. The semiconductor laser device according to claim 1, wherein a dimension of the second support member in a light emitting direction from the semiconductor laser element is smaller than that of the first support member. The semiconductor laser device according to claim 1, wherein the second support member is made of a material containing diamond and copper. 2. The semiconductor laser according to claim 1, wherein the second support member includes a main body portion made of aluminum nitride, a through hole provided in the main body portion, and a conductive layer filled in the through hole. apparatus. 2. The semiconductor laser according to claim 1, wherein the second support member has one or more metal coating layers on the surface of the insulating main body, and the total thickness of the metal coating layers is 2 μm or more. apparatus. The semiconductor laser device according to claim 1, wherein the first support member is disposed on a first heat dissipation member. The semiconductor laser device according to claim 1, wherein a second heat dissipation member is disposed on the second support member.

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