JP2011108743A - Semiconductor laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser device having a superior heat-dissipation effect. <P>SOLUTION: In a semiconductor laser element 101, a first wire 111 joined with a second electrode pad 121 formed on the top face of a sub-mount 120 and bonded with a top-face electrode formed on the top face of the semiconductor laser element 101 and a second wire 122 bonded with the top face of the second electrode pad 121 are mounted near the laser-beam outgoing surface of the semiconductor laser element 101. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device having a good heat dissipation effect.

  FIG. 6 is a cross-sectional view of a conventional semiconductor laser device. A conventional semiconductor laser device 430 is configured by bonding a semiconductor laser element 401 to a submount 420. Here, the semiconductor laser element 401 includes a substrate 410, an active layer 402, a first semiconductor layer 405 formed on the upper surface of the active layer 402, and a second semiconductor layer 407 formed on the lower surface of the active layer 402. The upper electrode 406 is formed on the upper surface of the substrate 410, and the lower electrode 408 is formed on the lower surface of the second semiconductor layer 407. A first wire 411 is bonded to the upper surface of the upper electrode 406, and the lower surface of the lower electrode 408 is bonded to an electrode pad 421 formed on the submount 420. Further, the semiconductor laser element 401 has a front end surface 403 and a rear end surface 404 as opposed resonator end surfaces. The reflectance of the front end surface 403 is lower than the reflectance of the rear end surface 404, and the front end surface 403 and the rear end surface 404 are mirrors. It plays a role and functions as a resonator. With this configuration, when a voltage is applied between the upper surface electrode 406 and the lower surface electrode 408, light traveling through the active layer 402 is enhanced, and laser light is emitted from the front end surface 403 with low reflectivity.

  In the semiconductor laser device 430 having such a configuration, conventionally, there has been a problem that the light density is not uniform between the front end face 403 and the rear end face 404 during the operation of the semiconductor laser element 401. For this purpose, Patent Document 1 proposes a semiconductor laser element 401 in which the bonding position of the first wire 411 connected to the upper surface electrode 406 is provided on the front end surface 403 side from the middle between the front end surface 403 and the rear end surface 404. Yes.

  As another problem during the operation of the semiconductor laser element 401, the vicinity of the front end face 403 from which the laser beam is emitted has the largest heat generation in the cavity direction, and the semiconductor laser element 401 is caused by the temperature rise in the vicinity of the front end face 403. It has been a problem that the light emission characteristics of the light source deteriorate. However, in Patent Document 1, the heat dissipation characteristics of the semiconductor laser element 401 have not been studied.

Japanese Patent Laid-Open No. 9-232689

  Therefore, in order to solve such a problem, the present invention is an excellent device that efficiently emits heat generated in the vicinity of the laser light emitting surface from which the laser light is emitted while keeping the light density in the cavity direction of the semiconductor laser element uniform. An object of the present invention is to provide a semiconductor laser device having excellent heat dissipation characteristics.

  To achieve the above object, a semiconductor laser device according to a first configuration of the present invention is formed on an active layer, a first semiconductor layer disposed on the upper surface of the active layer, and an upper surface of the first semiconductor layer. The upper surface electrode, the first wire bonded to the upper surface electrode, the second semiconductor layer disposed on the lower surface of the active layer, and the lower surface electrode formed on the lower surface of the second semiconductor layer A semiconductor laser element and a submount, wherein a second electrode pad and a lower electrode formed on the upper surface of the submount are bonded to each other; a second wire is bonded to the upper surface of the second electrode pad; The bonding position of the second wire is provided in the vicinity of the laser light emitting surface of the semiconductor laser element.

  In the semiconductor laser device having this configuration, the heat generation in the resonator is the largest in the vicinity of the laser light emitting surface from which the laser light is emitted, but by bringing the bonding position of the first wire and the second wire close to each other in the vicinity of the laser light emitting surface. Heat can be released from the first wire and the second wire together. Thereby, the temperature rise of the semiconductor laser element during operation can be suppressed, and the deterioration of the light emission characteristics can be prevented. In addition, the light density distribution is maximized near the laser light emission surface and the carrier density is the lowest. However, even if either the upper surface electrode or the lower surface electrode is an n-side electrode, electrons are transmitted from the first wire or the second wire. Can be injected. Thereby, a high current density can be supplied to a region where the carrier density is insufficient, and the carrier density in the resonator direction can be made uniform.

  According to another aspect of the present invention, there is provided a semiconductor laser device having the above-described configuration, wherein the semiconductor laser element is a two-wavelength type semiconductor laser element that emits laser light having a different wavelength, and the bottom electrode includes a second electrode and a third electrode that are insulated from each other. A third electrode pad that is insulated from the second electrode pad is formed on the upper surface of the submount, the second electrode and the second electrode pad are joined, the third electrode and the third electrode pad are joined, A third wire is bonded to the upper surface of the third electrode pad, and the bonding position of the third wire is provided in the vicinity of the laser light emitting surface of the semiconductor laser element.

  In the semiconductor laser device having this configuration, the two-wavelength semiconductor laser element generates heat during operation, but in the vicinity of the laser light emission surface, heat is emitted from the first wire and the second wire or the first wire and the third wire. can do. Thereby, the fall of the light emission characteristic of the two wavelength type semiconductor laser element at the time of operation | movement can be suppressed.

  In addition, the present invention is a semiconductor laser device having the above-described configuration, wherein a fourth electrode pad that is insulated from both the second electrode pad and the third electrode pad is formed on the upper surface of the submount, and 1 is formed on the upper surface of the fourth electrode pad. A wavelength-type semiconductor laser device is bonded, a fourth wire is bonded to the upper surface of the fourth electrode pad, and a bonding position of the fourth wire is provided in the vicinity of the laser light emitting surface of the one-wavelength-type semiconductor laser device. To do.

  The semiconductor laser device having this configuration can provide a three-wavelength semiconductor laser device by combining a one-wavelength semiconductor laser element and a two-wavelength semiconductor laser element. In addition, heat generated in the vicinity of the laser light emitting surface from which the laser light is emitted in the one-wavelength semiconductor laser element can be efficiently radiated through the fourth wire.

  As described above, according to the present invention, it is possible to provide a semiconductor laser device that suppresses a temperature rise in the vicinity of the laser light emitting surface from which laser light is emitted during operation of the semiconductor laser element and has a good heat dissipation effect.

1 is an overall perspective view of a semiconductor laser device according to a first embodiment of the present invention. Sectional drawing along A-A 'of the semiconductor laser apparatus by 1st Embodiment of this invention shown in FIG. Overall perspective view of a semiconductor laser device according to a second embodiment of the present invention. Sectional drawing along B-B 'of the semiconductor laser apparatus by 2nd Embodiment of this invention shown in FIG. Overall perspective view of a semiconductor laser device according to a third embodiment of the present invention. Sectional view of a typical semiconductor laser device

  Hereinafter, a semiconductor laser device according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is an overall perspective view of the semiconductor laser device according to the first embodiment of the present invention, and FIG. 2 is along AA ′ of the semiconductor laser device according to the first embodiment of the present invention shown in FIG. It is sectional drawing. The structure of the semiconductor laser device 130 according to the first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the semiconductor laser device 130 includes a semiconductor laser element 101 and a submount 120, and the semiconductor laser element 101 is formed on the substrate 110, the active layer 102, and the upper surface of the active layer 102. The first semiconductor layer 105 is formed, and the second semiconductor layer 107 is formed on the lower surface of the active layer 102. The upper electrode 106 is formed on the upper surface of the substrate 110, and the second semiconductor layer 107 is formed. A lower surface electrode 108 is formed on the lower surface of each of the electrodes, and has a front end surface 103 and a rear end surface 104 as opposed resonator end surfaces. The first wire 111 is bonded to the upper surface of the upper electrode 106, and the lower surface of the lower electrode 108 is bonded to the second electrode pad 121 formed on the submount 120. A second wire 122 is bonded to the second electrode pad 121, and the bonding positions of the first wire 111 and the second wire 122 are provided in the vicinity of the front end surface 103. The first wire 111 and the second wire 122 are made of fine metal wires such as Au and Al. One of the upper electrode 106 and the lower electrode 108 is an n-side electrode, and the other is a p-side electrode. Can do. The front end face 103 is a laser light emitting face covered with a low-reflectance reflecting film, and the rear end face 104 is a resonator end face formed with a high-reflecting reflecting film. The front end surface 103 is an example of the “laser light emitting surface” in the present invention.

  With the above configuration, when a voltage is applied between the first wire 111 and the second wire 122, laser light is emitted from the front end surface 103 of the semiconductor laser element 101, and the vicinity of the front end surface 103 generates the largest amount of heat in the resonator direction. Become. At this time, heat can be efficiently released from the second wire 122 provided in the vicinity of the front end surface 103. Further, the first wire 111 and the second wire 122 are provided close to each other in the vicinity of the front end surface 103, and heat can be released from the first wire 111 and the second wire 122 together. As a result, heat near the front end surface 103 is efficiently radiated through the first wire 111 and the second wire 122, suppressing heat generation near the front end surface 103, and suppressing deterioration of the light emission characteristics of the semiconductor laser element 101. it can. In the present embodiment, both the first wire 111 and the second wire 122 are provided in the vicinity of the front end surface 103. However, the present invention is not limited to this case, and the first wire 111 and the second wire 122 are resonated. By bonding at substantially the same position in the vessel direction, the heat of the semiconductor laser device 101 can be efficiently released from the first wire 111 and the second wire 122.

  The light density distribution between the front end face 103 and the rear end face 104 in the active layer 102 is maximized in the vicinity of the front end face 103 that emits light, and the carrier distribution between the front end face 103 and the rear end face 104 is near the end face 103. Although the lowest carrier density is shown, according to the semiconductor laser device 101 in the present embodiment, the first wire 111 and the second wire 122 are bonded in the vicinity of the front end surface 103, and either the upper surface electrode 106 or the lower surface electrode 108 is n. Even when the side electrode is formed, electrons can be injected from the vicinity of the front end face 103. Thereby, the current density of the supplied current is maximized in the vicinity of the front end face 103, and a high current density is supplied to a region where the carrier density is insufficient, so that the carrier density in the direction of the resonator can be made uniform.

(Second Embodiment)
FIG. 3 is an overall perspective view of the semiconductor laser device according to the second embodiment of the present invention, and FIG. 4 is taken along the line BB ′ of the semiconductor laser device according to the second embodiment of the present invention shown in FIG. It is sectional drawing. The structure of the semiconductor laser device 230 according to the second embodiment of the present invention will be described with reference to FIGS. Note that the description of the configuration common to the first embodiment is omitted.

  As shown in FIGS. 3 and 4, the semiconductor laser device 230 includes a semiconductor laser element 201 and a submount 220. The semiconductor laser element 201 is a two-wavelength type semiconductor laser element, and a second semiconductor laser element 201a and a third semiconductor laser element 201b that oscillate laser beams having different wavelengths are integrated in a state of being separated from each other. That is, the second semiconductor laser element 201a and the third semiconductor laser element 201b have the common upper surface electrode 206 and substrate 210 on the upper surface, and have the second electrode 208a and the third electrode 208b that are insulated from each other as the lower surface electrodes. . In addition, a first semiconductor layer, an active layer, and a second semiconductor layer are formed between the substrate 210 and the second electrode 208a and the third electrode 208b (not shown in FIG. 4), and as a laser light emitting surface, It has the 2nd front end surface 203a and the 3rd front end surface 203b. The active layer and the semiconductor layer of the second semiconductor laser element 201a and the third semiconductor laser element 201b are different from each other.

  In addition, a second electrode pad 221a and a third electrode pad 221b that are insulated from each other are formed on the submount 220, the second electrode pad 221a and the second electrode 208a are joined, and the third electrode pad 221b and the third electrode pad 221b are joined together. The electrode 208b is joined. The second wire 222a is bonded to the second electrode pad 221a, and the third wire 222b is bonded to the third electrode pad 221b. The bonding position of the second wire 222a is provided in the vicinity of the second front end face 203a, and the bonding position of the third wire 222b is provided in the vicinity of the third front end face 203b. The first wire 211 bonded on the upper surface electrode 206 is provided in the vicinity of the laser light emitting surface of the semiconductor laser element 201 and in the vicinity of the intermediate point between the second front end surface 203a and the third front end surface 203b. The first wire 211, the second wire 222a, and the third wire 222b are arranged at substantially the same position in the resonator direction.

  With this configuration, when a voltage is applied between the first wire 211 and the second wire 222a or between the first wire 211 and the third wire 222b, it is the laser light emitting surface of the second semiconductor laser element 201a or the third semiconductor laser element 201b. Laser light is emitted from the second front end face 203a or the third front end face 203b. At this time, heat is generated in the vicinity of the laser light emission surface (second front end surface 203a or third front end surface 203b) from which the laser light of two wavelengths is emitted, but the second wire 222a provided in the vicinity of the laser light emission surface or Heat can be efficiently released from the third wire 222b. The first wire 211 is bonded to the second wire 222a and the third wire 222b at substantially the same position in the resonator direction, and the first wire 211 and the second wire 222a or the first wire 211 and the third wire 222b are used. In addition, heat can be released. Thereby, heat in the vicinity of the second front end face 203a or the third front end face 203b is efficiently released, and deterioration of the light emission characteristics of the semiconductor laser element 201 due to heat generation can be suppressed. In the present embodiment, all of the first wire 211, the second wire 222a, and the third wire 222b are provided in the vicinity of the laser light emitting surface. However, the present invention is not limited to this case, and these wires resonate. By bonding at substantially the same position in the vessel direction, heat can be efficiently released from a plurality of wires.

  Further, in the second semiconductor laser element 201a and the third semiconductor laser element 201b, the distribution of light density in the resonator direction in each active layer becomes maximum near the second front end face 203a and the third front end face 203b that emit light. The carrier density is insufficient. However, according to the semiconductor laser device 201 of the present embodiment, the first wire 211 bonded in the vicinity of the intermediate point between the second front end surface 203a and the third front end surface 203b when the upper surface electrode 206 is an n-side electrode. Electrons can be injected, and the current density of the supplied current is maximized in the vicinity of the second front end face 203a and the third front end face 203b. Thereby, a high current density is supplied to a region where the carrier density is insufficient, and the carrier density in the cavity direction in each active layer can be made uniform in the second semiconductor laser element 201a and the third semiconductor laser element 201b. .

(Third embodiment)
FIG. 5 is an overall perspective view of the semiconductor laser device according to the third embodiment of the present invention. The structure of the semiconductor laser device 330 according to the third embodiment of the present invention will be described with reference to FIG.

  A semiconductor laser device 330 according to the third embodiment is a three-wavelength semiconductor laser device in which the one-wavelength semiconductor laser element shown in the first embodiment and the two-wavelength semiconductor laser element shown in the second embodiment are combined. A second electrode pad 321a, a third electrode pad 321b, and a fourth electrode pad 321c that are insulated from each other are formed on the submount 320, and a bottom electrode of the one-wavelength semiconductor laser element 301c is joined to the fourth electrode pad 321c. The two bottom electrodes to be insulated of the two-wavelength semiconductor laser element 301b are joined to the second electrode pad 321a and the third electrode pad 321b, respectively.

  The second wire 322a is bonded to the second electrode pad 321a, the third wire 322b is bonded to the third electrode pad 321b, the fourth wire 322c is bonded to the fourth electrode pad 321c, and the third wire 322b is provided near the third front end face 303b, and the fourth wire 322c is provided near the fourth front end face 303c. The first wire 311 bonded to the upper electrode of the two-wavelength semiconductor laser element 301b is provided in the vicinity of an intermediate point between the second front end surface 303a and the third front end surface 303b, which are laser light emitting surfaces. The fifth wire 311c bonded to the upper surface electrode of the element 301c is provided in the vicinity of the fourth front end face 303c. A monitoring photodiode 340 is provided on the submount 320, and a sixth wire 341 is provided on the photodiode 340.

  At this time, the first wire 311, the third wire 322 b, the fourth wire 322 c, and the fifth wire 311 c are arranged at substantially the same position in the resonator direction of the one-wavelength semiconductor laser element 301 c and the two-wavelength semiconductor laser element 301 b. ing. Thereby, the heat in the vicinity of the third front end face 303b is efficiently released from the first wire 311 and the third wire 322b, and the heat in the vicinity of the fourth front end face 303c is released from the fourth wire 322c and the fifth wire 311c. At the same time, it is released efficiently. In this embodiment, the first wire 311, the third wire 322 b, the fourth wire 322 c, and the fifth wire 311 c are all provided in the vicinity of the laser light emission surface, but the first wire 311 and the third wire 322 b or Even if the fourth wire 322c and the fifth wire 311c are bonded at substantially the same position in the cavity direction of each semiconductor laser element, heat is generated from the first wire 311 and the third wire 322b or the fourth wire 322c and the fifth wire 311c. Can be efficiently released.

101, 201 Semiconductor laser element
201a Second semiconductor laser element
201b Third semiconductor laser element 102 Active layer 103, 203 Front end face
203a, 303a Second front end face
203b, 303b Third front end face
303c Fourth front end surface 104 Rear end surface 105 First semiconductor layer 106, 206 Upper surface electrode 107 Second semiconductor layer 108 Lower surface electrode
208a Second electrode
208b Third electrode 110, 210 Substrate 111, 211, 311 First wire 120, 220, 320 Submount 121, 221a, 321a Second electrode pad
221b, 321b Third electrode pad
321c Fourth electrode pad 122, 222a, 322a Second wire
222b, 322b Third wire
322c 4th wire
311c Fifth wire 130, 230, 330 Semiconductor laser device

Claims (3)

An active layer; a first semiconductor layer disposed on an upper surface of the active layer; an upper surface electrode formed on the upper surface of the first semiconductor layer; a first wire bonded to the upper surface electrode;
A semiconductor laser device including a second semiconductor layer disposed on the lower surface of the active layer, and a lower surface electrode formed on the lower surface of the second semiconductor layer, and a submount,
The second electrode pad formed on the upper surface of the submount and the lower surface electrode are joined,
A second wire is bonded to the upper surface of the second electrode pad;
A semiconductor laser device, wherein a bonding position of the first wire and the second wire is provided in the vicinity of a laser light emitting surface of the semiconductor laser element. The semiconductor laser element is a two-wavelength type semiconductor laser element that emits laser beams having different wavelengths,
The bottom electrode is composed of a second electrode and a third electrode which are insulated from each other,
A third electrode pad that is insulated from the second electrode pad is formed on the upper surface of the submount;
The second electrode and the second electrode pad are joined,
The third electrode and the third electrode pad are joined,
A third wire is bonded to the upper surface of the third electrode pad;
The semiconductor laser device according to claim 1, wherein the bonding position of the third wire is provided in the vicinity of a laser light emitting surface of the semiconductor laser element. A fourth electrode pad is formed on the top surface of the submount to insulate both the second electrode pad and the third electrode pad;
A single-wavelength semiconductor laser element is bonded on the upper surface of the fourth electrode pad,
A fourth wire is bonded to the upper surface of the fourth electrode pad;
3. The semiconductor laser device according to claim 2, wherein the bonding position of the fourth wire is provided in the vicinity of the laser light emitting surface of the one-wavelength semiconductor laser element.

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