JP2011035130A - Semiconductor laser apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser apparatus, wherein bonded laser devices are prevented from being mutually peeled off. <P>SOLUTION: A semiconductor laser device 40 configuring the semiconductor laser apparatus includes a first semiconductor laser device 10, a second semiconductor laser device 20 including an electrode layer 26 electrically connected to a side of a semiconductor layer 23, and a wiring electrode 11 formed in contact with the surface of a semiconductor layer 3 in the first semiconductor laser device 10. Moreover, a side of the electrode layer 26 in the second semiconductor laser device 20 is bonded to a surface of the wiring electrode 11 which is opposite to the first semiconductor laser device 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device including a first semiconductor laser element and a second semiconductor laser element.

  Conventionally, in a CD / CD-R drive, an infrared semiconductor laser element that emits infrared light having a wavelength of about 780 nm has been used as a light source. Further, in a DVD drive, a red semiconductor laser element that emits red light having a wavelength of about 650 nm has been used as a light source.

  On the other hand, in recent years, a DVD that can be recorded / reproduced using blue-violet light has been developed. For such DVD recording / reproduction, a blue DVD drive using a blue-violet semiconductor laser element having a wavelength of about 405 nm is being developed at the same time. This DVD drive requires compatibility with conventional CD / CD-R and DVD.

  In this case, a method of providing a plurality of optical disk pickups for individually emitting infrared light, red light, and blue-violet light in a DVD drive, or individually providing infrared, red, and blue-violet laser elements in one optical disk pickup Depending on the method, compatibility with conventional CDs, DVDs and recordable / reproducible DVDs is realized. However, since this method increases the number of parts, it may be difficult to reduce the size of the pickup device, simplify the configuration, and reduce the price.

  In order to suppress such an increase in the number of components, conventionally, a two-wavelength semiconductor laser element in which an infrared laser element and a red laser element are integrated on one chip has been put into practical use. On the other hand, since the blue-violet laser element is not formed on a GaAs substrate or the like, it is very difficult to make the blue-violet laser element into one chip together with the infrared and red laser elements. Therefore, conventionally, an integrated semiconductor laser element in which a red laser element and an infrared laser element are joined to a blue-violet laser element has been proposed (for example, see Patent Document 1).

Patent Document 1 discloses a semiconductor laser device in which a red semiconductor laser element and an infrared semiconductor laser element are bonded and integrated on the surface of a blue-violet semiconductor laser element. In the semiconductor laser device described in Patent Document 1, the p-side pad electrodes of the red semiconductor laser element and the infrared semiconductor laser element are on the semiconductor layer (nitride-based p-type semiconductor layer) of the blue-violet semiconductor laser element. The laser elements are bonded to each other on the surface of the insulating film made of SiO _{2 so as} to be driven while being electrically insulated from each other. The insulating film of the blue-violet semiconductor laser element is formed so as to extend from the end of the element (p-type cladding layer) to the side surface of the ridge (projection) formed in the center of the element. Thereby, the insulating film has a function as a current blocking layer for forming a current passage portion in the ridge (convex portion).

JP 2006-128602 A

However, in the semiconductor laser device disclosed in Patent Document 1, generally, the adhesion between the nitride semiconductor layer and the insulating film made of SiO ₂ in the blue-violet semiconductor laser element is not so good. First, since the p-side pad electrode of each of the red semiconductor laser element and the infrared semiconductor laser element is bonded onto the surface of the insulating film (current blocking layer) formed on the semiconductor layer of the blue-violet semiconductor laser element, There is a problem that the red and infrared semiconductor laser elements are easily separated from the blue-violet semiconductor laser element together with the insulating film (current blocking layer) of the blue-violet semiconductor laser element. Also, in the manufacturing process, when a blue-violet laser element wafer and a red / infrared laser element wafer are bonded to each other and stress is applied when cleaving or dividing into chips, the reason is as follows. Thus, there is a problem that the wafer of the red / infrared laser element bonded through the insulating film is easily peeled from the wafer of the blue-violet laser element.

  The present invention has been made in order to solve the above-described problems, and one object of the present invention is to provide a semiconductor laser device capable of suppressing separation of bonded semiconductor laser elements from each other. Is to provide.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, a semiconductor laser device according to an aspect of the present invention includes a first conductive type first semiconductor layer, a first active layer, and a second conductive type second semiconductor layer stacked in this order. A first semiconductor laser element, a third semiconductor layer of a first conductivity type or a second conductivity type, a second active layer, and a fourth semiconductor layer of the other of the first conductivity type or the second conductivity type; A second semiconductor laser element including a first electrode electrically connected to the semiconductor layer side; and a wiring electrode formed in direct contact with the surface of the second semiconductor layer of the first semiconductor laser element, The first electrode side of the second semiconductor laser element is bonded to the surface of the wiring electrode opposite to the first semiconductor laser element.

In the semiconductor laser device according to one aspect of the present invention, as described above, the semiconductor laser device is formed in direct contact with the surface of the first semiconductor laser element, the second semiconductor laser element, and the second semiconductor layer of the first semiconductor laser element. And the first electrode side of the second semiconductor laser element is bonded to the surface of the wiring electrode opposite to the first semiconductor laser element. That is, the second semiconductor laser element is joined to the first semiconductor laser element side at the portion of the wiring electrode made of metal formed in direct contact with the surface of the second semiconductor layer. Unlike the case of being formed through an insulating film made of SiO ₂ or the like laminated on the surface of the second semiconductor layer, the wiring electrode made of metal having better adhesion than the second semiconductor layer and the insulating film Adhesiveness can be improved by the amount of direct contact. As a result, it is possible to prevent the second semiconductor laser element having the first electrode portion bonded to the wiring electrode from peeling from the first semiconductor laser element side. In the manufacturing process, the wafers are separated from each other when stress is applied to the wafer in the cleaving process or chip forming process after bonding the wafer of the first semiconductor laser element and the wafer of the second semiconductor laser element. Can be suppressed.

  In the semiconductor laser device according to the above aspect, the wiring electrode is preferably formed in a Schottky contact with the second semiconductor layer of the first semiconductor laser element. With this configuration, since the second semiconductor layer of the first semiconductor laser element and the wiring electrode are insulated from each other by the Schottky barrier, the second semiconductor laser element can be separated from the first semiconductor laser element side. While suppressing, it is possible to insulate the semiconductor laser elements joined to each other.

In this case, preferably, the second conductivity type is p-type, the second semiconductor layer is made of a nitride-based semiconductor, and the wiring electrode includes at least one of Ti, Al, Hf, Ta, and Mo. . If comprised in this way, the electrode for wiring can be formed in the state which carried out the Schottky contact reliably with respect to the surface of the 2nd semiconductor layer which consists of a p-type nitride-type semiconductor. In addition, the adhesion between the second semiconductor layer made of a nitride-based semiconductor and the metal constituting the wiring electrode is greater than the adhesion between the second semiconductor layer made of a nitride-based semiconductor and an insulating film made of SiO ₂ or the like. Therefore, peeling of the second semiconductor laser element from the first semiconductor laser element can be effectively suppressed.

  In the semiconductor laser device according to the aforementioned aspect, the second semiconductor layer of the first semiconductor laser element preferably includes a high resistance region on the surface on the side in contact with the wiring electrode. According to this configuration, the first semiconductor laser element and the wiring electrode are insulated from each other by the high resistance region of the second semiconductor layer, so that the second semiconductor laser element is peeled off from the first semiconductor laser element side. Insulating property between the semiconductor laser elements bonded to each other can be improved.

  In the semiconductor laser device according to the above aspect, preferably, the first semiconductor laser element is electrically connected to the second semiconductor layer side in the current path portion of the second semiconductor layer, and a wiring electrode is formed. A second electrode formed in direct contact with the surface of the second semiconductor layer in the non-region; According to this structure, the second electrode made of metal is electrically connected to the first semiconductor laser element in the current path portion and directly contacts the surface of the second semiconductor layer in a portion other than the current path portion. Since the second semiconductor layer and the second electrode made of a metal having better adhesion than the insulating film are in direct contact with each other in the region other than the current passage portion, the second semiconductor layer and the second electrode It is possible to improve the adhesion. Thereby, it can suppress that a 2nd electrode peels from the 2nd semiconductor layer surface of a 1st semiconductor laser element.

  In the semiconductor laser device according to the first aspect, preferably, an optical waveguide is formed on a surface of the first semiconductor laser element facing the second semiconductor laser element, and the second semiconductor laser element is an optical waveguide. One wiring electrode is provided on each side of the optical waveguide, and two wiring electrodes are formed so as to be in direct contact with the surface of each second semiconductor layer on both sides of the optical waveguide, and the first semiconductor of each wiring electrode is formed. The first electrode side of each second semiconductor laser element is bonded to the surface opposite to the laser element to constitute a three-wavelength semiconductor laser element. With this configuration, the three-wavelength semiconductor laser element can be formed in a state in which the first semiconductor laser element and each of the two second semiconductor laser elements are insulated from each other. Can be driven independently.

It is sectional drawing for demonstrating the schematic structure of the semiconductor laser apparatus by this invention. It is sectional drawing which showed the structure of the semiconductor laser apparatus by 1st Embodiment of this invention. 1 is a plan view showing a structure of a semiconductor laser device according to a first embodiment of the present invention. It is the expanded sectional view which showed the detailed structure of the part by which the electrode for wiring was joined to the blue-violet semiconductor laser element by 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 1st Embodiment of this invention. It is a top view for demonstrating the manufacturing process of the semiconductor laser apparatus by 1st Embodiment of this invention. It is sectional drawing which showed the structure of the semiconductor laser apparatus by 2nd Embodiment of this invention. It is sectional drawing which showed the structure of the semiconductor laser apparatus by 3rd Embodiment of this invention. It is the top view which showed the structure of the semiconductor laser apparatus by 3rd Embodiment of this invention. It is sectional drawing which showed the structure of the semiconductor laser apparatus by 4th Embodiment of this invention. It is the top view which showed the structure of the semiconductor laser apparatus by 4th Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 4th Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 4th Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the semiconductor laser apparatus by 4th Embodiment of this invention. It is sectional drawing which showed the structure of the semiconductor laser apparatus by 5th Embodiment of this invention. It is sectional drawing which showed the structure of the semiconductor laser apparatus by 6th Embodiment of this invention.

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

  First, with reference to FIG. 1, before describing a specific embodiment of the present invention, a schematic configuration of a semiconductor laser device according to the present invention will be described by taking a semiconductor laser element 40 as an example.

  The semiconductor laser device according to the present invention includes a semiconductor laser element 40 as shown in FIG. The semiconductor laser element 40 is an integrated semiconductor laser element in which the second semiconductor laser element 20 is bonded to the surface of the first semiconductor laser element 10.

  The first semiconductor laser element 10 has a structure in which a first conductivity type semiconductor layer 1, an active layer 2, and at least a part of a second conductivity type semiconductor layer 3 are sequentially stacked. The semiconductor layer 1 is composed of a first conductivity type cladding layer having a band gap larger than that of the active layer 2. Here, in the pn junction type first semiconductor laser element 10, the semiconductor layer 1 and the semiconductor layer 3 have different conductivity types. The semiconductor layer 1 may be p-type and the semiconductor layer 3 may be n-type, or the semiconductor layer 1 may be n-type and the semiconductor layer 3 may be p-type. The semiconductor layer 1 and the semiconductor layer 3 are examples of the “first conductive type first semiconductor layer” and the “second conductive type second semiconductor layer” of the present invention, respectively.

  The active layer 2 has a single layer, a single quantum well (SQW) structure, or a multiple quantum well (MQW) structure. The active layer 2 may be undoped or doped. The semiconductor layer 3 is composed of a second conductivity type cladding layer having a band gap larger than that of the active layer 2. Note that a light guide layer, a carrier block layer, or the like may be formed between the semiconductor layer 1 and the active layer 2. Further, a contact layer may be provided on the semiconductor layer 3 opposite to the active layer 2. In this case, the contact layer is preferably made of a semiconductor having a smaller band gap than the semiconductor layer 3. In addition, a light guide layer, a carrier block layer, or the like may be formed between the active layer 2 and the semiconductor layer 3.

  Moreover, in this invention, the semiconductor layer 1 may be comprised with the board | substrate or the semiconductor layer, and may be comprised with both the board | substrate and the semiconductor layer. When the semiconductor layer 1 is composed of both a substrate and a semiconductor layer, the substrate is formed on the side of the semiconductor layer 1 opposite to the side on which the semiconductor layer 3 is formed (the lower surface side of the semiconductor layer 1).

Further, on the surface of the flat semiconductor layer 3, a striped ohmic electrode layer 4 extending along the resonator direction (A direction) is formed. A current blocking layer 5 is formed on the upper surface of the flat portion of the semiconductor layer 3 and on both side surfaces of the ohmic electrode layer 4. As a result, an optical waveguide is formed in the active layer 2 in the lower region of the ohmic electrode layer 4. The ohmic electrode layer 4 has a metal layer containing at least one of Pt, Pd, Rh, and Ni. Further, the current blocking layer _{5, SiO 2, Al 2 O 3} , ZrO 2, TiO 2, Ta 2 O 5, La 2 O 3, Si, AlN, and the like AlGaN and SiN. Moreover, you may form the current block layer 5 so that it may have a laminated structure using the said material.

  Here, in the present invention, as shown in FIG. 1, the current blocking layer 5a on the B2 side is formed in almost all regions on the surface of the semiconductor layer 3 from the ohmic electrode layer 4 to the end on the B2 side. On the other hand, the current blocking layer 5b on the B1 side is formed only in a partial region on the surface of the semiconductor layer 3 in the B1 direction from the ohmic electrode layer 4. The wiring electrode 11 is formed in direct contact with the upper surface of the semiconductor layer 3 in a region where the current blocking layer 5b on the B1 side is not formed. The wiring electrode 11 is provided as a lead-out wiring when the second semiconductor laser element 20 is joined.

In the present invention, the wiring electrode 11 made of metal is formed in direct contact with the upper surface of the semiconductor layer 3 without the current blocking layer 5b (insulating film made of SiO ₂ or the like). The electrode 11 and the semiconductor layer 3 are in a state of good adhesion. The electrode layer 26 of the second semiconductor laser element 20 is bonded to the wiring electrode 11 provided on the first semiconductor laser element 10 side via a conductive adhesive layer 30 such as AuSn solder. Here, when the semiconductor layer 3 is composed of a nitride-based semiconductor, the adhesion between the semiconductor layer 3 and the wiring electrode 11 made of metal is larger than the adhesion between the semiconductor layer 3 and the current blocking layer 5b. It is possible to effectively suppress peeling of the second semiconductor laser element 20 with respect to the first semiconductor laser element 10. In the present invention, the conductive adhesive layer may be made of a solder material such as Au, Sn, In, Pb, Ge, Ag, Cu, or Si or an alloy material thereof. Further, other joining methods that do not use solder may be used.

  Here, when the surface of the semiconductor layer 3 is p-type, the wiring electrode 11 has a metal layer containing at least one of Ti, Al, Hf, Ta, and Mo on the contact surface side with the semiconductor layer 3. It is preferable to have. As a result, the wiring electrode 11 is formed in a Schottky contact with the semiconductor layer 3. That is, since there is a Schottky barrier at the interface between the wiring electrode 11 and the semiconductor layer 3, it is difficult for current to flow from the semiconductor layer 3 side to the wiring electrode 11, and the semiconductor layer 3 and the wiring electrode 11. Is insulated. When the semiconductor layer 3 is n-type, the wiring electrode 11 has a metal layer containing at least one of Au, Pd, Ni, Ir, and Pt on the contact surface side with the semiconductor layer 3. preferable. As a result, the wiring electrode 11 is formed in a Schottky contact with the semiconductor layer 3.

The semiconductor layer 3 may include a high resistance region on the surface on the side where the wiring electrode 11 contacts. In this case, the p-type or n-type dopant (Mg or Si) is inactivated by performing hydrogen diffusion in an atmosphere composed of H ₂ gas or a gas containing H ₂ (such as NH ₃ gas) in the manufacturing process. Therefore, a high resistance region can be formed in the semiconductor layer. In addition, a high resistance region can be formed in the semiconductor layer 3 even in an atmosphere containing H ₂ in an inert gas such as N ₂ gas, O ₂ gas, or Ar gas.

  Further, in the manufacturing process, the p-type or n-type dopant (Mg or Si) is deactivated by ion-implanting an impurity that deactivates the p-type or n-type dopant into the surface of the semiconductor layer 3. Therefore, it is possible to form a high resistance region in the semiconductor layer. Here, when the semiconductor layer 3 is p-type, it is preferable to ion-implant any of C, B, Si, and P impurities. Further, when the semiconductor layer 3 is n-type, it is preferable to ion-implant any of C, B, and P impurities. Note that when a high resistance region is formed on the surface of the semiconductor layer 3, a Schottky contact is made regardless of whether the semiconductor layer 3 is p-type or n-type, and therefore, the wiring electrode 11 includes Ti, Al, Hf, It is possible to configure using Ta, Mo, Ag, Pt, Pd, Rh, Ni, Au, or the like.

An electrode layer 6 (pad electrode) extending in the A direction is formed on predetermined regions of the ohmic electrode layer 4 and the current block layer 5 (5a and 5b). In addition, an insulating layer 7 made of SiO ₂ is formed on the upper surface of the electrode layer 6 to prevent contact with the electrode layer 26 of the second semiconductor laser element 20. An electrode layer 8 is formed on the lower surface of the semiconductor layer 1. The electrode layer 6 is an example of the “second electrode” in the present invention, and the electrode layer 26 is an example of the “first electrode” in the present invention.

  As shown in FIG. 1, the second semiconductor laser element 20 has a structure in which a first conductivity type semiconductor layer 21, an active layer 22, and a second conductivity type semiconductor layer 23 are sequentially stacked. Here, in the pn junction type second semiconductor laser element 20, the semiconductor layer 21 and the semiconductor layer 23 have different conductivity types. The semiconductor layer 21 may be p-type and the semiconductor layer 23 may be n-type, or the semiconductor layer 21 may be n-type and the semiconductor layer 23 may be p-type. The semiconductor layer 21 and the semiconductor layer 23 are respectively “the first semiconductor type of the first conductivity type or the second conductivity type” and “the fourth of the other of the first conductivity type or the second conductivity type” of the present invention. It is an example of a “semiconductor layer”.

  The semiconductor layer 21 is made of a cladding layer having a band gap larger than that of the active layer 22. The active layer 22 is composed of a single layer, an SQW structure, or an MQW structure. The active layer 22 may be undoped or doped. The semiconductor layer 23 is made of a clad layer having a band gap larger than that of the active layer 22. A light guide layer, a carrier block layer, or the like may be formed between the semiconductor layer 21 and the active layer 22. Further, a contact layer may be provided on the semiconductor layer 23 opposite to the active layer 22. In this case, the contact layer is preferably made of a semiconductor having a smaller band gap than the semiconductor layer 23. Further, a light guide layer, a carrier block layer, or the like may be formed between the active layer 22 and the semiconductor layer 23.

  Moreover, the semiconductor layer 21 may be comprised with the board | substrate or the semiconductor layer, and may be comprised with both the board | substrate and the semiconductor layer. When the semiconductor layer 21 includes both the substrate and the semiconductor layer, the substrate is formed on the side of the semiconductor layer 21 opposite to the side on which the semiconductor layer 23 is formed (the upper surface side of the semiconductor layer 21).

Further, on the surface (lower surface) of the flat semiconductor layer 23, a stripe-shaped ohmic electrode layer 24 extending along the resonator direction (A direction) is formed. A current blocking layer 25 is formed on the lower surface of the flat portion of the semiconductor layer 23 and on both side surfaces of the ohmic electrode layer 24. Thereby, an optical waveguide is formed in the active layer 22 in the upper region of the ohmic electrode layer 24. The current blocking layer 25 is made of SiO ₂ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ , La ₂ O ₃ , Si, AlN, AlGaN, SiN, or the like. Further, the current blocking layer 25 may be formed using the above material so as to have a laminated structure.

Further, in the first semiconductor laser element 10 and the second semiconductor laser element 20, a light emitting surface and a light reflecting surface are respectively formed at both ends in the resonator direction (direction perpendicular to the paper surface of FIG. 1). In addition, a low-reflectivity dielectric multilayer film is formed on the light emission surface of each semiconductor laser element, and a high-reflectivity dielectric multilayer film is formed on the light reflection surface. Here, as the dielectric multilayer film, GaN, AlN, BN, Al ₂ O ₃ , SiO ₂ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , La ₂ O ₃ , SiN, AlON and MgF ₂ , A multilayer film made of Ti ₃ O ₅ , Nb ₂ O _3, or the like which is a material having a different hybrid ratio can be used.

  An electrode layer 26 (pad electrode) extending in the A direction is formed on predetermined regions of the ohmic electrode layer 24 and the current blocking layer 25. An electrode layer 27 is formed on the upper surface of the semiconductor layer 21.

In the semiconductor laser device 40 according to the present invention, as described above, the first semiconductor laser device 10, the second semiconductor laser device 20, and the surface of the semiconductor layer 3 of the first semiconductor laser device 10 are formed in direct contact. The wiring electrode 11 is provided, and the electrode layer 26 side of the second semiconductor laser element 20 is bonded to the surface of the wiring electrode 11 opposite to the first semiconductor laser element 10. That is, since the second semiconductor laser element 20 is joined to the first semiconductor laser element 10 side at the portion of the wiring electrode 11 made of metal formed in direct contact with the surface of the semiconductor layer 3, for example, for wiring Unlike the case where the electrode 11 is formed through an insulating film made of SiO ₂ or the like provided on the surface of the semiconductor layer 3, the wiring electrode 11 made of a metal having better adhesion than the semiconductor layer 3 and the insulating film. Adhesiveness can be improved by the amount of direct contact. As a result, the second semiconductor laser element 20 in which the electrode layer 26 is bonded to the wiring electrode 11 can be prevented from peeling from the first semiconductor laser element 10 side. Also in the manufacturing process, when stress is applied to the wafer in the cleaving process or chip forming process after the wafer of the first semiconductor laser element 10 and the wafer of the second semiconductor laser element 20 are bonded together, Separation from each other can be suppressed.

  Further, in the semiconductor laser device 40 according to the present invention, the wiring electrode 11 is formed in a Schottky contact with the semiconductor layer 3 of the first semiconductor laser device 10, whereby the semiconductor layer of the first semiconductor laser device 10 is formed. 3 and the wiring electrode 11 are insulated from each other by the Schottky barrier, so that the second semiconductor laser element 20 is prevented from peeling from the first semiconductor laser element 10 side, and the semiconductor laser elements joined to each other are separated. Can be insulated.

(First embodiment)
First, the structure of the semiconductor laser device 100 according to the first embodiment of the present invention will be described with reference to FIGS. 2 is a cross-sectional view taken along line 1000-1000 in FIG.

  In the semiconductor laser device 100 of the present invention, as shown in FIG. 2, a red semiconductor laser element 70 having an oscillation wavelength of about 650 nm is bonded on the surface of a blue-violet semiconductor laser element 50 having an oscillation wavelength of about 405 nm. A two-wavelength semiconductor laser element 90 is fixed on a base (submount) 91 via a conductive adhesive layer 31 made of AuSn solder or the like. The blue-violet semiconductor laser element 50 and the red semiconductor laser element 70 are examples of the “first semiconductor laser element” and the “second semiconductor laser element” in the present invention, respectively.

In addition, as shown in FIG. 2, the blue-violet semiconductor laser device 50 includes an n-type Al _0.15 Ga _0.85 N doped with Si on an upper surface of an n-type GaN substrate 51 having a thickness of about 100 μm. Type cladding layer 52, active layer 53 having an MQW structure in which quantum well layers made of InGaN with a high In composition and barrier layers made of InGaN with a low In composition are alternately stacked, and Mg-doped with a thickness of about 400 nm A p-type cladding layer 54 made of p-type Al _0.07 Ga _0.93 N is formed. The n-type GaN substrate 51 and the n-type cladding layer 52 are the “first conductivity type first semiconductor layer” of the present invention, and the p-type cladding layer 54 is the “second conductivity type second semiconductor layer” of the present invention. It is an example of “semiconductor layer” and “nitride-based semiconductor”.

As shown in FIG. 2, the p-type cladding layer 54 includes a convex portion 54a formed at a substantially central portion in the width direction (B direction) of the element, and a flat portion extending on both sides (B direction) of the convex portion 54a. 54b. Further, on the protrusion 54 a of the p-type cladding layer 54, a p-side contact layer 55 made of Mg-doped p-type In _0.02 Ga _0.98 N having a thickness of about 10 nm and a p-side contact layer 55 A p-side ohmic electrode 56 is formed that is stacked in the order of Pt layer, Pd layer, and Pt layer. A ridge 60 for forming an optical waveguide is formed in the active layer 53 by the convex portion 54a of the p-type cladding layer 54, the p-side contact layer 55, and the p-side ohmic electrode 56. The ridge 60 has a width of about 1.5 μm in the B direction and is formed so as to extend along the resonator direction (A direction). The p-side contact layer 55 is an example of the “second conductivity type second semiconductor layer” in the present invention.

A current blocking layer 57 made of SiO ₂ is formed on a part of the upper surface of the flat portion 54 b of the p-type cladding layer 54 and on the side surface of the ridge 60.

  Here, in the first embodiment, the current block layer 57a on the B2 side centering on the ridge 60 is formed on the entire region from the flat portion 54b to the end on the B2 side, while the current block layer on the B1 side is formed. The layer 57b is formed only on a side surface of the ridge 60 and a partial region of the flat portion 54b on the B1 side. In addition, in the region where the current blocking layer 57b of the flat portion 54b on the B1 side is not formed, the wiring electrode 61 is formed so as to be in direct contact with the upper surface of the flat portion 54b. Thereby, the wiring electrode 61 made of metal is formed in direct contact with the flat portion 54b of the p-type cladding layer 54 without passing through the current blocking layer 57b, so that the wiring electrode 61 and the p-type cladding layer are formed. 54 is in a state of good adhesion.

  Further, in the first embodiment, a p-side pad electrode 78 (to be described later) of the red semiconductor laser element 70 is bonded onto the upper surface of the wiring electrode 61 via the conductive adhesive layer 32, whereby the two-wavelength semiconductor laser element 90. Is configured.

  Further, as shown in FIG. 4, the wiring electrode 61 includes a Ti layer 61 a having a thickness of about 10 nm to about 50 nm and a Pd layer having a thickness of about 100 nm to about 200 nm in order from the p-side contact layer 55. 61b and an Au layer 61c having a thickness of about 500 nm are laminated in this order. Thus, the wiring electrode 61 is formed in a Schottky contact with the p-type cladding layer 54 (flat portion 54b). That is, since a Schottky barrier exists at the interface between the wiring electrode 61 (Ti layer 61a) and the p-type cladding layer 54, current does not easily flow from the p-type cladding layer 54 side toward the wiring electrode 61. It is configured as follows. In addition, insulation between the p-type cladding layer 54 and the wiring electrode 61 is achieved by Schottky contact.

  Further, as shown in FIG. 3, the wiring electrode 61 has a resonator direction on a flat portion 54b in a region where a red semiconductor laser element 70 (outer shape is indicated by a two-dot chain line) of the blue-violet semiconductor laser element 50 is joined. It is formed so as to have a wire bond region 61d that extends along the (A direction) and protrudes in a convex shape in the B1 direction from a substantially central portion in the A direction. In FIG. 3, for convenience, the outer shape of the red semiconductor laser element 70 is indicated by a two-dot chain line, whereby the wiring electrode 61 and the p-side pad electrode 58 formed on the surface of the blue-violet semiconductor laser element 50. The shape is shown.

Also, as shown in FIG. 3, a p-side pad electrode 58 made of Au or the like is formed so as to cover predetermined regions on the ridge 60 and the current blocking layer 57. The p-side pad electrode 58 has a wire bond region 58a extending on the ridge 60 along the resonator direction (A direction) and projecting in a convex shape in the B2 direction from a substantially central portion in the A direction. Yes. Further, as shown in FIG. 2, an insulating layer 62 made of SiO ₂ is formed on the p-side pad electrode 58 to prevent contact with the p-side pad electrode 78 of the red semiconductor laser element 70 and the like. The insulating layer 62 is formed so as to cover the surface of the p-side pad electrode 58 excluding the wire bond region 58a. The p-side pad electrode 58 is an example of the “second electrode” in the present invention, and the p-side pad electrode 78 is an example of the “first electrode” in the present invention.

  Further, on the lower surface of the n-type GaN substrate 51, an n-side electrode 59 is formed in which an Al layer, a Pd layer, and an Au layer are stacked in order from the n-type GaN substrate 51.

  As shown in FIG. 2, the red semiconductor laser device 70 includes an n-type cladding layer 72 made of AlGaInP, a quantum well layer made of GaInP, and an AlGaInP on the lower surface of an n-type GaAs substrate 71 having a thickness of about 100 μm. An active layer 73 having an MQW structure in which barrier layers made of is alternately stacked and a p-type cladding layer 74 made of AlGaInP are formed. The n-type GaAs substrate 71 and the n-type cladding layer 72 are the “first conductivity type third semiconductor layer” of the present invention, and the p-type cladding layer 74 is the “second conductivity type fourth semiconductor layer” of the present invention. It is an example of a “semiconductor layer”.

  Further, as shown in FIG. 2, the p-type cladding layer 74 includes a convex portion 74a formed at a position close to the B1 side from a substantially central portion of the element, and a flat extending on both sides (B direction) of the convex portion 74a. Part 74b. Further, on the convex portion 74 a of the p-type cladding layer 74, a p-side contact layer 75 and a p-side ohmic electrode 76 that is laminated in the order of the Cr layer and the Au layer in order from the p-side contact layer 75 are formed. ing. A ridge 80 for forming an optical waveguide is formed in the active layer 73 by the convex portion 74 a of the p-type cladding layer 74, the p-side contact layer 75, and the p-side ohmic electrode 76. The ridge 80 has a width of about 2 μm in the B direction and is formed so as to extend along the resonator direction (A direction). The p-side contact layer 75 is an example of the “second conductivity type fourth semiconductor layer” in the present invention.

A current blocking layer 77 made of SiO ₂ is formed on the lower surface of the flat portion 74 b of the p-type cladding layer 74 and the side surface of the ridge 80. A p-side pad electrode 78 in which a Pt layer having a thickness of about 200 nm and an Au layer having a thickness of about 3 μm are stacked is formed on the lower surfaces of the ridge 80 and the current blocking layer 77.

  On the upper surface of the n-type GaAs substrate 71, an n-side electrode 79 is formed in which an AuGe layer, a Ni layer, and an Au layer are stacked in this order from the n-type GaAs substrate 71.

  As shown in FIG. 2, the blue-violet semiconductor laser device 50 is connected to a lead terminal via a metal wire 92 bonded to a wire bond region 58a of a p-side pad electrode 58, and an n-side electrode 59 is It is electrically fixed to the base 91 through a conductive adhesive layer 31 such as AuSn solder. The red semiconductor laser element 70 is connected to the lead terminal via a metal wire 93 bonded to the wire bond region 61 d of the wiring electrode 61 and is connected to the n-side electrode 79 via a metal wire 94. It is electrically fixed to the base 91. Thereby, in the two-wavelength semiconductor laser device 90, the p-side pad electrodes 58 and 78 of each semiconductor laser device are connected to the lead terminals insulated from each other, and the n-side electrodes 59 and 79 are connected via the base 91. It is configured to be connected to a common negative lead terminal (cathode common).

  A manufacturing process for the semiconductor laser device 100 according to the first embodiment is now described with reference to FIGS.

  In the manufacturing process of the semiconductor laser device 100 according to the first embodiment, first, as shown in FIG. 5, the n-type cladding layer 52, the active layer 53, and the p-type are formed on the upper surface of the n-type GaN substrate 51 by using the MOCVD method. The mold cladding layer 54 and the p-side contact layer 55 are stacked to form a semiconductor layer. Thereafter, the p-side ohmic electrode 56 is formed on the upper surface of the p-side contact layer 55 using a vacuum deposition method.

  After that, as shown in FIG. 5, a resist 65 extending in a stripe shape in the A direction (direction perpendicular to the paper surface) is patterned on the upper surface of the p-side ohmic electrode 56 using photolithography, and the resist 65 is masked. As a result, the p-side ohmic electrode 56, the p-side contact layer 55, and a part of the p-type cladding layer 54 are dry-etched toward the C1 side to form the ridge 60 in the semiconductor layer.

  Thereafter, in the manufacturing process of the first embodiment, as shown in FIG. 6, photolithography is applied to a predetermined region of the flat portion 54 b of the etched p-type cladding layer 54 using the photolithography (perpendicular to the paper surface). The resist 66 extending in a stripe shape is patterned. In this state, a current blocking layer 57 is formed on the surface of the p-type cladding layer 54 using a plasma CVD method or the like. As a result, a current blocking layer 57a is formed on the B1 side of the ridge 60, and a current blocking layer 57b is formed on the B2 side.

  After removing the resist 65, as shown in FIG. 7, the p-side pad electrode is continuously covered on a predetermined region of the current blocking layer 57 and the upper surface of the ridge 60 by using photolithography and vacuum deposition. 58 is patterned. Thereby, the p-side pad electrode 58 having a shape as shown in FIG. 3 is formed.

  Thereafter, as shown in FIG. 8, the wiring electrode 61 is patterned on the surface of the p-type cladding layer 54 from which the resist 66 has been removed, using photolithography and vacuum deposition. At this time, as shown in FIG. 4, first, a Ti layer 61a having a thickness of about 10 nm to about 50 nm is formed on the surface of the p-type cladding layer 54, and then a Pd having a thickness of about 100 nm to about 200 nm. A wiring electrode 61 is formed by laminating a layer 61b and an Au layer 61c having a thickness of about 500 nm in this order. Thereby, the wiring electrode 61 is formed at the contact interface with the p-type cladding layer 54 via the Ti layer 61a.

  Thereafter, the insulating layer 62 (see FIG. 8) is formed so as to cover a predetermined region of the p-side pad electrode 58 by using photolithography, plasma CVD, or the like. In this manner, a wafer on which the blue-violet semiconductor laser element 50 excluding the n-side electrode 59 is formed is manufactured.

  Next, as shown in FIG. 9, an n-type cladding layer 72, an active layer 73, a p-type cladding layer 74, a p-side contact layer 75, and a p-side ohmic electrode 76 are sequentially formed on the upper surface of the n-type GaAs substrate 71. After that, the ridge 80 and the current blocking layer 77 are formed. Thereafter, the p-side pad electrode 78 is formed so as to cover both side surfaces of the ridge 80 and the upper surface of the current blocking layer 77 by using a vacuum deposition method. Thereby, a wafer on which the red semiconductor laser element 70 excluding the n-side electrode 79 is formed is manufactured.

  After that, as shown in FIG. 10, the wafer on which the blue-violet semiconductor laser element 50 is formed and the wafer on which the red semiconductor laser element 70 is formed are conductive while the wiring electrode 61 and the p-side pad electrode 78 are opposed to each other. Bonding is performed using the adhesive layer 32. Thereby, the p-side pad electrode 78 of the red semiconductor laser element 70 is drawn out to the wiring electrode 61 side.

  Then, as shown in FIG. 11, after polishing the upper surface of the n-type GaAs substrate 71 so that the n-type GaAs substrate 71 has a thickness of about 100 μm, the n-type GaAs substrate 71 is used by vacuum deposition and photolithography. An n-side electrode 79 is formed on the upper surface. Subsequently, after polishing the lower surface of the n-type GaN substrate 51 so that the n-type GaN substrate 51 has a thickness of about 100 μm, a predetermined deposition on the lower surface of the n-type GaN substrate 51 is performed using vacuum deposition and photolithography. An n-side electrode 59 is formed in the region.

  Thereafter, at the separation position shown on the red semiconductor laser element 70 side in FIG. 12, the surface (upper surface) of the GaAs substrate 71 is scribed in the A direction using a diamond point, thereby forming an isolation groove 81 for element separation. Form. FIG. 11 is a cross-sectional view taken along line 1100-1100 in FIG.

  After that, the wafer is cleaved in a bar shape along the B direction at the cleavage position shown in FIG. 12, thereby forming the resonator surface of each semiconductor laser element. In addition, since the adhesion between the wiring electrode 61 and the p-type cladding layer 54 is high, the wafer of the red semiconductor laser element 70 is suppressed from being separated from the wafer of the blue-violet semiconductor laser element 50 during cleavage. . Then, a low-reflectance dielectric multilayer film is formed on the light-emitting side resonator surface, and a high-reflectivity dielectric multilayer film is formed on the light-reflection side resonator surface. Thereafter, the bar is divided into elements along the resonator direction (A direction) at the element dividing position shown in FIG. At this time, the wafer on which the blue-violet semiconductor laser element 50 is formed is divided in the B direction along the element dividing position, and the wafer on which the red semiconductor laser element 70 is formed is bonded to the wiring electrode 61. The part of the laser element (the part sandwiched in the B direction by the separation groove 81 shown in FIG. 11) remains. In this way, a chip of the two-wavelength semiconductor laser element 90 (see FIG. 2) is formed.

  Thereafter, using a ceramic collet, the two-wavelength semiconductor laser element 90 is pressed against the base 91 via the conductive adhesive layer 31 with the blue-violet semiconductor laser element 50 side down, and the two-wavelength semiconductor laser element 90 is pressed. The laser element 90 is fixed to the base 91. As a result, the n-side electrode 59 is electrically connected to the negative-side lead terminal via the base 91.

  Thereafter, as shown in FIG. 2, the p-side pad electrode 58 (wire bond region 58 a) of the blue-violet semiconductor laser device 50 and the lead terminal are connected by a metal wire 92. Further, the wiring electrode 61 (wire bond region 61 d) of the red semiconductor laser element 70 and the lead terminal are connected by a metal wire 93. Further, the n-side electrode 79 of the red semiconductor laser element 70 and the base 91 are connected by a metal wire 94. Thus, the semiconductor laser device 100 including the two-wavelength semiconductor laser element 90 according to the first embodiment is formed.

  In the first embodiment, as described above, the wiring electrode 61 is formed in a Schottky contact with the p-type cladding layer 54 of the blue-violet semiconductor laser element 50, so that the blue-violet semiconductor laser element 50 Since the p-type cladding layer 54 and the wiring electrode 61 are insulated from each other by the Schottky barrier, the semiconductor laser bonded to each other while suppressing the red semiconductor laser element 70 from peeling from the blue-violet semiconductor laser element 50 side. The elements can be insulated.

In the first embodiment, the p-type cladding layer 54 is made of a nitride-based semiconductor, and the wiring electrode 61 is made of a metal material including the Ti layer 61a, so that the p-type cladding layer 54 made of a nitride-based semiconductor is used. The wiring electrode 61 can be reliably formed in a Schottky contact with the flat portion 54b. The adhesion between the p-type cladding layer 54 made of a nitride-based semiconductor and the Ti layer 61a constituting the wiring electrode 61 is such that the p-type cladding layer 54 made of a nitride-based semiconductor and an insulating film made of SiO ₂ or the like ( Therefore, the peeling of the red semiconductor laser element 70 with respect to the blue-violet semiconductor laser element 50 can be effectively suppressed.

(Second Embodiment)
The second embodiment will be described with reference to FIGS. 3 and 13. In the second embodiment, unlike the first embodiment, a case where the p-side pad electrode 158 of the blue-violet semiconductor laser device 150 is formed in direct contact with the surface of the p-type cladding layer 54 will be described. The blue-violet semiconductor laser element 150 is an example of the “first semiconductor laser element” in the present invention, and the p-side pad electrode 158 is an example of the “second electrode” in the present invention.

  In the semiconductor laser device 200 according to the second embodiment of the present invention, as shown in FIG. 13, the two-wavelength semiconductor laser element 180 in which the red semiconductor laser element 70 is bonded on the surface of the blue-violet semiconductor laser element 150 is electrically conductive. It is fixed on the base 91 via the adhesive layer 31.

  Here, in the second embodiment, the current blocking layer 57c on the B2 side of the ridge 60 is formed only on a side surface of the ridge 60 and a partial region of the p-type cladding layer 54 (flat portion 54b) on the B2 side. . Further, the p-side pad electrode 158 is formed so as to be in direct contact with the upper surface of the flat portion 54b in the region where the current blocking layer 57c is not formed in the flat portion 54b on the B2 side. The planar shape of the p-side pad electrode 158 is the same as that of the p-side pad electrode 58 of the first embodiment shown in FIG.

  Similarly to the wiring electrode 61, the p-side pad electrode 158 is a Ti layer having a thickness of about 10 nm to about 50 nm and a Pd having a thickness of about 100 nm to about 200 nm in order from the p-type cladding layer 54. A layer and an Au layer having a thickness of about 500 nm are stacked in this order. Thereby, the p-side pad electrode 158 is formed in a Schottky contact with the p-type cladding layer 54. That is, since there is a Schottky barrier at the interface between the p-side pad electrode 158 and the p-type cladding layer 54, the p-side pad electrode 158 has improved insulation from the p-type cladding layer 54 in the flat portion 54b. Yes. In the ridge 60 portion, the p-side pad electrode 158 is connected to the p-side contact layer 55 via the p-side ohmic electrode 56, so that the p-side pad electrode 158 in this portion is directed toward the inside of the semiconductor layer. An electric current can be injected.

  In addition, the other structure of the semiconductor laser apparatus 200 in 2nd Embodiment is the same as that of the said 1st Embodiment. Further, in the manufacturing process of the semiconductor laser device 200 according to the second embodiment, as shown in FIG. 13, the resonator direction is only in a predetermined region of the p-type cladding layer 54 (flat portion 54b) on the B2 side of the ridge 60. The p-side pad electrode 158 extending in the B2 direction from the top of the ridge 60 is formed so as to directly contact the surface of the flat portion 54b where the current blocking layer 57c is not formed. Form. Other manufacturing processes are the same as those in the first embodiment.

  In the second embodiment, as described above, the p-side pad electrode 158 of the blue-violet semiconductor laser device 150 is p-type in the current passage portion (ridge 60) where the p-side ohmic electrode 56 of the p-type cladding layer 54 is formed. It is formed in direct contact with the flat portion 54b of the p-type cladding layer 54 in a region (B2 side) that is electrically connected to the cladding layer 54 side and in which the wiring electrode 61 is not formed. Therefore, the p-side pad electrode 158 made of metal is electrically connected to the blue-violet semiconductor laser device 150 in the current path portion, and directly contacts the flat portion 54b of the p-type cladding layer 54 in a portion other than the current path portion. Therefore, in the region other than the current path portion, the p-type cladding layer 54 is directly in contact with the p-side pad electrode 158 made of a metal having better adhesion than the insulating film. And the p-side pad electrode 158 can be improved. Thereby, also in the blue-violet semiconductor laser device 150, the p-side pad electrode 158 can be prevented from peeling from the surface of the p-type cladding layer 54.

  In the second embodiment, the p-side pad electrode 158 is made of a metal material containing Ti, so that the p-side pad electrode 158 is securely Schottky with respect to the flat portion 54b on the B2 side of the p-type cladding layer 54. It can be formed in contact. The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

(Third embodiment)
A third embodiment will be described with reference to FIGS. 14 and 15. In the third embodiment, unlike the second embodiment, a monochromatic type two-wavelength semiconductor laser element 350 composed of red and infrared semiconductor laser elements is joined to a blue-violet semiconductor laser element 150 to form a three-wavelength semiconductor laser. A case where the laser element 360 is formed will be described. 14 is a cross-sectional view taken along the line 3000-3000 in FIG.

  In the semiconductor laser device 300 according to the third embodiment of the present invention, as shown in FIG. 14, a monolithic type 2 comprising a red semiconductor laser element 370 and an infrared semiconductor laser element 380 on the surface of a blue-violet semiconductor laser element 150. A three-wavelength semiconductor laser element 360 to which the wavelength semiconductor laser element 350 is bonded is fixed on the base 91 via the conductive adhesive layer 31. The red semiconductor laser element 370, the infrared semiconductor laser element 380, and the two-wavelength semiconductor laser element 350 are examples of the “second semiconductor laser element” in the present invention.

  Here, in the third embodiment, the two-wavelength semiconductor laser element 350 is joined to the blue-violet semiconductor laser element 150 side in a state of straddling the ridge 60 of the blue-violet semiconductor laser element 150 in the B direction. When the three-wavelength semiconductor laser device 360 is viewed in a plan view, the p-side pad electrode 158 of the blue-violet semiconductor laser device 150 has a wire bond region 158a on the A1 side of the p-type cladding layer 54 as shown in FIG. It is formed in close contact with the area. In the region on the A2 side where the wire bond region 158a is not formed, the wiring electrode 63 for joining the infrared semiconductor laser element 380 is in direct contact with the p-type cladding layer 54 (flat portion 54b). Is formed. In FIG. 15, for convenience, the external shape of the two-wavelength semiconductor laser element 350 is indicated by a two-dot chain line, whereby the wiring electrode 63 and the p-side pad electrode formed on the surface of the blue-violet semiconductor laser element 150. A shape such as 158 is shown.

  Similarly to the wiring electrode 61, the wiring electrode 63 includes a Ti layer having a thickness of about 10 nm to about 50 nm and a Pd layer having a thickness of about 100 nm to about 200 nm in order from the p-type cladding layer 54. An Au layer having a thickness of about 500 nm is laminated in this order. Thereby, the wiring electrode 63 is formed in a Schottky contact with the p-type cladding layer 54 (flat portion 54b). That is, since there is a Schottky barrier at the interface between the wiring electrode 63 and the p-type cladding layer 54, the current is less likely to flow from the p-type cladding layer 54 side toward the wiring electrode 63. Yes. In addition, insulation between the p-type cladding layer 54 and the wiring electrode 63 is achieved by Schottky contact.

  Further, as shown in FIG. 15, the wiring electrode 63 has a resonator direction (on the flat portion 54b of the region where the infrared semiconductor laser device 380 (outer shape is indicated by a broken line) of the blue-violet semiconductor laser device 150 is joined. A wire bond region 63d that extends along the direction B2 and protrudes in a convex shape in the direction B2 is formed.

  As shown in FIG. 14, the infrared semiconductor laser device 380 constituting the two-wavelength semiconductor laser device 350 has an n-type cladding layer 382 made of AlGaAs on the lower surface of the n-type GaAs substrate 71 and a low Al composition. An active layer 383 having an MQW structure in which quantum well layers made of AlGaAs and barrier layers made of AlGaAs having a high Al composition are alternately stacked, and a p-type cladding layer 384 made of AlGaAs are formed. The n-type cladding layer 382 is an example of the “first conductive type third semiconductor layer” in the present invention, and the p-type cladding layer 384 is an example of the “second conductive type fourth semiconductor layer” in the present invention. is there.

  The p-type cladding layer 384 includes a convex portion 384a formed at a position close to the B2 side from the substantially central portion of the element, and flat portions 384b extending on both sides (B direction) of the convex portion 384a. Yes. A p-side contact layer 385 and a p-side ohmic electrode 386 are formed on the convex portion 384 a of the p-type cladding layer 384. A ridge 390 for forming an optical waveguide is formed in the active layer 383 by the convex portion 384a of the p-type cladding layer 384, the p-side contact layer 385, and the p-side ohmic electrode 386. The ridge 390 has a width of about 2 μm in the B direction and is formed so as to extend along the resonator direction (A direction). The p-side contact layer 385 is an example of the “second conductivity type fourth semiconductor layer” in the present invention.

Further, a current blocking layer 87 made of SiO ₂ is formed on the lower surface of the flat portion 384 b of the p-type cladding layer 384 and on the side surface of the ridge 390. A p-side pad electrode 388 is formed on the lower surfaces of the ridge 390 and the current blocking layer 87. The p-side pad electrode 388 is an example of the “first electrode” in the present invention.

  The red semiconductor laser element 370 constituting the two-wavelength semiconductor laser element 350 is formed on the lower surface of the n-type GaAs substrate 71 with the infrared semiconductor laser element 380 and the recess 391 therebetween. The red semiconductor laser element 370 has the same element structure as the red semiconductor laser element 70 of the first embodiment.

  As shown in FIG. 14, the blue-violet semiconductor laser device 150 is connected to a lead terminal via a metal wire 92 bonded to the wire bond region 158a of the p-side pad electrode 158, and the n-side electrode 59 is It is electrically fixed to the base 91. The red semiconductor laser element 370 is connected to the lead terminal via a metal wire 93 bonded to the wire bond region 61 d and is attached to the base 91 via a metal wire 94 wire bonded to the n-side electrode 79. Electrically fixed. The infrared semiconductor laser element 380 is connected to a lead terminal via a metal wire 395 bonded to the wire bond region 63 d of the wiring electrode 63. Thus, in the three-wavelength semiconductor laser element 360, the p-side pad electrode of each semiconductor laser element is connected to the lead terminals insulated from each other, and the n-side electrode of each semiconductor laser element is shared via the base 91. Connected to the negative lead terminal.

  In addition, the other structure of the semiconductor laser apparatus 300 in 3rd Embodiment is the same as that of the said 2nd Embodiment.

  Further, in the manufacturing process of the semiconductor laser device 300 in the third embodiment, the blue-violet semiconductor laser element 150 in which the wiring electrodes 61 and 63 are formed on both sides of the ridge 60 by the same manufacturing process as in the second embodiment, respectively. Are bonded to the wafer on which the two-wavelength semiconductor laser element 350 is formed. At this time, as shown in FIG. 14, the wiring electrode 61 and the p-side pad electrode 78 of the red semiconductor laser element 370 are opposed to each other, and the wiring electrode 63 and the p-side pad electrode 388 of the infrared semiconductor laser element 380 are Both wafers are bonded while facing each other. As a result, as shown in FIG. 15, the p-side pad electrode 78 of the red semiconductor laser element 370 is drawn out to the wiring electrode 61 side, and the p-side pad electrode 388 of the infrared semiconductor laser element 380 is connected to the wiring electrode 63 side. Pulled out. Thereafter, the chip of the three-wavelength semiconductor laser element 360 is formed by cleaving the wafer and dividing the element.

In forming the wafer of the two-wavelength semiconductor laser element 350, first, on the upper surface of the n-type GaAs substrate 71, an n-type cladding layer 382, an active layer 383, a p-type cladding layer 384, and a p-type cladding layer 384, which become the infrared semiconductor laser element 380. A side contact layer 385 and a p-side ohmic electrode 386 are sequentially formed. Thereafter, a part of the semiconductor layer is etched to expose a part of the n-type GaAs substrate 71, leaving a region to be the recess 391 in a part of the exposed part, thereby forming a red semiconductor laser element 370. An n-type cladding layer 72, an active layer 73, a p-type cladding layer 74, a p-side contact layer 75, and a p-side ohmic electrode 76 are sequentially formed. Thereafter, ridges 80 and 390, a current blocking layer 77, and p-side pad electrodes 78 and 388 are formed, respectively. In this way, a wafer of the two-wavelength semiconductor laser element 350 excluding the n-side electrode 79 is manufactured. Other manufacturing processes are the same as those in the first embodiment.
And join.

  In the third embodiment, as described above, the red semiconductor laser element 370 constituting the two-wavelength semiconductor laser element 350 is in direct contact with the surface of the p-type cladding layer 54 on the B1 side of the blue-violet semiconductor laser element 150. It is bonded on the surface of the formed wiring electrode 61 and the infrared semiconductor laser element 380 is formed in direct contact with the p-type cladding layer 54 on the B2 side of the blue-violet semiconductor laser element 150. A three-wavelength semiconductor laser element 360 is formed on the surface of the electrode 63. As a result, the three-wavelength semiconductor laser element 360 can be formed in a state where the blue-violet semiconductor laser element 150 and the two-wavelength semiconductor laser element 350 are insulated, so that the individual laser elements can be electrically independent. It can be driven. The remaining effects of the third embodiment are similar to those of the aforementioned second embodiment.

(Fourth embodiment)
The fourth embodiment will be described with reference to FIGS. 5 to 8 and FIGS. 16 to 19. In the fourth embodiment, unlike the first embodiment, the case where the high resistance region 54c is formed in the surface layer portion of the p-type cladding layer 54 on the side to which the wiring electrode 61 is joined will be described. 16 is a cross-sectional view taken along line 4000-4000 in FIG.

  That is, in the fourth embodiment, as shown in FIG. 16, a high resistance region 54c having a predetermined thickness is formed in the vicinity of the surface of the p-type cladding layer 54 (flat portion 54b) on the B1 side of the blue-violet semiconductor laser device 50. Is formed. The wiring electrode 61 is configured to be in contact with the p-type cladding layer 54 via the high resistance region 54c. Thus, the insulation between the wiring electrode 61 to which the red semiconductor laser element 70 is bonded and the blue-violet semiconductor laser element 50 is further enhanced.

  Further, as shown in FIG. 17, the high resistance region 54c has a plane area larger than the plane area of the wiring electrode 61 in a plan view, and is below the wiring electrode 61 in the resonator direction (see FIG. 17). (A direction) is formed so as to extend in a strip shape. Therefore, the wiring electrode 61 to which the red semiconductor laser element 70 (see FIG. 16) is bonded is configured to be completely insulated from the p-type cladding layer 54 by the high resistance region 54c. In addition, the other structure of the semiconductor laser apparatus 400 in 4th Embodiment is the same as that of the said 1st Embodiment.

In the manufacturing process of the semiconductor laser device 400 according to the fourth embodiment, when the wafer of the blue-violet semiconductor laser device 50 is formed, the n-type cladding layer 52 to the p-type cladding layer 54 are formed on the upper surface of the n-type GaN substrate 51. Then, the wafer is heat-treated in an N ₂ atmosphere in an electric furnace, and p-type is formed by desorbing H ₂ in the semiconductor layer. In this case, the heat treatment temperature is set to about 600 ° C. to about 1000 ° C., and the heat treatment time is set to about 5 minutes to about 60 minutes.

Next, as shown in FIG. 18, a mask 67 made of SiO ₂ is patterned on the upper surface of the p-type cladding layer 54 using photolithography. The mask 67 is preferably formed to a thickness of about 100 nm or more and about 500 nm or less. Thereafter, heat treatment is performed on the wafer in an atmosphere containing H ₂ in an electric furnace. At this time, the heat treatment temperature is set to about 300 ° C. to about 1000 ° C., and the heat treatment time is set to about 5 minutes to 60 minutes. By this heat treatment, H ₂ is diffused into the p-type cladding layer 54 exposed from the patterned mask 67 and the p-type dopant (Mg) is inactivated, so that the p-type cladding layer 54 has a surface layer portion. A high resistance region 54c is formed. At this time, since the p-type cladding layer 54 below the mask 67 is covered with the mask made of SiO ₂ , H ₂ is not diffused inside and the resistance is not increased. Note that the heat treatment in the N ₂ atmosphere described above may be performed in a state where the p-type cladding layer 54 other than the portion where the p-side ohmic electrode 56 (see FIG. 16) is formed is covered with a mask made of SiO ₂ . In this case, only the portion of the p-type cladding layer 54 that forms the p-side ohmic electrode 56 is desorbed by H ₂ to become p-type.

  In the fourth embodiment, by using the manufacturing process described above, the p-type cladding layer 54 alone has an electric resistivity of about 2 Ωcm or more and 4 Ωcm or less, whereas the high resistance region 54c has a portion of about 10 Ωcm or more. The surface layer portion of the p-type cladding layer 54 is increased in resistance so as to have an electric resistivity of 1000 Ωcm or less.

  After the heat treatment, a p-side contact layer 55 and a p-side ohmic electrode 56 are formed on the upper surface of the p-type cladding layer 54 from which the mask 67 has been removed, and then, as shown in FIG. 19, photolithography and dry etching are used. The ridge 60 is formed in the semiconductor layer in the region where the high resistance region 54c is not formed. Thereafter, a wafer of the blue-violet semiconductor laser device 50 shown in FIG. 8 is formed by the same manufacturing process as in the first embodiment.

Here, the high resistance region 54c of the p-type cladding layer 54 can also be formed by the following method. That is, after forming up to the p-side pad electrode 58 by the manufacturing process shown in FIGS. 5 to 7, about 100 keV or more is applied to the p-type cladding layer 54 using the p-side pad electrode 58 as a mask as shown in FIG. 20. Boron (B) is ion-implanted under conditions set to an implantation energy of about 200 keV or less and a dose of about 2 × 10 ¹⁵ cm ⁻² . As a result, the p-type dopant (Mg) contained in the surface layer portion of the p-type cladding layer 54 is inactivated, so that a depth of about 0.1 μm or more and about 0.3 μm or less from the upper surface of the p-type cladding layer 54 is obtained. In this region, a high resistance region 54c having an impurity concentration of about 10 ²⁰ cm ⁻³ is formed. Note that as an impurity element to be ion-implanted, C, Si, or P may be used in addition to boron. Even in this case, the high resistance region 54c can be formed in the vicinity of the surface of the p-type cladding layer 54 (flat portion 54b). Other manufacturing processes in the fourth embodiment are the same as those in the first embodiment.

  In the fourth embodiment, as described above, the high resistance region 54c is formed in the surface layer portion of the p-type cladding layer 54 on the side in contact with the wiring electrode 61. Since the element 50 and the wiring electrode 61 are insulated from each other, the insulation between the semiconductor laser elements bonded to each other can be further improved while preventing the red semiconductor laser element 70 from peeling from the blue-violet semiconductor laser element 50 side. Can be increased. The remaining effects of the fourth embodiment are similar to those of the aforementioned first embodiment.

(Fifth embodiment)
The fifth embodiment will be described with reference to FIG. In the fifth embodiment, unlike the second embodiment, the case where the high resistance region 54c is formed in the surface layer portion of the p-type cladding layer 54 to which the p-side pad electrode 158 is bonded will be described.

  That is, as in the fourth embodiment, a high resistance region 54c having a predetermined thickness is formed in the vicinity of the surface of the p-type cladding layer 54 (flat portion 54b) on the B1 side of the blue-violet semiconductor laser device 150. . The wiring electrode 61 is configured to be in contact with the p-type cladding layer 54 via the high resistance region 54c. Thereby, the insulation between the wiring electrode 61 to which the red semiconductor laser element 70 is bonded and the blue-violet semiconductor laser element 150 is further enhanced.

  The remaining structure of the semiconductor laser device 500 in the fifth embodiment is similar to that of the aforementioned second embodiment, and the manufacturing process in the fifth embodiment is similar to that of the aforementioned fourth embodiment. The effects of the fifth embodiment are the same as those of the second and fourth embodiments.

(Sixth embodiment)
The sixth embodiment will be described with reference to FIG. In the sixth embodiment, unlike the third embodiment, a case will be described in which high resistance regions 54c are respectively formed in the surface layer portion of the p-type cladding layer 54 to which the wiring electrodes 61 and 63 are joined. .

  That is, in the sixth embodiment, as shown in FIG. 22, the blue-violet semiconductor laser device 150 has a predetermined thickness near the surface of the p-type cladding layer 54 (flat portion 54b) on both the B1 side and the B2 side. A high resistance region 54c is formed. The wiring electrodes 61 and 63 are configured to contact the p-type cladding layer 54 via the high resistance region 54c, respectively. Thereby, the insulation between the wiring electrode 61 to which the red semiconductor laser element 370 is bonded and the blue-violet semiconductor laser element 150 is further improved, and the wiring electrode 63 to which the infrared semiconductor laser element 380 is bonded to the blue-violet semiconductor laser element 380. Insulation with the semiconductor laser element 150 is further enhanced.

  The remaining configuration of the semiconductor laser apparatus 600 in the sixth embodiment is similar to that of the aforementioned third embodiment, and the manufacturing process in the sixth embodiment is similar to that of the aforementioned fourth embodiment. The effects of the sixth embodiment are also the same as those of the third and fourth embodiments.

  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 third and sixth embodiments, the red / infrared two-wavelength that is the “second semiconductor laser element” of the present invention is placed on the blue-violet semiconductor laser element that is the “first semiconductor laser element” of the present invention. Although an example in which a semiconductor laser element is bonded is shown, the present invention is not limited to this. For example, as the “first semiconductor laser element” of the present invention, a red semiconductor laser element which is the “second semiconductor laser element” of the present invention is joined to a two-wavelength semiconductor laser element composed of a blue semiconductor laser element and a green semiconductor laser element. Then, an RGB three-wavelength semiconductor laser element may be formed.

  In the first to sixth embodiments, the wiring electrode formed directly on the p-type cladding layer of the blue-violet semiconductor laser element, which is the “first semiconductor laser element” of the present invention, is formed on the surface of the present invention. Although an example in which a red semiconductor laser element or the like which is a “second semiconductor laser element” is bonded is shown, the present invention is not limited to this. For example, the blue-violet semiconductor as the “second semiconductor laser element” of the present invention is formed on the surface of the wiring electrode directly formed on the p-type cladding layer of the red semiconductor laser element as the “first semiconductor laser element” of the present invention. A laser element or the like may be bonded.

1 Semiconductor layer (first conductivity type first semiconductor layer)
3 Semiconductor layer (second conductivity type second semiconductor layer)
6 Electrode layer (second electrode)
21 Semiconductor layer (first conductivity type third semiconductor layer)
23 Semiconductor layer (second conductivity type fourth semiconductor layer)
26 Electrode layer (first electrode)
DESCRIPTION OF SYMBOLS 10 1st semiconductor laser element 11, 61, 63 Wiring electrode 20 2nd semiconductor laser element 50, 150 Blue-violet semiconductor laser element (1st semiconductor laser element)
51 n-type GaN substrate (first conductivity type first semiconductor layer)
52 n-type cladding layer (first conductive type first semiconductor layer)
54 p-type cladding layer (second semiconductor layer of second conductivity type, nitride-based semiconductor)
54c high resistance region 55 p-side contact layer (second conductivity type second semiconductor layer)
58, 158 p-side pad electrode (second electrode)
70, 370 Red semiconductor laser element (second semiconductor laser element)
71 n-type GaAs substrate (first conductivity type third semiconductor layer)
72,382 n-type cladding layer (first conductive type third semiconductor layer)
74, 384 p-type cladding layer (second conductivity type fourth semiconductor layer)
75, 385 p-side contact layer (second conductivity type fourth semiconductor layer)
78, 388 p-side pad electrode (first electrode)
350 Two-wavelength semiconductor laser element (second semiconductor laser element)
360 Three-wavelength semiconductor laser device 380 Infrared semiconductor laser device (second semiconductor laser device)

Claims (6)

A first semiconductor laser element in which a first semiconductor layer of a first conductivity type, a first active layer, and a second semiconductor layer of a second conductivity type are sequentially stacked;
One third semiconductor layer of the first conductivity type or the second conductivity type, a second active layer, and the other fourth semiconductor layer of the first conductivity type or the second conductivity type are stacked in this order, and the fourth semiconductor layer A second semiconductor laser element including a first electrode electrically connected to the side;
A wiring electrode formed in direct contact with the surface of the second semiconductor layer of the first semiconductor laser element,
A semiconductor laser device, wherein the first electrode side of the second semiconductor laser element is bonded to a surface of the wiring electrode opposite to the first semiconductor laser element.   2. The semiconductor laser device according to claim 1, wherein the wiring electrode is formed in a Schottky contact with the second semiconductor layer of the first semiconductor laser element. The second conductivity type is p-type,
The second semiconductor layer is made of a nitride-based semiconductor,
The semiconductor laser device according to claim 2, wherein the wiring electrode includes at least one of Ti, Al, Hf, Ta, and Mo.   4. The semiconductor laser device according to claim 1, wherein the second semiconductor layer of the first semiconductor laser element includes a high resistance region on a surface on a side where the wiring electrode contacts. 5.   The first semiconductor laser element is electrically connected to the second semiconductor layer side in a current path portion of the second semiconductor layer, and the second semiconductor layer is formed in a region where the wiring electrode is not formed. The semiconductor laser device according to claim 1, comprising a second electrode formed in direct contact with the surface. An optical waveguide is formed on the surface of the first semiconductor laser element facing the second semiconductor laser element, and one second semiconductor laser element is provided on each side of the optical waveguide. ,
Two wiring electrodes are formed so as to be in direct contact with the surface of each of the second semiconductor layers on both sides of the optical waveguide,
Each of the wiring electrodes is configured as a three-wavelength semiconductor laser element by bonding the first electrode side of each of the second semiconductor laser elements to the surface opposite to the first semiconductor laser element of each wiring electrode. The semiconductor laser device according to any one of claims 1 to 5.

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