JP2004193302A - Semiconductor laser element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser element that can prevent the occurrence of defective assembling caused by the short-circuiting of an element section itself when the laser element is assembled. <P>SOLUTION: This semiconductor laser element is provided with a first semiconductor laser element section 10 which is formed on an n-type GaAs substrate 1 and contains a light emitting layer 12, semiconductor layers 13-17, and a p-side electrode 18 in this order from the substrate 1 side; a second semiconductor laser element section 20 which is formed on the substrate 1 and contains a light emitting layer 22, semiconductor layers 23-27, and a p-side electrode 28 in this order from the substrate 1 side; and a separating groove 4 provided for electrically separating the first and second semiconductor laser element sections 10 and 20 from each other, and having a width which becomes wider as going toward the front end section of the laser element. The maximum width W of the separating groove 4 and the distances t from the light emitting layers 12 and 22 to the p-side electrodes 18 and 28 are adjusted to meet the relation of t≥0.2 W. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor laser device, and more particularly, to a semiconductor laser device having a plurality of semiconductor laser device units.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a monolithic semiconductor laser device capable of independently extracting a plurality of laser beams from one chip has been known. Further, as such a monolithic semiconductor laser device, an element portion for emitting a red laser beam of 650 nm band for reproducing a DVD (digital video disk) and an infrared laser beam of 780 nm band for reproducing a CD (compact disk). There is known a device in which an element unit that emits light is integrated on the same substrate (for example, see Patent Document 1).
[0003]
Conventionally, a monolithic semiconductor laser device using a junction-down assembling method in which the light-emitting layer is brought close to a heat sink in order to efficiently radiate heat generated in the light-emitting layer of the semiconductor laser device has been known ( For example, see Patent Document 2).
[0004]
FIG. 21 is a sectional view showing an example of a conventional semiconductor laser device. FIG. 22 is a cross-sectional view showing a state where the semiconductor laser device according to the conventional example shown in FIG. 21 is fused to a heat sink. First, the structure of a conventional semiconductor laser device will be described with reference to FIGS.
[0005]
As shown in FIG. 21, a semiconductor laser device according to a conventional example includes a first semiconductor laser device unit 110 having an AlGaAs-based semiconductor layer and a second semiconductor laser device unit 120 having an AlGaInP-based semiconductor layer. The first semiconductor laser element 110 has a function of emitting infrared laser light in the 780 nm band, and the second semiconductor laser element 120 has a function of emitting red laser light in the 650 nm band. The first semiconductor laser element section 110 and the second semiconductor laser element section 120 are formed on the upper surface of the same n-type GaAs substrate 101.
[0006]
Separation grooves 104 for electrically separating the first semiconductor laser element 110 and the second semiconductor laser element 120 are provided between the first semiconductor laser element 110 and the second semiconductor laser element 120. Is provided. The separation groove 104 is formed in a shape including a sidewall having an asymmetric inclination. That is, the side wall of the isolation groove 104 on the side of the first semiconductor laser element portion 110 is inclined by about 40 ° (low angle A) so as to spread in a direction away from the n-type GaAs substrate 101. The side wall on the side of the two semiconductor laser element section 120 is inclined by about 70 ° (high angle B) so as to spread in a direction away from the n-type GaAs substrate 101. The maximum width of the separation groove 104 is about 30 μm.
[0007]
As a specific structure of the first semiconductor laser element section 110, an n-type GaAs substrate 101 having a thickness of about 1.5 μm is formed on the upper surface of the n-type GaAs substrate 101 inclined about 13 ° in the [011] direction from the (100) plane. Al _0.45 Ga _0.55 An n-type cladding layer 111 made of As is formed. The light emitting layer 112 is formed on the n-type cladding layer 111.
[0008]
A p-type Al having a thickness of about 0.2 μm is formed on the light emitting layer 112. _0.45 Ga _0.55 A p-type first cladding layer 113 made of As is formed. On the p-type first cladding layer 113, undoped Al having a thickness of about 20 nm _0.7 Ga _0.3 An etching stop layer 113a made of As is formed. A p-type Al having a thickness of about 1 μm is formed in a predetermined region on the etching stop layer 113a. _0.45 Ga _0.55 A p-type second cladding layer 114 made of As is formed. The p-type second cladding layer 114 is formed in a mesa shape (trapezoidal shape). On the second p-type cladding layer 114, a p-type contact layer 115 made of p-type GaAs having a thickness of about 0.1 μm is formed. The p-type second cladding layer 114 and the p-type contact layer 115 form a ridge.
[0009]
An n-type current blocking layer 116 of n-type GaAs having a thickness of about 1 μm is formed in a region on the etching stop layer 113a where the p-type second cladding layer 114 is not formed. On the upper surfaces of the n-type current block layer 116 and the p-type contact layer 115, a p-type cap layer 117 made of p-type GaAs having a thickness of about 1.5 μm is formed. On the p-type cap layer 117, a p-side electrode 118 composed of a Cr layer having a thickness of about 0.15 μm and an Au layer having a thickness of about 1 μm is formed from the lower layer to the upper layer.
[0010]
Further, as a specific structure of the second semiconductor laser element portion 120, an n-type (Al) having a thickness of about 1.5 μm is formed on the upper surface of the n-type GaAs substrate 101. _0.7 Ga _0.3 ) _0.5 In _0.5 An n-type cladding layer 121 made of P is formed. The light emitting layer 122 is formed on the n-type cladding layer 121.
[0011]
On the light emitting layer 122, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 A p-type first cladding layer 123 made of P is formed. An undoped In layer having a thickness of about 20 nm is formed on the p-type first cladding layer 123. _0.5 Ga _0.5 An etching stop layer 123a made of P is formed. In a predetermined region on the etching stop layer 123a, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 A p-type second cladding layer 124 made of P is formed. The p-type second cladding layer 124 is formed in a mesa shape (trapezoidal shape). On the second p-type cladding layer 124, a p-type contact layer 125 made of p-type GaInP having a thickness of about 0.1 μm is formed. The p-type second cladding layer 124 and the p-type contact layer 125 form a ridge.
[0012]
An n-type current blocking layer 126 made of n-type GaAs having a thickness of about 1 μm is formed in a region on the etching stop layer 123a where the p-type second cladding layer 124 is not formed. On the upper surfaces of the n-type current block layer 126 and the p-type contact layer 125, a p-type cap layer 127 made of p-type GaAs having a thickness of about 1.5 μm is formed. As will be described later, when assembling by a junction-down method, it is considered that the thickness of the p-type cap layer 127 is preferably smaller in consideration of heat dissipation, and is usually 2.0 μm or less. On the p-type cap layer 127, a p-side electrode 128 composed of a Cr layer having a thickness of about 0.15 μm and an Au layer having a thickness of about 1 μm is formed from the lower layer to the upper layer.
[0013]
On the back surface of the n-type GaAs substrate 101, an AuGe layer having a thickness of about 0.1 μm, a Ni layer having a thickness of about 30 nm, An n-side electrode 102 made of an Au layer having a thickness of 0.5 μm is formed.
[0014]
Further, as shown in FIG. 22, the first semiconductor laser element section 110 and the second semiconductor laser element section 120 formed on the upper surface of the same n-type GaAs substrate 101 generate heat generated in the light emitting layers 112 and 122. In order to dissipate heat, it is mounted on the upper surface of a heat sink 171 made of AlN by a junction down method. Specifically, the p-side electrode 118 of the first semiconductor laser element section 110 and the p-side electrode 128 of the second semiconductor laser element section 120 are connected to the heat sink 171 by the AuSn solder layers 173a and 173b having a thickness of about 3 μm. Is fused on the upper surface of the substrate.
[0015]
Then, in a region on the upper surface of the heat sink 171 corresponding to the p-side electrodes 118 and 128 of the first semiconductor laser element portion 110 and the second semiconductor laser element portion 120, a thickness of about 0.02 μm from the lower layer to the upper layer. And electrodes 174a and 174b formed of a Cr layer having a thickness of about 0.28 μm and an Au layer having a thickness of about 0.28 μm. Further, wires 180a to 180c are bonded to the electrode 174a, the electrode 174b, and the n-side electrode 102, respectively.
[0016]
Further, a region corresponding to the separation groove 104 on the upper surface of the heat sink 171 has a thickness of about 1 μm and a width of about 5 μm. ₂ An insulating film 172 is formed. The insulating film 172 is provided to prevent the solder layer 173a and the solder layer 173b from coming into contact with each other when they are melted. This insulating film 172 blocks the solder layers 173a and 173b which are likely to flow in the lateral direction toward the separation groove 104, so that a short circuit occurs between the first semiconductor laser element section 110 and the second semiconductor laser element section 120. Can be prevented.
[0017]
[Patent Document 1]
JP 2001-320132 A
[Patent Document 2]
Japanese Utility Model Publication No. 7-1812
[Problems to be solved by the invention]
However, since the solder layers 173a and 173b blocked by the insulating film 172 rise due to surface tension, the first semiconductor laser element portion 110 and the second semiconductor laser element where the solder layers 173a and 173b are located on the side surfaces of the separation groove 104. In some cases, the contact may come from the p-side region of the portion 120 to the n-side region beyond the light emitting layers 112 and 122. In this case, there is a disadvantage that the element section itself is short-circuited. As a result, when assembling the semiconductor laser device, there is a problem that an assembly failure occurs due to a short circuit of the device portion itself.
[0018]
The present invention has been made to solve the above problems,
An object of the present invention is to provide a semiconductor laser device capable of preventing an assembly failure due to a short circuit of an element portion itself when assembling the semiconductor laser device.
[0019]
Another object of the present invention is to prevent the semiconductor laser element itself from being short-circuited while preventing the heat radiation characteristics of the semiconductor laser element from deteriorating.
[0020]
Means for Solving the Problems and Effects of the Invention
In order to achieve the above object, the present inventors have conducted intensive studies and found that there is a certain relationship between the distance from the light emitting layer to the electrode where the short circuit failure of the element portion itself occurs and the width of the separation groove. I found it. Further, it has been found that if the distance from the light emitting layer to the electrode is set to be equal to or more than a certain value according to the width of the separation groove, it is possible to suppress occurrence of short circuit failure of the element portion itself.
[0021]
That is, a semiconductor laser device according to a first aspect of the present invention is formed on a substrate, and a first semiconductor laser device portion including a first light emitting layer, a first semiconductor layer, and a first electrode, and And a second semiconductor laser element portion including a second light emitting layer, a second semiconductor layer, and a second electrode, and a first semiconductor laser element portion and a second semiconductor laser element portion are electrically separated from the substrate side. And a separation groove whose width increases toward the tip of the element, wherein the maximum width of the separation groove is W, and the first electrode and the second electrode are separated from the first light emitting layer and the second light emitting layer. When the distance t is t, the relationship of t ≧ 0.2 W is satisfied.
[0022]
In the semiconductor laser device according to the first aspect, as described above, the relationship between the maximum width W of the separation groove and the distance t from the first light emitting layer and the second light emitting layer to the first electrode and the second electrode is: By setting so as to satisfy t ≧ 0.2 W, for example, the first electrode of the first semiconductor laser element and the second electrode of the second semiconductor laser element are fused to the base via the fusion layer. In this case, the melted fusion layer flows laterally toward the separation groove and contacts from the p-side region located on the side surface of the separation groove to the n-side region beyond the first and second light emitting layers. Can be suppressed. Thereby, it is possible to prevent a short circuit of the device portions of the first semiconductor laser device portion and the second semiconductor laser device portion. As a result, when assembling the semiconductor laser device, it is possible to prevent an assembly failure due to a short circuit of the device portion itself.
[0023]
Also, the distance t from the first light emitting layer and the second light emitting layer to the first electrode and the second electrode is set to a value near 0.2 times (t = 0.2 W) the maximum width of the separation groove. If it is set, it is possible to prevent an assembly failure due to a short circuit of the element portion itself while suppressing the distance t from the first light emitting layer and the second light emitting layer to the first electrode and the second electrode from becoming too large. As a result, it is possible to prevent an assembly failure due to a short circuit of the element portion itself while preventing the heat radiation characteristics from deteriorating.
[0024]
In the above case, preferably, the separation groove includes a side wall having an inclination angle of 55 ° or less. In this manner, when the inclination angle of the side wall of the separation groove is 55 ° or less, the first semiconductor layer and the first electrode and the second semiconductor layer and the second electrode Setting the thickness can easily prevent the element portion itself from being short-circuited.
[0025]
In the semiconductor laser device according to the first aspect, preferably, the first electrode of the first semiconductor laser device portion and the second electrode of the second semiconductor laser device portion are attached to the base by a fusion layer. An insulating film is formed in a region corresponding to the separation groove of the base. According to this structure, the first electrode of the first semiconductor laser element portion and the second electrode of the second semiconductor laser element portion are formed by two fusion layers provided corresponding to the first electrode and the second electrode, respectively. When the base material is fused to the base through the insulating film, the flow of each fused layer in the lateral direction toward the separation groove can be blocked by the insulating film. This can prevent the two fused layers respectively corresponding to the first electrode and the second electrode from coming into contact with each other, so that a short circuit between the first semiconductor laser element unit and the second semiconductor laser element unit can be prevented. Can be prevented. Therefore, with this configuration, it is possible to prevent both a short-circuit failure of the element unit itself and a short-circuit failure of the two element units.
[0026]
A semiconductor laser device according to a second aspect of the present invention is formed on a substrate and includes, from the substrate side, a first semiconductor laser device portion including a first light emitting layer, a first semiconductor cap layer, and a first electrode; A second semiconductor laser device portion formed on the substrate side and including a second light emitting layer, a second semiconductor cap layer, and a second electrode; a first semiconductor laser device portion and a second semiconductor laser device portion; An isolation groove provided for electrical isolation, wherein the first semiconductor cap layer and the second semiconductor cap layer include a first concave portion and a second concave portion, respectively, and the first electrode and the second electrode are Along the first concave portion of the first semiconductor cap layer and the second concave portion of the second semiconductor cap layer, respectively, they are formed so as to reflect the shapes of the first concave portion and the second concave portion.
[0027]
In the semiconductor laser device according to the second aspect, as described above, the shapes of the first concave portion and the second concave portion are reflected along the first concave portion of the first semiconductor cap layer and the second concave portion of the second semiconductor cap layer. By forming the first electrode and the second electrode as described above, for example, the first electrode of the first semiconductor laser element and the second electrode of the second semiconductor laser element are mounted on the base via a fusion layer. When fusion is performed, the fused layer flows into the concave portion of the first electrode and the concave portion of the second electrode, so that the fused layer flows to the separation groove side and the side surface of the separation groove. From the p-side region located above the first and second light-emitting layers to the n-side region. This can prevent the element portions of the first semiconductor laser element portion and the second semiconductor laser element portion from being short-circuited. Further, since the melted fusion layer can be prevented from flowing to the separation groove side, the two fusion layers provided corresponding to the first electrode and the second electrode, respectively, are prevented from contacting each other. Therefore, a short circuit failure between the first semiconductor laser element and the second semiconductor laser element can be suppressed. As a result, when assembling the semiconductor laser device, it is possible to prevent an assembly failure due to a short circuit of the device portion itself and a short circuit between the device portions. Also, by providing the first and second semiconductor cap layers with the first and second semiconductor cap layers, respectively, the first and second light emitting layers can be depressed from the first light emitting layer and the second light emitting layer to the first electrode and the second electrode. Since the distance to the portion can be shortened, it is possible to prevent the heat radiation characteristics from deteriorating. As a result, it is possible to prevent an assembly failure due to a short circuit while preventing heat radiation characteristics from deteriorating.
[0028]
In the semiconductor laser device according to the second aspect, preferably, the first electrode of the first semiconductor laser device portion and the second electrode of the second semiconductor laser device portion are attached to the base by a fusion layer. The first recess of the first semiconductor cap layer and the second recess of the second semiconductor cap layer have substantially the same depth as the thickness of the fusion layer. According to this structure, when the first electrode of the first semiconductor laser element portion and the second electrode of the second semiconductor laser element portion are fused to the base via the fusion layer, the fused layer is melted. Can be satisfactorily flowed into the concave portion of the first electrode and the concave portion of the second electrode, so that the molten fusion layer can be effectively prevented from flowing to the separation groove side.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0030]
(1st Embodiment)
FIG. 1 is a sectional view showing a semiconductor laser device according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a light emitting layer of a first semiconductor laser device portion of the semiconductor laser device according to the first embodiment shown in FIG. 1, and FIG. 3 is a semiconductor laser according to the first embodiment shown in FIG. It is an expanded sectional view of the light emitting layer of the 2nd semiconductor laser element part of an element. FIG. 4 is a sectional view showing a state where the semiconductor laser device according to the first embodiment shown in FIG. 1 is fused to a heat sink. First, the structure of the semiconductor laser device according to the first embodiment will be described with reference to FIGS.
[0031]
As shown in FIG. 1, the semiconductor laser device according to the first embodiment includes a first semiconductor laser device portion 10 having an AlGaAs-based semiconductor layer and a second semiconductor laser device portion 20 having an AlGaInP-based semiconductor layer. . The first semiconductor laser element section 10 has a function of emitting infrared laser light in the 780 nm band, and the second semiconductor laser element section 20 has a function of emitting red laser light in the 650 nm band. The first semiconductor laser element section 10 and the second semiconductor laser element section 20 are formed on the upper surface of the same n-type GaAs substrate 1. The n-type GaAs substrate 1 is an example of the “substrate” of the present invention.
[0032]
Further, between the first semiconductor laser element section 10 and the second semiconductor laser element section 20, a separation groove 4 for electrically separating the first semiconductor laser element section 10 and the second semiconductor laser element section 20 is provided. Is provided. The separation groove 4 is formed in a shape including a sidewall having an asymmetric inclination. That is, the side wall of the isolation groove 4 on the first semiconductor laser element portion 10 side is inclined by about 40 ° (low angle A) so as to spread in a direction away from the n-type GaAs substrate 1. The side wall on the side of the two semiconductor laser elements 20 is inclined by about 70 ° (high angle B) so as to spread in a direction away from the n-type GaAs substrate 1. The maximum width W of the separation groove 4 is about 30 μm.
[0033]
The specific structure of the first semiconductor laser element unit 10 that emits infrared laser light in the 780 nm band is as follows: on the upper surface of the n-type GaAs substrate 1 inclined about 13 ° in the [011] direction from the (100) plane. N-type Al having a thickness of about 1.5 μm _0.45 Ga _0.55 An n-type cladding layer 11 made of As is formed. A light emitting layer 12 is formed on the n-type cladding layer 11. The light emitting layer 12 is an example of the “first light emitting layer” of the present invention.
[0034]
As shown in FIG. 2, the light emitting layer 12 has an Al thickness of about 7 nm. _0.1 Ga _0.9 Five well layers 12a made of As and Al having a thickness of about 7 nm _0.35 Ga _0.65 It includes a first MQW active layer 12e in which four barrier layers 12b made of As are alternately stacked. An undoped Al having a thickness of about 50 nm is sandwiched between the first MQW active layers 12e. _0.35 Ga _0.65 An n-side light guide layer 12c and a p-side light guide layer 12d made of As are provided. The first MQW active layer 12e, the n-side light guide layer 12c, and the p-side light guide layer 12d constitute the light emitting layer 12.
[0035]
As shown in FIG. 1, p-type Al having a thickness of about 0.2 μm is formed on the light emitting layer 12. _0.45 Ga _0.55 A p-type first cladding layer 13 made of As is formed. An undoped Al having a thickness of about 20 nm is formed on the p-type first cladding layer 13. _0.7 Ga _0.3 An etching stop layer 13a made of As is formed. In a predetermined region on the etching stop layer 13a, a p-type Al having a thickness of about 1 μm is formed. _0.45 Ga _0.55 A p-type second cladding layer 14 made of As is formed. The p-type second cladding layer 14 is formed in a mesa shape (trapezoidal shape). On the second p-type cladding layer 14, a p-type contact layer 15 made of p-type GaAs having a thickness of about 0.1 μm is formed. The p-type second cladding layer 14 and the p-type contact layer 15 form a ridge.
[0036]
In the region where the p-type second cladding layer 14 is not formed on the etching stop layer 13a, an n-type current blocking layer 16 made of n-type GaAs having a thickness of about 1 μm is formed. A p-type cap layer 17 made of p-type GaAs having a thickness of about 4.5 μm is formed on the upper surfaces of the n-type current block layer 16 and the p-type contact layer 15. On the p-type cap layer 17, a p-side electrode 18 composed of a Cr layer having a thickness of about 0.15 μm and an Au layer having a thickness of about 1 μm is formed from the lower layer to the upper layer.
[0037]
The p-type first cladding layer 13, the etching stop layer 13a, the p-type second cladding layer 14, the p-type contact layer 15, the n-type current blocking layer 16, and the p-type cap layer 17 are the “first semiconductor” of the present invention. Layer). The p-side electrode 18 is an example of the “first electrode” of the present invention.
[0038]
Further, as a specific structure of the second semiconductor laser element unit 20 that emits red laser light in the 650 nm band, an n-type (Al) having a thickness of about 1.5 μm is formed on the upper surface of the n-type GaAs substrate 1. _0.7 Ga _0.3 ) _0.5 In _0.5 An n-type cladding layer 21 made of P is formed. The light emitting layer 22 is formed on the n-type cladding layer 21. The light emitting layer 22 is an example of the “second light emitting layer” of the present invention.
[0039]
As shown in FIG. 3, the light emitting layer 22 has an In thickness of about 6 nm. _0.5 Ga _0.5 P and three well layers 22a each having a thickness of about 6 nm (Al _0.5 Ga _0.5 ) _0.5 In _0.5 It includes a second MQW active layer 22e in which two P barrier layers 22b are alternately stacked. An undoped (Al) layer having a thickness of about 50 nm sandwiches the second MQW active layer 22e. _0.5 Ga _0.5 ) _0.5 In _0.5 An n-side light guide layer 22c and a p-side light guide layer 22d made of P are provided. The light emitting layer 22 is configured by the second MQW active layer 22e, the n-side light guide layer 22c, and the p-side light guide layer 22d.
[0040]
As shown in FIG. 1, a p-type (Al) having a thickness of about 0.2 μm is formed on the light emitting layer 22. _0.7 Ga _0.3 ) _0.5 In _0.5 A p-type first cladding layer 23 made of P is formed. An undoped In layer having a thickness of about 20 nm is formed on the p-type first cladding layer 23. _0.5 Ga _0.5 An etching stop layer 23a made of P is formed. A predetermined region on the etching stop layer 23a has a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 A p-type second cladding layer 24 made of P is formed. The p-type second cladding layer 24 is formed in a mesa shape (trapezoidal shape). On the p-type second cladding layer 24, a p-type contact layer 25 made of p-type GaInP having a thickness of about 0.1 μm is formed. The p-type second cladding layer 24 and the p-type contact layer 25 form a ridge.
[0041]
In the region where the p-type second cladding layer 24 is not formed on the etching stop layer 23a, an n-type current blocking layer 26 of n-type GaAs having a thickness of about 1 μm is formed. A p-type cap layer 27 of p-type GaAs having a thickness of about 4.5 μm is formed on the upper surfaces of the n-type current block layer 26 and the p-type contact layer 25. On the p-type cap layer 27, a p-side electrode 28 composed of a Cr layer having a thickness of about 0.15 μm and an Au layer having a thickness of about 1 μm is formed from the lower layer to the upper layer.
[0042]
The p-type first cladding layer 23, the etching stop layer 23a, the p-type second cladding layer 24, the p-type contact layer 25, the n-type current block layer 26, and the p-type cap layer 27 are the “second semiconductor” of the present invention. Layer). The p-side electrode 28 is an example of the “second electrode” of the present invention.
[0043]
Then, on the back surface of the n-type GaAs substrate 1, an AuGe layer having a thickness of about 0.1 μm, a Ni layer having a thickness of about 30 nm, An n-side electrode 2 made of an Au layer having a thickness of 0.5 μm is formed.
[0044]
Then, as shown in FIG. 4, the first semiconductor laser element unit 10 and the second semiconductor laser element unit 20 formed on the upper surface of the same n-type GaAs substrate 1 dissipate the heat generated in the light emitting layers 12 and 22. In order to dissipate heat, it is mounted on the upper surface of a heat sink 71 made of AlN by a junction down method. Specifically, the p-side electrode 18 of the first semiconductor laser element section 10 and the p-side electrode 28 of the second semiconductor laser element section 20 are provided with a heat sink 71 by AuSn solder layers 73a and 73b having a thickness of about 3 μm. Is fused on the upper surface of the substrate. The heat sink 71 is an example of the “base” of the present invention, and the solder layers 73a and 73b are an example of the “fusion layer” of the present invention.
[0045]
Then, in a region on the upper surface of the heat sink 71 corresponding to the p-side electrodes 18 and 28 of the first semiconductor laser device portion 10 and the second semiconductor laser device portion 20, a thickness of about 0.02 μm from the lower layer to the upper layer. Are formed of a Cr layer having a thickness of about 0.28 μm and an Au layer having a thickness of about 0.28 μm. Wires 80a to 80c are bonded to the electrode 74a, the electrode 74b, and the n-side electrode 2, respectively.
[0046]
Further, in the first embodiment, a region having a thickness of about 1 μm and a width of about 5 μm ₂ An insulating film 72 is formed. The insulating film 72 is provided to prevent the two solder layers 73a and 73b provided corresponding to the p-side electrodes 18 and 28 from contacting each other by flowing toward the separation groove 4 during fusion. Is provided.
[0047]
FIG. 5 is a graph showing the relationship between the distance t from the p-side electrode to the light emitting layer and the failure rate due to short-circuit when the maximum width W of the separation groove is about 30 μm. FIG. 6 is a graph showing the state of occurrence of an assembly failure (short circuit failure) when the maximum width W of the separation groove and the distance t from the p-side electrode to the light emitting layer are used as parameters. The shape of the separation groove is as follows: low angle: about 40 °, high angle: about 70 °. In addition, “「 ”and“ ◎ ”in FIG. 6 indicate that there is no defective assembly, and“ × ”indicates that there is defective assembly.
[0048]
Referring to FIG. 5, it has been found that when the distance t from the p-side electrode to the light emitting layer is about 6 μm or more, the defective assembly rate due to short circuit can be reduced to 0%. On the other hand, it was found that if the distance t from the p-side electrode to the light emitting layer was smaller than about 6 μm, assembly failure occurred, and the smaller the distance t, the higher the assembly failure rate. For example, when the distance t is about 3 μm, it can be seen that the defective assembly rate due to a short circuit is as high as about 50%. This is because the distance t from the p-side electrode to the light-emitting layer is too small with respect to the maximum width W (about 30 μm) of the separation groove, so that the solder layer extends over the light-emitting layer from the p-side region located on the side surface of the separation groove. It is considered that this is due to contact with the n-side region. In this case, since the semiconductor laser element itself is short-circuited, it is considered that an assembly failure has occurred.
[0049]
Further, referring to FIG. 6, it can be seen that when the maximum width W of the separation groove is about 20 μm and the distance t from the p-side electrode to the light emitting layer is about 4 μm or more, no assembly failure occurs. Similarly, the maximum width W of the separation groove is about 30 μm, the distance t from the p-side electrode to the light emitting layer is about 6 μm or more, and the maximum width W of the separation groove is about 40 μm, and the distance t from the p-side electrode to the light emitting layer is about It can be seen that if the separation groove has a maximum width W of about 60 μm or more and the distance t from the p-side electrode to the light emitting layer is about 12 μm or more, no assembly failure occurs. The inventor of the present application has determined from the results of FIG. 6 that the shortest distance t from the p-side electrode to the light emitting layer where no assembly failure occurs with respect to the maximum width W of the separation groove (the distance t indicated by “◎” in FIG. 6). Can be represented by an approximate expression of t = 0.2 W. Thus, if the width W of the separation groove and the distance t from the p-side electrode to the light emitting layer satisfy the relational expression of t ≧ 0.2 W, it is considered that no defective assembly occurs.
[0050]
Here, in the first embodiment, the maximum width W of the separation groove 4 and each of the layers 13 and 13a from the light emitting layers 12 and 22 to the p-side electrodes 18 and 28 satisfy the relational expression of t ≧ 0.2 W. , 14, 15 and 17 and 23, 23a, 24, 25 and 27 are set. Specifically, as shown in FIGS. 1 and 2, the width W of the separation groove 4 is set to about 30 μm, and the distance t from the p-side electrodes 18 and 28 to the light emitting layers 12 and 22 is about The thickness of each of the layers 13, 13a, 14, 15 and 17 and 23, 23a, 24, 25 and 27 is set so as to be 7 μm. Accordingly, in the first embodiment, t = about 7 μm and 0.2W = about 6 μm, so that the relational expression represented by t ≧ 0.2 W is satisfied.
[0051]
FIG. 7 shows the shortest distance t at which assembly failure (short circuit failure) does not occur when the maximum width W of the separation groove and the distance t from the p-side electrode to the light emitting layer are parameters, and the inclination angle of the side wall of the separation groove. (Low angle and high angle) are graphs showing the results of the investigation. Note that “□” in FIG. 7 indicates the case where the low angle is about 50 ° and the high angle is about 60 °, and “△” indicates the case where the low angle is about 55 ° and the high angle is about 55 °. Is shown. When the low angle is about 50 ° and the high angle is about 60 °, an n-type GaAs substrate inclined about 5 ° in the [011] direction from the (100) plane is used, and the low angle is about 55 °. When the high angle is about 55 °, an n-type GaAs substrate that is not inclined is used.
[0052]
Referring to FIG. 7, in the case of a separation groove having a low angle of about 50 ° and a high angle of about 60 °, when the maximum width W of the separation groove is about 30 μm, the distance from the p-side electrode to the light emitting layer where short-circuit failure does not occur. When the minimum value of t was about 6 μm and the maximum width W of the separation groove was about 60 μm, the minimum value of the distance t from the p-side electrode where no short circuit failure occurred to the light emitting layer was about 12 μm. This is the same as the case of the separation groove having a low angle of about 40 ° and a high angle of about 70 ° shown in FIG. In the case of a separation groove having a low angle of about 55 ° and a high angle of about 55 °, when the maximum width W of the separation groove is about 30 μm, the minimum value of the distance t from the p-side electrode to the light emitting layer where short-circuit failure does not occur is obtained. When the maximum width W of the separation groove was about 60 μm, the minimum value of the distance t from the p-side electrode where no short-circuit failure occurred to the light emitting layer was about 10 μm. 6 and 7, in the case of the separation groove having a low angle of about 55 ° or less, the maximum width W of the separation groove and the distance t from the p-side electrode to the light emitting layer are at least t ≧ 0.2 W If the relational expression is satisfied, it is considered that assembly failure does not occur.
[0053]
In the first embodiment, as described above, the relationship between the maximum width W of the separation groove 4 and the distance t from the light emitting layers 12 and 22 to the p-side electrodes 18 and 28 satisfies t ≧ 0.2 W. By setting, when the p-side electrode 18 of the first semiconductor laser element section 10 and the p-side electrode 28 of the second semiconductor laser element section 20 are fused to the heat sink 71 via the solder layers 73a and 73b, the melting is performed. The solder layers 73a and 73b that flow laterally toward the separation groove 4 and contact from the p-side region located on the side surface of the separation groove 4 to the n-side region beyond the light emitting layers 12 and 22 are suppressed. can do. Thereby, it is possible to prevent a short circuit of the device portions of the first semiconductor laser device portion 10 and the second semiconductor laser device portion 20 themselves.
[0054]
Further, by forming the insulating film 72 in a region corresponding to the separation groove 4 of the heat sink 71, the flow of the solder layers 73a and 73b in the lateral direction toward the separation groove 4 can be blocked by the insulating film 72. . Thereby, the two solder layers 73a and 73b corresponding to the electrodes 18 and 28 can be prevented from contacting each other, so that the distance between the first semiconductor laser element section 10 and the second semiconductor laser element section 20 can be reduced. Short circuit can be prevented. Therefore, with this configuration, it is possible to prevent both a short-circuit failure of the element unit itself and a short-circuit failure of the two element units.
[0055]
The distance t (about 7 μm) from the light emitting layers 12 and 22 to the p-side electrodes 18 and 28 is set to a value near 0.2 times (about 6 μm) the maximum width of the separation groove 4. Therefore, the light emitting layers 12 and 22 can be prevented from largely separating from the heat sink 71, so that the first semiconductor laser element unit 10 and the second It is also possible to prevent the heat radiation characteristics of the two semiconductor laser element unit 20 from deteriorating.
[0056]
8 to 15 are sectional views for explaining the manufacturing process of the semiconductor laser device according to the first embodiment shown in FIG. Next, the manufacturing process of the semiconductor laser device according to the first embodiment will be described with reference to FIGS. 1 to 4 and FIGS.
[0057]
First, as shown in FIG. 8, the first semiconductor laser element unit 10 (see FIG. 1) is formed on the upper surface of the n-type GaAs substrate 1 by using MOCVD (Metal Organic Chemical Vapor Deposition). The respective semiconductor layers constituting (1) are grown.
[0058]
Specifically, an n-type Al having a thickness of about 1.5 μm is _0.45 Ga _0.55 N-type cladding layer 11 made of As, light-emitting layer 12, p-type Al having a thickness of about 0.2 μm _0.45 Ga _0.55 P-type first cladding layer 13 made of As, undoped Al having a thickness of about 20 nm _0.7 Ga _0.3 As etching stop layer 13a made of As, p-type Al having a thickness of about 1 μm _0.45 Ga _0.55 A p-type second cladding layer 14 made of As and a p-type contact layer 15 made of p-type GaAs having a thickness of about 0.1 μm are sequentially grown.
[0059]
The light emitting layer 12 has an undoped Al having a thickness of about 50 nm as shown in FIG. _0.35 Ga _0.65 On the n-side optical guide layer 12c made of As, a first MQW active layer 12e and undoped Al having a thickness of about 50 nm _0.35 Ga _0.65 It is formed by sequentially growing a p-side light guide layer 12d made of As. Further, the first MQW active layer 12e is formed of Al having a thickness of about 7 nm. _0.1 Ga _0.9 Five well layers 12a made of As and Al having a thickness of about 7 nm _0.35 Ga _0.65 It is formed by alternately stacking four barrier layers 12b made of As.
[0060]
Next, as shown in FIG. 9, a predetermined region of each semiconductor layer constituting the first semiconductor laser element unit 10 is removed by using photolithography and wet etching.
[0061]
Next, as shown in FIG. 10, the second semiconductor laser element section 20 (see FIG. 1) is formed on the entire surface of each of the semiconductor layers constituting the n-type GaAs substrate 1 and the first semiconductor laser element section 10 by MOCVD. The respective semiconductor layers constituting (1) are grown.
[0062]
More specifically, an n-type (Al) layer having a thickness of about 1.5 μm _0.7 Ga _0.3 ) _0.5 In _0.5 An n-type cladding layer 21 made of P, a light-emitting layer 22, and a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P-type first cladding layer 23 made of P, undoped In having a thickness of about 20 nm _0.5 Ga _0.5 P-type etching stop layer 23a, p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 A p-type second cladding layer 24 made of P and a p-type contact layer 25 made of p-type GaInP having a thickness of about 0.1 μm are sequentially grown.
[0063]
The light emitting layer 22 has an undoped (Al) having a thickness of about 50 nm as shown in FIG. _0.5 Ga _0.5 ) _0.5 In _0.5 On the n-side light guide layer 22c made of P, a second MQW active layer 22e and an undoped (Al _0.5 Ga _0.5 ) _0.5 In _0.5 It is formed by sequentially growing a p-side light guide layer 22d made of P. Also, the second MQW active layer 22e has an In thickness of about 6 nm. _0.5 Ga _0.5 P and three well layers 22a each having a thickness of about 6 nm (Al _0.5 Ga _0.5 ) _0.5 In _0.5 It is formed by alternately stacking two P barrier layers 22b.
[0064]
Next, as shown in FIG. 11, a predetermined region of each semiconductor layer forming the second semiconductor laser element unit 20 is removed by using photolithography technology and wet etching. Then, a SiO 2 is formed in a predetermined region on the upper surfaces of the p-type contact ₂ The films 31a and 31b are formed.
[0065]
Next, as shown in FIG. ₂ Using the film 31a as a mask, a predetermined region from the p-type contact layer 15 to the etching stop layer 13a is removed by wet etching to form a ridge portion composed of the p-type second cladding layer 14 and the p-type contact layer 15. Form. Subsequently, the SiO ₂ Using the film 31b as a mask, a predetermined region from the p-type contact layer 25 to the etching stop layer 23a is removed by wet etching to form a ridge portion composed of the p-type second cladding layer 24 and the p-type contact layer 25. Form.
[0066]
Next, as shown in FIG. ₂ Using the films 31a and 31b as selective growth masks, ₂ An n-type current blocking layer 36 of n-type GaAs having a thickness of about 1 μm is formed in a region other than the region where the films 31a and 31b are formed. After this, the SiO ₂ The films 31a and 31b are removed.
[0067]
Next, as shown in FIG. 14, a p-type cap layer 37 made of p-type GaAs having a thickness of about 4.5 μm is formed on the entire surface.
[0068]
Next, as shown in FIG. 15, a predetermined region from the p-type cap layer 37 (see FIG. 14) to the n-type GaAs substrate 1 is removed by wet etching, thereby forming the isolation groove 4. At this time, since each semiconductor layer to be etched is formed on the upper surface of the n-type GaAs substrate 1 inclined about 13 ° in the [011] direction from the (100) plane, the separation groove 4 has an asymmetric inclination. It is formed in a shape including a side wall. That is, the side wall of the isolation groove 4 on the first semiconductor laser element portion 10 side is inclined by about 40 ° (low angle A) so as to spread in a direction away from the n-type GaAs substrate 1 and the second semiconductor of the isolation groove 4 The side wall on the side of the laser element section 20 is formed so as to be inclined at about 70 ° (high angle B) so as to spread in a direction away from the n-type GaAs substrate 1. The maximum width W of the separation groove 4 is about 30 μm.
[0069]
Due to the formation of the separation groove 4, each semiconductor layer (the n-type cladding layer 11, the light-emitting layer 12, the p-type first cladding layer 13, the etching stop layer 13 a, the p-type second cladding layer 14) constituting the first semiconductor laser element portion 10 is formed. , P-type contact layer 15, n-type current blocking layer 16 and p-type cap layer 17), and each semiconductor layer (n-type cladding layer 21, light emitting layer 22, p The first type clad layer 23, the etching stop layer 23a, the second p-type clad layer 24, the p-type contact layer 25, the n-type current block layer 26, and the p-type cap layer 27) are formed.
[0070]
Finally, as shown in FIG. 1, a Cr layer having a thickness of about 0.15 μm is formed on the upper surfaces of the p-type cap layers 17 and 27 from the lower layer to the upper layer using a vapor deposition method. The p-side electrodes 18 and 28 are formed of an Au layer having a thickness of. Thereafter, an AuGe layer having a thickness of about 0.1 μm and a thickness of about 30 nm are sequentially formed on the back surface of the n-type GaAs substrate 1 from the side closer to the back surface of the n-type GaAs substrate 1 by vapor deposition. An n-side electrode 2 composed of a Ni layer and an Au layer having a thickness of about 0.5 μm is formed. Thus, a semiconductor laser device including the first semiconductor laser device portion 10 and the second semiconductor laser device portion 20 is formed.
[0071]
The p-side electrode 18 of the first semiconductor laser element section 10 and the p-side electrode 28 of the second semiconductor laser element section 20 are connected to the heat sink via solder layers 73a and 73b of AuSn having a thickness of about 3 μm, respectively. Fused on 71 electrodes 74a and 74b. At this time, the separation groove 4 is arranged in a region corresponding to the insulating film 72 on the upper surface of the heat sink 71. Then, by bonding wires 80a to 80c to the electrode 74a, the electrode 74b, and the n-side electrode 2, respectively, the structure shown in FIG. 4 is obtained.
[0072]
(2nd Embodiment)
FIG. 16 is a sectional view showing a semiconductor laser device according to the second embodiment of the present invention. FIG. 17 is a cross-sectional view showing a state where the semiconductor laser device according to the second embodiment shown in FIG. 16 is fused to a heat sink. In the second embodiment, unlike the first embodiment, an example in which a concave portion for suppressing the solder layer from flowing into the separation groove side is formed in the p-type cap layer constituting the semiconductor laser element portion. explain. Other configurations of the second embodiment are the same as those of the first embodiment.
[0073]
That is, in the second embodiment, as shown in FIG. 16, a first semiconductor laser element section 10a having an AlGaAs-based semiconductor layer and a second semiconductor laser element section 20a having an AlGaInP-based semiconductor layer are included. The first semiconductor laser element section 10a has a function of emitting infrared laser light in the 780 nm band, and the second semiconductor laser element section 20a has a function of emitting red laser light in the 650 nm band. The first semiconductor laser element section 10a and the second semiconductor laser element section 20a are formed on the upper surface of the same n-type GaAs substrate 1.
[0074]
As a specific structure of the first semiconductor laser element portion 10a, as in the first embodiment, an n-type cladding layer 11, a light-emitting layer 12, a p-type first cladding layer 13, An etching stop layer 13a, a p-type second cladding layer 14, a p-type contact layer 15, and an n-type current blocking layer 16 are formed.
[0075]
Here, in the second embodiment, a p-type cap layer 47 made of p-type GaAs having a thickness of about 4.5 μm is formed on the upper surfaces of the n-type current block layer 16 and the p-type contact layer 15. In a predetermined region of the p-type cap layer 47, a first concave portion 47a having a depth D of about 3 μm is formed. The depth D (about 3 μm) of the first recess 47a is substantially the same as the thickness t2 (about 3 μm) of a solder layer 83a (see FIG. 17) described later. Further, on the p-type cap layer 47, a concave p-side electrode 48 is formed along the first concave portion 47a of the p-type cap layer 47 so as to reflect the shape of the first concave portion 47a. The p-side electrode 48 has a Cr layer having a thickness of about 0.15 μm and an Au layer having a thickness of about 1 μm from the lower layer to the upper layer. Note that the p-type cap layer 47 is an example of the “first semiconductor cap layer” of the present invention, and the p-side electrode 48 is an example of the “first electrode” of the present invention.
[0076]
Further, as a specific structure of the second semiconductor laser element section 20a, as in the first embodiment, an n-type cladding layer 21, a light emitting layer 22, a p-type first cladding layer are formed on the upper surface of the n-type GaAs substrate 1. 23, an etching stop layer 23a, a p-type second cladding layer 24, a p-type contact layer 25, and an n-type current blocking layer 26 are formed.
[0077]
Here, in the second embodiment, a p-type cap layer 57 made of p-type GaAs having a thickness of about 4.5 μm is formed on the upper surfaces of the n-type current block layer 26 and the p-type contact layer 25. In a predetermined region of the p-type cap layer 57, a second concave portion 57a having a depth D of about 3 μm is formed. The depth D (about 3 μm) of the second recess 57a is substantially the same as the thickness t2 (about 3 μm) of a solder layer 83b (see FIG. 17) described later. On the p-type cap layer 57, a concave p-side electrode 58 is formed along the second concave portion 57a of the p-type cap layer 57 so as to reflect the shape of the second concave portion 57a. The p-side electrode 58 has a Cr layer having a thickness of about 0.15 μm and an Au layer having a thickness of about 1 μm from the lower layer to the upper layer. The p-type cap layer 57 is an example of the “second semiconductor cap layer” of the present invention, and the p-side electrode 58 is an example of the “second electrode” of the present invention.
[0078]
Further, between the first semiconductor laser element section 10a and the second semiconductor laser element section 20a, the first semiconductor laser element section 10a and the second semiconductor laser element section 20a are electrically connected similarly to the first embodiment. Separation grooves 4 for separation are provided. An n-side electrode 2 is formed on the back surface of the n-type GaAs substrate 1.
[0079]
Then, as shown in FIG. 17, the first semiconductor laser element section 10a and the second semiconductor laser element section 20a formed on the upper surface of the same n-type GaAs substrate 1 have the same structure as the heat sink 71 in the first embodiment. It is installed on the upper surface. Specifically, the p-side electrode 48 of the first semiconductor laser element section 10a and the p-side electrode 58 of the second semiconductor laser element section 20a are connected via solder layers 83a and 83b made of AuSn having a thickness t2 of about 3 μm. , Are fused on the upper surface of the heat sink 71. The solder layers 83a and 83b are an example of the “fusion layer” of the present invention. Further, as in the first embodiment, an insulating film 72 is formed in a region corresponding to the separation groove 4 on the upper surface of the heat sink 71.
[0080]
Electrodes 74a and 74b are formed on the upper surface of the heat sink 71 in regions corresponding to the p-side electrodes 48 and 58 of the first semiconductor laser element portion 10a and the second semiconductor laser element portion 20a. Wires 80a to 80c are bonded to the electrode 74a, the electrode 74b, and the n-side electrode 2, respectively.
[0081]
In the second embodiment, as described above, the shapes of the first concave portion 47a and the second concave portion 57a are reflected along the first concave portion 47a of the p-type cap layer 47 and the second concave portion 57a of the p-type cap layer 57. Thus, by forming concave p-side electrodes 48 and 58, molten solder layers 83a and 83b flow into the concave portions of p-side electrode 48 and the concave portions of p-side electrode 58, and thus are melted. It is possible to prevent the solder layers 83a and 83b from flowing from the p-side region located on the side surface of the separation groove 4 and coming into contact with the solder layers 83a and 83b from the light-emitting layers 12 and 22 to the n-side region. Accordingly, it is possible to prevent the element portions of the first semiconductor laser element portion 10a and the second semiconductor laser element portion 20a from being short-circuited. Further, since the molten solder layers 83a and 83b can be prevented from flowing toward the separation groove 4, the two solder layers 83a and 83b provided corresponding to the p-side electrodes 48 and 58 respectively come into contact with each other. Therefore, short-circuit failure between the first semiconductor laser element section 10a and the second semiconductor laser element section 20a can also be suppressed. As a result, when assembling the semiconductor laser device, it is possible to prevent an assembly failure due to a short circuit of the device portion itself and a short circuit between the device portions.
[0082]
By providing the first concave portion 47a and the second concave portion 57a in the p-type cap layers 47 and 57, respectively, the distance from the light emitting layers 12 and 22 to the concave portions of the p-side electrodes 48 and 58 is shortened accordingly. Therefore, it is possible to prevent the heat radiation characteristics from deteriorating. As a result, it is possible to prevent heat radiation characteristics from deteriorating.
[0083]
Further, the first concave portion 47a of the p-type cap layer 47 and the second concave portion 57a of the p-type cap layer 57 are formed to have a depth D (about 3 μm) substantially equal to the thickness t2 (about 3 μm) of the solder layers 83a and 83b. By doing so, the molten solder layers 83a and 83b can flow into the concave portions of the p-side electrode 48 and the p-side electrode 58 satisfactorily, so that the molten solder layers 83a and 83b separate. Flow to the groove 4 side can be effectively suppressed.
[0084]
18 to 20 are cross-sectional views for explaining the manufacturing process of the semiconductor laser device according to the second embodiment shown in FIG. Next, the manufacturing process of the semiconductor laser device according to the second embodiment will be described with reference to FIGS.
[0085]
First, as shown in FIG. 18, a first semiconductor laser element unit 10a (see FIG. 16) and a second semiconductor laser element unit are formed by using the same manufacturing process as that of the first embodiment shown in FIGS. 20a (see FIG. 16) are formed up to the isolation groove 4 for electrically isolating them from each other. The thicknesses and compositions of the p-type cap layers 47 and 57 are the same as those of the p-type cap layers 17 and 27 of the first embodiment. Thereafter, a resist 91 is formed in a predetermined region on the surface of the separation groove 4 and the p-type cap layers 47 and 57.
[0086]
Next, in the second embodiment, as shown in FIG. 19, the resist 91 is used as a mask to remove the upper surfaces of the p-type cap layers 47 and 57 to a depth of about 3 μm by wet etching. Thus, a first concave portion 47a and a second concave portion 57a having a depth D of about 3 μm are formed in predetermined regions of the p-type cap layers 47 and 57. After that, the resist 91 is removed.
[0087]
Next, in the second embodiment, as shown in FIG. 20, after forming a resist 36 so as to fill the separation groove 4, the first concave portion 47a of the p-type cap layer 47 and the p-type Along the second concave portion 57a of the cap layer 57, from the lower layer to the upper layer, a Cr layer having a thickness of about 0.15 μm and a thickness of about 1 μm are formed so as to reflect the shapes of the first concave portion 47a and the second concave portion 57a. The p-side electrodes 48 and 58 having a concave shape and made of an Au layer having a thickness of 5 nm are formed.
[0088]
Finally, an n-side electrode 2 is formed on the back surface of the n-type GaAs substrate 1, as shown in FIG. Thus, the semiconductor laser device according to the second embodiment is formed.
[0089]
Then, as shown in FIG. 17, the p-side electrode 48 of the first semiconductor laser element section 10a and the p-side electrode 58 of the second semiconductor laser element section 20a are placed on the electrodes 74a and 74b of the heat sink 71, respectively. Fusion is performed via solder layers 83a and 83b made of AuSn having a thickness of 3 μm. At this time, the separation groove 4 is arranged in a region corresponding to the insulating film 72 on the upper surface of the heat sink 71. Then, by bonding wires 80a to 80c to the electrode 74a, the electrode 74b, and the n-side electrode 2, respectively, the structure shown in FIG. 17 is obtained.
[0090]
It should be noted that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description of the embodiments, and includes all modifications within the scope and meaning equivalent to the terms of the claims.
[0091]
For example, in the first and second embodiments, an example of a semiconductor laser device in which a device that emits 650 nm red laser light and a device that emits 780 nm infrared laser light are monolithically integrated has been described. However, the present invention is not limited to this, and can be applied to a semiconductor laser device in which devices that emit laser beams of other different wavelengths are monolithically integrated. Further, the present invention is also applicable to a semiconductor laser device in which devices that emit laser beams of the same wavelength are monolithically integrated. Specifically, a nitride-based semiconductor laser device having an active layer made of AlGaInN (e.g., an oscillation wavelength of 350 to 500 nm), a II-VI group semiconductor laser device having an active layer made of ZnO or MgZnSSeTe, or a semiconductor laser made of GaInAs The same or different semiconductor lasers such as an element (for example, an oscillation wavelength of 980 nm, a 1.3 μm band, or a 1.55 μm band) and a semiconductor laser element made of GaInAsNP (for example, a 1.3 μm band or a 1.55 μm band) are monolithically integrated. The present invention can also be applied to a semiconductor laser device.
[0092]
In the first and second embodiments, the p-side electrode of the semiconductor laser element is fused to the heat sink via the AuSn solder layer. However, the present invention is not limited to this. Other materials may be used as the fusion layer.
[0093]
Further, in the first embodiment, the inclination angle of the side wall of the isolation groove 4 on the first semiconductor laser element portion 10 side is set to about 40 ° (low angle A), but the present invention is not limited to this. If the low angle is about 55 ° or less, the same effect can be obtained.
[0094]
In the first embodiment, the maximum width W of the separation groove 4 is set to about 30 μm, and the distance t from the p-side electrodes 18 and 28 to the light emitting layers 12 and 22 is set to about 7 μm. The invention is not limited to this, and it is only necessary that the relational expression represented by t ≧ 0.2 W is satisfied. If the relational expression represented by t ≧ 0.2 W is satisfied, a new semiconductor layer may be added between the p-side electrode and the light emitting layer.
[0095]
In the second embodiment, the depth D of the first concave portion 47a of the p-type cap layer 47 and the second concave portion 57a of the p-type cap layer 57 is set to the same thickness (about 3 μm) as the thickness of the solder layers 83a and 83b. However, the present invention is not limited to this, and the depth D of the first concave portion 47a and the second concave portion 57a may be set to a size different from the thickness of the solder layers 83a and 83b.
[0096]
Further, in the second embodiment, the insulating film 72 is formed in the region corresponding to the separation groove 4 on the upper surface of the heat sink 71, but the present invention is not limited to this, and the insulating film is not formed. Is also good.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a semiconductor laser device according to a first embodiment of the present invention.
FIG. 2 is an enlarged sectional view of a light emitting layer of a first semiconductor laser device portion of the semiconductor laser device according to the first embodiment shown in FIG.
FIG. 3 is an enlarged sectional view of a light emitting layer of a second semiconductor laser device portion of the semiconductor laser device according to the first embodiment shown in FIG.
FIG. 4 is a sectional view showing a state where the semiconductor laser device according to the first embodiment shown in FIG. 1 is fused to a heat sink.
FIG. 5 is a graph showing a relationship between a distance t from a p-side electrode to a light emitting layer and an assembling failure rate due to a short circuit when a maximum width W of a separation groove is about 30 μm.
FIG. 6 is a graph showing the state of occurrence of an assembly failure (short circuit failure) when the maximum width W of the separation groove and the distance t from the p-side electrode to the light emitting layer are used as parameters.
FIG. 7 shows the shortest distance t at which no assembly failure (short circuit failure) occurs when the maximum width W of the separation groove and the distance t from the p-side electrode to the light emitting layer are parameters, and the inclination angle of the side wall of the separation groove. (Low angle and high angle) are graphs showing the results of the investigation.
FIG. 8 is a sectional view for explaining the manufacturing process of the semiconductor laser device according to the first embodiment shown in FIG. 1;
FIG. 9 is a sectional view for explaining the manufacturing process of the semiconductor laser device according to the first embodiment shown in FIG. 1;
FIG. 10 is a sectional view for explaining the manufacturing process of the semiconductor laser device according to the first embodiment shown in FIG. 1;
FIG. 11 is a sectional view for explaining the manufacturing process of the semiconductor laser device according to the first embodiment shown in FIG. 1;
FIG. 12 is a sectional view for explaining the manufacturing process of the semiconductor laser device according to the first embodiment shown in FIG. 1;
FIG. 13 is a sectional view for explaining the manufacturing process of the semiconductor laser device according to the first embodiment shown in FIG. 1;
FIG. 14 is a sectional view for explaining the manufacturing process of the semiconductor laser device according to the first embodiment shown in FIG. 1;
FIG. 15 is a sectional view for explaining the manufacturing process of the semiconductor laser device according to the first embodiment shown in FIG. 1;
FIG. 16 is a sectional view showing a semiconductor laser device according to a second embodiment of the present invention.
17 is a cross-sectional view showing a state where the semiconductor laser device according to the second embodiment shown in FIG. 16 is fused to a heat sink.
FIG. 18 is a cross-sectional view for explaining the manufacturing process of the semiconductor laser device according to the second embodiment shown in FIG.
FIG. 19 is a cross-sectional view for explaining the manufacturing process of the semiconductor laser device according to the second embodiment shown in FIG.
20 is a cross-sectional view for explaining the manufacturing process of the semiconductor laser device according to the second embodiment shown in FIG.
FIG. 21 is a sectional view showing an example of a conventional semiconductor laser device.
22 is a cross-sectional view showing a state where the semiconductor laser device according to the conventional example shown in FIG. 21 is fused to a heat sink.
[Explanation of symbols]
1 n-type GaAs substrate (substrate)
4 Separation groove
10, 10a First semiconductor laser element unit
12 light emitting layer (first light emitting layer)
13 p-type first cladding layer (first semiconductor layer)
13a Etching stop layer (first semiconductor layer)
14 p-type second cladding layer (first semiconductor layer)
15 p-type contact layer (first semiconductor layer)
16 n-type current block layer (first semiconductor layer)
17 p-type cap layer (first semiconductor layer)
18, 48 p-side electrode (first electrode)
20, 20a Second semiconductor laser element unit
22 Light emitting layer (second light emitting layer)
23 p-type first cladding layer (second semiconductor layer)
23a etching stop layer (second semiconductor layer)
24 p-type second cladding layer (second semiconductor layer)
25 p-type contact layer (second semiconductor layer)
26 n-type current block layer (second semiconductor layer)
27 p-type cap layer (second semiconductor layer)
28, 58 p-side electrode (second electrode)
47 p-type cap layer (first semiconductor cap layer)
47a First recess
57 p-type cap layer (second semiconductor cap layer)
57a Second recess
71 Heat sink (base)
72 Insulation film
73a, 73b, 83a, 83b Solder layer (fusion layer)

Claims (5)

A first semiconductor laser element portion formed on a substrate and including a first light emitting layer, a first semiconductor layer, and a first electrode from the substrate side;
A second semiconductor laser element portion formed on the substrate and including, from the substrate side, a second light emitting layer, a second semiconductor layer, and a second electrode;
A separation groove provided to electrically separate the first semiconductor laser element portion and the second semiconductor laser element portion, the separation groove having a groove width increasing toward an element tip;
When a maximum width of the separation groove is W and a distance from the first light emitting layer and the second light emitting layer to the first electrode and the second electrode is t, a relationship of t ≧ 0.2 W is satisfied. Semiconductor laser device. 2. The semiconductor laser device according to claim 1, wherein said separation groove includes a side wall having an inclination angle of 55 ° or less. The first electrode of the first semiconductor laser element unit and the second electrode of the second semiconductor laser element unit are attached to a base by a fusion layer,
The semiconductor laser device according to claim 1, wherein an insulating film is formed in a region of the base corresponding to the separation groove. A first semiconductor laser element portion formed on a substrate and including, from the substrate side, a first light emitting layer, a first semiconductor cap layer, and a first electrode;
A second semiconductor laser element portion formed on the substrate and including a second light emitting layer, a second semiconductor cap layer, and a second electrode from the substrate side;
A separation groove provided for electrically separating the first semiconductor laser element from the second semiconductor laser element;
The first semiconductor cap layer and the second semiconductor cap layer include a first recess and a second recess, respectively.
The first electrode and the second electrode may have shapes of the first recess and the second recess along a first recess of the first semiconductor cap layer and a second recess of the second semiconductor cap layer, respectively. A semiconductor laser device that is formed to reflect. The first electrode of the first semiconductor laser element unit and the second electrode of the second semiconductor laser element unit are attached to a base by a fusion layer,
5. The semiconductor laser device according to claim 4, wherein the first recess of the first semiconductor cap layer and the second recess of the second semiconductor cap layer have substantially the same depth as the thickness of the fusion layer.

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