JP2008066571A - Semiconductor laser element, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser element which can suppress a deterioration of an element characteristic. <P>SOLUTION: This semiconductor laser element is provided with a pair of trenches 20 which are opposed to each other across a current injection area 70, also have a depth reaching a GaAs substrate 1 from an upper face of an element part 50, and are provided so as to extend in parallel to a side end of the element part 50. Further, steps 30a are provided on both-side ends of the element part 50 so as to extend in parallel to the trench 20, and in an area which is positioned beneath the bottom of the step 30a on the back of the GaAs substrate 1, a scribe line 40 is provided so as to extend in parallel to the step 30a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor laser device and a manufacturing method thereof, and more particularly to a semiconductor laser device capable of emitting laser light with high output and a manufacturing method thereof.

  Conventionally, there has been known a broad area type semiconductor laser element capable of emitting laser light with high output by forming a current injection width (stripe width) to 10 μm or more (for example, see Patent Document 1). .

Patent Document 1 describes a broad area type semiconductor laser device having a stripe ridge having a stripe width of 10 μm or more and two-dimensional photonic crystallization on both sides of a light emitting region in an active layer and a p-type cladding layer. Has been. In such a conventional broad area type semiconductor laser device, an element isolation groove is generally formed in the element length direction of the element surface (upper surface) on which the active layer (light emitting layer) is formed. After providing a scribe line on the bottom surface in parallel with the element isolation groove, element isolation is performed by applying stress to the element.
JP 2004-172506 A

  However, in the conventional broad area type semiconductor laser element described above, an element isolation groove is formed, a scribe line is provided on the bottom surface of the element isolation groove in parallel with the element isolation groove, and then element isolation is performed by applying stress to the element. When performing, there was an inconvenience that the edge portion after element separation was chipped. For this reason, a crystal defect is caused in the active layer (light emitting layer) due to the lack of the edge portion, and the crystal defect in the active layer (light emitting layer) expands and proliferates at the time of high output operation of the semiconductor laser device. there were. As a result, there has been a problem that device characteristics are deteriorated.

  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 degradation of device characteristics and a method for manufacturing the same. It is to be.

  In order to achieve the above object, a semiconductor laser device according to a first aspect of the present invention includes a substrate, a light emitting layer formed on the surface of the substrate, and a current blocking layer for limiting a current injection region of the light emitting layer. The element portion is opposed to the current injection region, and has a pair of grooves provided so as to reach a position deeper than the light emitting layer from the upper surface of the element portion and to extend in parallel with the side end surface of the element portion. Yes.

  In the semiconductor laser device according to the first aspect, as described above, they face each other across the current injection region, reach a position deeper than the light emitting layer from the upper surface of the element portion, and extend parallel to the side end surface of the element portion. By providing a pair of grooves as described above, the current injection region side and the side end face side of the element part (light emitting layer) can be separated by the groove part, so that the edge part of the side end face is chipped during element isolation. Even when crystal defects are caused in the light emitting layer due to the chipping, the crystal defects in the light emitting layer can be prevented from extending to the current injection region. That is, crystal defects in the light emitting layer are present in a region near the side end face of the light emitting layer. Therefore, the crystal defect is caused by the groove part separating the current injection region side and the side end face side of the element part (light emitting layer). Extension to the current injection region can be prevented. As a result, it is possible to suppress the growth of crystal defects in the light emitting region corresponding to the current injection region. Therefore, even when the semiconductor laser device is operated at a high output, the deterioration rate of the device is prevented from increasing. can do. As a result, it is possible to suppress deterioration of element characteristics.

  In the semiconductor laser device according to the first aspect, preferably, the groove portion is provided over the entire length of the element portion so as to extend in parallel with the side end face of the element portion. With this configuration, since the current injection region side and the side end face side of the element portion (light emitting layer) can be completely separated by the groove portion, the edge portion of the side end face is chipped during element separation. Even when crystal defects are caused in the light emitting layer due to the chipping, the crystal defects in the light emitting layer can be effectively suppressed from extending into the current injection region. This effectively suppresses the growth of crystal defects in the light emitting region corresponding to the current injection region, so that even when the semiconductor laser device is operated at a high output, the deterioration rate of the device is increased. Can be effectively suppressed. As a result, it is possible to effectively suppress the deterioration of element characteristics.

  In the semiconductor laser device according to the first aspect, the groove portion can be provided at a depth reaching the substrate from the upper surface of the element portion.

  In the semiconductor laser device according to the first aspect, preferably, an electrode for injecting a current into the light emitting layer is formed on the element portion, and the groove portion is opposed to the electrode as viewed in a plan view. It is provided to do. If comprised in this way, since a groove part is provided in the area | region in which an electrode is not formed, the process of removing the electrode which covers the upper surface of an element part can be skipped when providing a groove part. Thereby, even when the electrode for injecting an electric current into the light emitting layer is formed on the element portion, the groove portion can be provided while suppressing an increase in the number of manufacturing steps.

  In the semiconductor laser device according to the first aspect, preferably, stepped portions are provided on both side end faces of the element portion so as to extend in parallel with the groove portion, and are the back surface of the substrate, the bottom surface of the stepped portion. A scribe line is provided in a region located directly below so as to extend in parallel with the stepped portion. With this configuration, the thickness of the portion where element isolation is performed can be reduced, so that element isolation can be easily performed starting from a scribe line provided on the back surface of the substrate. As a result, it is possible to suppress the occurrence of cracks and chips in the groove during element isolation, so that the groove can be easily provided and the grooves are cracked and chipped. Thus, it is possible to suppress crystal defects from being caused in the light emitting layer.

  In this case, preferably, the bottom surface of the stepped portion is provided at a position deeper than the bottom surface of the groove portion. With this configuration, the thickness of the portion where element isolation is performed can be made smaller than the thickness of the bottom portion of the bottom of the groove portion, so that element isolation is more easily performed using the scribe line provided on the back surface of the substrate as a starting point. be able to. As a result, it is possible to effectively suppress the occurrence of cracks and chips in the groove during element isolation, so that the groove can be provided more easily and cracks and chips are generated in the groove. As a result, it is possible to effectively prevent crystal defects from being caused in the light emitting layer.

  According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor laser device, comprising: forming a light emitting layer and a current blocking layer for limiting a current injection region of the light emitting layer on a surface of a substrate; A step of forming a pair of first groove portions so as to face each other across the region and have a depth reaching the substrate from the upper surface of the element portion and extend in a predetermined direction; and the first groove portion in the element portion Forming a resonator surface orthogonal to the extending direction of the first and second elements, and isolating the element outside the pair of first groove portions along the first groove portions.

  In the method of manufacturing the semiconductor laser device according to the second aspect, as described above, the semiconductor laser device is opposed to the current injection region, has a depth reaching the substrate from the upper surface of the device portion, and extends in a predetermined direction. Thus, by providing the step of forming a pair of first groove portions, the current injection region side of the element portion (light emitting layer) and the region side for element isolation can be separated from each other by the first groove portion. In this case, even when a chip occurs in the edge portion of the side end face and a crystal defect is caused in the light emitting layer due to the chip, it is possible to suppress the crystal defect in the light emitting layer from extending into the current injection region. That is, crystal defects in the light emitting layer are present in a region in the vicinity of the region of the light emitting layer where element isolation is performed. Therefore, the current injection region side of the element portion (light emitting layer) and the region side where element isolation is performed The separated first groove can prevent the crystal defect from extending into the current injection region. As a result, it is possible to suppress the growth of crystal defects in the light emitting region corresponding to the current injection region. Therefore, even when the semiconductor laser device is operated at a high output, the deterioration rate of the device is prevented from increasing. can do. As a result, it is possible to suppress deterioration of element characteristics.

  In the method of manufacturing a semiconductor laser device according to the second aspect, preferably, in the step of forming the first groove portion, when the resonator surface is formed in the element portion, the resonator surface of the element portion extends over the entire length of the element portion. Forming a first groove so as to extend in a direction orthogonal to the first direction. With this configuration, the current injection region side of the element portion (light emitting layer) and the element isolation region side can be completely separated by the first groove portion. Even when a chip is formed and a crystal defect is caused in the light emitting layer due to the chip, it is possible to effectively suppress the crystal defect in the light emitting layer from extending into the current injection region. This effectively suppresses the growth of crystal defects in the light emitting region corresponding to the current injection region, so that even when the semiconductor laser device is operated at a high output, the deterioration rate of the device is increased. Can be effectively suppressed. As a result, it is possible to effectively suppress the deterioration of element characteristics.

  In the method of manufacturing a semiconductor laser device according to the second aspect, preferably, before the step of forming the first groove portion, a step of forming an electrode for injecting current into the light emitting layer on the element portion, The step of forming the first groove portion includes a step of forming a pair of first groove portions so as to be opposed to each other with the electrode interposed therebetween in plan view. If comprised in this way, since a 1st groove part will be provided in the area | region in which an electrode is not formed, the process of removing the electrode which covers the upper surface of an element part can be skipped when forming a 1st groove part. Thereby, even when an electrode for injecting current into the light emitting layer is formed on the element portion, the first groove portion can be formed while suppressing an increase in the number of manufacturing steps.

  In the method of manufacturing a semiconductor laser device according to the second aspect, preferably, the step of forming the first groove includes a step of forming the first groove by etching. With this configuration, even when the first groove portion is opposed to the current injection region, has a depth reaching the substrate from the upper surface of the element portion, and extends in a predetermined direction, The first groove can be easily formed by etching.

  In the method for manufacturing a semiconductor laser device according to the second aspect, preferably, the step of performing element isolation is a step of forming a second groove portion outside the pair of first groove portions so as to extend in parallel with the first groove portion. And a step of providing a scribe line so as to extend in parallel with the second groove portion in a region located on the back surface of the substrate and directly below the bottom surface of the second groove portion, and a step of dividing the substrate from the scribe line as a starting point. including. With this configuration, the thickness of the portion where element isolation is performed can be reduced, so that the element isolation can be easily performed by the process of dividing the substrate starting from the scribe line. Thereby, in the process of dividing the substrate, it is possible to suppress the occurrence of cracks and chips in the first groove portion, so that the first groove portion can be easily formed and the first groove portion is cracked. In addition, the occurrence of crystal defects in the light-emitting layer due to occurrence of chips and the like can be suppressed.

  In this case, preferably, the step of forming the second groove includes a step of forming the second groove deeper than the first groove. According to this structure, the thickness of the portion where the element is separated can be made smaller than the thickness of the bottom portion of the bottom of the first groove, so that the element separation can be performed more easily by the process of dividing the substrate starting from the scribe line. It can be performed. Thereby, in the step of dividing the substrate, it is possible to effectively suppress the occurrence of cracks and chips in the first groove portion, so that the first groove portion can be formed more easily and the first groove portion can be formed. It is possible to effectively suppress the occurrence of crystal defects in the light emitting layer due to the occurrence of cracks and chips in the groove.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The semiconductor laser device according to an embodiment of the present invention is a broad area type semiconductor laser device that can emit laser light with high output and has a light emission pattern that is not unimodal.

  FIG. 1 is an overall perspective view of a semiconductor laser device according to an embodiment of the present invention, and FIG. 2 is a plan view of the semiconductor laser device according to the embodiment shown in FIG. 3 to 6 are views for explaining the structure of the semiconductor laser device according to the embodiment shown in FIG. First, the structure of a semiconductor laser device according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the element unit 50 of the semiconductor laser device according to the embodiment has a length (L1) of about 1000 μm in a direction orthogonal to the resonator surface 60 (arrow Y direction). And has a width (W1) of about 800 μm in the direction along the resonator surface 60 (arrow X direction). The element unit 50 is formed with a pair of resonator surfaces 60 that are cleaved surfaces.

In addition, as shown in FIGS. 1 and 3, the semiconductor laser device according to the present embodiment is formed on an GaAs substrate 1 having a thickness of about 100 μm and an n-type Al _0.48 Ga _{0. An} n-type cladding layer 2 made of ₅₂ As is formed. A light emitting layer 3 is formed on the n-type cladding layer 2. As shown in FIG. 4, the light emitting layer 3 includes two quantum well layers 3a made of GaAs having a thickness of about 9 nm and one barrier made of Al _0.39 Ga _0.61 As having a thickness of about 8 nm. An active layer 3c having an MQW (multiple quantum well) structure in which layers 3b are alternately stacked is included. Also, light guide layers 3d and 3e made of Al _0.39 Ga _0.61 As having a thickness of about 30 nm are provided so as to sandwich the active layer 3c. The light emitting layer 3 is constituted by the active layer 3c and the light guide layers 3d and 3e. The GaAs substrate 1 is an example of the “substrate” in the present invention.

Further, as shown in FIG. 3, a p-type cladding layer 4 made of p-type Al _0.49 Ga _0.51 As having a thickness of about 1.2 μm is formed on the light guide layer 3 e of the light emitting layer 3. ing. A p-type contact layer 5 made of p-type GaAs having a thickness of about 0.5 μm is formed on the p-type cladding layer 4. A p-type cap layer 6 made of p-type GaAs having a thickness of about 0.5 μm is formed on the p-type contact layer 5. A current blocking layer 7 is formed in a predetermined region on the p-type cap layer 6. As shown in FIGS. 2, 3, and 5, the current blocking layer 7 has an opening 7c in a region corresponding to the current injection region 70 in plan view. The current injection region 70 formed in the region corresponding to the opening 7c of the current blocking layer 7 has a width W2 of about 360 μm and a direction orthogonal to the resonator surface 60 as shown in FIG. It is formed in an elongated shape (stripe shape) extending in the (arrow Y direction).

  Further, in the vicinity of the resonator surface 60 of the element unit 50, a current non-injection region 7 d having a length L 2 of about 25 μm from each resonator surface 60 is formed by the current blocking layer 7. Thus, by forming the current non-injection region 7d in the vicinity of the resonator surface 60, the temperature rise in the vicinity of the resonator surface 60 is suppressed during high output operation, and the semiconductor laser element of COD (catalytic optical damage) is used. Destruction is suppressed.

As shown in FIGS. 1 and 3, the current blocking layer 7 includes an n-type AlGaAs made of n-type Al _0.7 Ga _0.3 As having a thickness of about 0.6 μm from the p-type cap layer 6 side. It has a two-layer structure in which a layer 7a and an n-type GaAs layer 7b having a thickness of about 0.3 μm are stacked.

  As shown in FIG. 3, the Cr layer, the Au layer, the Pt layer, and the Au layer are formed on the p-type cap layer 6 and the current blocking layer 7 from the p-type cap layer 6 and current blocking layer 7 side. A p-side electrode 8 having a thickness of about 2.3 μm is formed by sequentially stacking layers. The P-side electrode 8 is an example of the “electrode” in the present invention. On the back surface of the GaAs substrate 1, an Au layer, a Ge layer, an Au layer, an Ni layer, an Au layer, a Pt layer, and an Au layer are sequentially stacked from the GaAs substrate 1 side. An n-side electrode 9 having a thickness of 1.2 μm is formed.

  Here, in the present embodiment, as shown in FIGS. 1 to 3, a pair of grooves 20 facing each other with the current injection region 70 interposed therebetween is formed in the semiconductor laser element by etching. The groove portion 20 has a width W3 (see FIG. 3) of about 10 μm and is formed over the entire length of the element portion 50 so as to extend in the direction of arrow Y, which is a direction orthogonal to the resonator surface 60. Further, as shown in FIGS. 1 and 3, the groove portion 20 is formed from the upper surface of the element portion 50 to a depth reaching the GaAs substrate 1 that is deeper than the light emitting layer 3. Since the pair of groove portions 20 are formed by etching, the groove portions 20 are formed without causing crystal defects in the light emitting layer 3. In addition, as shown in FIG. 2, the pair of groove portions 20 are provided so as to face each other with the p-side electrode 8 interposed therebetween when seen in a plan view.

  Further, in the present embodiment, as shown in FIGS. 1 to 3, both end surfaces extending in the direction orthogonal to the resonator surface 60 (the arrow Y direction) of the element unit 50 extend along the side end surfaces. A step portion 30 a is provided over the entire length of the element portion 50. The step portion 30a is formed when elements are separated by a groove portion 30 (see FIG. 17) described later. The bottom surface of the stepped portion 30a has a width (W4) of about 5 μm. Further, the bottom surface of the stepped portion 30 a is formed on the GaAs substrate 1 and at a position deeper than the pair of groove portions 20.

  Further, in the present embodiment, as shown in FIGS. 1, 3, and 6, the region located on the back surface of the GaAs substrate 1 and directly below the bottom surface of the stepped portion 30a provided on both side end surfaces is provided. The scribe line 40, which is a base point for element isolation, is provided so as to extend in parallel with the stepped portion 30a. Specifically, the scribe line 40 is provided at the edge portion on the back surface of the GaAs substrate 1. As shown in FIG. 6, the scribe line 40 is provided at a position separated from each resonator surface 60 by a length L3 of 50 μm or more. That is, the scribe line 40 has a length of about 900 μm (L1: about 1000 μm) symmetrically from the center in the length direction (arrow Y direction) of the element unit 50 (L1: about 1000 μm). L4).

Further, as shown in FIG. 2, a front dielectric layer 10 having a total thickness of about 142 nm and a front reflectance of 4% is formed on the resonator surface 60 on the laser beam emission side (A side). . The front dielectric layer 10 is composed of a Si layer having a thickness of about 2 nm and an Al ₂ O ₃ layer having a thickness of about 140 nm from the resonator surface 60 side. Further, the rear dielectric layer 11 having a total thickness of about 590 nm and a rear reflectance of 95% is formed on the resonator surface 60 opposite to the laser beam emitting side (B side). The rear dielectric layer 11 includes, from the resonator surface 60 side, an Al ₂ O ₃ layer having a thickness of about 120 nm, a Si layer having a thickness of about 55 nm, and an Al ₂ O ₃ layer having a thickness of about 120 nm. And an Si layer having a thickness of about 55 nm and an Al ₂ O ₃ layer having a thickness of about 120 nm.

  In the present embodiment, as described above, they face each other with the current injection region 70 interposed therebetween, have a depth reaching the GaAs substrate 1 from the upper surface of the element unit 50, and extend in parallel with the side end surface of the element unit 50. As described above, by providing the pair of groove portions 20 over the entire length of the element portion 50, the current injection region 70 side and the side end face side of the element portion 50 can be completely separated by the groove portion 20. Even when the edge portion of the side end face is chipped and a crystal defect is caused in the light emitting layer 3 (active layer 3c) due to the chipping, the crystal defect in the light emitting layer 3 is extended to the current injection region 70. It can be effectively suppressed. That is, since the crystal defect in the light emitting layer 3 exists in a region near the side end face of the light emitting layer 3, the crystal defect is caused by the groove 20 separating the current injection region 70 side and the side end face side of the element part 50. Can be prevented from extending into the current injection region 70. As a result, it is possible to effectively suppress the growth of crystal defects in the light emitting region corresponding to the current injection region 70. Therefore, even when the semiconductor laser device is operated at a high output, the deterioration rate of the device is increased. Can be effectively suppressed. As a result, it is possible to effectively suppress the deterioration of element characteristics.

  In the present embodiment, the groove 20 is provided so as to be opposed to each other with the P-side electrode 8 interposed therebetween in a plan view, so that when the groove 20 is provided, the P-side electrode 8 that covers the upper surface of the element portion 50 is provided. Can be omitted, so that even when the P-side electrode 8 for injecting current into the light emitting layer 3 is formed on the element portion 50, while suppressing an increase in manufacturing steps, A groove 20 can be provided.

  7 to 20 are views for explaining a method of manufacturing the semiconductor laser device according to the embodiment of the present invention shown in FIG. Next, with reference to FIGS. 1-5 and FIGS. 7-20, the manufacturing method of the semiconductor laser element by one Embodiment of this invention is demonstrated.

First, as shown in FIG. 7, GaAs having a thickness of about 350 μm and an inclination of about 4 ° from the {100} crystal plane using MOCVD (Metal Organic Chemical Vapor Deposition) or the like. On the upper surface of the substrate 1, an n-type cladding layer 2 made of n-type Al _0.48 Ga _0.52 As having a thickness of about 3.3 μm, a light emitting layer 3, and a p-type Al ₀ having a thickness of about 1.2 μm. P-type cladding layer 4 made of _.49 Ga _0.51 As, p-type contact layer 5 made of p-type GaAs having a thickness of about 0.5 μm, and p-type made of p-type GaAs having a thickness of about 0.5 μm. The mold cap layer 6 is grown sequentially.

As shown in FIG. 4, the light emitting layer 3 is formed on an optical guide layer 3d made of Al _0.39 Ga _0.61 As having a thickness of about 30 nm, an active layer 3c having an MQW structure, and about The light guide layer 3e made of Al _0.39 Ga _0.61 As having a thickness of 30 nm is formed by sequentially growing. The active layer 3c includes two quantum well layers 3a made of GaAs having a thickness of about 9 nm and one barrier layer 3b made of Al _0.39 Ga _0.61 As having a thickness of about 8 nm alternately. It is formed by stacking.

Next, as shown in FIG. 8, n-type AlGaAs made of n-type Al _0.18 Ga _0.82 As having a thickness of about 0.6 μm on the p-type cap layer 6 from the p-type cap layer 6 side. By sequentially growing a layer 7a and an n-type GaAs layer 7b having a thickness of about 0.3 μm, a current blocking layer 7 composed of two layers of an n-type AlGaAs layer 7a and an n-type GaAs layer 7b is formed.

  Then, as shown in FIG. 9, a resist film 12 is formed in a predetermined region on the current blocking layer 7 using a photolithography technique. Thereafter, as shown in FIG. 10, the current blocking layer 7 is etched using the formed resist film 12 as a mask. Thus, an opening 7c corresponding to the current injection region 70 having a width W2 (about 360 μm) as shown in FIGS. 2 and 5 is formed in the current blocking layer 7. Thereafter, the formed resist film 12 is removed to obtain the shape shown in FIG.

  Next, as shown in FIG. 12, the Cr layer and Au are formed on the p-type cap layer 6 and the current blocking layer 7 from the p-type cap layer 6 and current blocking layer 7 side by using a vacuum deposition method or the like. A p-side electrode 8 having a total thickness of about 2.3 μm in which a layer, a Pt layer, and an Au layer are sequentially stacked is formed.

  Subsequently, as shown in FIG. 13, a resist film 13 is formed in predetermined regions on the current blocking layer 7 and the p-side electrode 8 by using a photolithography technique. Next, as shown in FIG. 14, etching is performed over the entire length of the element portion 50 to the depth reaching the GaAs substrate 1 using the formed resist film 13 as a mask. Thereby, as shown in FIGS. 1 to 3, a pair of groove portions 20 that are opposed to each other with the current injection region 70 and the P-side electrode 8 interposed therebetween and that extend in the arrow Y direction are formed. The groove 20 is an example of the “first groove” in the present invention. Thereafter, the formed resist film 13 is removed to obtain the shape shown in FIG.

  Next, as illustrated in FIG. 16, a resist film 14 is formed again in predetermined regions on the current blocking layer 7 and the p-side electrode 8 by using a photolithography technique. Then, as shown in FIG. 17, etching is performed over the entire length of the element portion 50 to the depth reaching the GaAs substrate 1 using the formed resist film 14 as a mask. At this time, etching is performed so as to be deeper than the depth of the groove 20 formed previously. Thereby, the groove part 30 extended in parallel with the groove part 20 is formed. Thereafter, the formed resist film 14 is removed. The groove 30 is an example of the “second groove” in the present invention.

Next, the back surface of the GaAs substrate 1 is thinned by using a method such as polishing until the thickness of the GaAs substrate 1 is about 100 μm. This is to make it easier to split the GaAs substrate 1 in the subsequent element isolation step. Next, as shown in FIG. 18, the Au layer, the Ge layer, the Au layer, the Ni layer, and the Au layer are formed on the back surface of the GaAs substrate 1 from the GaAs substrate 1 side by using a vacuum deposition method or the like. Then, an n-side electrode 9 having a total thickness of about 1.2 μm is formed by sequentially stacking a Pt layer and an Au layer. Then, the GaAs substrate 1 is cleaved in the X direction to form a pair of resonator surfaces 60, and a dielectric layer is formed on the formed resonator surfaces 60. Specifically, as shown in FIG. 2, an Si layer having a thickness of about 2 nm is formed on the resonator surface 60 on the laser beam emitting side (A side) of the element unit 50 from the resonator surface 60 side. A front dielectric layer 10 having a thickness of about 142 nm and a front reflectance of 4% is formed by laminating an Al ₂ O ₃ layer having a thickness of about 140 nm. Further, an Al ₂ O ₃ layer having a thickness of about 120 nm and an Si layer having a thickness of about 55 nm are formed on the resonator surface 60 on the opposite side (B side) to the laser light emitting side from the resonator surface 60 side. And an Al ₂ O ₃ layer having a thickness of about 120 nm, an Si layer having a thickness of about 55 nm, and an Al ₂ O ₃ layer having a thickness of about 120 nm. A rear dielectric layer 11 having a reflectance of 95% is formed.

  Next, as shown in FIG. 19 and FIG. 20, a scribe line 40 extending in parallel with the groove 30 is provided in a region located on the back surface of the GaAs substrate 1 and immediately below the bottom surface of the groove 30. At this time, as shown in FIG. 20, the scribe line 40 is formed so as to be separated from each resonator surface 60 by a length L3 of 50 μm or more. Specifically, a length (L4) of about 900 μm, which is a length smaller than the length of the element unit 50 (L1: about 1000 μm), symmetrically from the center in the length direction (arrow Y direction) of the element unit 50. A scribe line 40 is formed. This suppresses the occurrence of chipping in the corner portion of the GaAs substrate 1 during element isolation.

  Finally, by applying stress to the element, the GaAs substrate 1 is divided and element isolation is performed. Thus, the semiconductor laser device according to the embodiment of the present invention shown in FIG. 1 is formed.

  In the present embodiment, as described above, the element portion has a depth reaching the GaAs substrate 1 from the upper surface of the element portion 50 and is opposed to the current injection region 70 and extends in the arrow Y direction. By forming the pair of groove portions 20 over the entire length of 50, the current injection region 70 side of the element portion 50 and the region side where element isolation is performed can be completely separated by the groove portion 20. Even when a chip occurs in the edge portion of the side end face and a crystal defect is caused in the light emitting layer 3 due to the chip, it is possible to effectively suppress the crystal defect in the light emitting layer 3 from extending to the current injection region 70. it can. That is, crystal defects in the light emitting layer 3 exist in a region near the region where the element isolation of the light emitting layer 3 is performed. Therefore, the current injection region 70 side of the element unit 50 and the region side where the element isolation is performed are separated. The separating groove 20 can prevent crystal defects from extending into the current injection region 70. As a result, it is possible to effectively suppress the growth of crystal defects in the light emitting region corresponding to the current injection region 70. Therefore, even when the semiconductor laser device is operated at a high output, the deterioration rate of the device is increased. Can be effectively suppressed. As a result, it is possible to effectively suppress the deterioration of element characteristics.

  In the present embodiment, the pair of groove portions 20 are formed so as to be opposed to each other with the P-side electrode 8 interposed therebetween in plan view, thereby covering the upper surface of the element portion 50 when the groove portions 20 are formed. Since the step of removing the P-side electrode 8 can be omitted, even if the P-side electrode 8 for injecting current into the light emitting layer 3 is formed on the element portion 50, the increase in the number of manufacturing steps is suppressed. However, the groove 20 can be formed.

  Further, in the present embodiment, by forming the groove 20 by etching, the groove 20 is opposed to the current injection region 70, and has a depth reaching the GaAs substrate 1 from the upper surface of the element portion 50, and Even when formed so as to extend in the direction of the arrow Y, the groove 20 can be easily formed by etching.

  In the present embodiment, when element isolation is performed, the groove portion 30 is formed outside the pair of groove portions 20 so as to extend in parallel with the groove portion 20, and is the back surface of the GaAs substrate 1, and the bottom surface of the groove portion 30. A scribe line 40 is provided in a region located directly below the groove portion 30 so as to extend in parallel with the groove portion 30, and the GaAs substrate 1 is divided starting from the scribe line 40, thereby reducing the thickness of the portion where element isolation is performed. Therefore, the GaAs substrate 1 can be easily divided from the scribe line 40 as a starting point during the element isolation process. Thereby, when the GaAs substrate 1 is divided, it is possible to prevent the groove 20 from being cracked and chipped, so that the groove 20 can be easily formed and the groove 20 is cracked and chipped. It is possible to suppress the occurrence of crystal defects in the light emitting layer 3 due to the occurrence of.

  In the present embodiment, by forming the groove portion 30 deeper than the groove portion 20, the thickness of the portion where the element is separated can be made smaller than the thickness of the lower portion of the bottom surface of the groove portion 20. The GaAs substrate 1 can be divided more easily from the scribe line 40 as a starting point. Thereby, when the GaAs substrate 1 is divided, it is possible to effectively prevent the groove 20 from being cracked and chipped, so that the groove 20 can be formed more easily and the groove 20 is cracked. Further, it is possible to effectively suppress the occurrence of crystal defects in the light emitting layer 3 due to the occurrence of chipping and the like.

  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 embodiment but by the scope of claims for patent, and includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above-described embodiment, an example in which the pair of groove portions is formed over the entire length of the element portion has been described. However, the present invention is not limited thereto, and the pair of groove portions may be formed over substantially the entire length of the element portion. In addition, there may be a part where a groove is not formed.

  In the above-described embodiment, an example in which the pair of groove portions is formed from the upper surface of the element portion to the depth reaching the GaAs substrate is shown. However, the present invention is not limited to this, and the pair of groove portions is deeper than the light emitting layer. If it has reached, it does not have to reach the GaAs substrate.

  Further, in the above embodiment, the step portion is provided on both end faces of the element portion, and the bottom surface of the step portion is provided at a position deeper than the bottom surface of the pair of groove portions. However, the bottom surface of the stepped portion may be provided at the same position as the bottom surface of the pair of groove portions or shallower than the bottom surface of the pair of groove portions. In addition, when the bottom surface of the stepped portion is provided at the same depth position as the bottom surface of the pair of groove portions, the groove portion before the stepped portion can be formed in the same step as the step of forming the groove portion. The step portion can be provided while suppressing an increase in the number of manufacturing steps.

  Moreover, in the said embodiment, although the example which provided the level | step-difference part in the both-ends end surface of the element part was shown, this invention will not be restricted to this, If element isolation is performed in the area | region outside a pair of groove part, You may make it the structure which does not provide a level | step-difference part in a both-ends end surface.

  Moreover, in the said embodiment, although the example which provided the scribe line in the position 50 micrometers or more apart from each resonator surface was shown, this invention is not limited to this, A scribe line may be reached to each resonator surface. Further, it may be provided over the entire length of the element portion. That is, the length of the scribe line may be configured to be the same as the length of the element portion.

1 is an overall perspective view of a semiconductor laser device according to an embodiment of the present invention. FIG. 2 is a plan view of the semiconductor laser device according to the embodiment of the present invention shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line 100-100 in FIG. 2. It is sectional drawing which showed the structure of the light emitting layer of the semiconductor laser element by one Embodiment of this invention. It is the perspective view which abbreviate | omitted the p side electrode of the semiconductor laser element by one Embodiment of this invention. It is the top view which looked at the semiconductor laser element by one Embodiment of this invention shown in FIG. 1 from the back surface side. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. 2 is a cross-sectional view for explaining a method of manufacturing the semiconductor laser device according to one embodiment of the present invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG. It is a top view for demonstrating the manufacturing method of the semiconductor laser element by one Embodiment of this invention shown in FIG.

Explanation of symbols

1 GaAs substrate (substrate)
2 n-type cladding layer 3 light emitting layer 3a quantum well layer 3b barrier layer 3c active layer 3d, 3e light guide layer 4 p-type cladding layer 5 p-type contact layer 6 p-type cap layer 7 current blocking layer 8 p-side electrode (electrode)
9 N-side electrode 10 Front dielectric layer 11 Rear dielectric layer 20 Groove (first groove)
30a Step part 30 Groove part (2nd groove part)
40 Scribe line 50 Element part 60 Resonator surface 70 Current injection region

Claims (12)

A substrate,
An element portion including a light emitting layer formed on the surface of the substrate and a current blocking layer for limiting a current injection region of the light emitting layer;
And a pair of grooves provided so as to face each other with the current injection region interposed therebetween, to reach a position deeper than the light emitting layer from the upper surface of the element portion, and to extend in parallel to a side end surface of the element portion. A semiconductor laser device characterized by the above.   2. The semiconductor laser device according to claim 1, wherein the groove portion is provided over the entire length of the element portion so as to extend in parallel with a side end surface of the element portion.   The semiconductor laser device according to claim 1, wherein the groove portion is provided at a depth reaching the substrate from an upper surface of the element portion. An electrode for injecting current into the light emitting layer is formed on the element portion,
4. The semiconductor laser device according to claim 1, wherein the groove portion is provided so as to be opposed to each other with the electrode interposed therebetween in a plan view. On both side end faces of the element part, a step part is provided so as to extend in parallel with the groove part,
5. A scribe line is provided in a region on the back surface of the substrate, which is located directly below the bottom surface of the step portion, so as to extend in parallel with the step portion. The semiconductor laser device according to any one of the above.   6. The semiconductor laser device according to claim 5, wherein a bottom surface of the step portion is provided at a position deeper than a bottom surface of the groove portion. Forming a light emitting layer and an element portion including a current blocking layer for limiting a current injection region of the light emitting layer on a surface of the substrate;
Forming a pair of first grooves so as to face each other across the current injection region, to have a depth reaching the substrate from the upper surface of the element portion, and to extend in a predetermined direction;
Forming a resonator surface perpendicular to the direction in which the first groove extends in the element portion;
And a step of separating the elements outside the pair of first groove portions along the first groove portions.   The step of forming the first groove portion includes the first groove portion extending in a direction perpendicular to the resonator surface of the element portion over the entire length of the element portion when the resonator surface is formed in the element portion. The method of manufacturing a semiconductor laser device according to claim 7, comprising a step of forming one groove portion. Before the step of forming the first groove,
Forming an electrode for injecting a current into the light emitting layer on the element portion;
9. The method according to claim 7, wherein the step of forming the first groove portion includes a step of forming a pair of the first groove portions so as to face each other with the electrode interposed therebetween in a plan view. The manufacturing method of the semiconductor laser element of description.   The method for manufacturing a semiconductor laser device according to claim 7, wherein the step of forming the first groove includes a step of forming the first groove by etching. The step of separating the elements includes
Forming a second groove portion on the outside of the pair of first groove portions so as to extend in parallel with the first groove portion;
Providing a scribe line so as to extend in parallel with the second groove portion in a region located on the back surface of the substrate and directly below the bottom surface of the second groove portion;
The method for manufacturing a semiconductor laser device according to claim 7, comprising a step of dividing the substrate with the scribe line as a starting point.   12. The method of manufacturing a semiconductor laser device according to claim 11, wherein the step of forming the second groove portion includes a step of forming the second groove portion deeper than the first groove portion.

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