JP5250759B2 - Nitride-based semiconductor laser device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a nitride semiconductor laser element and a method for manufacturing the same, and more particularly to a nitride semiconductor laser element in which a nitride semiconductor element layer having a light emitting layer is formed on a substrate and a method for manufacturing the same.

  In recent years, low-power lasers for reproduction have been put into practical use as nitride-based semiconductor lasers as light sources for next-generation optical discs, while higher output and longer life of semiconductor lasers have been studied for application to high-speed recording devices. ing. The main factor that limits the increase in output and life of semiconductor lasers is that the cavity facet deteriorates due to the amount of heat generated by carriers and light near the cavity facet during operation. In particular, a semiconductor laser element employs a structure in which laser light output is exclusively obtained from the other end surface (light emitting surface) by coating one end surface (light reflecting surface) of the resonator end surface with a high reflectance film. For this reason, since the light density distribution in the resonator is particularly large near the light exit surface, the deterioration of the light exit surface tends to be more severe than that of the light reflection surface.

  Conventionally, a nitride-based semiconductor having a light-emitting layer and comprising a nitride-based semiconductor layer formed on a substrate and a pair of resonator end faces formed at the end of the nitride-based semiconductor layer in the optical waveguide direction A manufacturing method of a laser element and a nitride semiconductor laser device is known (see, for example, Patent Document 1).

  In the nitride-based semiconductor laser device disclosed in Patent Document 1, a wafer-like semiconductor device in which a semiconductor device layer made of GaN or the like and an electrode are formed on a transparent substrate made of GaN or SiC is cleaved. Thus, a pair of resonator end faces (light emitting surface and light reflecting surface) substantially perpendicular to the crystal growth surface (main surface) of the transparent substrate is formed. A pair of resonator end faces are formed with dielectric films having different reflectivities so that a high-power laser beam can be emitted from the light emitting surface side. Note that the semiconductor element layer having the light emitting layer has substantially the same size (planar area) as the transparent substrate in plan view.

Patent registration No. 3505478

  However, in the method of manufacturing the nitride semiconductor laser element and the nitride semiconductor laser device disclosed in Patent Document 1, the semiconductor element layer having the light emitting layer is substantially the same as the transparent substrate in plan view. Since the resonator end face is formed substantially perpendicular to the main surface of the transparent substrate, the heat generated by the laser emitted light in the resonator near the light emitting surface is generated by the semiconductor near the light emitting surface. Heat is transferred from the inside of the element layer to the transparent substrate side having a plane area equal to the plane area of the semiconductor element layer. In such a configuration, when the output of the semiconductor laser is increased, there may be a case where heat is not sufficiently radiated on the transparent substrate side due to an increase in the amount of heat generated by the laser emitted light in the vicinity of the light emitting surface. It is believed that there is. In this case, the heat generated by the laser beam is not properly dissipated, and the resonator end face generates excessive heat. For this reason, the nitride-based semiconductor laser element disclosed in Patent Document 1 has a problem that the cavity facet is likely to deteriorate as the output of the semiconductor laser increases.

  The present invention has been made in order to solve the above-described problems, and one object of the present invention is to suppress the deterioration of the resonator end face accompanying the increase in the output of the semiconductor laser. A nitride-based semiconductor laser device and a manufacturing method thereof are provided.

Means for Solving the Problems and Effects of the Invention

  To achieve the above object, a nitride-based semiconductor laser device according to a first aspect of the present invention includes a substrate, and a nitride-based semiconductor device layer formed on the main surface of the substrate and having a light emitting layer, The first end surface of the nitride-based semiconductor element layer includes a resonator end surface and an inclined surface formed in the vicinity of the resonator end surface and inclined at a predetermined angle with respect to the main surface of the substrate. The angle formed with the main surface is an acute angle.

  In the nitride-based semiconductor laser device according to the first aspect of the present invention, as described above, the first end surface of the nitride-based semiconductor device layer is formed in the vicinity of the resonator end surface and the resonator end surface, and at least the main surface of the substrate. The nitride-based semiconductor element layer has a plane area larger than the plane area in the vicinity of the light emitting layer and the substrate side, by including the inclined surface inclined at a predetermined angle while forming an acute angle with the surface. Since they are connected, the cross-sectional area of the path that radiates heat to the substrate side can be increased by the increase in the plane area. Thereby, even when the output of the semiconductor laser is increased, the nitride system in which the heat generation of the laser emission light in the vicinity of the cavity end face is formed with an inclined surface extending in the laser beam emission direction from the cavity end face It diffuses to the substrate side appropriately through the inside of the semiconductor element layer. Therefore, excessive heat generation of the resonator end face by the laser emission light is suppressed. As a result, it is possible to suppress the deterioration of the cavity end face as the output of the semiconductor laser increases. Moreover, the lifetime of the semiconductor laser can be extended by suppressing the deterioration of the cavity end face.

  In the nitride-based semiconductor laser device according to the first aspect, preferably, the nitride-based semiconductor device layer includes a first conductivity type first cladding layer formed on a substrate side of the light emitting layer, and a substrate side of the light emitting layer. And the inclined surface of the first end face includes at least the end face of the first clad layer. According to this structure, the inclined surface is formed toward the substrate starting from the first cladding layer located near the lower portion of the light emitting layer on the resonator end surface formed on the substrate. The generated heat of the laser light can be diffused more efficiently to the substrate side.

  In the nitride semiconductor laser element according to the first aspect, preferably, the inclined surface of the first end face is formed at least on the emission side of the laser light emitted from the light emitting layer. If comprised in this way, it can suppress easily that the resonator end surface by the side of the light emission accompanying a bigger heat_generation | fever at the time of laser operation | movement deteriorates.

  In the present invention, the laser beam emission side is distinguished by the magnitude relationship of the intensity of the laser beam emitted from the pair of resonator end faces. That is, the resonator end face on the side with relatively high laser beam emission intensity is the light emission side, and the resonator end face on the side with relatively low laser beam emission intensity is the light reflection side.

  In the nitride semiconductor laser element according to the first aspect, preferably, the substrate includes a main surface including a (H, K, -HK, 0) plane, and the substrate includes a (1-100) plane. In the case of having a main surface, at least the inclined surface of the first end surface starts from the side surface on one side of the recess formed in the substrate so as to extend in the [11-20] direction in the main surface of the substrate ( 1-110) is a growth surface of a nitride-based semiconductor element layer, and when the substrate has a main surface consisting of (11-20) surface, at least the inclined surface of the first end surface is within the main surface of the substrate. This is a growth surface of a nitride-based semiconductor element layer composed of a (11-22) plane starting from a side surface on one side of a recess formed in a substrate so as to extend in a [1-100] direction in a stripe shape. If comprised in this way, the inclined surface which consists of two types of growth surfaces which consist of said (1-101) plane and (11-22) plane is formed simultaneously with the crystal growth of a nitride-type semiconductor element layer, respectively. Can do.

  In the configuration in which the substrate has a main surface composed of (H, K, -H-K, 0) plane, preferably, the side opposite to the first end surface of the nitride-based semiconductor element layer with respect to the direction in which the resonator extends. And a second end face extending in a direction substantially perpendicular to the main surface of the substrate. If comprised in this way, the nitride type semiconductor layer which made the resonator end surface of the 1st end surface side and the 2nd end surface on the opposite side to a 1st end surface a pair of resonator surface can be formed.

  In the configuration further including the second end surface, the second end surface is preferably formed substantially perpendicular to the main surface of the substrate starting from the other side surface of the recess formed in the substrate. With this configuration, when the nitride-based semiconductor layer is formed on the main surface of the substrate, for example, the c-axis direction ([0001] direction in the (H, K, -HK, 0) plane of the substrate) ) Substantially perpendicular to the main surface of the substrate without using a cleavage step (000) using the other side surface of the recess formed in the [K, -H, -K + H, 0] direction substantially orthogonal to -1) A nitride-based semiconductor element layer having a resonator end face (second end face) made of a plane can be easily formed.

  A method for manufacturing a nitride-based semiconductor laser device according to a second aspect of the present invention includes a nitride-based semiconductor device having a first end face including an inclined surface inclined at a predetermined angle with respect to a main surface of the substrate on a substrate. Forming a resonator end face extending substantially perpendicularly to the main surface of the substrate by etching in a part of the inclined surface, and forming an angle between the inclined surface and the main surface of the substrate. Is an acute angle.

  In the method for manufacturing a nitride-based semiconductor laser device according to the second aspect of the present invention, as described above, the nitride semiconductor laser device has a first end face including an inclined surface inclined at a predetermined angle while forming an acute angle with respect to at least the main surface of the substrate. The nitride-based semiconductor element layer comprises: a step of forming a nitride-based semiconductor element layer; and a step of forming a resonator end face extending substantially perpendicular to the main surface of the substrate in a partial region of the inclined surface. Since it is connected to the substrate side through a plane area larger than the plane area in the vicinity of the light emitting layer, the cross-sectional area of the path radiating heat to the substrate side can be increased by the increase in the plane area. Thereby, even when the output of the semiconductor laser is increased, the nitride system in which the heat generation of the laser emission light in the vicinity of the cavity end face is formed with an inclined surface extending in the laser beam emission direction from the cavity end face It diffuses to the substrate side appropriately through the semiconductor element layer. Therefore, excessive heat generation of the resonator end face by the laser emission light is suppressed. Thereby, it is possible to form a nitride-based semiconductor laser element in which the degradation of the cavity end face accompanying the increase in output of the semiconductor laser is suppressed. In addition, the lifetime of the nitride-based semiconductor laser device can be extended by suppressing the deterioration of the cavity end face.

  In the method for manufacturing a nitride-based semiconductor laser device according to the second aspect, preferably, the substrate has a main surface composed of (H, K, -HK, 0) plane, and the first surface is formed on the substrate. Prior to the step of forming the nitride-based semiconductor element layer including the end face, a step of forming a recess extending in a stripe shape in the [K, -H, -K + H, 0] direction in the main surface of the substrate is further performed. The step of forming a nitride-based semiconductor element layer having a first end surface including an inclined surface on the substrate includes a first end surface comprising a growth surface of the nitride-based semiconductor element layer starting from one side surface of the recess. Forming a step. If comprised in this way, the 1st end surface including the inclined surface which consists of the growth surface of a nitride-type semiconductor element layer can be formed simultaneously at the time of the crystal growth of a nitride-type semiconductor element layer.

  In the method for manufacturing a nitride-based semiconductor laser device according to the second aspect, preferably, the step of forming the nitride-based semiconductor device layer starts with the other side surface of the recess formed in the substrate as a starting point. The method further includes a step of forming a second end face made of a growth surface of the nitride-based semiconductor element layer extending substantially perpendicular to the surface. If comprised in this way, the 2nd end surface extended substantially perpendicular | vertical with respect to the main surface of a board | substrate can be easily formed simultaneously with the inclined 1st end surface at the time of crystal growth of a nitride-type semiconductor element layer.

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

(First embodiment)
FIG. 1 is a perspective view showing the structure of a nitride-based semiconductor laser device according to the first embodiment of the present invention. 2 to 4 are cross-sectional views for explaining the structure of the nitride-based semiconductor laser device shown in FIG. First, the structure of the nitride-based semiconductor laser device 50 according to the first embodiment will be described with reference to FIGS.

  In the nitride-based semiconductor laser device 50 according to the first embodiment, as shown in FIGS. 1 and 2, the nitride-based semiconductor laser device 50 is formed on an n-type GaN substrate 1 having a thickness of about 100 μm and has a thickness of about 3 μm to about 4 μm. A semiconductor laser element layer 3 having a thickness of about 3.1 μm is formed on an underlayer 2 made of AlGaN. The n-type GaN substrate 1 and the semiconductor laser element layer 3 are examples of the “substrate” and the “nitride-based semiconductor element layer” in the present invention, respectively. Further, as shown in FIG. 2, the semiconductor laser element layer 3 is formed so that the length L1 between the laser element end portions (in the direction of arrow A) is about 1560 μm.

  Here, in the first embodiment, as shown in FIG. 2, the semiconductor laser element layer 3 is formed on the main surface composed of the m-plane ((1-100) plane) that is a nonpolar plane of the n-type GaN substrate 1. , Formed through the underlayer 2. The semiconductor laser element layer 3 is formed with a light emitting surface 20 a and a light reflecting surface 20 b that are substantially perpendicular to the main surface of the n-type GaN substrate 1. The light emitting surface 20a and the light reflecting surface 20b are examples of the “first end surface” and the “second end surface” in the present invention, respectively. In the present invention, the light emitting surface 20a and the light reflecting surface 20b are distinguished from each other by the magnitude relationship of the intensity of the laser light emitted from the respective resonator end faces on the light emitting side and the light reflecting side. That is, the side with relatively high laser beam emission intensity is the light emission surface 20a, and the side with relatively low laser beam emission intensity is the light reflection surface 20b.

In the first embodiment, as shown in FIG. 2, the semiconductor laser element layer 3 has a direction perpendicular to the main surface of the n-type GaN substrate 1 ([1-100]) from the lower end of the light emitting surface 20a. Direction (C2 direction)) is inclined by an angle θ ₁ (= about 62 °), and a laser beam emission direction (A1 direction (from the light emission surface 20a to the laser element) emitted from a region in the vicinity of the light emitting layer 6 described later) Inclined surfaces 20c and 20d extending in the direction away from the outside)) are formed. Further, it is inclined from the upper end of the light emitting surface 20a by an angle θ ₁ (= about 62 °) with respect to a direction perpendicular to the main surface of the n-type GaN substrate 1 ([1-100] direction (C2 direction)). In addition, an inclined surface 20e extending in the A2 direction is formed. Therefore, as shown in FIG. 2, the inclined surfaces 20c, 20d and 20e and the main surface of the n-type GaN substrate 1 are formed to form an acute angle. The inclined surfaces 20c, 20d and 20e are examples of the “first end surface” in the present invention.

  In the first embodiment, as shown in FIG. 3, the inclined surface 20c extends obliquely from an n-type cladding layer 5 (described later) located below the light emitting surface 20a toward the n-type GaN substrate 1 side. The n-type GaN substrate 1 is formed so as to be connected to the inclined surface 20d through an end surface 20f extending substantially perpendicular to the main surface. The n-type cladding layer 5 is an example of the “nitride-based semiconductor element layer” and “first conductivity type first cladding layer” in the present invention. Therefore, as shown in FIG. 3, the n-type cladding layer 5 formed on the laser beam emission side is n-type GaN substrate at a position farther in the laser beam emission direction (A1 direction) than the light emission surface 20a. The first base layer 2 and the buffer layer 4 are connected to each other.

  In the first embodiment, as shown in FIG. 2, the underlayer 2 is formed during the crystal growth of the underlayer 2 and extends in a stripe shape in the [11-20] direction of the n-type GaN substrate 1. A crack 30 is formed. The inclined surfaces 20d and 20e of the semiconductor laser element layer 3 are constituted by facets (growth surfaces) composed of a (1-101) surface that grows from the upper end of the inner side surface 30a of the crack 30 of the underlayer 2 as a starting point. ing. The crack 30 is an example of the “recessed portion” of the present invention, and the inner side surface 30a is an example of the “side surface of one side of the recessed portion” of the present invention.

  In the first embodiment, as shown in FIG. 2, the light reflecting surface 20b of the semiconductor laser element layer 3 is in a direction perpendicular to the main surface of the n-type GaN substrate 1 ([1-100] direction (C2 direction)). ) And an end face made of a (000-1) plane that is crystal-grown so as to take over the inner side face 30b made of the (000-1) face of the crack 30. The inner side surface 30b is an example of the “side surface on the other side of the recess” in the present invention.

  In the first embodiment, when the underlayer 2 made of AlGaN is crystal-grown, a crack 30 as a recess is formed in the underlayer 2 by utilizing the lattice constant difference between the n-type GaN substrate 1 and the underlayer 2. After forming the crystal of the underlayer 2, the inner surface including the (000-1) plane (inside the recess) is formed by mechanical scribe, laser scribe, dicing, etching, or the like from the surface side of the underlayer 2. Side surface) may be formed. Moreover, when forming a recessed part using the said method, it is good also considering the base layer 2 as GaN which has the lattice constant similar to the n-type GaN board | substrate 1 which is a board | substrate (base substrate). Furthermore, as will be described later, a concave portion (first surface) having an inner side surface (000-1) directly on the surface side of crystal growth on the n-type GaN substrate 1 by mechanical scribing, laser scribing, dicing, etching, or the like. The groove portion 92) of the fourth embodiment may be formed.

The semiconductor laser element layer 3 includes a buffer layer 4, an n-type cladding layer 5, a light emitting layer 6, a p-type cladding layer 7 and a p-type contact layer 8, as shown in FIGS. 1 and 2. It is out. Specifically, as shown in FIG. 3, the upper surface of the underlayer 2 formed on the n-type GaN substrate 1 is made of undoped Al _0.01 Ga _0.99 N having a thickness of about 1.0 μm. A buffer layer 4 and an n-type cladding layer 5 made of Ge-doped Al _0.07 Ga _0.93 N having a thickness of about 1.9 μm are formed.

A light emitting layer 6 is formed on the n-type cladding layer 5. As shown in FIG. 4, the light emitting layer 6 includes an n-side carrier block made of Al _0.2 Ga _0.8 N having a thickness of about 20 nm in order from the side closer to the n-type cladding layer 5 (see FIG. 2). Layer 6a, n-side light guide layer 6b made of undoped In _0.02 Ga _0.98 N having a thickness of about 20 nm, multiple quantum well (MQW) active layer 6e, and undoped having a thickness of about 0.08 μm The p-side light guide layer 6f made of In _0.01 Ga _0.99 N and the carrier block layer 6g made of Al _0.25 Ga _0.75 N having a thickness of about 20 nm are formed. The MQW active layer 6e includes three quantum well layers 6c made of undoped In _0.15 Ga _0.85 N having a thickness of about 2.5 nm, and undoped In _0.02 Ga _0. Three quantum barrier layers 6 d made of ₉₈ N are alternately stacked. The n-type cladding layer 5 has a larger band gap than the MQW active layer 6e. Further, a light guide layer having an intermediate band gap between the n-side carrier block layer 6a and the MQW active layer 6e may be formed between the n-side carrier block layer 6a and the MQW active layer 6e. The MQW active layer 6e may be formed with a single layer or a single quantum well (SQW) structure.

As shown in FIGS. 1 and 2, on the light emitting layer 6, a flat portion and a convex portion formed to protrude upward (C2 direction) from a substantially central portion of the flat portion and having a thickness of about 1 μm. A p-type cladding layer 7 made of Mg-doped Al _0.07 Ga _0.93 N is formed. The p-type cladding layer 7 has a larger band gap than the MQW active layer 6e. A p-type contact layer 8 made of undoped In _0.07 Ga _0.93 N having a thickness of about 3 nm is formed on the convex portion of the p-type cladding layer 7. A ridge extending in the form of a stripe (elongated) in the resonator direction (direction A in FIG. 1) as an optical waveguide of the nitride-based semiconductor laser device 50 is formed by the convex portion of the p-type cladding layer 7 and the p-type contact layer 8. Part 21 is configured. The buffer layer 4, the light emitting layer 6 and the p-type contact layer 8 are examples of the “nitride-based semiconductor element layer” in the present invention. The p-type cladding layer 7 is an example of the “nitride-based semiconductor element layer” and the “second conductivity type second cladding layer” in the present invention.

Further, as shown in FIG. 1, SiO ₂ having a thickness of about 200 nm so as to cover the upper surface of the flat portion other than the convex portion of the p-type cladding layer 7 of the semiconductor laser element layer 3 and both side surfaces of the ridge portion 21. A current blocking layer 9 made of is formed.

  Further, on the upper surfaces of the current blocking layer 9 and the p-type contact layer 8, a Pt layer having a thickness of about 5 nm and a Pd layer having a thickness of about 100 nm are arranged in order from the side closer to the upper surface of the p-type contact layer 8. A p-side electrode 10 made of an Au layer having a thickness of about 150 nm is formed.

  Further, as shown in FIGS. 1 and 2, an Al layer having a thickness of about 10 nm and a thickness of about 20 nm are sequentially formed on the back surface of the n-type GaN substrate 1 from the side closer to the n-type GaN substrate 1. An n-side electrode 11 composed of a Pt layer and an Au layer having a thickness of about 300 nm is formed. As shown in FIG. 2, the n-side electrode 11 is formed on the entire back surface of the n-type GaN substrate 1 so as to extend to both sides of the nitride-based semiconductor laser device 50 in the direction of arrow A.

  5 to 11 are a sectional view and a plan view for explaining a manufacturing process of the nitride-based semiconductor laser device according to the first embodiment shown in FIG. A manufacturing process for the nitride-based semiconductor laser device 50 according to the first embodiment is now described with reference to FIGS. 1, 2, 4 and 5 to 11.

First, as shown in FIG. 5, an underlying layer 2 made of AlGaN having a thickness of about 3 μm to about 4 μm is grown on an n-type GaN substrate 1 using metal organic chemical vapor deposition (MOCVD). Let Note that when the underlying layer 2 is grown, n type GaN substrate 1 [0001] direction of the base layer 2 made of AlGaN than the lattice constant _{c 1} of the [0001] small direction of the lattice constant _{c 2 (c} 1> c ₂ ), the underlying layer 2 that has reached a predetermined thickness generates a tensile stress R inside the underlying layer 2 in an attempt to match the lattice constant c ₁ of the n-type GaN substrate 1. As a result, as the underlayer 2 locally shrinks in the A direction, cracks 30 as shown in FIG. 5 are formed in the underlayer 2. FIG. 5 schematically shows a state in which the crack 30 is spontaneously formed in the underlayer 2.

  Further, when the n-type GaN substrate 1 on which the crack 30 is formed is viewed in plan, the crack 30 is substantially orthogonal to the [0001] direction (A direction) of the n-type GaN substrate 1 as shown in FIG. It is formed to extend in a stripe shape along the [11-20] direction (B direction).

  In the first embodiment, as shown in FIG. 5, when the crack 30 is formed in the foundation layer 2, the crack 30 is made of the (000-1) plane of the AlGaN layer, and the n-type GaN substrate 1. An inner side surface 30b reaching the (1-100) plane of the upper surface of the upper surface is formed. The inner side surface 30 b is formed substantially perpendicular to the main surface made of the (1-100) plane of the n-type GaN substrate 1. Here, since the crack 30 is formed using the tensile stress R (see FIG. 5) generated in the underlayer 2, an external processing technique (for example, mechanical scribe, laser scribe, dicing and etching) is used. Etc.), the inner side surface 30b can be easily matched with the crystallographic plane index (000-1) plane. As a result, the inner side surface 30b can be formed as an extremely flat (000-1) plane. Therefore, when the semiconductor laser element layer 3 is grown on the flat inner side surface 30b, (000-1) ) Semiconductor laser element layer 3 having a flat end face ((000-1) face) that takes over the face can be easily grown.

  In the first embodiment, the crack 30 reaching the vicinity of the main surface of the n-type GaN substrate 1 is formed in the underlayer 2 as described above. Therefore, the underlayer 2 having a lattice constant different from that of the n-type GaN substrate 1 is formed. The lattice distortion of can be released. Therefore, the crystal quality of the underlayer 2 is improved, and the semiconductor laser element layer 3 formed on the underlayer 2 can be in a high quality crystal state. As a result, the electrical characteristics of the n-type clad layer 5, the n-side carrier block layer 6a, the carrier block layer 6g, the p-type clad layer 7 and the p-type contact layer 8 formed in the steps described later are improved. It is possible to suppress light absorption in the layer. Furthermore, the internal loss of the light emitting layer 6 (n-side carrier block layer 6a, n-side light guide layer 6b, MQW active layer 6e, p-side light guide layer 6f, and carrier block layer 6g) is reduced, and light emission of the light-emitting layer 6 is achieved. Efficiency can be improved. In the first embodiment, the crack 30 reaching the vicinity of the main surface of the n-type GaN substrate 1 is formed in the base layer 2, but the base layer 2 is formed in the thickness direction of the base layer 2 (C2 direction in FIG. 5). You may make it form the groove part of the depth equivalent to this thickness. Even if comprised in this way, since the internal strain of the foundation layer 2 can be released by the groove part having a depth corresponding to the thickness of the foundation layer 2, the same effect as the case of forming the crack 30 can be obtained. .

  Next, as shown in FIG. 7, the buffer layer 4, the n-type cladding layer 5, the light emitting layer 6 (see FIG. 4 for details), p on the base layer 2 on which the crack 30 is formed, using MOCVD. The semiconductor laser device layer 3 is formed by sequentially growing the mold cladding layer 7 and the p-type contact layer 8.

In the formation of the semiconductor laser element layer 3, specifically, first, the substrate temperature is maintained at a growth temperature of about 1000 ° C., TMGa (trimethylgallium) as a Ga material and TMAl (trimethylaluminum) as an Al material. A carrier gas made of H ₂ containing) is supplied into the reaction furnace to grow the buffer layer 4 on the n-type GaN substrate 1. Next, a carrier gas composed of H ₂ containing TMGa and TMAl and GeH ₄ (monogermane) which is a raw material of Ge impurities for obtaining n-type conductivity is supplied into the reaction furnace, and the buffer layer 4 An n-type cladding layer 5 is grown thereon. Thereafter, an H ₂ gas containing TMGa and TMAl is supplied into the reaction furnace, and the n-side carrier block layer 6 a is grown on the n-type cladding layer 5.

Next, with the substrate temperature lowered to a growth temperature of about 850 ° C. and maintained in a nitrogen gas atmosphere in which NH ₃ gas is supplied into the reaction furnace, the Ga source TEGa (triethylgallium) and In source A certain TMIn (trimethylindium) is supplied to grow the n-side light guide layer 6b, the MQW active layer 6e, and the p-side light guide layer 6f. Then, TMGa and TMAl are supplied into the reactor to grow the carrier block layer 6g. Thereby, the light emitting layer 6 (refer FIG. 4) is formed.

Next, with the substrate temperature raised to a growth temperature of about 1000 ° C. and maintained in a hydrogen gas and nitrogen gas atmosphere in which NH ₃ gas is supplied into the reaction furnace, the source material of Mg, which is a p-type impurity, is used. A certain Mg (C ₅ H ₅ ) ₂ (cyclopentanedienylmagnesium), TMGa as a Ga raw material, and TMAl as an Al raw material are supplied to grow a p-type cladding layer 7 on the light emitting layer 6. Thereafter, TEGa as the Ga source and TMIn as the In source are supplied in a nitrogen gas atmosphere in which NH ₃ gas is supplied into the reactor while the substrate temperature is again lowered to the growth temperature of about 850 ° C. Then, the p-type contact layer 8 is grown. In this way, the semiconductor laser element layer 3 is formed on the base layer 2.

Here, in the manufacturing process according to the first embodiment, as shown in FIG. 8, when the semiconductor laser element layer 3 is grown on the base layer 2, the cracks 30 extending in a stripe shape in the B direction (see FIG. 6). A facet (growth surface) composed of a (1-101) plane extending in a direction inclined by an angle θ ₁ (= about 62 °) with respect to the main surface of the n-type GaN substrate 1 is formed starting from the upper end portion of the inner side surface 30a. Is done. At the same time, the semiconductor laser element layer 3 has an end surface extending in the [1-100] direction (C2 direction) so as to take over the (000-1) plane of the crack 30 starting from the upper end portion of the inner side surface 30b of the crack 30. Crystals grow while forming ((000-1) plane). As a result, a light reflecting surface 20b having a (000-1) plane is formed in the semiconductor laser element layer 3. In the process of crystal growth of the semiconductor laser element layer 3, the growth rate of the portion where the (1-101) plane and (000-1) plane are formed and the surface (upper surface) of the semiconductor laser element layer 3 are arrows. From the difference with the growth rate grown in the C2 direction (see FIG. 7), not only the flatness of the (1-101) plane and the (000-1) plane but also the flatness of the surface (upper surface) of the semiconductor laser element layer 3. It can also improve the property.

  Then, p-type annealing is performed in a nitrogen gas atmosphere under a temperature condition of about 800 ° C.

In the manufacturing process according to the first embodiment, as shown in FIG. 9, a mask layer 22 made of SiO ₂ and having a thickness of several hundred nm is formed so as to cover the upper surface of the semiconductor laser element layer 3. Further, a resist (resist pattern) 23 is formed on the upper surface of the mask layer 22 by photolithography. Then, as shown in FIG. 10, the mask layer 22 where the resist 23 is not formed is removed by wet etching with hydrofluoric acid. After that, as shown in FIG. 10, the mask layer 22 is removed and the facet composed of the (1-101) plane of the semiconductor laser element layer 3 is exposed to dry portions such as reactive ion etching such as Cl _2. Etching is performed. As a result, as shown in FIG. 11, a light emitting surface 20 a that extends in the [1-100] direction (C2 direction) and includes a part of the n-type cladding layer 5 and the light emitting layer 6 is formed in the semiconductor laser element layer 3. Is done. At that time, as shown in FIG. 11, an inclined surface 20c extending obliquely from the vicinity of the upper end portion of the n-type cladding layer 5 toward the n-type GaN substrate 1 side, and an end surface 20f substantially parallel to the light emitting surface 20a Is formed.

  Thereafter, as shown in FIG. 12, the mask layer 22 and the resist 23 are removed from the semiconductor laser element layer 3 by wet etching with hydrofluoric acid. As a result, the inclined surfaces 20d and 20e made of the (1-101) plane and the light emitting surface 20a and the inclined surface 20c by the etching are formed on the end surface of the semiconductor laser element layer 3 on the laser beam emitting side.

  Next, as shown in FIG. 1, after forming a resist pattern on the upper surface of the p-type contact layer 8 by photolithography, dry etching or the like is performed using the resist pattern as a mask to form the ridge portion 21. . Thereafter, the current blocking layer 9 is formed so as to cover the upper surface of the flat portion other than the convex portion of the p-type cladding layer 7 and both side surfaces of the ridge portion 21. As shown in FIGS. 1 and 13, the p-side electrode 10 is formed on the current blocking layer 9 and the p-type contact layer 8 on which the current blocking layer 9 is not formed, using a vacuum deposition method. FIG. 13 shows a cross-sectional structure along the resonator direction (A direction) of the semiconductor laser element at the position where the p-type contact layer 8 is formed (near the ridge portion 21).

  Thereafter, as shown in FIG. 13, the back surface of the n-type GaN substrate 1 is polished so that the thickness of the n-type GaN substrate 1 is about 100 μm, and then the n-type GaN substrate 1 is formed by vacuum deposition. An n-side electrode 11 is formed on the back surface so as to be in contact with the n-type GaN substrate 1.

  Then, as shown in FIG. 13, the [0001] direction (A direction) of the n-type GaN substrate 1 is formed by laser scribe or mechanical scribe at a position where a predetermined (0001) plane on the back side of the n-side electrode 11 is to be formed. The linear scribe groove 31 is formed so as to extend in a direction perpendicular to () (direction B in FIG. 1). In this state, as shown in FIG. 13, by applying a load with the back surface side of the n-type GaN substrate 1 as a fulcrum so that the front surface side (upper side) of the wafer is opened, the wafer is positioned at the position of the scribe groove 31 (cleavage line). 500).

  Thereafter, the element is divided into chips along the resonator direction (A direction), whereby the nitride-based semiconductor laser element 50 according to the first embodiment shown in FIGS. 1 and 2 is formed.

In the first embodiment, as described above, the semiconductor laser element layer 3 includes the light emitting surface 20a and the main surface (m-plane (1-100) surface) of the n-type GaN substrate 1 in the vicinity of the light emitting surface 20a. And inclined surfaces 20c and 20d extending at an angle θ ₁ (= about 62 °) with respect to the [1-100] direction perpendicular to the main surface of the n-type GaN substrate 1 while forming an acute angle with Since the semiconductor laser element layer 3 is connected to the n-type GaN substrate 1 side through a plane area larger than the plane area in the vicinity of the light emitting layer 6, the semiconductor laser element layer 3 radiates heat to the n-type GaN substrate 1 side as much as the plane area increases. The cross-sectional area (inclined surfaces 20c and 20d, end surface 20f, main surface ((1-100) surface) of n-type cladding layer 5) and light emitting surface 20a in the direction C1 to the main surface of n-type cladding layer 5 Surrounded by an extended virtual surface (dashed line) Thereby increasing the area S (see FIG. 3)). Thereby, even when the output of the nitride-based semiconductor laser device 50 is increased, the heat generation of the laser emission light in the vicinity of the light emission surface 20a is an inclined surface extending in the laser beam emission direction from the light emission surface 20a. It is appropriately diffused to the n-type GaN substrate 1 side through the inside of the semiconductor laser element layer 3 on which 20c and 20d are formed. Therefore, excessive heat generation at the resonator end face (light emission surface 20a) due to the laser emission light is suppressed. As a result, it is possible to suppress deterioration of the resonator end face (light emitting surface 20a) as the output of the semiconductor laser increases. In addition, the lifetime of the nitride-based semiconductor laser device 50 can be extended by suppressing the deterioration of the cavity end face (light emitting surface 20a).

  In the first embodiment, the inclined surfaces 20c and 20d are provided on the side of the emission direction (A1 direction) of the laser light emitted from the light emitting layer 6 from the n-type cladding layer 5 located below the light emitting surface 20a and the n-type GaN substrate. By constituting so as to extend obliquely toward the 1 side, starting from the n-type cladding layer 5 located near the lower portion of the light emitting layer 6 on the light emitting surface 20a, on the laser light emitting direction (A1 direction) side, Further, since the inclined surfaces 20c and 20d are formed toward the n-type GaN substrate 1, the heat generated by the laser light (emitted light) generated in the vicinity of the light emitting layer 6 is diffused more efficiently to the n-type GaN substrate 1 side. Can be made.

  In the first embodiment, the light emitting surface 20a and the inclined surfaces 20c, 20d, and 20e are formed on the emitting side of the laser light emitted from the light emitting layer 6, so that light with greater heat generation during laser operation. It is possible to easily suppress the deterioration of the light emission surface 20a on the emission side.

  In the first embodiment, the inclined surfaces 20 c and 20 e are n-type so as to extend in a stripe shape in the [11-20] direction in the main surface (m-plane (1-100) plane) of the n-type GaN substrate 1. By configuring the semiconductor laser device layer 3 to have a growth surface (facet) composed of the (1-101) plane starting from the inner surface 30a of the crack 30 formed in the GaN substrate 1, (1-101) The inclined surfaces 20c and 20e formed of a growth surface having a surface can be formed simultaneously with the crystal growth of the semiconductor laser element layer 3.

  In the first embodiment, the semiconductor laser element layer 3 is formed on the opposite side of the light emitting surface 20a and the inclined surfaces 20c and 20e, and the main surface (m-plane) of the n-type GaN substrate 1 is formed. By providing the light reflecting surface 20b extending in the [1-100] direction which is substantially perpendicular to the (1-100) plane), the light emitting surface 20a and the light reflecting on the opposite side of the light emitting surface 20a are provided. The semiconductor laser element layer 3 having the surface 20b as a pair of resonator surfaces can be formed.

  In the first embodiment, the light reflecting surface 20b of the semiconductor laser element layer 3 is arranged in the [11-20] direction (in FIG. 6) in the main surface (m-plane (1-100) plane) of the n-type GaN substrate 1. The n-type GaN substrate 1 is formed substantially perpendicular to the main surface of the n-type GaN substrate 1 with the inner surface 30b of the crack 30 formed in the n-type GaN substrate 1 extending in a stripe shape in the (B direction) as a starting point. When the semiconductor laser element layer 3 is formed on the main surface of the GaN substrate 1, the c-axis direction ([0001] direction) in the m-plane ((1-100) plane) of the n-type GaN substrate 1 is substantially increased. Using the inner surface 30b of the crack 30 formed in the orthogonal [11-20] direction, a resonance composed of a (000-1) plane substantially perpendicular to the main surface of the n-type GaN substrate 1 without using a cleavage step. Semiconductor laser having a container end surface (light reflecting surface 20b) The device layer 3 can be easily formed.

  In the first embodiment, the semiconductor element layer is formed by forming the semiconductor laser element layer 3 on the n-type GaN substrate 1 having a main surface composed of a nonpolar plane (m-plane ((1-100) plane)). An internal electric field such as a piezo electric field and spontaneous polarization generated in the (light emitting layer 6) can be reduced. As a result, heat generation of the semiconductor laser element layer 3 (light emitting layer 6) including the vicinity of the cavity end face (light emitting surface 20a) is further suppressed, so that the lifetime of the nitride semiconductor laser element 50 can be extended. .

(First modification of the first embodiment)
FIG. 14 is a cross-sectional view for explaining the structure of a nitride-based semiconductor laser device 60 according to the first modification of the first embodiment of the present invention. 15 and 16 are cross-sectional views for explaining a manufacturing process for the nitride-based semiconductor laser device 60 according to the first modification of the first embodiment of the present invention. With reference to FIGS. 14 to 16, the nitride-based semiconductor laser device 60 according to the first modification of the first embodiment differs from the first embodiment in that it is inclined with respect to the light emitting surface 60 a of the semiconductor laser device layer 3. The case where the terrace part 60e is provided between the surfaces 60c will be described.

  In the first modification of the first embodiment, in the manufacturing process of the nitride-based semiconductor laser device 60, as shown in FIG. 15, the upper surface of the semiconductor laser device layer 3 formed by crystal growth is covered so as to cover the upper surface. The same mask layer 22 and photolithography resist 23 as in the first embodiment are formed. Then, as shown in FIG. 16, the semiconductor laser element layer 3 is extended in the [1-100] direction (C2 direction) by etching similar to the first embodiment, and a part of the n-type cladding layer 5 and A light emitting surface 60a including the light emitting layer 6 is formed. The light emitting surface 60a is an example of the “first end surface” in the present invention.

  Here, in the first modification of the first embodiment, as shown in FIG. 16, the n-type cladding layer 5 below the light emitting surface 60a is controlled by controlling the etching conditions when forming the light emitting surface 60a. An inclined surface 60c extending obliquely toward the n-type GaN substrate 1 side, and a terrace portion 60e connecting the inclined surface 60c and the light emitting surface 60a are formed. As a result, as shown in FIG. 14, on the laser light emitting side end surface of the semiconductor laser element layer 3, the inclined surface 60d made of the (1-101) plane, the light emitting surface 60a by the etching process, the inclined surface 60c, and the terrace are formed. Each part 60e is formed. The inclined surfaces 60c and 60d and the terrace portion 60e are examples of the “first end surface” in the present invention.

  Further, as shown in FIG. 14, when the semiconductor laser element layer 3 is formed, the [1-100] direction so as to take over the (000-1) plane of the crack 30 starting from the upper end portion of the inner surface 30 b of the crack 30. The light reflecting surface 60b is formed while forming an end surface ((000-1) surface) extending in the (C2 direction). The light reflecting surface 60b is an example of the “second end surface” in the present invention.

  The remaining structure and manufacturing process of the nitride-based semiconductor laser device 60 according to the first modification of the first embodiment are the same as those of the first embodiment. The effects of the nitride-based semiconductor laser device 60 according to the first modification of the first embodiment are the same as those of the first embodiment.

(Second modification of the first embodiment)
FIG. 17 is a cross-sectional view for explaining the structure of a nitride-based semiconductor laser device 65 according to a second modification of the first embodiment of the present invention. Referring to FIG. 17, in the nitride-based semiconductor laser device 65 according to the second modification of the first embodiment, unlike the first embodiment, the semiconductor laser device layer 3 is a nonpolar surface of the n-type GaN substrate 1. A case where the base layer 2 is formed on the main surface consisting of the a-plane ((11-20) plane) will be described.

Here, in the second modification of the first embodiment, as shown in FIG. 17, the semiconductor laser element layer 3 has a direction perpendicular to the main surface of the n-type GaN substrate 1 from the lower end of the light emitting surface 65a. It is inclined by an angle θ ₂ (= about 58 °) with respect to the ([11-20] direction (C2 direction)), and the emission direction (A1 direction (light emission surface 65a) of the vicinity of the light emitting layer 6 emits. Inclined surfaces 65c and 65d extending in the direction away from the laser element to the outside of the laser element)). Further, it is inclined from the upper end portion of the light emitting surface 65a by an angle θ ₂ (= about 58 °) with respect to a direction perpendicular to the main surface of the n-type GaN substrate 1 ([11-20] direction (C2 direction)). In addition, an inclined surface 65e extending in the A2 direction is formed. Therefore, as shown in FIG. 17, inclined surfaces 65c, 65d and 65e and the main surface of n-type GaN substrate 1 are formed to form an acute angle. The light emitting surface 65a and the inclined surfaces 65c, 65d and 65e are examples of the “first end surface” in the present invention.

  In the second modification of the first embodiment, the inclined surface 65c of the semiconductor laser element layer 3 is inclined from the n-type cladding layer 5 located below the light emitting surface 65a toward the n-type GaN substrate 1 side. It is formed to extend and to be connected to the inclined surface 65 d via an end surface 65 f extending substantially perpendicular to the main surface of the n-type GaN substrate 1. Further, the inclined surfaces 65d and 65e of the semiconductor laser element layer 3 are constituted by facets (growth surfaces) composed of a (11-22) surface on which crystal growth starts from the upper end portion of the inner side surface 30a of the crack 30 of the underlayer 2. ing.

  In the second modification of the first embodiment, the light reflecting surface 65b of the semiconductor laser element layer 3 is in a direction perpendicular to the main surface of the n-type GaN substrate 1 ([11-20] direction (C2 direction)). While extending, it is comprised by the end surface which consists of the (000-1) surface which carried out the crystal growth so that the inner surface 30b which consists of the (000-1) surface of the crack 30 might be taken over. The light reflecting surface 65b is an example of the “second end surface” in the present invention.

  The remaining structure and manufacturing process of the nitride-based semiconductor laser device 65 according to the second modification of the first embodiment are the same as those of the first embodiment. The effect of the nitride-based semiconductor laser device 65 according to the second modification of the first embodiment is the same as that of the first embodiment.

[Example]
18 and 19 are photomicrographs obtained by observing the crystal growth of the semiconductor layer on the n-type GaN substrate by the manufacturing process of the first embodiment shown in FIG. 8 using a scanning electron microscope. With reference to FIGS. 6, 18, and 19, an experiment performed for confirming the effect of the first embodiment will be described.

  In this confirmation experiment, first, an MOCVD method is performed on an n-type GaN substrate having a main surface consisting of an m-plane ((1-100) plane) using a manufacturing process similar to the manufacturing process of the first embodiment described above. Was used to form an underlayer made of AlGaN having a thickness of 3 μm to 4 μm. At this time, cracks as shown in FIGS. 18 and 19 were formed in the underlayer due to the difference in lattice constant between the n-type GaN substrate and the underlayer. At this time, as shown in FIG. 19, the crack forms a (000-1) plane (the inner surface on the left side of the crack in the photograph) extending in a direction perpendicular to the main surface of the n-type GaN substrate. Was confirmed. Further, as shown in FIG. 6, it was confirmed that the cracks were formed in a stripe shape in the [11-20] direction (B direction) orthogonal to the [0001] direction of the n-type GaN substrate.

  Next, a semiconductor layer made of GaN was epitaxially grown on the underlayer using MOCVD. As a result, as shown in FIG. 19, the (000-1) plane of GaN that extends in the vertical direction so that the semiconductor layer takes over this plane orientation is formed on the inner side of the (000-1) plane of the crack. However, crystal growth was confirmed in the [1-100] direction (C2 direction). Thereby, it was confirmed that it is possible to form the resonator end surface (light emitting surface or light reflecting surface) of the semiconductor layer using one side (inner side surface) of the crack provided in the underlayer. As shown in FIG. 19, simultaneously with the formation of the resonator end face, a growth surface (facet) composed of a (1-101) plane of GaN is formed on the inner surface opposite to the (000-1) plane of the crack. It was confirmed that it was formed. In addition, it was confirmed that the crack that had reached the n-type GaN substrate at the time of formation was partially filled with the gap as the semiconductor layers were stacked.

  From the results of the above confirmation experiment, in the nitride-based semiconductor laser device and the manufacturing method thereof according to the present invention, a resonator having a (000-1) plane in the semiconductor layer (light emitting layer) simultaneously with the formation of the semiconductor layer by crystal growth. It was confirmed that one side of the end surface (end surface on the light reflecting surface side) and an inclined surface (end surface on the light emitting surface side) composed of the (1-101) plane can be formed simultaneously.

(Second Embodiment)
FIG. 20 is a sectional view showing the structure of a nitride-based semiconductor laser device according to the second embodiment of the present invention. Referring to FIG. 20, in the nitride-based semiconductor laser device 70 according to the second embodiment, unlike the first embodiment, an n-type GaN substrate 71 having a main surface made of (11-2-5) plane is provided. The semiconductor laser element layer 3 is formed after forming the crack 30 extending in the [1-100] direction of the n-type GaN substrate 71 (the direction perpendicular to the paper surface of FIG. 20) in the underlying layer 2 on the main surface. The case will be described. The n-type GaN substrate 71 is an example of the “substrate” in the present invention.

Here, in the second embodiment, as shown in FIG. 20, the semiconductor laser element layer 3 is disposed on the main surface composed of the (11-2-5) plane of the n-type GaN substrate 71 with the base layer 2 interposed therebetween. Is formed. At this time, the semiconductor laser element layer 3 includes a light emitting surface 70a extending in a direction substantially equal to the direction ([11-2-5] direction (C2 direction)) perpendicular to the main surface of the n-type GaN substrate 71, and light Inclined by an angle θ ₃ (= about 57 °) with respect to the [11-2-5] direction from the vicinity of the lower part of the emission surface 70a, and in the emission direction (A1 direction) of the laser light emitted from the region near the light emitting layer 6 An extending inclined surface 70c and an inclined surface 70d are formed via an end surface 70f. Further, an inclined surface 70e is inclined from the upper end portion of the light emitting surface 70a by an angle θ ₃ (= about 57 °) with respect to the [11-2-5] direction of the n-type GaN substrate 71 and extends in the A2 direction. Is formed. Therefore, as shown in FIG. 20, the inclined surfaces 70c, 70d and 70e and the main surface of the n-type GaN substrate 71 are formed at an acute angle. The light emitting surface 70a and the inclined surfaces 70c, 70d and 70e are examples of the “first end surface” in the present invention. In the semiconductor laser element layer 3, a light reflecting surface 70 b perpendicular to the main surface of the n-type GaN substrate 71 is formed. The light reflecting surface 70b is an example of the “second end surface” in the present invention.

  The remaining structure and manufacturing process of the nitride-based semiconductor laser device 70 according to the second embodiment are the same as those of the first embodiment. The effect of the nitride-based semiconductor laser device 70 according to the second embodiment is the same as that of the first embodiment.

(Third embodiment)
FIG. 21 is a sectional view showing the structure of a nitride-based semiconductor laser device according to the third embodiment of the present invention. First, referring to FIG. 21, the nitride-based semiconductor laser device 80 according to the third embodiment has a semipolar main surface composed of (11-2-2) plane, unlike the first embodiment. After forming the crack 30 extending in the [1-100] direction of the n-type GaN substrate 81 (direction perpendicular to the paper surface of FIG. 21) in the underlying layer 2 on the main surface using the n-type GaN substrate 81, the semiconductor laser A case where the element layer 3 is formed will be described. The n-type GaN substrate 81 is an example of the “substrate” in the present invention.

Here, in the third embodiment, as shown in FIG. 21, a semiconductor laser having a stacked structure similar to that of the first embodiment on the main surface made of the (11-2-2) plane of the n-type GaN substrate 81. The element layer 3 is formed via the base layer 2. At this time, the semiconductor laser element layer 3 includes a light emitting surface 80a extending in a direction substantially equal to the direction perpendicular to the main surface of the n-type GaN substrate 81 ([11-2-2] direction (C2 direction)), and light Inclined by an angle θ ₄ (= about 27 °) with respect to the [11-2-2] direction from the vicinity of the lower part of the emission surface 80a, and in the emission direction (A1 direction) of the laser light emitted from the region near the light emitting layer 6 An extending inclined surface 80c and an inclined surface 80d are formed via an end surface 80f. Further, an inclined surface 80e is inclined from the upper end portion of the light emitting surface 80a by an angle θ ₄ (= about 27 °) with respect to the [11-2-2] direction of the n-type GaN substrate 81 and extends in the A2 direction. Is formed. Therefore, as shown in FIG. 21, inclined surfaces 80c, 80d and 80e and the main surface of n-type GaN substrate 81 are formed to form an acute angle. The light emitting surface 80a and the inclined surfaces 80c, 80d, and 80e are examples of the “first end surface” in the present invention.

In the third embodiment, as shown in FIG. 21, a light reflecting surface extending in a direction substantially equal to a direction perpendicular to the main surface of the n-type GaN substrate 81 ([11-2-2] direction (C2 direction)). 80b and an angle θ ₅ (= about 32 °) with respect to the [11-2-2] direction from the vicinity of the lower part of the light reflecting surface 80b, and an inclined surface 80g extending in the A2 direction and an end surface 80h. An inclined surface 80i is formed. In addition, an inclined surface 80j is inclined from the upper end of the light reflecting surface 80b by an angle θ ₅ (= about 32 °) with respect to the [11-2-2] direction of the n-type GaN substrate 81 and extends in the A1 direction. Is formed. The light reflecting surface 80b is an example of the “second end surface” in the present invention. The remaining structure of the nitride semiconductor laser element 80 according to the third embodiment is similar to that of the aforementioned first embodiment.

  22 to 24 are cross-sectional views for explaining the manufacturing process of the nitride-based semiconductor laser device according to the third embodiment of the invention. A manufacturing process for the nitride-based semiconductor laser device 80 according to the third embodiment is now described with reference to FIGS.

In the third embodiment, the base layer 2 and the semiconductor laser element layer 3 are sequentially formed on the main surface composed of the (11-2-2) plane of the n-type GaN substrate 81 by the same manufacturing process as in the first embodiment. Form. At that time, as shown in FIG. 22, the angle θ ₄ (= about 27 °) with respect to the main surface of the n-type GaN substrate 81, starting from the upper end portion of the inner surface 30a of the crack 30 previously formed in the underlayer 2. ) Facets composed of (11-22) planes extending in an inclined direction are formed. At the same time, the semiconductor laser element layer 3 extends in a direction inclined by an angle θ ₅ (= about 32 °) with respect to the main surface of the n-type GaN substrate 81, starting from the upper end portion of the inner side surface 30b of the crack 30 ( The crystal grows while forming a facet composed of the (000-1) plane.

Next, as shown in FIG. 23, after forming the mask layer 22 and the resist 23 on the semiconductor laser element layer 3, the mask layer 22 is partially removed by wet etching with hydrofluoric acid. Further, dry etching using Cl ₂ or the like is performed on the portion where the facets ((11-22) plane and (000-1) plane) are exposed. Accordingly, as shown in FIG. 23, a light emitting surface 80a and a light reflecting surface 80b including a part of the n-type cladding layer 5 and the light emitting layer 6 are formed in the semiconductor laser element layer 3, respectively. As shown in FIG. 23, the light emitting surface 80a is formed to have a substantially (11-25) surface and the light reflecting surface 80b is formed to have a substantially (−1-12-5) surface by dry etching. The

  Thereafter, the mask layer 22 and the resist 23 are completely removed from the semiconductor laser element layer 3 by wet etching with hydrofluoric acid. Thus, inclined surfaces 80d and 80e made of (11-22) plane and light emitting surface 80a, inclined surface 80c and end surface 80f by the etching are formed on the end surface of the semiconductor laser element layer 3 on the laser beam emitting side. . Further, inclined surfaces 80i and 80j made of a (000-1) plane, a light reflecting surface 80b, an inclined surface 80g, and an end surface 80h by the etching are formed on the end surface of the semiconductor laser element layer 3 on the laser light reflecting side.

  Next, the ridge portion 21 (see FIG. 1), the current blocking layer 9 (see FIG. 1), and the p-side electrode 10 are formed by the same manufacturing process as in the first embodiment. In the third embodiment, the ridge portion 21 is formed to extend substantially in the [11-25] direction (A1 direction).

  Thereafter, as shown in FIG. 24, the back surface of the n-type GaN substrate 81 is polished so that the thickness of the n-type GaN substrate 81 is about 100 μm, and then the n-type GaN substrate 81 is formed by vacuum evaporation. An n-side electrode 11 is formed on the back surface so as to be in contact with the n-type GaN substrate 81.

  Then, as shown in FIG. 24, a direction (in FIG. 1) perpendicular to the A direction of the n-type GaN substrate 81 is formed on the back side of the n-side electrode 11 located almost directly under the crack 30 by laser scribe or mechanical scribe. A linear scribe groove 31 is formed so as to extend in the (B direction). In this state, as shown in FIG. 24, by applying a load with the back surface side of the n-type GaN substrate 1 as a fulcrum so that the front surface side (upper side) of the wafer is opened, the wafer is positioned at the position of the scribe groove 31 (cleavage line). 550).

  Thereafter, the element is divided into chips along the resonator direction (A direction), whereby the nitride-based semiconductor laser element 80 according to the third embodiment shown in FIG. 21 is formed. The effect of the nitride-based semiconductor laser device 80 according to the third embodiment is the same as that of the first embodiment.

(Fourth embodiment)
FIG. 25 is a sectional view showing the structure of a nitride-based semiconductor laser device according to the fourth embodiment of the present invention. 26 to 29 are cross-sectional views for explaining a manufacturing process for a nitride-based semiconductor laser device according to the fourth embodiment of the present invention. With reference to FIGS. 1 and 25 to 29, the nitride semiconductor laser device 90 according to the fourth embodiment differs from the first embodiment in that the m-plane ((1-100) of the n-type GaN substrate 91. The case where the semiconductor laser element layer 3 is formed after the groove portion 92 extending in the [11-20] direction (direction perpendicular to the paper surface of FIG. 25) is formed on the main surface composed of the surface) using the etching technique. To do. The n-type GaN substrate 91 is an example of the “substrate” in the present invention, and the groove 92 is an example of the “concave” in the present invention.

  In the nitride-based semiconductor laser device 90 according to the fourth embodiment of the present invention, as shown in FIG. 25, the semiconductor laser device layer 3 having the same stacked structure as that of the first embodiment is formed on the n-type GaN substrate 91. Has been. Further, the semiconductor laser element layer 3 has a length L1 between laser element end portions (A direction) of about 1560 μm and a cavity direction which is the [0001] direction with respect to the main surface of the n-type GaN substrate 71. A substantially vertical light emitting surface 90a and light reflecting surface 90b are formed. The light emitting surface 90a and the light reflecting surface 90b are examples of the “first end surface” and the “second end surface” in the present invention, respectively.

  Here, in the fourth embodiment, as shown in FIG. 26, unlike the manufacturing process of the nitride-based semiconductor laser device 50 in the first embodiment, the m-plane ((1-100) plane of the n-type GaN substrate 91. ) By using an etching technique and having a width W1 of about 10 μm in the [0001] direction (A direction), a depth of about 2 μm, and a [11-20] direction (perpendicular to the paper surface). A groove portion 92 extending in the right direction). The grooves 92 are formed in a stripe shape in the A direction at a period of about 1570 μm (= W1 + L2). At that time, the groove 92 includes an inner side surface 92 a formed of a (0001) plane substantially perpendicular to the (1-100) plane of the n-type GaN substrate 91 and (1-100) of the n-type GaN substrate 91. An inner side surface 92b composed of a (000-1) plane substantially perpendicular to the plane is formed. The inner side surfaces 92a and 92b are examples of the “side surface on one side of the recess” and the “side surface on the other side of the recess” of the present invention, respectively.

  Thereafter, as shown in FIG. 27, the buffer layer 4, the n-type cladding layer 5, the light emitting layer 6, the p-type cladding layer 7 and the p-type contact are formed on the n-type GaN substrate 91 by the same manufacturing process as in the first embodiment. The semiconductor laser element layer 3 is formed by sequentially laminating the layers 8.

At this time, in the fourth embodiment, as shown in FIG. 27, the angle θ ₁ (with respect to the main surface of the n-type GaN substrate 91 starts from the upper end portion of the inner side surface 92a made of the (0001) plane of the groove portion 92. = About 62 °) A facet (growth surface) composed of a (1-101) plane extending in an inclined direction is formed. At the same time, the semiconductor laser element layer 3 has an end surface extending in the [1-100] direction (C2 direction) so as to take over the (000-1) plane of the groove portion 92, starting from the upper end portion of the inner side surface 92b of the groove portion 92. Crystals grow while forming ((000-1) plane). As a result, a light reflecting surface 90b composed of a (000-1) plane is formed in the semiconductor laser element layer 3.

  In the fourth embodiment, the same etching process as in the first embodiment extends to the semiconductor laser element layer 3 in the [1-100] direction (C2 direction) as shown in FIG. A light emitting surface 90 a including a part of the layer 5 and the light emitting layer 6 is formed. At that time, as shown in FIG. 28, an inclined surface 90c extending obliquely from the vicinity of the upper end portion of the n-type cladding layer 5 toward the n-type GaN substrate 91 side, and an end surface 90f substantially parallel to the light emitting surface 90a Is formed. As a result, as shown in FIG. 29, as in the first embodiment, the laser light emitting side end surface of the semiconductor laser element layer 3 has inclined surfaces 90d and 90e made of (1-101) planes, and an etching process. As a result, a light emitting surface 90a and an inclined surface 90c are formed. The inclined surfaces 90c, 90d, and 90e are examples of the “first end surface” in the present invention.

  Then, the current blocking layer 9 (see FIG. 1), the p-side electrode 10 and the n-side electrode 11 are sequentially formed by the same manufacturing process as in the first embodiment. Then, as shown in FIG. 29, at a position corresponding to the (000-1) semiconductor end surface on the back surface side of the n-side electrode 11 and a position where a predetermined (0001) surface is to be formed, by laser scribe or mechanical scribe, A linear scribe groove 93 is formed so as to extend parallel to the groove portion 92 of the n-type GaN substrate 91 (in a direction perpendicular to the paper surface of FIG. 26). In this state, as shown in FIG. 29, by applying a load with the back surface side of the n-type GaN substrate 91 as a fulcrum so that the front surface side (upper side) of the wafer opens, the wafer is positioned at the position of the scribe groove 93 (cleavage). Cleave at line 600).

  Thereafter, the device is divided into chips along the resonator direction (A direction), whereby the nitride-based semiconductor laser device 90 according to the fourth embodiment shown in FIG. 25 is formed.

In the fourth embodiment, as described above, the semiconductor laser element layer 3 includes the light emitting surface 90a and the main surface (m-plane (1-100) surface) of the n-type GaN substrate 91 in the vicinity of the light emitting surface 90a. And inclined surfaces 90c and 90d extending at an angle θ ₁ (= about 62 °) with respect to the [1-100] direction perpendicular to the main surface of the n-type GaN substrate 91 while forming an acute angle with Since the semiconductor laser element layer 3 is connected to the n-type GaN substrate 91 side via a plane area larger than the plane area in the vicinity of the light emitting layer 6, heat radiation to the n-type GaN substrate 91 side is increased by the increase in the plane area. The cross-sectional area (inclined surfaces 90c and 90d, end surface 90f, main surface ((1-100) surface) of n-type cladding layer 5) and light emitting surface 90a in the direction C1 to the main surface of n-type cladding layer 5 Due to the extended virtual plane (dashed line) Enclosed area S (see FIG. 25)) can be increased. Thereby, even when the output of the nitride-based semiconductor laser device 90 is increased, the heat generation of the laser emission light in the vicinity of the light emission surface 90a extends more in the laser beam emission direction than the light emission surface 90a. The light is appropriately diffused toward the n-type GaN substrate 91 through the inside of the semiconductor laser element layer 3 in which 90c and 90d are formed. Therefore, excessive heat generation of the resonator end face (light emission surface 90a) due to the laser emission light is suppressed. As a result, it is possible to suppress deterioration of the resonator end face (light emitting surface 90a) as the output of the semiconductor laser increases. In addition, the lifetime of the nitride-based semiconductor laser device 90 can be extended by suppressing the deterioration of the cavity end face (light emitting surface 90a).

  The remaining effects of the nitride-based semiconductor laser device 90 according to the fourth embodiment are similar to those of the aforementioned first embodiment.

(Modification of the fourth embodiment)
FIG. 30 is a cross-sectional view for explaining the structure of a nitride-based semiconductor laser device 95 according to a modification of the fourth embodiment of the present invention. Referring to FIG. 30, in the nitride-based semiconductor laser device 95 according to the modification of the fourth embodiment, the semiconductor laser device layer 3 is a nonpolar surface of the n-type GaN substrate 91, unlike the fourth embodiment. The case where it forms on the main surface which consists of a surface ((11-20) surface) is demonstrated.

Here, in the modified example of the fourth embodiment, as shown in FIG. 30, the semiconductor laser element layer 3 has a direction perpendicular to the main surface of the n-type GaN substrate 91 [[ 11-20] direction (C2 direction)) and an emission direction (A1 direction (from the light emission surface 95a to the laser beam) emitted from a region near the light emitting layer 6 while being inclined by an angle θ ₂ (= about 58 °). Inclined surfaces 95c and 95d extending in the direction away from the element)) are formed. Further, it is inclined from the upper end portion of the light emitting surface 95a by an angle θ ₂ (= about 58 °) with respect to a direction perpendicular to the main surface of the n-type GaN substrate 91 ([11-20] direction (C2 direction)). In addition, an inclined surface 95e extending in the A2 direction is formed. Therefore, as shown in FIG. 30, inclined surfaces 95c, 95d and 95e and the main surface of n-type GaN substrate 91 are formed to form an acute angle. The light emitting surface 95a and the inclined surfaces 95c, 95d, and 95e are examples of the “first end surface” in the present invention.

  In the modification of the fourth embodiment, the inclined surface 95c of the semiconductor laser element layer 3 extends obliquely from the n-type cladding layer 5 located below the light emitting surface 95a toward the n-type GaN substrate 91 side. The n-type GaN substrate 91 is formed so as to be connected to the inclined surface 95d through an end surface 95f extending substantially perpendicularly to the main surface. Further, the inclined surfaces 95d and 95e of the semiconductor laser element layer 3 are constituted by facets made of the (11-22) plane grown from the upper end of the inner side face 92a made of the (0001) plane of the groove 92. .

  In the modification of the fourth embodiment, the light reflecting surface 95b of the semiconductor laser element layer 3 extends in the direction perpendicular to the main surface of the n-type GaN substrate 91 ([11-20] direction (C2 direction)). The groove portion 92 is constituted by an end face made of a (000-1) plane which is crystal-grown so as to take over the inner side face 92b made of the (000-1) face. The light reflecting surface 95b is an example of the “second end surface” in the present invention.

  In the modification of the fourth embodiment, the semiconductor laser element layer 3 is formed on the non-polar plane ((11-20) plane) of the n-type GaN substrate 91 to generate the semiconductor element layer (light emitting layer 6). It is possible to reduce internal electric fields such as piezo electric field and spontaneous polarization. As a result, the heat generation of the semiconductor laser element layer 3 (light emitting layer 6) including the vicinity of the cavity end face (light emitting surface 95a) is further suppressed, so that the nitride-based semiconductor laser element 95 has the same structure as in the first embodiment. Long life can be achieved.

  The remaining structure and manufacturing process of the nitride-based semiconductor laser device 95 according to the modification of the fourth embodiment are the same as those of the fourth embodiment. The remaining effects of the nitride-based semiconductor laser device 95 according to the modification of the fourth embodiment are similar to those of the aforementioned fourth embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the second embodiment, the nitride-based semiconductor laser element 70 is formed by forming the semiconductor laser element layer 3 on the n-type GaN substrate 71 having the main surface composed of the (11-2-5) plane. Although an example has been shown, the present invention is not limited to this, and a semiconductor laser element layer may be formed on an n-type GaN substrate having a main surface made of a (1-10-4) plane. In this case, the inclined surface formed in the vicinity of the cavity facet on the light emitting side is a facet composed of a (000-1) plane accompanying crystal growth during the formation of the semiconductor laser element layer. In this case, the light reflecting surface is formed by a crystal growth surface composed of a (1-101) plane substantially perpendicular to the main surface of the n-type GaN substrate. The inclination angle of the inclined surface (facet) is about 65 ° with respect to the direction ([1-10-4] direction) perpendicular to the main surface of the n-type GaN substrate.

  In the third embodiment, the nitride-based semiconductor laser device 80 is formed by forming the semiconductor laser device layer 3 on the n-type GaN substrate 81 having the (11-2-2) plane main surface. Although an example has been shown, the present invention is not limited to this, and a semiconductor laser element layer may be formed on an n-type GaN substrate having a main surface made of a (1-10-1) plane. In this case, the inclined surface formed in the vicinity of the cavity facet on the light emitting side is a facet composed of (1-101) plane accompanying crystal growth at the time of forming the semiconductor laser element layer, and is formed on the light reflecting surface side. The inclined surface is a facet composed of a (000-1) plane. The inclination angle of the inclined surface is about 34 ° on the light emitting surface side and about the light reflecting surface side with respect to the direction ([1-10-1] direction) perpendicular to the main surface of the n-type GaN substrate. It has about 28 °.

  In the third embodiment, the inclined surface 80d on the side (angle θ4 = about 27 °) with the smaller inclination angle with respect to the direction ([11-2-2] direction) perpendicular to the main surface of the n-type GaN substrate. And 80e on the light emitting surface 80a side, and the inclined surface 80i on the side (angle θ5 = about 32 °) having a larger inclination angle than the inclined surfaces 80d and 80e with respect to the [11-2-2] direction. However, the present invention is not limited to this, and the resonator end face on the inclined surfaces 80d and 80e side is used as the light reflecting surface, and the inclined surfaces 80i and 80j side are also provided. You may comprise so that a resonator end surface may be made into a light-projection surface (the relationship between the angle of inclination and the relationship between a resonator end surface is made contrary to the above). If comprised in this way, the inclined surface by the side of a light-emitting surface will make an acute angle with respect to the main surface ((11-2-2) plane) of an n-type GaN substrate rather than the inclined surface by the side of a light-emitting surface. Therefore, the cross-sectional area (region S in FIG. 3) of the path radiating heat from the n-type cladding layer 5 (see FIG. 3) on the light emitting surface side to the n-type GaN substrate 1 (see FIG. 3) side is further increased. It can be formed large. As a result, the heat generated by the laser beam can be radiated more effectively to the n-type GaN substrate 1 side.

  In the third embodiment, the example in which the inclined surfaces 80g (etching surface) and 80i (facets) are formed (remained) below the light reflecting surface 80b (see FIG. 24) is shown. However, the present invention is not limited to this, and dry etching for forming the light reflecting surface 80b (see FIG. 24) may be performed so that the light reflecting surface 80b reaches the inside of the n-type GaN substrate 81. Thereby, a nitride semiconductor laser element having a laser element structure similar to that of the nitride semiconductor laser element 90 (see FIG. 25) shown in the fourth embodiment can be formed.

  In the nitride semiconductor laser elements according to the first to fourth embodiments, the semiconductor laser element layer 3 is shown as being formed of a nitride semiconductor layer such as AlGaN or InGaN. Not limited to this, the semiconductor laser element layer 3 may be formed of a nitride semiconductor layer having a Wurtz structure made of AlN, InN, BN, TlN, or a mixed crystal thereof.

  In the nitride semiconductor laser elements according to the first to fourth embodiments, an example in which an n-type GaN substrate made of GaN is used as a substrate and an underlayer made of AlGaN is formed on the n-type GaN substrate has been shown. However, the present invention is not limited to this, and an InGaN substrate may be used as the substrate, and a base layer made of GaN or AlGaN may be formed on the InGaN substrate.

In the nitride semiconductor laser elements according to the first to fourth embodiments, an example in which a GaN substrate is used as the substrate has been described. However, the present invention is not limited to this, and for example, the a-plane ((11-20) An r-plane ((1102) plane) sapphire substrate or a-plane ((11-20) plane) or m-plane ((1-100) plane) on which a nitride-based semiconductor whose main surface is a main surface is grown in advance An a-plane SiC substrate or m-plane SiC substrate on which a nitride-based semiconductor as a main surface is grown in advance may be used. It may also be used such as LiAlO ₂ · LiGaO ₂ substrate a non-polar nitride-based semiconductor were previously grown above.

  In the manufacturing process of the nitride semiconductor laser device according to the first to third embodiments, cracks are spontaneously formed in the underlayer using the lattice constant difference between the n-type GaN substrate and the underlayer. However, the present invention is not limited to this. The present invention is not limited to this, and only the both end portions of the base layer 2 in the B direction (see FIG. 6) (regions corresponding to the end portions in the B direction of the n-type GaN substrate 1). Scribe scratches may be formed. Even if comprised in this way, the crack extended in a B direction can be introduce | transduced from the scribe flaw of both ends.

In the nitride-based semiconductor laser devices according to the first to fourth embodiments, a lower cladding layer, a light emitting layer (active layer), an upper cladding layer, and the like are sequentially formed on a flat substrate, and a current path thereon is formed. Although an example of forming a nitride semiconductor laser element having a structure gain waveguide type oxide stripe structure narrowly limited by the current blocking layer has been shown, the present invention is not limited to this, and the ridge portion is made of SiO ₂ or AlGaN. A nitride semiconductor laser element having a gradient index waveguide type ridge waveguide structure embedded with a current blocking layer may be formed.

1 is a perspective view showing a structure of a nitride-based semiconductor laser device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the cavity direction of the semiconductor laser device, for explaining the structure of the nitride-based semiconductor laser device shown in FIG. 1. FIG. 2 is an enlarged cross-sectional view showing details in the vicinity of a light emitting surface of the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 3 is an enlarged cross-sectional view showing details of a light emitting layer of the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 2. FIG. 8 is a cross-sectional view for explaining the manufacturing process for the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 6 is a plan view for explaining the manufacturing process for the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 8 is a cross-sectional view for explaining the manufacturing process for the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 6 is an enlarged cross-sectional view for explaining a manufacturing process for the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 8 is a cross-sectional view for explaining the manufacturing process for the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 8 is a cross-sectional view for explaining the manufacturing process for the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 8 is a cross-sectional view for explaining the manufacturing process for the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 8 is a cross-sectional view for explaining the manufacturing process for the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 8 is a cross-sectional view for explaining the manufacturing process for the nitride-based semiconductor laser device according to the first embodiment shown in FIG. 1. FIG. 6 is a cross-sectional view showing the structure of a nitride-based semiconductor laser device according to a first modification of the first embodiment of the present invention. FIG. 16 is a cross-sectional view for explaining a manufacturing process for the nitride-based semiconductor laser device according to the first modification example of the first embodiment shown in FIG. 14. FIG. 16 is a cross-sectional view for explaining a manufacturing process for the nitride-based semiconductor laser device according to the first modification example of the first embodiment shown in FIG. 14. It is sectional drawing which showed the structure of the nitride type semiconductor laser element by the 2nd modification of 1st Embodiment of this invention. It is the microscope picture which observed the mode of crystal growth of the semiconductor layer on the n-type GaN substrate by the manufacturing process of 1st Embodiment shown in FIG. 8 using the scanning electron microscope. It is the microscope picture which observed the mode of crystal growth of the semiconductor layer on the n-type GaN substrate by the manufacturing process of 1st Embodiment shown in FIG. 8 using the scanning electron microscope. It is sectional drawing which showed the structure of the nitride type semiconductor laser element by 2nd Embodiment of this invention. It is sectional drawing which showed the structure of the nitride type semiconductor laser element by 3rd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the nitride type semiconductor laser element by 3rd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the nitride type semiconductor laser element by 3rd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the nitride type semiconductor laser element by 3rd Embodiment of this invention. It is sectional drawing which showed the structure of the nitride type semiconductor laser element by 4th Embodiment of this invention. FIG. 26 is a cross-sectional view for illustrating the manufacturing process for the nitride-based semiconductor laser device according to the fourth embodiment shown in FIG. 25. FIG. 26 is a cross-sectional view for illustrating the manufacturing process for the nitride-based semiconductor laser device according to the fourth embodiment shown in FIG. 25. FIG. 26 is a cross-sectional view for illustrating the manufacturing process for the nitride-based semiconductor laser device according to the fourth embodiment shown in FIG. 25. FIG. 26 is a cross-sectional view for illustrating the manufacturing process for the nitride-based semiconductor laser device according to the fourth embodiment shown in FIG. 25. It is sectional drawing which showed the structure of the nitride type semiconductor laser element by the modification of 4th Embodiment of this invention.

Explanation of symbols

1, 71, 81, 91 n-type GaN substrate (substrate)
2 Underlayer 3 Semiconductor laser element layer (nitride-based semiconductor element layer)
4 Buffer layer (nitride semiconductor element layer)
5 n-type cladding layer (nitride-based semiconductor element layer, first conductivity type first cladding layer)
6 Light emitting layer (Nitride semiconductor element layer)
7 p-type cladding layer (nitride-based semiconductor element layer, second conductivity type second cladding layer)
8 p-type contact layer (nitride semiconductor element layer)
20a, 60a, 65a, 70a, 80a, 90a, 95a Light exit surface (first end surface)
20b, 60b, 65b, 70b, 80b, 90b, 95b Light reflecting surface (second end surface)
20c, 60c, 65c, 70c, 80c, 90c, 95c Inclined surface (first end surface)
20d, 60d, 65d, 70d, 80d, 90d, 95d Inclined surface (first end surface)
20e, 65e, 70e, 80e, 90e, 95e Inclined surface (first end surface)
30 Crack (recess)
30a, 92a Inner side surface (side surface of one side of the recess)
30b, 92b Inner side surface (side surface on the other side of the recess)
60e Terrace (first end)
92 Groove (recess)

Claims (9)

A substrate,
A nitride-based semiconductor element layer formed on the main surface of the substrate and having a light-emitting layer;
The first end surface of the nitride-based semiconductor element layer includes a resonator end surface and an inclined surface formed in the vicinity of the resonator end surface and inclined at a predetermined angle with respect to at least the main surface of the substrate,
The nitride-based semiconductor laser device, wherein an angle formed between the inclined surface and the main surface of the substrate is an acute angle. The nitride-based semiconductor element layer includes a first conductivity type first cladding layer formed on the substrate side of the light emitting layer and a second conductivity type formed on the light emitting layer opposite to the substrate side. A second cladding layer of
2. The nitride-based semiconductor laser device according to claim 1, wherein the inclined surface of the first end surface includes at least an end surface of the first cladding layer.   3. The nitride semiconductor laser element according to claim 1, wherein the inclined surface of the first end face is formed at least on a laser beam emission side emitted from the light emitting layer. The substrate includes a main surface composed of (H, K, -H-K, 0) planes,
When the substrate has the main surface composed of a (1-100) plane, at least the inclined surface of the first end surface extends in a stripe shape in the [11-20] direction in the main surface of the substrate. A growth surface of the nitride-based semiconductor element layer composed of a (1-101) plane starting from one side surface of the recess formed in the substrate;
When the substrate has the main surface composed of (11-20) plane, at least the inclined surface of the first end surface extends in a stripe shape in the [1-100] direction in the main surface of the substrate. 4. The growth surface of the nitride-based semiconductor element layer formed of a (11-22) plane starting from one side surface of the recess formed in the substrate, according to claim 1. Nitride semiconductor laser device.   A second end face formed at an end of the nitride-based semiconductor element layer opposite to the first end face with respect to a direction in which the resonator extends, and extending in a direction substantially perpendicular to the main surface of the substrate; The nitride-based semiconductor laser device according to claim 4, comprising:   The nitride-based semiconductor laser according to claim 5, wherein the second end surface is formed substantially perpendicular to the main surface of the substrate, starting from the other side surface of the recess formed in the substrate. element. Forming a nitride-based semiconductor element layer having a first end face including an inclined surface inclined at a predetermined angle with respect to a main surface of the substrate on the substrate;
Forming a resonator end surface extending substantially perpendicularly to the main surface of the substrate by etching in a partial region of the inclined surface;
A method of manufacturing a nitride-based semiconductor laser device, wherein an angle formed between the inclined surface and the main surface of the substrate is an acute angle. The substrate has a main surface composed of (H, K, -H-K, 0) planes,
Prior to the step of forming the nitride-based semiconductor element layer including the first end face on the substrate, the substrate is placed in the [K, -H, -K + H, 0] direction in the main surface of the substrate. Further comprising forming a recess extending in a stripe shape,
The step of forming the nitride-based semiconductor element layer having the first end surface including the inclined surface on the substrate includes a growth surface of the nitride-based semiconductor element layer starting from one side surface of the recess. The method for manufacturing a nitride semiconductor laser element according to claim 7, comprising a step of forming the first end face.   The step of forming the nitride-based semiconductor element layer includes the step of forming the nitride-based semiconductor element layer extending substantially perpendicular to the main surface of the substrate, starting from the other side surface of the recess formed in the substrate. The method for manufacturing a nitride-based semiconductor laser device according to claim 8, further comprising a step of forming a second end face made of a growth surface.