JP2011077327A - Semiconductor laser integrated element and method for manufacturing the same - Google Patents

Abstract

A semiconductor laser integrated device capable of accurately aligning the optical axes of a plurality of semiconductor laser structures having different output wavelengths and a method for manufacturing the same.
A semiconductor laser integrated device 1 includes a gallium nitride semiconductor substrate 11 having a main surface 11a and a back surface 11b, an optical resonator 10 provided on the main surface 11a and having a pair of resonance end surfaces 10a and 10b, And an optical resonator 50 provided on the back surface 11b and having a pair of resonance end faces 50a and 50b. The angle formed between the main surface 11a and the back surface 11b and the c-plane of the gallium nitride based semiconductor crystal is 45 ° or more and 135 ° or less, and the optical resonator 10 has an active layer 17 containing indium epitaxially grown on the main surface 11a. The optical resonator 50 has an active layer 57 containing indium epitaxially grown on the back surface 11b. The peak wavelengths of the emission wavelengths of the active layers 17 and 57 are different from each other.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor laser integrated device and a manufacturing method thereof.

  Patent Document 1 describes a laser light emitting device having an oscillation wavelength of at least two out of each wavelength such as blue, green, and red. The laser light emitting device described in Patent Document 1 includes a GaN-based semiconductor laser diode having a nonpolar plane or a semipolar plane as a main surface for crystal growth, and an AlInGaP-based semiconductor laser diode. A diode is mounted on the support substrate by bonding.

  Patent Document 2 discloses a GaN substrate, a first laser structure formed by crystal growth on the GaN substrate, and the GaN after being formed by crystal growth on a substrate different from the GaN substrate. A multi-wavelength laser is described that includes one or more second laser structures mounted on a substrate.

JP 2008-288527 A JP 2008-294322 A

  In recent years, as semiconductor lasers having a green oscillation wavelength have been put into practical use, a method of integrating a plurality of semiconductor laser structures having different output wavelengths such as blue, green, and red into one element has been studied. Yes. For example, in the methods described in Patent Document 1 and Patent Document 2, first, a plurality of semiconductor laser elements having different output wavelengths are individually formed and integrated by mounting these semiconductor laser elements on one substrate. I am trying. However, in such a system, there is a problem that it is extremely difficult to mount a plurality of fine semiconductor laser elements on one substrate while aligning the optical axes of each other.

  The present invention has been made in view of the above-described problems, and provides a semiconductor laser integrated device capable of accurately aligning the optical axes of a plurality of semiconductor laser structures having different output wavelengths and a method for manufacturing the same. Objective.

  In order to solve the above problems, a semiconductor laser integrated device according to the present invention is provided on a main surface of a gallium nitride semiconductor substrate having a main surface and a back surface along the main surface, and a main surface of the gallium nitride semiconductor substrate. And a second optical resonator having a pair of resonant end faces provided on the back surface of the gallium nitride based semiconductor substrate, a main surface of the gallium nitride based semiconductor substrate, The angle formed between the back surface and the c-plane of the gallium nitride based semiconductor crystal is not less than 45 ° and not more than 135 °, and the first optical resonator includes a first optical resonator containing indium epitaxially grown on the main surface of the gallium nitride based semiconductor substrate. The second optical resonator has a second active layer containing indium epitaxially grown on the back surface of the gallium nitride based semiconductor substrate. Light emission The peak wavelength of the wavelength is different from the peak wavelength of the emission wavelength of the second active layer.

  The method for fabricating a semiconductor laser integrated device according to the present invention has a main surface and a back surface along the main surface, and an angle formed between the main surface and the back surface and the c-plane of the gallium nitride semiconductor crystal is 45 ° or more and 135 °. A step of epitaxially growing a first semiconductor stacked portion having a first active layer containing indium on a main surface of a gallium nitride based semiconductor substrate, and a step of forming a protective film on the first semiconductor stacked portion And a step of epitaxially growing a second semiconductor laminated portion having a second active layer containing indium on the back surface of the gallium nitride based semiconductor substrate, and after removing the protective film, the first semiconductor laminated portion has a first And forming the second optical waveguide structure in the second semiconductor laminate, and cleaving the gallium nitride based semiconductor substrate to form the first optical waveguide structure and a pair of resonance end faces And a step of forming a second optical resonator having a second optical waveguide structure and a pair of resonant end faces, the emission wavelength of the first active layer, The emission wavelengths of the two active layers are different from each other.

  In the semiconductor laser integrated device and the manufacturing method thereof, an optical resonator is provided on each of the main surface and the back surface of the gallium nitride based semiconductor substrate. The angle formed between the main surface and the back surface and the c-plane of the gallium nitride semiconductor crystal is 45 ° or more and 135 ° or less, and the main surface and the back surface are nonpolar surfaces (semipolar surfaces or nonpolar surfaces). By growing an active layer made of a group III-V compound semiconductor containing indium on the surface, a piezo electric field due to distortion of the crystal structure can be reduced and luminous efficiency can be increased.

  In the semiconductor laser integrated device and the manufacturing method thereof, an active layer is provided on the main surface and the back surface of a single gallium nitride semiconductor substrate. In this case, an active layer or the like is provided on each of the main surface and the back surface. It is possible to grow a crystal and form a semiconductor laser structure using a normal semiconductor process. Therefore, the semiconductor laser structures can be accurately aligned as compared with the conventional one in which the semiconductor laser element grown on another substrate is mounted. Moreover, since the peak wavelength of the emission wavelength of the first active layer and the peak wavelength of the emission wavelength of the second active layer are different from each other, the output wavelengths of these semiconductor laser structures can be made different from each other. That is, according to the semiconductor laser integrated device and the manufacturing method thereof, the optical axes of a plurality of semiconductor laser structures having different output wavelengths can be accurately aligned.

  Further, in the semiconductor laser integrated device and the manufacturing method thereof, the main surface and the back surface of the gallium nitride semiconductor substrate are 63 ° to 80 ° or 100 ° to 117 ° in the m-axis direction with respect to the c-plane of the gallium nitride semiconductor crystal. It is preferably a semipolar plane inclined within a range of 0 ° or less.

  In the semiconductor laser integrated device and the manufacturing method thereof, the main surface of the gallium nitride based semiconductor substrate is the {H, 0, -H, L} plane (where H and L are natural numbers) of the gallium nitride based semiconductor crystal, The back surface of the gallium nitride based semiconductor substrate is the {-H, 0, H, -L} plane of the gallium nitride based semiconductor crystal, and the indium composition of the second active layer is larger than the indium composition of the first active layer. May be a feature. When the main surface of the gallium nitride semiconductor substrate is the {H, 0, -H, L} plane of the gallium nitride semiconductor crystal, the {-H, 0, H, -L} plane serving as the back surface is the main surface. The degree of indium uptake is higher. Accordingly, by making the indium composition of the second active layer on the back surface larger than the indium composition of the first active layer on the main surface, the first and second active layers having different peak wavelengths of the emission wavelength are suitable. Can get to.

  For example, the peak wavelength of the emission wavelength of the first active layer is 430 [nm] or more and 480 [nm] or less, and the peak wavelength of the emission wavelength of the second active layer is 500 [nm] or more and 550 [nm] or less. Thus, a semiconductor laser integrated device capable of outputting blue laser light and green laser light can be obtained.

  Further, in the semiconductor laser integrated device and the manufacturing method thereof, the main surface and the back surface of the gallium nitride based semiconductor substrate are 59 ° to 80 ° or 100 ° to 121 ° in the a-axis direction with respect to the c-plane of the gallium nitride based semiconductor crystal. It is preferably a semipolar plane inclined within a range of 0 ° or less.

  Further, in the semiconductor laser integrated device and the manufacturing method thereof, the main surface of the gallium nitride based semiconductor substrate is the {-H, -H, 2H, -L} plane of the gallium nitride based semiconductor crystal (where H and L are natural numbers). The back surface of the gallium nitride based semiconductor substrate is the {H, H, -2H, L} plane of the gallium nitride based semiconductor crystal, and the indium composition of the second active layer is larger than the indium composition of the first active layer This may be a feature. When the main surface of the gallium nitride based semiconductor substrate is the {-H, -H, 2H, -L} surface of the gallium nitride based semiconductor crystal, the {H, H, -2H, L} surface which is the back surface is the main surface. The degree of indium uptake is higher than the surface. Accordingly, by making the indium composition of the second active layer on the back surface larger than the indium composition of the first active layer on the main surface, the first and second active layers having different peak wavelengths of the emission wavelength are suitable. Can get to.

  For example, the peak wavelength of the emission wavelength of the first active layer is 430 [nm] or more and 480 [nm] or less, and the peak wavelength of the emission wavelength of the second active layer is 500 [nm] or more and 550 [nm] or less. Thus, a semiconductor laser integrated device capable of outputting blue laser light and green laser light can be obtained.

  In the semiconductor laser integrated device, it is preferable that the optical waveguide directions of the first and second optical resonators extend along the direction in which the c-axis of the gallium nitride based semiconductor crystal is projected onto the main surface and the back surface. Similarly, in the method of manufacturing the semiconductor laser integrated device, in the step of forming the first and second optical waveguide structures, the optical waveguide direction of the first and second optical waveguide structures is the c-axis of the gallium nitride based semiconductor crystal. It is preferable to form the first and second optical waveguide structures so as to extend along the directions projected onto the main surface and the back surface.

  In addition, the semiconductor laser integrated device has the optical waveguide direction of the first optical resonator and the optical waveguide direction of the second optical resonator as viewed from the normal direction of the main surface and the back surface of the gallium nitride based semiconductor substrate. The formed angle may be 2 ° or less. Similarly, the semiconductor laser integrated device manufacturing method includes the first optical waveguide in the first and second optical waveguide structure forming steps when viewed from the normal direction of the main surface and the back surface of the gallium nitride based semiconductor substrate. The angle formed by the optical waveguide direction of the structure and the optical waveguide direction of the second optical waveguide structure may be 2 ° or less. According to the semiconductor laser integrated device and the manufacturing method thereof according to the present invention described above, it is possible to provide a semiconductor laser integrated device in which the optical axes of the plurality of semiconductor laser structures are accurately aligned.

  According to the semiconductor laser integrated device and the manufacturing method thereof according to the present invention, the optical axes of a plurality of semiconductor laser structures having different output wavelengths can be aligned with high accuracy.

It is sectional drawing which shows the structure of one Embodiment of the semiconductor laser integrated element by this invention. FIG. 2 is a side sectional view taken along line II-II of the semiconductor laser integrated device 1 shown in FIG. 1. (A)-(c) It is a figure which shows the manufacturing process of the semiconductor laser integrated element 1 shown by FIG. (A), (b) It is a figure which shows the manufacturing process of the semiconductor laser integrated element 1 shown by FIG. (A), (b) It is a figure which shows the manufacturing process of the semiconductor laser integrated element 1 shown by FIG. (A), (b) It is a figure which shows the manufacturing process of the semiconductor laser integrated element 1 shown by FIG. (A), (b) It is a figure which shows the manufacturing process of the semiconductor laser integrated element 1 shown by FIG. (A), (b) It is a figure which shows the manufacturing process of the semiconductor laser integrated element 1 shown by FIG. (A), (b) It is a figure which shows the manufacturing process of the semiconductor laser integrated element 1 shown by FIG. FIG. 3 is a diagram showing a manufacturing process of the semiconductor laser integrated element 1 shown in FIG. (A)-(c) It is a figure which shows the manufacturing process of the semiconductor laser integrated element 1 shown by FIG. (A), (b) It is a figure which shows the manufacturing process of the semiconductor laser integrated element 1 shown by FIG.

  Embodiments of a semiconductor laser integrated device and a manufacturing method thereof according to the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  1 and 2 are drawings schematically showing the structure of a semiconductor laser integrated device according to an embodiment of the present invention. 1 and 2, a plurality of semiconductor lasers each outputting laser light having a wavelength of 430 [nm] or more and 480 [nm] or less and laser light having a wavelength of 500 [nm] or more and 550 [nm] or less. A semiconductor laser integrated device 1 having a structure will be described.

The semiconductor laser integrated element 1 includes a gallium nitride based semiconductor substrate 11. Gallium nitride based semiconductor substrate 11 is made of gallium nitride-based semiconductor _{In S Al T Ga 1-S} -T N (0 ≦ S <1,0 ≦ T <1,0 ≦ S + T <1), for example, be composed of GaN or the like Can do. The gallium nitride based semiconductor substrate 11 has a main surface 11a and a back surface 11b along the main surface 11a. The main surface 11a and the back surface 11b are inclined with respect to the c-plane of the gallium nitride based semiconductor crystal.

  As shown in FIG. 2, the inclination angles of the main surface 11a and the back surface 11b are determined by the normal vectors NV1 (main surface 11a) and NV2 (back surface 11b) indicating the normal axis Nx, and the c-axis vector indicating the c-axis direction. It is defined by angles α1 and α2 formed with VC. These angles α1 and α2 are in the range of 45 ° or more and 135 ° or less with respect to a reference plane Rx (that is, {0001} plane or {000-1} plane) orthogonal to the c-axis of the gallium nitride semiconductor crystal. be able to. The gallium nitride based semiconductor substrate 11 can be, for example, GaN. According to this angular range, the nonpolar (semipolar or nonpolar) nature of GaN can be provided.

  Furthermore, the main surface 11a and the back surface 11b are preferably inclined in the m-axis or a-axis direction with respect to the c-plane of the gallium nitride based semiconductor crystal. When tilted in the direction of the m-axis, the tilt angles α1 and α2 are preferably in the range of 63 ° to 80 ° or 100 ° to 117 °. Moreover, when it inclines in the direction of a axis | shaft, it is preferable that inclination-angle (alpha) 1 and (alpha) 2 exist in the range of 59 degrees or more and 80 degrees or less, or 100 degrees or more and 121 degrees or less. According to these angular ranges in which the main surface 11a and the back surface 11b are semipolar surfaces, an InGaN layer having an indium composition suitable for an active layer for generating light having a long wavelength of 500 [nm] or more and 550 [nm] or less. Can provide.

  As an example in which the main surface 11a and the back surface 11b are inclined in the m-axis direction within the above-mentioned inclination angle range, the main surface 11a is a {H, 0, -H, L} plane (where H And L is a natural number), and the back surface 11b can be a {-H, 0, H, -L} plane of a gallium nitride based semiconductor crystal. When the main surface 11a is the {2, 0, -2, 1} plane of the gallium nitride based semiconductor crystal and the back surface 11b is the {-2, 0, 2, -1} plane of the gallium nitride based semiconductor crystal, c The inclination angle α1 of the main surface 11a with respect to the surface is 75 °, and the inclination angle α2 of the back surface 11b with respect to the c surface is 105 °.

  Further, as an example in which the main surface 11a and the back surface 11b are inclined in the a-axis direction within the above-mentioned inclination angle range, the main surface 11a is a {-H, -H, 2H, -L} plane of a gallium nitride based semiconductor crystal. (However, H and L are natural numbers), and the back surface 11b can be a {H, H, -2H, L} plane of a gallium nitride based semiconductor crystal. When the main surface 11a is the {1, 1, -2, 1} plane of the gallium nitride based semiconductor crystal and the back surface 11b is the {-1, -1, 2, -1} plane of the gallium nitride based semiconductor crystal, The inclination angle α1 of the main surface 11a with respect to the c-plane is 73 °, and the inclination angle α2 of the back surface 11b with respect to the c-plane is 107 °.

  The semiconductor laser integrated device 1 of the present embodiment includes a first semiconductor laser structure 1A formed by epitaxial growth on the main surface 11a of the gallium nitride based semiconductor substrate 11, and an epitaxial growth on the back surface 11b of the gallium nitride based semiconductor substrate 11. And a formed second semiconductor laser structure 1B. The first semiconductor laser structure 1A includes a first optical resonator 10 having a pair of resonant end faces 10a and 10b, and the second semiconductor laser structure 1B includes a second pair of resonant end faces 50a and 50b. An optical resonator 50 is included. The first semiconductor laser structure 1A outputs laser light having a wavelength range of 430 [nm] to 480 [nm], and the second semiconductor laser structure 1B has a wavelength range of 500 [nm] to 550 [nm]. Outputs laser light.

  The first semiconductor laser structure 1A includes an n-type semiconductor layer 13 provided on the main surface 11a of the gallium nitride based semiconductor substrate 11, an n-type cladding layer 15 provided on the n-type semiconductor layer 13, and an n-type An active layer 17 provided on the cladding layer 15 and a p-type cladding layer 19 provided on the active layer 17 are provided. The second semiconductor laser structure 1B includes an n-type cladding layer 55 provided on the back surface 11b of the gallium nitride based semiconductor substrate 11, an active layer 57 provided on the n-type cladding layer 55, and an active layer 57. And a p-type cladding layer 59 provided thereon.

  The n-type semiconductor layer 13 is made of an n-type (first conductivity type) gallium nitride semiconductor, and can be made of, for example, GaN. The thickness of the n-type semiconductor layer 13 is 1000 [nm], for example. The n-type cladding layers 15 and 55 constitute part of the first and second optical resonators 10 and 50, respectively. The n-type cladding layers 15 and 55 are made of an n-type gallium nitride semiconductor, and can be made of, for example, GaN, AlGaN, InAlGaN, or the like. The n-type cladding layers 15 and 55 have a thickness of, for example, 1200 [nm]. The p-type cladding layers 19 and 59 constitute part of the first and second optical resonators 10 and 50, respectively. The p-type cladding layers 19 and 59 are made of a p-type (second conductivity type) gallium nitride semiconductor, and can be made of, for example, GaN, AlGaN, InAlGaN, or the like. The thickness of the p-type cladding layers 19 and 59 is, for example, 400 [nm].

  The active layer 17 is a first active layer in the present embodiment, and constitutes a part of the first optical resonator 10. The active layer 57 is a second active layer in the present embodiment, and constitutes a part of the second optical resonator 50. The active layers 17 and 57 may be formed of a single layer or may have a quantum well structure. If required, the quantum well structure can include alternating well layers and barrier layers. The well layer can be made of a III-V group compound semiconductor containing indium, such as InGaN, and the barrier layer can be made of InGaN, GaN, or the like having a larger band gap energy than the well layer. In one embodiment, the thickness of the well layer (InGaN) is, for example, 3 [nm], the thickness of the barrier layer (GaN) is, for example, 15 [nm], and the number of well layers is, for example, two. Can do. The emission wavelengths of the active layers 17 and 57 are controlled by the band gap of the well layer, the indium composition, the thickness thereof, and the like. The active layers 17 and 57 have different emission wavelengths, and the active layer 17 has an indium composition that generates blue light having a peak wavelength in the range of 430 [nm] to 480 [nm]. The active layer 57 may have an indium composition that generates green light having a peak wavelength in the range of 500 [nm] to 550 [nm]. In this case, the indium composition of the well layer of the active layer 57 is larger than the indium composition of the well layer of the active layer 17.

  Here, the main surface 11a is the {H, 0, -H, L} plane of the gallium nitride based semiconductor crystal, and the back surface 11b is the {-H, 0, H, -L} plane of the gallium nitride based semiconductor crystal. In this case, the {-H, 0, H, -L} plane has a higher degree of indium incorporation in the semiconductor layer grown thereon than the {H, 0, -H, L} plane. Therefore, as described above, the indium composition of the well layer of the active layer 57 formed on the back surface 11b can be easily made larger than the indium composition of the well layer of the active layer 17 formed on the main surface 11a. The main surface 11a is the {-H, -H, 2H, -L} plane of the gallium nitride based semiconductor crystal, and the back surface 11b is the {H, H, -2H, L} plane of the gallium nitride based semiconductor crystal. In this case, the {H, H, -2H, L} plane has a higher degree of indium incorporation in the semiconductor layer grown thereon than {-H, -H, 2H, -L}. Therefore, as described above, the indium composition of the well layer of the active layer 57 formed on the back surface 11b can be easily made larger than the indium composition of the well layer of the active layer 17 formed on the main surface 11a.

  The first semiconductor laser structure 1 </ b> A further includes a first light guide layer 21 between the n-type cladding layer 15 and the active layer 17. Similarly, the second semiconductor laser structure 1 </ b> B further includes a first light guide layer 61 between the n-type cladding layer 55 and the active layer 57. The first semiconductor laser structure 1 </ b> A further includes a second light guide layer 23 between the active layer 17 and the p-type cladding layer 19. Similarly, the second semiconductor laser structure 1B further includes a second light guide layer 63 between the active layer 57 and the p-type cladding layer 59. The first light guide layers 21 and 61 and the second light guide layers 23 and 63 confine light in the vicinity of the active layers 17 and 57 without escaping light to the gallium nitride based semiconductor substrate 11 to reduce the threshold current. Is provided.

  The first light guide layer 21 can include a first layer 31 made of GaN or InGaN and a second layer 33 made of InGaN. The first layer 31 is provided on the n-type cladding layer 15, and the second layer 33 is provided between the first layer 31 and the active layer 17. The first light guide layer 61 can include a first layer 71 made of GaN or InGaN and a second layer 73 made of InGaN. The first layer 71 is provided on the n-type cladding layer 55, and the second layer 73 is provided between the first layer 71 and the active layer 57.

  The indium composition of the second layer 33 is larger than the indium composition of the first layer 31 and smaller than the indium composition of the InGaN well layer in the active layer 17. Similarly, the indium composition of the second layer 73 is larger than that of the first layer 71 and smaller than that of the InGaN well layer in the active layer 57. In one embodiment, the first layers 31 and 71 can be made of n-type GaN, and the second layers 33 and 73 can be made of n-type InGaN. The thickness of the first layers 31 and 71 is, for example, 200 [nm], and the thickness of the second layers 33 and 73 is, for example, 65 [nm].

  The second light guide layer 23 can include a first layer 35 made of GaN or InGaN and a second layer 37 made of InGaN. The first layer 35 is provided on the active layer 17, and the second layer 37 is provided between the active layer 17 and the first layer 35. The second light guide layer 63 can include a first layer 75 made of GaN or InGaN and a second layer 77 made of InGaN. The first layer 75 is provided on the active layer 57, and the second layer 77 is provided between the active layer 57 and the first layer 75.

  The indium composition of the second layer 37 is larger than the indium composition of the first layer 35 and smaller than the indium composition of the InGaN well layer in the active layer 17. Similarly, the indium composition of the second layer 77 is larger than the indium composition of the first layer 75 and smaller than the indium composition of the InGaN well layer in the active layer 57. In one embodiment, the first layers 35 and 75 are made of p-type GaN, and the second layers 37 and 77 are made of undoped InGaN. The thickness of the first layers 35 and 75 is, for example, 200 [nm], and the thickness of the second layers 37 and 77 is, for example, 65 [nm].

  The first semiconductor laser structure 1 </ b> A further includes an electron block layer 27. The electron blocking layer 27 is provided so as to divide the second light guide layer 23 into two in the layer thickness direction. In the present embodiment, the electron blocking layer 27 is provided between the first layer 35 and the second layer 37. Yes. The second semiconductor laser structure 1B further includes an electron block layer 67. The electron blocking layer 67 is provided so as to divide the second light guide layer 63 into two in the layer thickness direction. In the present embodiment, the electron blocking layer 67 is provided between the first layer 75 and the second layer 77. Yes. The electron block layers 27 and 67 can be made of p-type AlGaN, for example. The thickness of the electron block layers 27 and 67 is, for example, 20 [nm].

  Each of the first semiconductor laser structure 1A and the second semiconductor laser structure 1B further includes p-type contact layers 41 and 81 provided on the p-type cladding layers 19 and 59, respectively. The p-type contact layers 41 and 81 can be made of, for example, GaN, AlGaN, or the like. A part of the p-type cladding layer 19 and the p-type contact layer 41 have a ridge shape extending in a predetermined optical waveguide direction, and the side surface of the ridge shape and the surface of the p-type cladding layer 19 are covered with an insulating film 47. ing. Similarly, a part of the p-type cladding layer 59 and the p-type contact layer 81 have a ridge shape extending in a predetermined optical waveguide direction, and the side surface of the ridge shape and the surface of the p-type cladding layer 59 are insulating films 87. Covered by.

  The extending directions of these ridges, that is, the optical waveguide directions of the first and second optical resonators 10 and 50, extend along the direction in which the c-axis of the gallium nitride based semiconductor crystal is projected onto the main surface 11a and the back surface 11b. Yes. Further, the ridge of the first optical resonator 10 and the ridge of the second optical resonator 50 can be formed on one gallium nitride based semiconductor substrate 11 by etching or the like. For example, the first light is viewed from the normal direction of the main surface 11a and the back surface 11b of the gallium nitride based semiconductor substrate 11 (in other words, the thickness direction of the gallium nitride based semiconductor substrate 11). The angle formed by the optical waveguide direction of the resonator 10 and the optical waveguide direction of the second optical resonator 50 can be 2 ° or less.

  The first semiconductor laser structure 1 </ b> A further includes an anode electrode 45. The anode electrode 45 is provided on the ridge of the first optical resonator 10 and is in contact with the p-type contact layer 41 through the opening of the insulating film 47. The second semiconductor laser structure 1B further includes an anode electrode 85. The anode electrode 85 is provided on the ridge of the second optical resonator 50 and is in contact with the p-type contact layer 81 through the opening of the insulating film 87.

  The semiconductor laser integrated device 1 further includes a cathode electrode 99. The cathode electrode 99 is a cathode electrode common to the first semiconductor laser structure 1 A and the second semiconductor laser structure 1 B, and is provided on the side surface 11 c of the gallium nitride based semiconductor substrate 11. The side surface 11 c is a side surface of the gallium nitride based semiconductor substrate 11 along the optical waveguide direction of the first and second optical resonators 10 and 50.

A method for manufacturing the semiconductor laser integrated device 1 having the above configuration will be described below. Each semiconductor layer is epitaxially grown by metal organic vapor phase epitaxy, and raw materials include trimethylgallium (TMGa), trimethylaluminum (TMAl), trimethylindium (TMIn), ammonia (NH ₃ ), and silane ( SiH ₄ ) is used.

  First, as shown in FIG. 3A, a wafer-like gallium nitride based semiconductor substrate 101 is prepared. The gallium nitride based semiconductor substrate 101 becomes the gallium nitride based semiconductor substrate 11 in the semiconductor laser integrated element 1, and the composition and the plane orientation of the main surface 101a and the back surface 101b are the same as those of the gallium nitride based semiconductor substrate 11 described above. is there. In this embodiment, for example, a gallium nitride substrate having a {20-21} plane inclined by 75 ° in the m-axis direction from the (0001) plane of the gallium nitride crystal as the main surface 101a is used as the gallium nitride based semiconductor substrate 101. Can do. In this case, the plane orientation of the back surface 101b of the gallium nitride based semiconductor substrate 101 is {−202-1}. The gallium nitride based semiconductor substrate 101 is preferably a double-sided polished substrate whose thickness is reduced to 200 [μm] in order to improve mutual alignment accuracy between the main surface 101a and the back surface 101b.

  After this gallium nitride based semiconductor substrate 101 is placed on a susceptor in the reactor so that the {20-21} plane (ie, the main surface 101a) is the growth plane, each semiconductor layer is epitaxially grown by the following growth procedure. (See FIG. 3 (b)). First, an n-type semiconductor layer 13 made of an n-type gallium nitride semiconductor such as GaN is epitaxially grown on the main surface 101a. The thickness of the n-type semiconductor layer 13 is 1000 [nm], for example. Next, an n-type cladding layer 15 made of an n-type gallium nitride semiconductor such as InAlGaN is epitaxially grown on the n-type semiconductor layer 13. The thickness of the n-type cladding layer 15 is, for example, 1200 [nm]. Subsequently, the first layer 31 and the second layer 33 constituting the first light guide layer 21 are sequentially epitaxially grown on the n-type cladding layer 15. The first layer 31 is made of, for example, n-type GaN or InGaN, and the second layer 33 is made of, for example, undoped InGaN. The thickness of the first layer 31 is, for example, 200 [nm], and the thickness of the second layer 33 is, for example, 65 [nm].

  Subsequently, the active layer 17 (first active layer) is epitaxially grown on the second layer 33 of the first light guide layer 21. The composition and structure of the active layer 17 are the same as those described above. When the active layer 17 has a multiple quantum well structure, for example, a barrier layer made of, for example, GaN (thickness 15 nm in one embodiment) and a well layer, for example, made of InGaN (thickness 3 nm in one embodiment). ) And grow alternately. The peak wavelength of the emission wavelength of the well layer is, for example, 440 [nm].

  Subsequently, the second layer 37 constituting the second light guide layer 23, the electron blocking layer 27, and the first layer 35 constituting the second light guide layer 23 are epitaxially grown in order on the active layer 17. The second layer 37 is made of, for example, undoped InGaN, and the second layer 33 is made of, for example, p-type GaN or InGaN. The electron block layer 27 is made of, for example, p-type AlGaN. The thickness of the second layer 37 is, for example, 65 [nm], the thickness of the electron blocking layer 27 is, for example, 20 [nm], and the thickness of the first layer 35 is, for example, 200 [nm].

  Subsequently, a p-type cladding layer 19 made of a p-type gallium nitride semiconductor such as p-type InAlGaN is epitaxially grown on the first layer 35. The thickness of the p-type cladding layer 19 is, for example, 400 [nm]. Then, a contact layer 41 made of a p-type gallium nitride semiconductor such as p-type GaN is epitaxially grown on the p-type cladding layer 19. The thickness of the contact layer 41 is, for example, 50 [nm].

  Through the above steps, the first semiconductor stacked unit 103 is formed on the main surface 101a. The first semiconductor stack 103 includes an n-type semiconductor layer 13, an n-type cladding layer 15, a first light guide layer 21, an active layer 17, a second light guide layer 23, an electron block layer 27, a p-type cladding layer 19, And a contact layer 41.

Subsequently, as shown in FIG. 3C, a protective film 105 is formed on the first semiconductor stacked portion 103 (in this embodiment, on the contact layer 41). The protective film 105 can be made of, for example, SiO ₂ . In one embodiment, a SiO ₂ film having a thickness of 500 [nm] is formed as the protective film 105 on the first semiconductor stacked portion 103 by plasma CVD. This protective film 105 is provided to protect the first semiconductor stacked portion 103 when another semiconductor layer is grown on the back surface 101b of the gallium nitride based semiconductor substrate 101 in a later step.

  Subsequently, the gallium nitride based semiconductor substrate 101 is turned over (FIG. 4A), the back surface 101b is finish-polished, and then the gallium nitride based semiconductor substrate 101 is placed on the susceptor in the reaction chamber so that the back surface 101b becomes the growth surface. To place.

  Subsequently, the n-type cladding layer 55, the first layer 31 of the first light guide layer 61, and the first light guide layer 61 have the same thickness and composition as the corresponding semiconductor layers of the first semiconductor stacked portion 103. Second layer 33, active layer 57 (second active layer), second layer 37 of second light guide layer 63, electron blocking layer 67, first layer 35 of second light guide layer 63, p The second cladding layer 107 is formed by epitaxially growing the mold cladding layer 59 and the contact layer 81 in this order on the back surface 101b (FIG. 4B). In the second semiconductor stacked portion 107, the peak wavelength of the emission wavelength of the well layer of the active layer 57 is, for example, 520 [nm].

  Subsequently, the protective film 105 is removed by immersing the gallium nitride based semiconductor substrate 101 on which the first and second semiconductor stacked portions 103 and 107 are formed in hydrofluoric acid. Then, as illustrated in FIG. 5A, a resist film 109 is applied on the first semiconductor stacked portion 103. Further, as shown in FIG. 5B, after a resist film is applied also on the second semiconductor stacked portion 107, a resist pattern 111 for forming a ridge is formed by a normal photolithography technique. The longitudinal direction of the resist pattern 111 (that is, the optical waveguide direction) is preferably along the direction in which the c-axis of the gallium nitride based semiconductor substrate 101 is projected on the back surface 101b.

Subsequently, as illustrated in FIG. 6A, for example, dry etching using Cl ₂ is performed on the second semiconductor stacked unit 107 using the resist pattern 111 as a mask. At this time, the etching depth is, for example, 450 [nm], and it is preferable that the electron blocking layer 67 is exposed. Thereby, the ridge shape of the second semiconductor laser structure 1B is formed, and the second optical waveguide structure is formed.

Subsequently, as illustrated in FIG. 6B, an insulating film 87 is formed so as to cover the surface of the second semiconductor stacked portion 107. The insulating film 87 is formed, for example, by depositing SiO ₂ to a thickness of 300 [nm] by plasma CVD. Thereafter, ultrasonic cleaning with acetone is performed, and the insulating film 87 on the ridge is removed (lifted off) together with the resist pattern 111 to form an opening (FIG. 7A).

  Subsequently, as shown in FIG. 7B, an anode electrode 85 is formed on the ridge (that is, on the contact layer 81) of the second semiconductor stacked unit 107. That is, after a resist film is applied on the first semiconductor multilayer portion 103 to protect the first semiconductor multilayer portion 103, a resist pattern is formed on the surface of the second semiconductor multilayer portion 107. This resist pattern has an opening in the ridge portion of the second semiconductor stacked portion 107. Then, Ni and Au (both having a thickness of 10 [nm]) to be the anode electrode 85 are sequentially vacuum deposited. Thereafter, ultrasonic cleaning with acetone is performed, and the resist pattern is removed (lifted off) to form the anode electrode 85.

  Subsequently, as shown in FIG. 8A, after the second semiconductor stacked portion 107 and the anode electrode 85 are protected by the resist film 113, the gallium nitride based semiconductor substrate 101 is turned over. Then, as shown in FIG. 8B, a resist pattern 115 for forming a ridge is formed on the first semiconductor stacked portion 103. The longitudinal direction of resist pattern 115 (that is, the optical waveguide direction) is preferably along the direction in which the c-axis of gallium nitride based semiconductor substrate 101 is projected onto main surface 101a. The longitudinal direction of the resist pattern 115 is preferably aligned with the longitudinal direction of the ridge formed in the second semiconductor stacked portion 107, and the angle formed by these directions is preferably 2 ° or less. Thereby, the angle formed by the optical waveguide direction of the first semiconductor multilayer portion 103 and the optical waveguide direction of the second semiconductor multilayer portion 107 can be made 2 ° or less.

Subsequently, dry etching using Cl ₂ is performed on the first semiconductor stacked portion 103 using the resist pattern 115 as a mask. At this time, the etching depth is, for example, 450 [nm], and it is preferable that the electron blocking layer 27 is exposed. Thereby, the ridge shape of the first semiconductor laser structure 1A is formed, and the first optical waveguide structure is formed.

Subsequently, as illustrated in FIG. 9A, an insulating film 47 is formed so as to cover the surface of the first semiconductor stacked unit 103. The insulating film 47 is formed, for example, by depositing SiO ₂ to a thickness of 300 [nm] by plasma CVD. Thereafter, ultrasonic cleaning with acetone is performed, and the insulating film 47 on the ridge is removed (lifted off) together with the resist pattern 115 to form an opening (FIG. 9B).

  Subsequently, as illustrated in FIG. 10, an anode electrode 45 is formed on the ridge of the first semiconductor stacked unit 103 (that is, on the contact layer 41). That is, after a resist film is applied on the second semiconductor multilayer portion 107 to protect the second semiconductor multilayer portion 107, a resist pattern is formed on the surface of the first semiconductor multilayer portion 103. This resist pattern has an opening in the ridge portion of the first semiconductor stacked portion 103. Then, Ni and Au (both having a thickness of 10 nm) to be the anode electrode 45 are sequentially vacuum deposited. Thereafter, ultrasonic cleaning with acetone is performed, and the resist pattern is removed (lifted off) to form the anode electrode 45.

  Subsequently, as shown in FIG. 11A, the gallium nitride based semiconductor substrate 101 on which the first semiconductor stacked portion 103 and the second semiconductor stacked portion 107 are formed is broken in a direction perpendicular to the longitudinal direction of the ridge. Cleavage (primary cleavage) is performed by 117. Thus, the first optical resonator 10 (see FIGS. 1 and 2) having the first optical waveguide structure and the pair of resonance end faces 10a and 10b, and the second optical waveguide structure and the pair of resonance end faces 50a. , 50b are formed, a first semiconductor laser structure 1A including the first optical resonator 10 and a second optical resonance are formed. Bar-shaped semiconductor laser bars 119 each having a plurality of second semiconductor laser structures 1B including the device 50 are produced (FIG. 11B).

  Subsequently, a reflection film is formed on both of the pair of cleavage surfaces of the semiconductor laser bar 119. In general, the reflection film of a semiconductor laser element increases the reflectance by alternately laminating two kinds of refractive index materials so that a single wavelength (resonance wavelength) has a peak in reflectance. However, in the present embodiment, the output wavelength (430 [nm] or more and 480 [nm] or less) of the first semiconductor laser structure 1A and the output wavelength (500 [nm] or more and 550 [nm] of the second semiconductor laser structure 1B). In order to realize a high reflectance with respect to both of the above and the following), it is preferable to form two types of reflective films so that each wavelength region has a peak reflectance.

  Subsequently, as shown in FIG. 11C, the semiconductor laser bar 119 is cleaved (secondary cleaving) along the optical waveguide direction of the first and second semiconductor laser structures 1A and 1B. As a result, a chip including a pair of first and second semiconductor laser structures 1A and 1B and a gallium nitride based semiconductor substrate 11 is manufactured. The chips thus manufactured are arranged on a metal mask 121 as shown in FIG. The metal mask 121 has a plurality of openings 121a for the cathode electrode 99 (FIG. 1). Then, Ti, Al, Ti, and Au are deposited through the openings 121a of the metal mask 121 so that the thicknesses of Ti, Al, Ti, and Au are 20 [nm], 200 [nm], 50 [nm], and 300 [nm], respectively. Are deposited on the side surfaces of the gallium nitride based semiconductor substrate 11 of each chip. Thus, the cathode electrode 99 is formed on the side surface of the gallium nitride based semiconductor substrate 11, and the semiconductor laser integrated device 1 of this embodiment is completed (FIG. 12B).

  The effects of the semiconductor laser integrated device 1 and the manufacturing method thereof according to this embodiment will be described. In the semiconductor laser integrated device 1 and the manufacturing method thereof described above, the optical resonators 10 and 50 are provided on the main surface 11a and the back surface 11b of the gallium nitride based semiconductor substrate 11, respectively. The angle formed between the main surface 11a and the back surface 11b and the c-plane of the gallium nitride based semiconductor crystal is 45 ° or more and 135 ° or less, and the main surface 11a and the back surface 11b are nonpolar surfaces (semipolar surfaces or nonpolar surfaces). Therefore, by growing the active layers 17 and 57 containing indium on these surfaces, the piezo electric field due to the distortion of the crystal structure can be reduced and the luminous efficiency can be increased.

  In the semiconductor laser integrated device 1 and the manufacturing method thereof described above, the active layers 17 and 57 are provided on the main surface 11a and the back surface 11b of one gallium nitride based semiconductor substrate 11. In this case, the main surface 11a The semiconductor stacked portions 103 and 107 including the active layers 17 and 57 can be crystal-grown on the upper and back surfaces 11b, respectively, and the semiconductor laser structures 1A and 1B can be formed using a normal semiconductor process. Therefore, the semiconductor laser structures 1A and 1B can be accurately aligned as compared with the conventional one in which the semiconductor laser element grown on another substrate is mounted. Moreover, since the peak wavelength of the emission wavelength of the active layer 17 and the peak wavelength of the emission wavelength of the active layer 57 are different from each other, the output wavelengths of these semiconductor laser structures 1A and 1B can be made different from each other. That is, according to the semiconductor laser integrated device 1 and the manufacturing method thereof of the present embodiment, the optical axes of the plurality of semiconductor laser structures 1A and 1B having different output wavelengths can be accurately aligned.

  In the present embodiment, the main surface 11a of the gallium nitride based semiconductor substrate 11 is the {H, 0, -H, L} plane of the gallium nitride based semiconductor crystal, and the back surface 11b is the {- H, 0, H, -L} plane, and the indium composition of the active layer 57 is preferably larger than the indium composition of the active layer 17. As described above, the {-H, 0, H, -L} plane has a higher degree of indium uptake than the {H, 0, -H, L} plane of the gallium nitride based semiconductor crystal. By making the indium composition of the active layer 57 larger than the indium composition of the active layer 17 on the main surface 11a, the active layers 17 and 57 having different peak wavelengths of the emission wavelength can be suitably obtained. For example, the peak wavelength of the emission wavelength of the active layer 17 is not less than 430 [nm] and not more than 480 [nm], and the peak wavelength of the emission wavelength of the active layer 57 is not less than 500 [nm] and not more than 550 [nm]. Thus, the semiconductor laser integrated element 1 that can output blue laser light and green laser light can be obtained.

  Alternatively, in the present embodiment, the main surface 11a of the gallium nitride based semiconductor substrate 11 is the {-H, -H, 2H, -L} plane of the gallium nitride based semiconductor crystal, and the back surface 11b is the gallium nitride based semiconductor crystal. It may be a {H, H, -2H, L} plane. As described above, the {H, H, -2H, L} plane has a higher degree of indium incorporation than the {-H, -H, 2H, -L} plane of the gallium nitride based semiconductor crystal. By making the indium composition of the active layer 57 larger than the indium composition of the active layer 17 on the main surface 11a, the active layers 17 and 57 having different emission wavelength peak wavelengths can be suitably obtained. For example, the peak wavelength of the emission wavelength of the active layer 17 is not less than 430 [nm] and not more than 480 [nm], and the peak wavelength of the emission wavelength of the active layer 57 is not less than 500 [nm] and not more than 550 [nm]. Thus, the semiconductor laser integrated element 1 that can output blue laser light and green laser light can be obtained.

  Further, as in this embodiment, the optical waveguide directions of the optical resonators 10 and 50 preferably extend along the direction in which the c-axis of the gallium nitride based semiconductor crystal is projected onto the main surface 11a and the back surface 11b. . Thereby, a cleavage plane (resonance end face) perpendicular to the optical waveguide direction can be easily formed.

  Further, as in the present embodiment, the first semiconductor multilayer portion 103 having the active layer 17 having a light emission wavelength shorter than that of the active layer 57 may be epitaxially grown before the second semiconductor multilayer portion 107 having the active layer 57. preferable. As described above, by growing the active layer 17 having a small indium composition and high heat resistance, damage to the active layer 57 having a large indium composition and low heat resistance can be reduced.

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor laser integrated element, 1A ... 1st semiconductor laser structure, 1B ... 2nd semiconductor laser structure, 10 ... 1st optical resonator, 50 ... 2nd optical resonator, 10a, 10b, 50a, 50b ... resonance end face, 11, 101 ... gallium nitride based semiconductor substrate, 11a, 101a ... main face, 11b, 101b ... back face, 11c ... side face, 13 ... n-type semiconductor layer, 15, 55 ... n-type cladding layer, 17, 57 ... active layer, 19, 59 ... p-type cladding layer, 21, 61 ... first light guide layer, 23, 63 ... second light guide layer, 27, 67 ... electron blocking layer, 31, 71 ... first layer, 33, 73 ... second layer, 35, 75 ... first layer, 37, 77 ... second layer, 41, 81 ... p-type contact layer, 45, 85 ... anode electrode, 47, 87 ... insulating film, 50: second optical resonator, 99: cathode electrode, 103 First stacked semiconductor layer, 105 ... protective layer, 107 ... second semiconductor lamination portion.

Claims (18)

A gallium nitride based semiconductor substrate having a main surface and a back surface along the main surface;
A first optical resonator provided on the main surface of the gallium nitride based semiconductor substrate and having a pair of resonance end faces;
A second optical resonator provided on the back surface of the gallium nitride based semiconductor substrate and having a pair of resonant end faces;
An angle formed by the main surface and the back surface of the gallium nitride based semiconductor substrate and the c plane of the gallium nitride based semiconductor crystal is 45 ° or more and 135 ° or less,
The first optical resonator has a first active layer containing indium epitaxially grown on the main surface of the gallium nitride based semiconductor substrate,
The second optical resonator has a second active layer containing indium epitaxially grown on the back surface of the gallium nitride based semiconductor substrate,
The semiconductor laser integrated device, wherein a peak wavelength of an emission wavelength of the first active layer and a peak wavelength of an emission wavelength of the second active layer are different from each other.   The main surface and the back surface of the gallium nitride based semiconductor substrate are inclined with respect to the c-plane of the gallium nitride based semiconductor crystal within a range of 63 ° to 80 ° or 100 ° to 117 ° in the m-axis direction. 2. The semiconductor laser integrated device according to claim 1, wherein the semiconductor laser integrated device is a polar surface. The main surface of the gallium nitride based semiconductor substrate is the {H, 0, -H, L} plane (where H and L are natural numbers) of the gallium nitride based semiconductor crystal, and the back surface of the gallium nitride based semiconductor substrate is A {-H, 0, H, -L} plane of a gallium nitride based semiconductor crystal,
3. The semiconductor laser integrated device according to claim 1, wherein the indium composition of the second active layer is larger than the indium composition of the first active layer.   The peak wavelength of the emission wavelength of the first active layer is 430 [nm] or more and 480 [nm] or less, and the peak wavelength of the emission wavelength of the second active layer is 500 [nm] or more and 550 [nm] or less. The semiconductor laser integrated device according to claim 3, wherein the semiconductor laser integrated device is provided.   The main surface and the back surface of the gallium nitride based semiconductor substrate are inclined with respect to the c-plane of the gallium nitride based semiconductor crystal within a range of 59 ° to 80 ° or 100 ° to 121 ° in the a-axis direction. 2. The semiconductor laser integrated device according to claim 1, wherein the semiconductor laser integrated device is a polar surface. The main surface of the gallium nitride based semiconductor substrate is a {-H, -H, 2H, -L} plane (where H and L are natural numbers) of the gallium nitride based semiconductor crystal, and the gallium nitride based semiconductor substrate The back surface is the {H, H, -2H, L} plane of the gallium nitride based semiconductor crystal,
6. The semiconductor laser integrated device according to claim 1, wherein the indium composition of the second active layer is larger than the indium composition of the first active layer.   The peak wavelength of the emission wavelength of the first active layer is 430 [nm] or more and 480 [nm] or less, and the peak wavelength of the emission wavelength of the second active layer is 500 [nm] or more and 550 [nm] or less. The semiconductor laser integrated device according to claim 6, wherein the semiconductor laser integrated device is provided.   2. The optical waveguide directions of the first and second optical resonators extend along a direction in which a c-axis of a gallium nitride based semiconductor crystal is projected onto the main surface and the back surface. The semiconductor laser integrated device according to any one of? 7.   The angle formed by the optical waveguide direction of the first optical resonator and the optical waveguide direction of the second optical resonator as viewed from the normal direction of the main surface and the back surface of the gallium nitride based semiconductor substrate is 2 The semiconductor laser integrated device according to claim 1, wherein the semiconductor laser integrated device is equal to or less than 0 °. The main surface of the gallium nitride semiconductor substrate having a main surface and a back surface along the main surface, and an angle formed by the main surface and the back surface and the c-plane of the gallium nitride semiconductor crystal is 45 ° or more and 135 ° or less Epitaxially growing a first semiconductor stacked portion having a first active layer containing indium on a surface;
Forming a protective film on the first semiconductor stacked portion;
Epitaxially growing a second semiconductor stacked portion having a second active layer containing indium on the back surface of the gallium nitride based semiconductor substrate;
Forming the first optical waveguide structure in the first semiconductor stacked portion after removing the protective film, and forming the second optical waveguide structure in the second semiconductor stacked portion;
A first optical resonator having the first optical waveguide structure and a pair of resonant end faces, and a second optical waveguide structure and a pair of resonant end faces, cleaved from the gallium nitride based semiconductor substrate. Forming a second optical resonator,
A method of manufacturing a semiconductor laser integrated device, wherein an emission wavelength of the first active layer and an emission wavelength of the second active layer are different from each other.   The main surface and the back surface of the gallium nitride based semiconductor substrate are inclined with respect to the c-plane of the gallium nitride based semiconductor crystal within a range of 63 ° to 80 ° or 100 ° to 117 ° in the m-axis direction. The method of manufacturing a semiconductor laser integrated device according to claim 10, wherein the semiconductor laser integrated device is a polar surface. The main surface of the gallium nitride based semiconductor substrate is the {H, 0, -H, L} plane (where H and L are natural numbers) of the gallium nitride based semiconductor crystal, and the back surface of the gallium nitride based semiconductor substrate is A {-H, 0, H, -L} plane of a gallium nitride based semiconductor crystal,
12. The method for manufacturing a semiconductor laser integrated device according to claim 10, wherein the indium composition of the second active layer is larger than the indium composition of the first active layer.   The peak wavelength of the emission wavelength of the first active layer is 430 [nm] or more and 480 [nm] or less, and the peak wavelength of the emission wavelength of the second active layer is 500 [nm] or more and 550 [nm] or less. The method for producing a semiconductor laser integrated device according to claim 12, wherein the semiconductor laser integrated device is provided.   The main surface and the back surface of the gallium nitride based semiconductor substrate are inclined with respect to the c-plane of the gallium nitride based semiconductor crystal within a range of 59 ° to 80 ° or 100 ° to 121 ° in the a-axis direction. The method of manufacturing a semiconductor laser integrated device according to claim 10, wherein the semiconductor laser integrated device is a polar surface. The main surface of the gallium nitride based semiconductor substrate is a {-H, -H, 2H, -L} plane (where H and L are natural numbers) of the gallium nitride based semiconductor crystal, and the gallium nitride based semiconductor substrate The back surface is the {H, H, -2H, L} plane of the gallium nitride based semiconductor crystal,
15. The method for manufacturing a semiconductor laser integrated device according to claim 10, wherein the indium composition of the second active layer is larger than the indium composition of the first active layer.   The peak wavelength of the emission wavelength of the first active layer is 430 [nm] or more and 480 [nm] or less, and the peak wavelength of the emission wavelength of the second active layer is 500 [nm] or more and 550 [nm] or less. The method for manufacturing a semiconductor laser integrated device according to claim 15, wherein the method is provided.   In the step of forming the first and second optical waveguide structures, the optical waveguide direction of the first and second optical waveguide structures projects the c-axis of the gallium nitride based semiconductor crystal onto the main surface and the back surface. 17. The method of manufacturing a semiconductor laser integrated element according to claim 10, wherein the first and second optical waveguide structures are formed so as to extend along a direction.   In the step of forming the first and second optical waveguide structures, when viewed from the normal direction of the main surface and the back surface of the gallium nitride based semiconductor substrate, the optical waveguide direction of the first optical waveguide structure and the first 18. The method of manufacturing a semiconductor laser integrated device according to claim 10, wherein an angle formed by the optical waveguide directions of the two optical waveguide structures is 2 ° or less.

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