Surface emitting laser device

Abstract

To improve characteristics of a surface emitting laser device.SOLUTION: A first light reflective layer 40 and a second light reflective layer 60 are made of a material containing Al and disposed to sandwich a light production layer 30 in the Z-axis direction of the light production layer 30. The first electrode 71 is provided on the side opposite to the second light reflective layer 60 with respect to the first light reflective layer 40 and is electrically connected to the first light reflective layer 40. A second electrode 72 is electrically connected to the second light reflective layer 60. A current constriction layer 53 is disposed between the second light reflective layer 60 and the first electrode 71 and includes a passing portion 531 configured to allow a current to pass therethrough and an insulating portion 532 surrounding the passing portion 531. The first electrode 71 includes an opening 712 that overlaps with the passing portion 531 in plan view. The first light reflective layer 40 includes a first region 441 that is provided at a position overlapping with the passing portion 531 and the opening 712 in plan view and contains Zn, and a second region 442 that is provided to surround the first region 441 in plan view.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a surface emitting laser device. [Background technology]

[0002] Patent Document 1 discloses a surface-emitting laser device. This surface-emitting laser device includes a substrate made of a compound semiconductor material, and an n-type semiconductor layer, an active layer, and a p-type semiconductor layer stacked on the substrate. The n-type semiconductor layer includes an n-type light reflecting layer, and the p-type semiconductor layer includes a p-type light reflecting layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-21879 A

[0004] [overview] However, there is still room for improvement in the characteristics of surface emitting laser devices.

[0005] A surface-emitting laser device according to one embodiment of the present disclosure includes a light generating layer, a first light reflecting layer and a second light reflecting layer made of a material containing Al and arranged on either side of the light generating layer in a thickness direction of the light generating layer, a first electrode provided on the opposite side of the first light reflecting layer to the second light reflecting layer and electrically connected to the first light reflecting layer, a second electrode electrically connected to the second light reflecting layer, a current constriction layer arranged between the second light reflecting layer and the second electrode and including a passing portion configured to allow a current to pass therethrough and an insulating portion surrounding the passing portion, wherein the first electrode includes an opening overlapping with the passing portion when viewed in the thickness direction, and the first light reflecting layer includes a first region provided at a position overlapping with the passing portion and the opening when viewed in the thickness direction and including Zn, and a second region arranged to surround the first region when viewed in the thickness direction. [Brief description of the drawings]

[0006] [Figure 1]FIG. 1 is a schematic plan view of a surface emitting laser device according to one embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the surface emitting laser device taken along the line F2-F2 in FIG. [Diagram 3] FIG. 3 is a schematic cross-sectional view showing an enlarged portion of the surface-emitting laser device of FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an enlarged portion of the surface-emitting laser device of FIG. [Diagram 5] FIG. 5 is a schematic plan view showing an enlarged portion of the surface-emitting laser device of FIG. [Figure 6] FIG. 6 is a schematic cross-sectional view for explaining the operation of the surface emitting laser device of FIG. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a surface-emitting laser device of a comparative example. [Figure 8] FIG. 8 is an explanatory diagram illustrating the reflective layer in the light reflective layer. [Figure 9] FIG. 9 is an explanatory diagram illustrating the reflective layer in the light reflective layer. [Figure 10] 10A to 10C are schematic cross-sectional views showing an example of a manufacturing process for the surface emitting laser device of FIG. [Figure 11] FIG. 11 is a schematic cross-sectional view showing a manufacturing process subsequent to FIG. [Figure 12] FIG. 12 is a schematic cross-sectional view showing a manufacturing process subsequent to FIG. [Figure 13] FIG. 13 is a schematic cross-sectional view showing a manufacturing process subsequent to FIG. [Figure 14] FIG. 14 is a schematic cross-sectional view showing a manufacturing process subsequent to FIG. [Figure 15] FIG. 15 is a schematic cross-sectional view showing a manufacturing process subsequent to FIG. [Figure 16] FIG. 16 is a schematic plan view of a surface emitting laser device according to a modified example.

[0007] [Detailed Description] Hereinafter, some embodiments of the surface-emitting laser device of the present disclosure will be described with reference to the accompanying drawings. Note that for simplicity and clarity of description, components shown in the drawings are not necessarily drawn to scale. Also, hatching lines may be omitted in cross-sectional views to facilitate understanding. The accompanying drawings are merely illustrative of embodiments of the present disclosure and should not be considered as limiting the present disclosure. Terms such as "first", "second", and "third" in the present disclosure are used merely to distinguish objects and do not rank the objects.

[0008] The following detailed description includes devices, systems, and methods embodying exemplary embodiments of the present disclosure. This detailed description is merely illustrative in nature and is not intended to limit the embodiments of the present disclosure or the application and uses of such embodiments.

[0009] The term "at least one" as used herein means "one or more" of the desired options. As an example, the term "at least one" as used herein means "only one option" or "both of two options" if the number of options is two. As another example, the term "at least one" as used herein means "only one option" or "any combination of two or more options" if the number of options is three or more.

[0010] (Embodiment) (Schematic configuration of a surface emitting laser device) Fig. 1 is a schematic plan view of a surface-emitting laser device 10 according to an embodiment. Fig. 2 is a cross-sectional view of the surface-emitting laser device 10 taken along the line F2-F2 in Fig. 1. Fig. 3 is a schematic cross-sectional view showing an enlarged portion of the surface-emitting laser device 10 in Fig. 2. Fig. 4 is a schematic cross-sectional view showing an enlarged portion of the surface-emitting laser device 10 in Fig. 2. Fig. 5 is a schematic plan view showing an enlarged portion of the surface-emitting laser device 10 in Fig. 1, illustrating the relationship between the light-emitting section 51, the connection section 711 and the opening 712 of the first electrode 71, the passage section 531 of the current confinement layer 53, and the first region 441.

[0011] 1 is a semiconductor laser device called a VCSEL (Vertical Cavity Surface Emitting Laser). The surface emitting laser device 10 has a roughly rectangular parallelepiped shape. In one example, the surface emitting laser device 10 has a rectangular plate shape.

[0012] The surface-emitting laser device 10 includes a device upper surface 11, a device lower surface 12, and a plurality of device side surfaces 13, 14, 15, and 16. The device upper surface 11 and the device lower surface 12 face in opposite directions. In the present disclosure, the direction in which the device upper surface 11 faces is defined as the thickness direction. The thickness direction of the surface-emitting laser device 10 is defined as the Z-axis direction. Two axial directions perpendicular to the Z-axis direction and perpendicular to each other are defined as the X-axis direction and the Y-axis direction. The term "planar view" used in the present disclosure refers to viewing an object from the thickness direction, that is, viewing from the Z-axis direction. In one example, the surface-emitting laser device 10 is rectangular in plan view, with the length in the Y-axis direction being shorter than the length in the X-axis direction. The shape of the surface-emitting laser device 10 in plan view can be changed arbitrarily. The device side surfaces 13 and 14 face in opposite directions to each other in the X-axis direction. The device side surfaces 15 and 16 face in opposite directions to each other in the Y-axis direction.

[0013] The surface-emitting laser device 10 includes a substrate 21 and a semiconductor layer 22 . In one example, the substrate 21 includes a compound semiconductor material. The substrate 21 includes, for example, a single crystal of a compound semiconductor material that forms a tetragonal crystal. The compound semiconductor material may be a III-V group semiconductor material. The substrate 21 is, for example, made of a GaAs single crystal containing an n-type impurity. The n-type impurity may be, for example, Si (silicon). The substrate 21 includes a first substrate surface 211 and a second substrate surface 212 that face in opposite directions in the Z-axis direction. In one example, the second substrate surface 212 constitutes the device bottom surface 12.

[0014] The semiconductor layer 22 is formed on the first substrate surface 211 of the substrate 21. The semiconductor layer 22 includes a first surface 221 and a second surface 222. The first surface 221 and the second surface 222 face in opposite directions in the Z-axis direction. The first surface 221 of the semiconductor layer 22 faces the same direction as the first substrate surface 211 of the substrate 21. The second surface 222 of the semiconductor layer 22 faces the first substrate surface 211 of the substrate 21. The second surface 222 of the semiconductor layer 22 contacts the first substrate surface 211 of the substrate 21. In one example, the first surface 221 of the semiconductor layer 22 constitutes the device top surface 11.

[0015] Semiconductor layer 22 includes light generating layer 30, first light reflecting layer 40, and second light reflecting layer 60. First light reflecting layer 40 and second light reflecting layer 60 are arranged to sandwich light generating layer 30 in the Z-axis direction. In one example, first light reflecting layer 40 is arranged on the opposite side of substrate 21 with respect to light generating layer 30. In one example, second light reflecting layer 60 is arranged on the substrate 21 side with respect to light generating layer 30. In one example, second light reflecting layer 60, light generating layer 30, and first light reflecting layer 40 are stacked in this order on first substrate surface 211 of substrate 21. Semiconductor layer 22 may include an intermediate layer in contact with first substrate surface 211 of substrate 21. The intermediate layer may include, for example, a buffer layer.

[0016] The surface-emitting laser device 10 includes a first electrode 71 and a second electrode 72. In one example, the first electrode 71 is a p-side electrode, and the second electrode 72 is an n-side electrode. The first electrode 71 is provided on the opposite side of the first light reflecting layer 40 to the second light reflecting layer 60. The first electrode 71 is provided on the device upper surface 11. The first electrode 71 is electrically connected to the first light reflecting layer 40. In detail, the surface-emitting laser device 10 includes an insulating film 73 formed on the device upper surface 11, and the insulating film 73 may be formed so as to expose the peripheral portion of the device upper surface 11. The first electrode 71 is provided on the insulating film 73. The first electrode 71 may be formed so as to expose the peripheral portion of the insulating film 73. The first electrode 71 may include an external connection portion 714. The external connection portion 714 connects the surface-emitting laser device 10 to the outside, and a conductor such as a bonding wire is connected to the external connection portion 714. Note that an external terminal electrically connected to the external connection portion 714 may be provided on the external connection portion 714, and a conductor such as a bonding wire may be connected to the external terminal.

[0017] The second electrode 72 is provided on the second light reflecting layer 60 on the opposite side to the first light reflecting layer 40. The second electrode 72 may be provided on the entire lower surface 12 of the device. The surface-emitting laser device 10 includes a substrate 21. The second electrode 72 is provided on a second substrate surface 212 of the substrate 21. The second electrode 72 is electrically connected to the second light reflecting layer 60.

[0018] (Photogenerating Layer) The light generating layer 30 includes an active layer 31. The active layer 31 is disposed between the first light reflecting layer 40 and the second light reflecting layer 60 in the Z-axis direction. The active layer 31 is a light emitting layer that emits light when a current is supplied thereto. In one example, the active layer 31 may have a QW (Quantum Well) structure including a quantum well layer and a barrier layer. The active layer 31 may have an MQW (Multi Quantum Well) structure in which quantum well layers and barrier layers are alternately stacked at any period. The quantum well layer may include GaAs (Gallium Arsenide), AlGaAs (Aluminum Gallium Arsenide), or InGaAs (Indium Gallium Arsenide). The quantum well layer may be undoped. The barrier layer may have a band gap larger than the band gap of the quantum well layer.

[0019] The light generating layer 30 may include a first cladding layer 32 and a second cladding layer 33. The first cladding layer 32 and the second cladding layer 33 are arranged to sandwich the active layer 31. The first cladding layer 32 is arranged on the first light reflecting layer 40 side with respect to the active layer 31. The first cladding layer 32 may include an impurity of a first conductivity type. The first conductivity type is, for example, p-type. The impurity of the first conductivity type may be, for example, C (carbon). The second cladding layer 33 is arranged on the second light reflecting layer 60 side with respect to the active layer 31. The second cladding layer 33 may include an impurity of a second conductivity type. The second conductivity type is, for example, n-type. The impurity of the second conductivity type may be, for example, Si (silicon).

[0020] The first cladding layer 32 and the second cladding layer 33 may contain Al. In one example, the first cladding layer 32 and the second cladding layer 33 contain AlGaAs. The first cladding layer 32 contains Alα1Ga(1-α1)As having an Al composition α1. The Al composition α1 may be 0.2 or more and 0.7 or less. The second cladding layer 33 contains Alα2Ga(1-α2)As having an Al composition α2. The Al composition α2 may be 0.2 or more and 0.7 or less. The Al compositions of the first cladding layer 32 and the second cladding layer 33 may be the same as each other or different from each other.

[0021] (First light reflecting layer and second light reflecting layer) The first light reflecting layer 40 is composed of a DBR layer (Distributed Bragg Reflector). The first light reflecting layer 40 may contain p-type impurities, which are a first conductive type. The first conductive type impurities may be, for example, C. The first light reflecting layer 40 has a refractive index that changes periodically along the Z-axis direction, and resonantly reflects a specific wavelength component. It can be said that the first light reflecting layer 40 has a reflectance that reflects a specific wavelength component.

[0022] The second light reflecting layer 60 is composed of a DBR layer. The second light reflecting layer 60 may contain n-type impurities, which are the second conductive type. The second conductive type impurities may be, for example, Si. The second light reflecting layer 60 has a refractive index that changes periodically along the Z-axis direction, and resonantly reflects a specific wavelength component. It can be said that the second light reflecting layer 60 has a reflectance that reflects a specific wavelength component.

[0023] The reflectance of the first light reflecting layer 40 and the reflectance of the second light reflecting layer 60 may be different from each other. In one example, the reflectance of the second light reflecting layer 60 is higher than the reflectance of the first light reflecting layer 40. The reflectance of the first light reflecting layer 40 and the reflectance of the second light reflecting layer 60 may be the same.

[0024] (Isolation groove and light-emitting part) Semiconductor layer 22 includes separation groove 52. The number of separation grooves 52 may be one or more than one. In one example, semiconductor layer 22 includes a plurality of separation grooves 52. Separation groove 52 is formed to be recessed from first surface 221 of semiconductor layer 22 toward second surface 222 of semiconductor layer 22. In one example, separation groove 52 passes through first surface 221 of semiconductor layer 22, first light reflecting layer 40 and light generating layer 30, and reaches second light reflecting layer 60. As shown in FIG. 1 and FIG. 5, separation groove 52 is annular in plan view. In one example, separation groove 52 is annular. The shape of separation groove 52 in plan view may be any shape, such as a polygonal shape, an elliptical shape, or the like.

[0025] 2, separation groove 52 includes inner circumferential surface 521, outer circumferential surface 522, and bottom surface 523 connecting inner circumferential surface 521 and outer circumferential surface 522. First light reflecting layer 40 and light generating layer 30 are exposed at inner circumferential surface 521 and outer circumferential surface 522 of separation groove 52. A portion of second light reflecting layer 60 is exposed at inner circumferential surface 521 and outer circumferential surface 522 of separation groove 52. Second light reflecting layer 60 is exposed at bottom surface 523 of separation groove 52.

[0026] 1 and 2, the semiconductor layer 22 includes a light emitting portion 51 surrounded by an isolation trench 52. The light emitting portion 51 may be partitioned into a plateau shape (mesa shape) by the isolation trench 52. The light emitting portion 51 may have any shape, such as a cylindrical shape. As shown in FIG. 1, the semiconductor layer 22 may include a plurality of light emitting portions 51.

[0027] The light emitting sections 51 are arranged at intervals from each other in the X-axis direction and the Y-axis direction in a plan view. In one example, the light emitting sections 51 are arranged in a staggered manner in a plan view. In particular, the light emitting sections 51 are arranged such that one light emitting section 51 is located at each of the three vertices of a triangle (for example, an equilateral triangle) in a plan view. It can also be said that the light emitting sections 51 are arranged such that one light emitting section 51 is located at each of the six vertices of a hexagon (for example, a regular hexagon) in a plan view. The light emitting sections 51 can be arranged in any manner, such as in a matrix or radial (concentric) pattern.

[0028] 2, light-emitting section 51 includes light-emitting section surface 511 constituting part of first surface 221 of semiconductor layer 22. Light-emitting section 51 also includes light-emitting section side surface 512 constituting separation groove 52. Light-emitting section side surface 512 is constituted by inner circumferential surface 521 of separation groove 52. Separation groove 52 extends from first surface 221 to partway through second light reflecting layer 60 in semiconductor layer 22. Therefore, light-emitting section side surface 512 is considered to be constituted by the side surfaces of first light reflecting layer 40 and light generating layer 30, and a part of the side surface of second light reflecting layer 60.

[0029] (Current confinement layer) As shown in FIG. 2, the light emitting section 51 may include a current confinement layer 53. The current confinement layer 53 is disposed between the first electrode 71 and the second light reflecting layer 60. The current confinement layer 53 is disposed between the first surface 221 of the semiconductor layer 22 and the second light reflecting layer 60. The current confinement layer 53 may be disposed between the light emitting section surface 511 and the light generating layer 30. In one example, the current confinement layer 53 is disposed in the first light reflecting layer 40. The current confinement layer 53 may be configured to constrict the current path of the light emitting section 51 in the Z-axis direction.

[0030] The current confinement layer 53 includes a passing portion 531 and an insulating portion 532. The passing portion 531 is made of a material containing Al. In one example, the passing portion 531 is made of Al having an Al composition γ. γ Ga (1-γ) The passing portion 531 is made of a material containing As. The Al composition γ may be 0.95 or more and 1.00 or less. The passing portion 531 may contain an impurity of the first conductivity type.

[0031] 5, the passing portion 531 is disposed in an inner region of the light-emitting portion 51. In one example, the passing portion 531 is disposed in the center of the light-emitting portion 51 in a plan view. In one example, the passing portion 531 may have a circular shape in a plan view. The diameter of the passing portion 531 may be 5 μm or more and 20 μm or less.

[0032] The insulating portion 532 is formed so as to surround the passing portion 531. The insulating portion 532 may be composed of an oxide layer. In one example, the insulating portion 532 includes an oxide layer containing Al. The oxide layer containing Al is, for example, Al 2 O 3 (alumina). The oxide layer may contain Ga or As. The insulating portion 532 is disposed on the side of the light-emitting portion side surface 512 of each light-emitting portion 51 with respect to the passing portion 531. For example, the insulating portion 532 is made of Al γ Ga (1-γ) The insulating portion 532 is formed by oxidizing the periphery of the layer containing As. In one example, the insulating portion 532 can be formed by performing a heat treatment in water vapor.

[0033] (insulating film) 2, the surface-emitting laser device 10 may include an insulating film 73 that covers the first surface 221 of the semiconductor layer 22. The insulating film 73 may be, for example, SiO 2 , silicon oxide such as SiO, SiN (silicon nitride), SiON, ZrO 2 (zirconium oxide) or TiO (titanium oxide). In one example, the insulating film 73 is a SiN film.

[0034] The semiconductor layer 22 includes an isolation trench 52 and a light emitting portion 51 surrounded by the isolation trench 52. The insulating film 73 covers a light emitting portion surface 511 and a light emitting portion side surface 512 of the light emitting portion 51. The insulating film 73 also covers an outer circumferential surface 522 and a bottom surface 523 of the isolation trench 52.

[0035] The insulating film 73 includes an opening 731 that exposes a portion of the light-emitting portion surface 511 of the light-emitting portion 51. The opening 731 of the insulating film 73 is formed so as to surround the passing portion 531 in a planar view. The opening 731 may be formed in an annular shape in a planar view. In one example, the opening 731 may be annular. The insulating film 73 includes a covering portion 732 in a region located inward from the opening 731. The covering portion 732 is circular in a planar view. The covering portion 732 overlaps with the insulating portion 532 of the current confinement layer 53 in a planar view.

[0036] (1st electrode) 2, the first electrode 71 covers the insulating film 73. The first electrode 71 may include a plurality of electrode films. The first electrode 71 may be composed of a single electrode film. The first electrode 71 may include, for example, Au (gold), Ti (titanium), or Pt (platinum). In one example, the first electrode 71 is composed of a stack of a Ti layer, a Pt layer, and an Au layer.

[0037] The first electrode 71 includes a connection portion 711 in the opening 731 of the insulating film 73. The connection portion 711 is electrically connected to the first light reflecting layer 40. Therefore, the first electrode 71 is electrically connected to the first light reflecting layer 40.

[0038] The first electrode 71 includes an opening 712 that selectively exposes a portion of the covering portion 732 of the insulating film 73. The opening 712 of the first electrode 71 is provided at a position overlapping with the passing portion 531 of the current confinement layer 53 in a planar view. As shown in Fig. 5, the opening 712 of the first electrode 71 has a circular shape in a planar view. The shape of the opening 712 of the first electrode 71 in a planar view can be any shape, such as a polygonal shape or an elliptical shape.

[0039] The second electrode 72 covers the second substrate surface 212 of the substrate 21. The second electrode 72 forms an ohmic contact with the second substrate surface 212 of the substrate 21. The second electrode 72 may include a plurality of electrode films. The second electrode 72 may be composed of one electrode film. The first electrode 71 may include, for example, Ni (nickel), Au, Ge (germanium), Ti, In (indium), Zn (zinc), etc. In one example, the first electrode 71 is composed of a stack of an AuGe layer, a Ni layer, and an Au layer.

[0040] (Layer configuration of first light reflective layer and second light reflective layer) As shown in FIG. 3, the first light reflective layer 40 includes a plurality of first reflective layers 41 and a plurality of second reflective layers 42. The plurality of first light reflective layers 40 and the plurality of second reflective layers 42 are alternately arranged in the Z-axis direction. The first reflective layer 41 and the second reflective layer 42 are made of a material containing Al. In one example, the first reflective layer 41 and the second reflective layer 42 contain AlGaAs. The first reflective layer 41 and the second reflective layer 42 have different Al compositions. The first reflective layer 41 is made of Al having an Al composition β1. β1 Ga (1-β1) The first reflective layer 41 may have an Al composition β1 of 0.70 or more and 0.97 or less. The second reflective layer 42 may have an Al composition β2 of β2 Ga (1-β2) The second reflective layer 42 includes As. The Al composition β2 of the second reflective layer 42 may be greater than 0 and equal to or less than 0.2. The refractive index of a reflective layer including AlGaAs decreases as the Al composition increases. Therefore, the first reflective layer 41 and the second reflective layer 42 have different refractive indices.

[0041] The second light reflective layer 60 includes a plurality of third reflective layers 61 and a plurality of fourth reflective layers 62. The plurality of third reflective layers 61 and the plurality of fourth reflective layers 62 are alternately arranged in the Z-axis direction. The third reflective layer 61 and the fourth reflective layer 62 are made of a material containing Al. In one example, the first reflective layer 41 and the second reflective layer 42 contain AlGaAs. The third reflective layer 61 and the fourth reflective layer 62 have different Al compositions. The third reflective layer 61 is made of Al having an Al composition β3. β3 Ga (1-β3) The third reflective layer 61 may have an Al composition β3 of 0.70 or more and 0.97 or less. The fourth reflective layer 62 may have an Al composition β4 of β4 Ga (1-β4) The fourth reflective layer 62 includes As. The Al composition β4 of the fourth reflective layer 62 may be greater than 0 and equal to or less than 0.2. The refractive index of a reflective layer including AlGaAs decreases as the Al composition increases. Therefore, the third reflective layer 61 and the fourth reflective layer 62 have mutually different refractive indices.

[0042] The number of layers of the first reflective layer 41 and the second reflective layer 42 included in the first light reflective layer 40 may be different from the number of layers of the third reflective layer 61 and the fourth reflective layer 62 included in the second light reflective layer 60. In one example, the number of layers of the third reflective layer 61 and the fourth reflective layer 62 included in the second light reflective layer 60 is greater than the number of layers of the first reflective layer 41 and the second reflective layer 42 included in the first light reflective layer 40.

[0043] (Area of ​​the first light-reflecting layer) As shown in FIG. 3 and FIG. 5, the first light reflecting layer 40 includes a first region 441 and a second region 442. The first region 441 is provided at a position overlapping the opening 712 of the first electrode 71 in a plan view. The opening 712 of the first electrode 71 is provided at a position overlapping the passing portion 531 of the current confinement layer 53 in a plan view. Therefore, it can be said that the first region 441 is provided at a position overlapping the passing portion 531 of the current confinement layer 53 in a plan view. And, it can be said that the first region 441 is provided at a position overlapping the passing portion 531 of the current confinement layer 53 and the opening 712 of the first electrode 71 in a plan view. The first region 441 is provided at the center of the light emitting portion 51 in a plan view. The second region 442 is provided so as to surround the first region 441 in a plan view.

[0044] 5, the first region 441 has a circular shape in a plan view. As shown in Fig. 3, the shape of the first region 441 in a plane passing through the center of the light emitting section 51 may be a semicircular shape. In one example, the first region 441 is a hemispherical region extending from the light emitting section surface 511 of the light emitting section 51 toward the passing section 531 of the current confinement layer 53.

[0045] As shown in FIG. 3 and FIG. 4, the first region 441 may be in contact with the connection portion 711 of the first electrode 71. The first region 441 may overlap the connection portion 711 of the first electrode 71 in a plan view. It can be said that the boundary portion 81 between the first region 441 and the second region 442 is disposed at a position overlapping the connection portion 711 of the first electrode 71 in a plan view. The boundary portion 81 may be, for example, a boundary portion on the light-emitting portion surface 511 of the light-emitting portion 51. The boundary portion 81 may be set in the first light reflecting layer 40 in the Z-axis direction. In one example, the first region 441 overlaps the entire connection portion 711 of the first electrode 71 in a plan view. It can be said that the boundary portion 81 between the first region 441 and the second region 442 is disposed at a position overlapping the outer end portion of the connection portion 711 of the first electrode 71 in a plan view. It can be said that the connection portion 711 of the first electrode 71 is electrically connected to the first region 441 of the first light reflecting layer 40. In plan view, the boundary portion 81 between the first region 441 and the second region 442 may be disposed outside the connection portion 711 of the first electrode 71.

[0046] The first region 441 is a region containing Zn (zinc). In one example, the first region 441 is a diffusion region in which Zn is diffused. The first region 441 may be a region configured such that the concentration of Zn decreases from the center O1 of the light-emitting portion surface 511 of the light-emitting portion 51 toward the periphery.

[0047] On the other hand, the second region 442 is a region that does not substantially contain Zn. Substantially not containing Zn means that Zn is not intentionally contained in the target object. The carrier concentration in the second region 442 is lower than the carrier concentration in the first region 441. The second region 442 may be a non-carrier region.

[0048] Therefore, the first region 441 can be said to be a region having a higher concentration of first conductivity type impurities than the second region 442. Also, the first region 441 can be said to be a region having a lower resistance value than the second region 442.

[0049] 4, the first light reflecting layer 40 may include a high concentration region 451 and a low concentration region 452. The high concentration region 451 and the low concentration region 452 are regions in which the carrier concentration is relatively high and low. In the Z-axis direction, the low concentration region 452 is provided between the high concentration region 451 and the first electrode 71. It can be said that the high concentration region 451 is disposed closer to the light generating layer 30 than the low concentration region 452 in the Z-axis direction. It can be said that the low concentration region 452 is disposed closer to the light emitting portion surface 511 of the light emitting portion 51 in the Z-axis direction.

[0050] The low concentration region 452 has a lower carrier concentration than the high concentration region 451. The high concentration region 451 is a region doped with C as a carrier. The carrier concentration of the high concentration region 451 is 1×10 17 cm -3 More than 1×10 19 cm -3 The low concentration region 452 may be a region doped with C as a carrier. The low concentration region 452 may be a non-carrier region not doped with C.

[0051] In the Z-axis direction, a thickness T1 of the high-concentration region 451 may be greater than a thickness T2 of the low-concentration region 452. The high-concentration region 451 and the low-concentration region 452 each include a first reflective layer 41 and a second reflective layer 42. The number of layers of the first reflective layer 41 and the second reflective layer 42 included in the high-concentration region 451 is greater than the number of layers of the first reflective layer 41 and the second reflective layer 42 included in the low-concentration region 452.

[0052] The first region 441 and the second region 442 of the first light reflecting layer 40 are formed in a low concentration region 452. In the low concentration region 452 containing C as an impurity, the first region 441 is a region containing C and Zn. Zn is a p-type impurity. In one example, the first region 441 may be a region containing C and Zn as carriers. In one example, the carrier concentration at the bottom end 441B of the first region 441 is 1.0×10 18 cm -3 The carrier concentration of the first region 441 may be about the same as the carrier concentration of the high concentration region 451. In one example, the carrier concentration at the lower end 441B of the first region 441 may be equal to the carrier concentration of the high concentration region 451. On the other hand, the second region 442 can be said to be a region that contains C and does not contain Zn.

[0053] (composition gradient, impurity concentration) The first light reflecting layer 40 is composed of a plurality of first reflecting layers 41 and a plurality of second reflecting layers 42 arranged alternately in the Z-axis direction. The first reflecting layers 41 and the second reflecting layers 42 are formed by, for example, a metal organic chemical vapor deposition (MOCVD) method.

[0054] The first light reflective layer 40 includes a first region 441 containing Zn and a second region 442 surrounding the first region 441. In the first region 441, the first reflective layer 41 and the second reflective layer 42 containing Zn may include a composition gradient of Al composition. The composition gradient means that the Al composition of the first reflective layer 41 and the second reflective layer 42 containing AlGaAs gradually increases or decreases in the Z-axis direction. FIG. 9 shows the first reflective layer 41 and the second reflective layer 42 of the first light reflective layer 40.

[0055] 9 shows a part of the first light reflecting layer 40, the first reflecting layer 41 and the second reflecting layer 42 included in the second region 442. The first reflecting layer 41 and the second reflecting layer 42 have a configuration in which the Al composition does not change in the Z-axis direction. The interface 822 between the first reflecting layer 41 and the second reflecting layer 42 is clear and distinct.

[0056] Fig. 8 shows a part of the first light reflecting layer 40, including a boundary portion 81 between the first region 441 and the second region 442. The density of the dot hatching in Fig. 8 indicates the magnitude of the Al composition.

[0057] The first light reflecting layer 40 includes a first reflecting layer 41 and a second reflecting layer 42. The first reflecting layer 41 includes a first portion 411 included in the first region 441 and a second portion 412 included in the second region 442. The second reflecting layer 42 includes a third portion 421 included in the first region 441 and a fourth portion 422 included in the second region 442. The second portion 412 of the first reflecting layer 41 and the fourth portion 422 of the second reflecting layer 42 included in the second region 442 have a uniform Al composition in the Z-axis direction. The interface 822 between the second portion 412 of the first reflecting layer 41 and the fourth portion 422 of the second reflecting layer 42 is clear and distinct. It can be said that the interface 822 exists between the first reflecting layer 41 and the second reflecting layer 42 in the second region 442 of the first light reflecting layer 40.

[0058] On the other hand, the first portion 411 of the first reflective layer 41 included in the first region 441 has an Al composition that gradually decreases in the Z-axis direction toward the third portion 421 of the second reflective layer 42. Also, the third portion 421 of the second reflective layer 42 included in the first region 441 has an Al composition that gradually increases in the Z-axis direction toward the first portion 411 of the first reflective layer 41. For this reason, the interface 821 between the first portion 411 of the first reflective layer 41 and the third portion 421 of the second reflective layer 42 is blurred more than the interface 822 between the second portion 412 of the first reflective layer 41 and the fourth portion 422 of the second reflective layer 42. It can be said that the interface 821 between the first portion 411 of the first reflective layer 41 and the third portion 421 of the second reflective layer 42 is unclear. In the first region 441, the first reflective layer 41 (first portion 411) and the second reflective layer 42 (third portion 421) adjacent to each other in the Z-axis direction may be partially mixed together, and the interface 821 may not exist in some places. It can be said that the first region 441 includes a portion where the interface 821 between the first portion 411 of the first reflective layer 41 and the third portion 421 of the second reflective layer 42 does not exist.

[0059] As described above, the first portion 411 of the first reflective layer 41 and the third portion 421 of the second reflective layer 42 included in the first region 441 have a composition gradient. As a result, the first portion 411 of the first reflective layer 41 and the third portion 421 of the second reflective layer 42 in the first region 441 have a lower electrical resistance than the second portion 412 of the first reflective layer 41 and the fourth portion 422 of the second reflective layer 42 in the second region 442 which do not have a composition gradient.

[0060] The interface 822 between the second portion 412 of the first reflective layer 41 and the fourth portion 422 of the second reflective layer 42 included in the second region 442 is clear. The refractive index of the second portion 412 and the refractive index of the fourth portion 422 are different from each other. For this reason, it can be said that the second portion 412 and the fourth portion 422 easily reflect light.

[0061] On the other hand, an interface 821 between the first portion 411 of the first reflective layer 41 and the third portion of the second reflective layer 42 included in the first region 441 is blurred more than an interface 822 between the second portion 412 of the first reflective layer 41 and the fourth portion 422 of the second reflective layer 42 included in the second region 442. Therefore, it can be said that the first portion 411 and the third portion 421 are less likely to reflect light than the second portion 412 and the fourth portion 422. Also, it can be said that the first portion 411 and the third portion 421 are more likely to transmit light than the second portion 412 and the fourth portion 422. In other words, the first portion 411 transmits light more easily than the second portion 412.

[0062] In the first region 441, the Zn concentration decreases from the center O1 of the light-emitting portion surface 511 of the light-emitting portion 51 toward the second region 442 in a plan view. The Zn concentration also decreases in the Z-axis direction from the light-emitting portion surface 511 of the light-emitting portion 51 toward the current confinement layer 53. For this reason, in the first region 441, the reflectance near the center O1 of the light-emitting portion surface 511 of the light-emitting portion 51 is lower than the reflectance of the peripheral portion in a plan view. Therefore, light passing through the first region 441 formed in a hemispherical shape toward the current confinement layer 53 is likely to be emitted from near the center O1 of the light-emitting portion surface 511 of the light-emitting portion 51.

[0063] The first region 441 contains more Zn than the second region 442. Zn is a p-type impurity, similar to C, which is an impurity contained in the first light reflecting layer 40. Therefore, the first region 441 containing Zn has a lower electrical resistance than the second region 442 not containing Zn.

[0064] The high concentration region 451 may have a composition gradient. The high concentration region 451 includes a first reflective layer 41 and a second reflective layer 42. The first reflective layer 41 and the second reflective layer 42 are formed by MOCVD. The composition gradient of the first reflective layer 41 and the second reflective layer 42 is obtained by adjusting the flow rate of an organic metal gas when the first reflective layer 41 and the second reflective layer 42 are formed by MOCVD. The high concentration region 451 including the first reflective layer 41 and the second reflective layer 42 having a composition gradient has low electrical resistance, similar to the first region 441.

[0065] The high concentration region 451 contains more C, which is a first conductivity type impurity, than the low concentration region 452. Therefore, the high concentration region 451 has a lower electrical resistance than the low concentration region 452. High concentration region 451 contains C as an impurity. First region 441 mainly contains C and Zn as impurities. The impurity concentration in high concentration region 451 may be equal to the impurity concentration at bottom end 441B of first region 441. Therefore, it can be said that the electrical resistance of high concentration region 451 is equal to the electrical resistance at bottom end 441B of first region 441. In this disclosure, "having the same impurity concentration" and "having the same electrical resistance" refer to a difference being within the range of manufacturing variation (e.g., 20%).

[0066] Second light reflecting layer 60 may or may not have a composition gradient. First cladding layer 32 and second cladding layer 33 of light generating layer 30 may or may not have a composition gradient. The composition gradient of second light reflecting layer 60, first cladding layer 32, and second cladding layer 33 is obtained similarly to the composition gradient in high concentration region 451 of first light reflecting layer 40. For example, third reflecting layer 61 and fourth reflecting layer 62 of second light reflecting layer 60 are formed by MOCVD. The composition gradient of third reflecting layer 61 and fourth reflecting layer 62 is obtained by adjusting the flow rate of metal organic gas when forming third reflecting layer 61 and fourth reflecting layer 62 by MOCVD.

[0067] (Method of manufacturing a surface-emitting laser device) Next, an example of a method for manufacturing the surface emitting laser device 10 shown in FIGS. 1 to 5 will be described. Figures 10 to 15 are schematic cross-sectional views showing exemplary manufacturing steps of the surface-emitting laser device 10. Figures 10 to 15 correspond to the cross-sectional structure of the surface-emitting laser device 10 shown in Figure 2. For ease of understanding, in Figures 10 to 15, the same reference numerals as in Figure 2 are used for components that are the same as the final components of the surface-emitting laser device 10.

[0068] As shown in FIG. 10, the method for manufacturing the surface-emitting laser device 10 includes forming a semiconductor layer 22 on a substrate 21. First, a substrate 21 is prepared. The substrate 21 may be in a wafer state. The substrate 21 may be in a wafer state for forming a plurality of surface-emitting laser devices 10.

[0069] The substrate 21 includes a first substrate surface 211 and a second substrate surface 212 that face in opposite directions in the Z-axis direction. Semiconductor layer 22 is formed on first substrate surface 211 of substrate 21. Semiconductor layer 22 includes second light reflecting layer 60, light generating layer 30, and first light reflecting layer 40. Second light reflecting layer 60, light generating layer 30, and first light reflecting layer 40 are sequentially stacked on substrate 21 to form semiconductor layer 22. Second light reflecting layer 60, light generating layer 30, and first light reflecting layer 40 are formed by MOCVD.

[0070] 11, the method for manufacturing the surface-emitting laser device 10 includes forming the first region 441. The first region 441 can be formed by, for example, a diffusion method. First, a supply source 90 is disposed on the first light reflecting layer 40. The supply source 90 is, for example, zinc oxide (ZnO 2 ) can be used. The supply source 90 can be formed by, for example, a sputtering method or a plasma CVD method. Next, Zn is diffused from the supply source 90 into the first light reflecting layer 40 by a diffusion method to form the first region 441.

[0071] 12, the method for manufacturing surface-emitting laser device 10 includes forming separation groove 52 in semiconductor layer 22. Separation groove 52 is formed deeper than light generating layer 30. Separation groove 52 is formed by selectively removing first light reflecting layer 40, light generating layer 30, and second light reflecting layer 60 by, for example, dry etching. Separation groove 52 forms a mesa portion that becomes light emitting portion 51. Light emitting portion 51 includes a light emitting portion surface 511 and a light emitting portion side surface 512.

[0072] 13, the method for manufacturing the surface-emitting laser device 10 includes forming the current confinement layer 53. The current confinement layer 53 is formed by a heat treatment in water vapor. 14, the method for manufacturing the surface-emitting laser device 10 includes forming an insulating film 73. The insulating film 73 is formed by, for example, a CVD method. The insulating film 73 is formed so as to cover the surfaces of the first light reflecting layer 40, the light generating layer 30, and the second light reflecting layer 60.

[0073] The manufacturing method of the surface-emitting laser device 10 includes forming an opening 731 in the insulating film 73. The opening 731 in the insulating film 73 is formed by selectively removing a portion covering the light-emitting surface 511 by, for example, an etching method (for example, wet etching). A part of the light-emitting surface 511 is exposed from the opening 731 in the insulating film 73.

[0074] 15, the method for manufacturing the surface-emitting laser device 10 includes forming a first electrode 71. The first electrode 71 is formed by a deposition method, a sputtering method, or the like. The manufacturing method of the surface-emitting laser device 10 includes forming an opening 712 in the first electrode 71. The opening 712 is formed by selectively removing a portion of the first electrode 71 that covers the light-emitting portion surface 511 of the light-emitting portion 51, for example, by an etching method (for example, wet etching).

[0075] The manufacturing method of the surface-emitting laser device 10 includes forming the second electrode 72. The second electrode 72 is formed on the second substrate surface 212 of the substrate 21. The second electrode 72 is formed by a deposition method, a sputtering method, or the like. The second electrode 72 may be formed prior to the first electrode 71. Also, the second electrode 72 may be formed prior to a step of forming an opening in the first electrode 71.

[0076] (Operation of the embodiment) Next, the operation of the surface emitting laser device 10 will be described. When a predetermined voltage is applied between the first electrode 71 and the second electrode 72, a driving current flows from the first electrode 71 to the second electrode 72 in the surface-emitting laser device 10. The driving current is confined by the insulating portion 532 of the current confinement layer 53, passes through the passing portion 531, and is supplied to the active layer 31 of the light generation layer 30. In the active layer 31, light is generated by the supplied driving current. This light is reflected by the first light reflecting layer 40 and the second light reflecting layer 60, and is amplified by resonance. The amplified light passes through the opening 712 of the first electrode 71 and is emitted as laser light to the outside of the surface-emitting laser device 10.

[0077] Here, a surface-emitting laser device 10X of a comparative example will be described. Note that, in the surface-emitting laser device 10X of the comparative example, the same members as those in the surface-emitting laser device 10 described above will be described using the same reference numerals.

[0078] 7 is a schematic cross-sectional view showing a surface-emitting laser device 10X of a comparative example. The surface-emitting laser device 10X of the comparative example is different from the surface-emitting laser device 10 of the embodiment in the configuration of the first light reflecting layer 40X. The first light reflecting layer 40X of the comparative example does not contain Zn, that is, there is no distinction between the first region 441 and the second region 442 shown in FIG. 3 and FIG. 4. Moreover, the first light reflecting layer 40X has no distinction between the high-concentration region 451 and the low-concentration region 452 shown in FIG. 3 and FIG. 4.

[0079] As shown in FIG. 7, in the surface-emitting laser device 10X of the comparative example, the driving current Id flows from the connection portion 711 of the first electrode 71 arranged outside the passing portion 531 of the current confinement layer 53 toward the passing portion 531 of the current confinement layer 53. As a result, current concentration occurs at the inner end of the insulating portion 532. That is, in the current confinement layer 53, the current density is higher in the portion close to the insulating portion 532 than in the center portion of the passing portion 531. Therefore, the efficiency of current injection into the vicinity of the center of the active layer 31 decreases. In addition, in the active layer 31, light is likely to be generated in the portion 84 close to the insulating portion 532 in a plan view. Therefore, the laser light L1X emitted from the surface-emitting laser device 10X of the comparative example passes through the opening 712 of the first electrode 71 and is emitted in a widened manner as shown by the white arrow. In order to increase the output of the laser light, it is considered to increase the driving current and enlarge the passing portion 531 of the current confinement layer 53. In this case, the current is concentrated at the end of the current confinement layer 53, and the spread of the laser light becomes larger.

[0080] FIG. 6 is a schematic cross-sectional view showing a surface-emitting laser device 10 of the embodiment. The surface-emitting laser device 10 of the embodiment includes a first region 441 arranged in the first light reflecting layer 40 so as to overlap the passing portion 531 of the current confinement layer 53 and the opening 712 of the first electrode 71, and a second region 442 surrounding the first region 441. The first region 441 contains Zn and has a lower electrical resistance than the second region 442. The first region 441 is a region formed in a hemispherical shape from the light-emitting portion surface 511 of the light-emitting portion 51 toward the passing portion 531 of the current confinement layer 53. Therefore, in the first region 441, the driving current Id flows from the connection portion 711 of the first electrode 71 toward the center of the light-emitting portion 51. The driving current Id passes from the first region 441 through the high concentration region 451 and the passing portion 531 of the current confinement layer 53, and is supplied to the active layer 31 of the light generating layer 30. The driving current Id also easily passes through the central portion of the passing portion 531 of the current confinement layer 53, and current concentration near the end of the insulating portion 532 can be alleviated, thereby reducing variation in current density at the passing portion 531. Therefore, the surface-emitting laser device 10 of the embodiment can improve the efficiency of current injection into the active layer 31 of the light generating layer 30 through the passing portion 531 of the current confinement layer 53. As a result, the light output characteristic of the surface-emitting laser device 10 with respect to the driving current Id can be improved.

[0081] In the active layer 31, light is easily generated in the entire range 83 overlapping with the passing portion 531 of the current confinement layer 53. In the surface-emitting laser device 10 of the embodiment, the laser light L1 is emitted along the Z-axis direction from the center of the light-emitting portion 51. When the passing portion 531 of the current confinement layer 53 is enlarged, light is generated in a portion of the active layer 31 according to the size of the passing portion 531, and therefore the laser light can be made high-power.

[0082] The first region 441 of the first light reflecting layer 40 is provided at a position overlapping the opening 712 of the first electrode 71 through which light passes in a plan view. The first region 441 is formed in a hemispherical shape, and the reflectance in the center portion is lower than that in the peripheral portion. Therefore, in the surface-emitting laser device 10 of the embodiment, the laser light is emitted from the center portion of the first region 441, that is, the center of the light-emitting section 51, along the Z-axis direction. In addition, in the first region 441, the concentration of Zn decreases from the center portion toward the boundary between the first region 441 and the second region 442. That is, in the first region 441, the concentration of Zn decreases concentrically with respect to the center O1 in a plan view. Therefore, in the first region 441, the same effect as a hemispherical lens is obtained, so that the radiation angle of the emitted laser light can be narrowed. As a result, the surface-emitting laser device 10 of the embodiment can improve the directivity of the emitted laser light.

[0083] (Effects of the embodiment) As described above, according to this embodiment, the following effects are achieved. (1) The surface-emitting laser device 10 includes a light generating layer 30, a first light reflecting layer 40 and a second light reflecting layer 60, a first electrode 71 and a second electrode 72, and a current narrowing layer 53. The first light reflecting layer 40 and the second light reflecting layer 60 are made of a material containing Al, and are arranged to sandwich the light generating layer 30 in the Z-axis direction of the light generating layer 30. The first electrode 71 is provided on the opposite side of the first light reflecting layer 40 to the second light reflecting layer 60, and is electrically connected to the first light reflecting layer 40. The second electrode 72 is electrically connected to the second light reflecting layer 60. The current narrowing layer 53 is arranged between the second light reflecting layer 60 and the second electrode 72, and includes a passing portion 531 configured to allow a current to pass therethrough, and an insulating portion 532 surrounding the passing portion 531. The first electrode 71 includes an opening 712 that overlaps with the passing portion 531 in a plan view. The first light reflecting layer 40 includes a first region 441 that is provided at a position overlapping with the passing portion 531 and the opening 712 in a planar view and contains Zn, and a second region 442 that is provided to surround the first region 441 in a planar view.

[0084] The driving current Id also easily passes through the central portion of the passing portion 531 of the current confinement layer 53, and current concentration near the end of the insulating portion 532 can be alleviated, thereby reducing variation in current density at the passing portion 531. Therefore, the surface-emitting laser device 10 of the embodiment can improve the efficiency of current injection into the active layer 31 of the light generating layer 30 through the passing portion 531 of the current confinement layer 53. As a result, the light output characteristic of the surface-emitting laser device 10 with respect to the driving current Id can be improved.

[0085] (2) In the active layer 31, light is easily generated in the entire range 83 overlapping with the passing portion 531 of the current confinement layer 53. In the surface-emitting laser device 10 of the embodiment, the laser light L1 is emitted along the Z-axis direction from the center of the light-emitting portion 51. When the passing portion 531 of the current confinement layer 53 is enlarged, light is generated in a portion of the active layer 31 according to the size of the passing portion 531, and therefore the laser light can be made high-power.

[0086] (3) The first region 441 of the first light reflecting layer 40 is provided at a position overlapping the opening 712 of the first electrode 71 through which light passes in a plan view. The first region 441 is formed in a hemispherical shape, and the reflectance in the center portion is lower than that in the peripheral portion. Therefore, in the surface-emitting laser device 10 of the embodiment, the laser light is emitted from the center portion of the first region 441, that is, the center of the light-emitting section 51, along the Z-axis direction. In addition, in the first region 441, the concentration of Zn decreases from the center portion toward the boundary between the first region 441 and the second region 442. That is, in the first region 441, the concentration of Zn decreases concentrically with respect to the center O1 in a plan view. Therefore, in the first region 441, the same effect as a hemispherical lens is obtained, so that the radiation angle of the emitted laser light can be narrowed. As a result, the surface-emitting laser device 10 of the embodiment can improve the directivity of the emitted laser light.

[0087] (4) The first region 441 contains more Zn than the second region 442. Zn is a p-type impurity, similar to C, which is an impurity contained in the first light reflecting layer 40. The first region 441 containing Zn has a lower electrical resistance than the second region 442 not containing Zn. This makes it possible to reduce the electrical resistance in the first light reflecting layer 40. This makes it possible to improve the efficiency of the driving current Id supplied from the first electrode 71 to the active layer 31.

[0088] (5) The interface 821 between the first portion 411 of the first reflective layer 41 and the third portion of the second reflective layer 42 included in the first region 441 is blurred more than the interface 822 between the second portion 412 of the first reflective layer 41 and the fourth portion 422 of the second reflective layer 42 included in the second region 442. Therefore, it can be said that the first portion 411 and the third portion 421 are less likely to reflect light than the second portion 412 and the fourth portion 422. Also, it can be said that the first portion 411 and the third portion 421 are more likely to transmit light than the second portion 412 and the fourth portion 422. That is, the first portion 411 transmits light more easily than the second portion 412. Therefore, it is possible to easily emit laser light from the center O1 of the light emitting portion 51, thereby improving the emission efficiency of the laser light.

[0089] (6) The surface-emitting laser device 10 of the embodiment can reduce current concentration of the drive current Id near the inner end of the insulating portion 532 of the current confinement layer 53. This can reduce heat generation due to the drive current Id.

[0090] (7) The high concentration region 451 may have a composition gradient. The high concentration region 451 includes a first reflective layer 41 and a second reflective layer 42. The first reflective layer 41 and the second reflective layer 42 are formed by MOCVD. The composition gradient of the first reflective layer 41 and the second reflective layer 42 is obtained by adjusting the flow rate of an organic metal gas when they are formed by MOCVD. The high concentration region 451 including the first reflective layer 41 and the second reflective layer 42 having a composition gradient has low electrical resistance, similar to the first region 441. Therefore, the efficiency of the drive current Id supplied from the first electrode 71 to the active layer 31 can be improved.

[0091] (8) The high concentration region 451 contains more C, which is an impurity of the first conductivity type, than the low concentration region 452. The high concentration region 451 has a lower electrical resistance than the low concentration region 452. Therefore, the efficiency of the drive current Id supplied from the first electrode 71 to the active layer 31 can be improved.

[0092] (Example of change) The above embodiment can be modified, for example, as follows. The above embodiment and the following modified examples can be combined with each other as long as no technical contradiction occurs. In the following modified examples, the same reference numerals as in the above embodiment are used for the parts common to the above embodiment, and the description thereof will be omitted.

[0093] The number of light emitting sections included in the surface emitting laser device may be changed as appropriate. As shown in FIG. 16, a surface-emitting laser device 110 including one light-emitting section 51 may be used.

[0094] The first light reflective layer 40 may contain p-type impurities such as Mg (magnesium), and the second light reflective layer 60 may contain n-type impurities such as Te (tellurium). The term "on" as used in this disclosure includes both the meanings of "on" and "above" unless the context clearly indicates otherwise. Thus, the phrase "a first layer is formed on a second layer" is intended to mean that in some embodiments, the first layer may be disposed directly on the second layer in contact with the second layer, while in other embodiments, the first layer may be disposed above the second layer without contacting the second layer. That is, the term "on" does not exclude a structure in which another layer is formed between the first layer and the second layer.

[0095] The Z-axis direction used in the present disclosure does not necessarily have to be a vertical direction, nor does it have to completely coincide with the vertical direction. Therefore, various structures according to the present disclosure (for example, the structure shown in FIG. 1) are not limited to the "up" and "down" of the Z-axis direction described in this specification being "up" and "down" of the vertical direction. For example, the X-axis direction may be a vertical direction, or the Y-axis direction may be a vertical direction.

[0096] (Additional Note) The technical ideas that can be understood from the present disclosure are described below. Note that, for the purpose of aiding understanding, not for the purpose of limitation, the components described in the appendices are given the reference symbols of the corresponding components in the embodiments. The reference symbols are shown as examples for the purpose of aiding understanding, and the components described in each appendix should not be limited to the components indicated by the reference symbols.

[0097] (Appendix 1) a light generating layer (30); a first light reflecting layer (40) and a second light reflecting layer (60) made of a material containing Al and disposed on either side of the light generating layer (30) in a thickness direction (Z) of the light generating layer (30); a first electrode (71) provided on the opposite side of the first light reflecting layer (40) to the second light reflecting layer (60) and electrically connected to the first light reflecting layer (40); a second electrode (72) electrically connected to the second light reflecting layer (60); a current confinement layer (53) disposed between the second light reflecting layer (60) and the first electrode (71), the current confinement layer (53) including a passing portion (531) configured to allow a current to pass therethrough, and an insulating portion (532) surrounding the passing portion (531); Including, the first electrode (71) includes an opening (712) that overlaps with the passage portion (531) when viewed from the thickness direction (Z), The first light reflecting layer (40) is a first region (441) that is provided at a position overlapping the passing portion (531) and the opening (712) when viewed from the thickness direction (Z) and that contains Zn; a second region (442) provided so as to surround the first region (441) when viewed from the thickness direction (Z); A surface emitting laser device comprising:

[0098] (Appendix 2) When viewed from the thickness direction (Z), at least a portion of the first region (441) overlaps with the first electrode (71). 2. A surface-emitting laser device as described in claim 1.

[0099] (Appendix 3) the first electrode (71) includes a connection portion (711) surrounding the passing portion (531) when viewed from the thickness direction (Z) and electrically connected to the first light reflecting layer (40); 3. A surface-emitting laser device according to claim 1 or 2.

[0100] (Appendix 4) When viewed from the thickness direction (Z), a boundary portion (81) between the first region (441) and the second region (442) is disposed at a position overlapping with or outside the connection portion (711) of the first electrode (71). 4. A surface-emitting laser device as described in appendix 3.

[0101] (Appendix 5) The concentration of Zn in the first region (441) is higher in a central portion than in a peripheral portion when viewed from the thickness direction (Z). 5. A surface-emitting laser device according to claim 1.

[0102] (Appendix 6) The first region (441) has a circular shape when viewed from the thickness direction (Z), and is formed so that the concentration of Zn decreases from the center toward the second region (442). 6. A surface-emitting laser device according to claim 1,

[0103] (Appendix 7) The first region (441) is formed in such a way that the concentration of Zn decreases from the upper surface of the first light reflecting layer (40) toward the light generating layer (30) in the thickness direction (Z). 7. A surface-emitting laser device according to claim 1.

[0104] (Appendix 8) The first light reflecting layer (40) is made of a material containing Al, and includes a plurality of first reflecting layers (41) and a plurality of second reflecting layers (42) alternately arranged in the thickness direction (Z), The Al composition of the first reflective layer (41) is higher than the Al composition of the second reflective layer (42). 8. A surface-emitting laser device according to claim 1.

[0105] (Appendix 9) an interface (821) between the first reflective layer (41) and the second reflective layer (42) in the first region (441) is blurred more than an interface (822) between the first reflective layer (41) and the second reflective layer (42) in the second region (442); 9. The surface-emitting laser device according to claim 8.

[0106] (Appendix 10) an interface (822) between the first reflective layer (41) and the second reflective layer (42) exists in the second region (442), while there is a portion where an interface (821) between the first reflective layer (41) and the second reflective layer (42) does not exist in the first region (441); 10. The surface-emitting laser device according to claim 8 or 9.

[0107] (Appendix 11) the second light reflecting layer (60) is made of a material containing Al, and includes a plurality of third reflecting layers (61) and a plurality of fourth reflecting layers (62) alternately arranged in the thickness direction (Z); The Al composition of the third reflective layer (61) is higher than the Al composition of the fourth reflective layer (62). 11. The surface-emitting laser device according to claim 8.

[0108] (Appendix 12) The number of the third reflective layers (61) is greater than the number of the first reflective layers (41); 12. The surface-emitting laser device according to claim 11.

[0109] (Appendix 13) the first light reflecting layer (40) includes a high concentration region (451) and a low concentration region (452) in which the carrier concentration is relatively high and low, the low concentration region (452) is provided between the high concentration region (451) and the first electrode (71) in the thickness direction (Z), and the first region (441) and the second region (442) are provided in the low concentration region (452); 13. A surface-emitting laser device according to any one of claims 1 to 12.

[0110] (Appendix 14) The thickness (T1) of the high concentration region (451) is greater than the thickness (T2) of the low concentration region (452). 14. The surface-emitting laser device according to claim 13.

[0111] (Appendix 15) an interface between the first reflective layer (41) and the second reflective layer (42) in the high concentration region (451) is blurred more than an interface between the first reflective layer (41) and the second reflective layer (42) in the second region (442); 15. The surface-emitting laser device according to claim 13 or 14.

[0112] (Appendix 16) a light-emitting portion (51) that penetrates the first light-reflecting layer (40) and the light-generating layer (30) in the thickness direction (Z) to reach the second light-reflecting layer (60) and is partitioned by an annular separation groove (52) when viewed in the thickness direction (Z); The first region (441) and the second region (442) are provided in the light-emitting portion (51). 16. The surface-emitting laser device according to claim 8,

[0113] (Appendix 17) The light emitting portion (51) has a circular shape when viewed from the thickness direction (Z), The passing portion (531) of the current confinement layer (53) is disposed at the center when viewed from the thickness direction (Z). 17. The surface-emitting laser device according to claim 16.

[0114] (Appendix 18) 18. The surface-emitting laser device according to claim 16 or 17, comprising a plurality of the light-emitting sections (51).

[0115] (Appendix 19) an insulating film (73) interposed between the first light reflecting layer (40) and the first electrode (71), the insulating film having an opening (731) formed so as to surround the passing portion (531) when viewed from the thickness direction (Z); the connection portion (711) of the first electrode (71) is disposed within the opening (731) of the insulating film (73); 5. The surface-emitting laser device according to claim 3 or 4.

[0116] (Appendix 20) the insulating film (73) includes a covering portion (732) in a region located inward from the opening (731); The opening (712) of the first electrode (71) is formed so as to expose a part of the covering portion (732). 20. The surface-emitting laser device of claim 19.

[0117] (Appendix 21) The light generating layer (30) includes an active layer (31) and a first cladding layer (32) and a second cladding layer (33) disposed on either side of the active layer (31). 21. The surface-emitting laser device according to claim 1.

[0118] (Appendix 22) A substrate (21) including a first substrate surface (211) and a second substrate surface (212) facing in opposite directions; the second light reflecting layer (60), the light generating layer (30), and the first light reflecting layer (40) are disposed on the first substrate surface (211); 22. A surface-emitting laser device according to claim 1.

[0119] (Appendix 23) The second electrode (72) is provided on the second substrate surface (212). 23. The surface-emitting laser device according to claim 22.

[0120] The above description is merely illustrative. Those skilled in the art may recognize that many more possible combinations and permutations are possible other than the components and methods (manufacturing processes) listed for the purpose of describing the technology of the present disclosure. The present disclosure is intended to embrace all alternatives, modifications, and alterations that fall within the scope of the present disclosure, including the scope of the claims. [Explanation of symbols]

[0121] 10,110 Surface emitting laser device 11 Top of device 12 Underside of device 13~16 Side of device 21 Substrate 211 First board surface 212 Second board surface 22 Semiconductor layer 221 Page 1 222 2nd page 30 Light generating layer 31 Active layer 32 First cladding layer 33 Second cladding layer 40 1st light reflective layer 41 1st reflective layer 411 Part 1 412 Part 2 42 Second reflective layer 421 Part 3 422 Part 4 441 First area 441B Bottom end 442 Second area 451 High concentration area 452 Low concentration area 51 Light emitting part 511 Light-emitting surface 512 Light-emitting part side 52 Separation groove 521 Inner surface 522 Outer surface 523 Bottom 53 Current confinement layer 531 Passage section 532 Insulation 60 Second light reflective layer 61 Third reflective layer 62 4th reflective layer 71 1st electrode 711 Connection 712 Aperture 714 External connection part 72 2nd electrode 73 Insulating Film 731 Aperture 732 Covering part 81 Boundary part 821 Interface 822 Interface 83 Range 84 parts 90 Source α1,α2 Al composition β1~β4 Al composition Id Drive current L1 Laser light O1 center T1, T2 thickness

Claims

1. a light generating layer; a first light reflecting layer and a second light reflecting layer, the first light reflecting layer and the second light reflecting layer being made of a material containing Al and disposed on either side of the light generating layer in a thickness direction of the light generating layer; a first electrode provided on the first light reflecting layer on the opposite side to the second light reflecting layer and electrically connected to the first light reflecting layer; a second electrode electrically connected to the second light reflecting layer; a current confinement layer including a passing portion disposed between the second light reflecting layer and the first electrode and configured to allow a current to pass therethrough, and an insulating portion surrounding the passing portion; Including, the first electrode includes an opening overlapping the passing portion when viewed in the thickness direction, The first light reflective layer is a first region provided at a position overlapping the passing portion and the opening when viewed from the thickness direction and containing Zn; A second region provided so as to surround the first region when viewed from the thickness direction; A surface emitting laser device comprising:

2. When viewed from the thickness direction, at least a portion of the first region overlaps with the first electrode.

2. The surface emitting laser device according to claim 1.

3. the first electrode includes a connection portion surrounding the passing portion when viewed from the thickness direction and electrically connected to the first light reflecting layer; 2. The surface emitting laser device according to claim 1.

4. When viewed from the thickness direction, a boundary portion between the first region and the second region is disposed at a position overlapping with or outside the connection portion of the first electrode.

4. The surface emitting laser device according to claim 3.

5. The concentration of Zn in the first region is higher in a central portion than in a peripheral portion when viewed in the thickness direction.

2. The surface emitting laser device according to claim 1.

6. The first region has a circular shape when viewed from the thickness direction, and is formed so that the concentration of Zn decreases from the center toward the second region.

2. The surface emitting laser device according to claim 1.

7. The first region is formed such that the concentration of Zn decreases from the upper surface of the first light reflecting layer toward the light generating layer in the thickness direction.

2. The surface emitting laser device according to claim 1.

8. the first light reflective layer is made of a material containing Al, and includes a plurality of first reflective layers and a plurality of second reflective layers alternately arranged in the thickness direction; The Al composition of the first reflective layer is higher than the Al composition of the second reflective layer.

2. The surface emitting laser device according to claim 1.

9. an interface between the first reflective layer and the second reflective layer in the first region is blurred more than an interface between the first reflective layer and the second reflective layer in the second region; 9. The surface emitting laser device according to claim 8.

10. an interface between the first reflective layer and the second reflective layer is present in the second region, while there is a portion where an interface between the first reflective layer and the second reflective layer is not present in the first region; 9. The surface emitting laser device according to claim 8.

11. the second light reflective layer is made of a material containing Al, and includes a plurality of third reflective layers and a plurality of fourth reflective layers alternately arranged in the thickness direction, The Al composition of the third reflective layer is higher than the Al composition of the fourth reflective layer.

9. The surface emitting laser device according to claim 8.

12. The number of the third reflective layers is greater than the number of the first reflective layers.

12. The surface emitting laser device according to claim 11.

13. the first light reflecting layer includes a high concentration region and a low concentration region in which carrier concentrations are relatively high and low, the low concentration region is provided between the high concentration region and the first electrode in the thickness direction, and the first region and the second region are provided in the low concentration region; 9. The surface emitting laser device according to claim 8.

14. The thickness of the high concentration region is greater than the thickness of the low concentration region.

14. The surface emitting laser device according to claim 13.

15. an interface between the first reflective layer and the second reflective layer in the high concentration region is blurred more than an interface between the first reflective layer and the second reflective layer in the second region; 14. The surface emitting laser device according to claim 13.

16. a light emitting portion that penetrates the first light reflecting layer and the light generating layer in the thickness direction to reach the second light reflecting layer and is partitioned by a separation groove that is annular when viewed in the thickness direction; The first region and the second region are provided in the light-emitting portion.

2. The surface emitting laser device according to claim 1.

17. The light emitting portion has a circular shape when viewed from the thickness direction, The passing portion of the current confinement layer is disposed at the center when viewed from the thickness direction.

17. The surface emitting laser device according to claim 16.

18. The surface emitting laser device according to claim 16 , comprising a plurality of the light emitting sections.

19. an insulating film interposed between the first light reflecting layer and the first electrode, the insulating film having an opening formed so as to surround the passing portion when viewed in the thickness direction; the connection portion of the first electrode is disposed in the opening of the insulating film; 4. The surface emitting laser device according to claim 3.

20. the insulating film includes a covering portion in a region located inward from the opening, The opening of the first electrode is formed to expose a part of the covering portion.

20. The surface emitting laser device according to claim 19.

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