Laser element, laser element array, and method for manufacturing laser element

Abstract

[Problem] Provides: a laser element having a concave mirror structure and exhibiting excellent optical properties; a laser element array; and a method for manufacturing the laser element. [Solution] The laser element according to this technology is equipped with a first light-reflecting layer, a second light-reflecting layer, and a laminate. The laminate includes an active layer and has a lens disposed on a first surface on one side of the first light-reflecting layer. In the lens, the longitudinal direction is defined as a first direction and the short-side direction is defined as a second direction. The lens has a lens shape protruding toward the first light-reflecting layer. The central portion of the lens in the first direction has a first width as the shortest width along the second direction, and the non-central portion of the lens in the first direction has a second width as the maximum width along the second direction. The height of the lens is constant, or the height at the central portion is greater than the height at the end. The top of the lens in the second direction has a constant radius of curvature. The first light-reflecting layer is laminated on the first surface, and a concave mirror with a concave shape is formed on the lens.

Description

Technical Field

[0001] This technology relates to a laser element that emits laser light in a direction perpendicular to the surface of a layer, an array of laser elements, and a method for manufacturing the laser element. Background Technology

[0002] One type of laser element is the VCSEL (Vertical-Cavity Surface-Emitting Laser) element. A VCSEL element has a structure in which an emissive layer is sandwiched between a pair of mirrors. A current-limiting structure is placed near the emissive layer, and current is concentrated through the current-limiting structure in a portion of the emissive layer to generate spontaneous emission light. The pair of mirrors form a resonator and reflect light of a predetermined wavelength from the spontaneous emission light toward the emissive layer to induce laser oscillation.

[0003] In VCSEL elements, as the resonator length, which is the distance between the pair of mirrors, increases, diffraction loss increases due to the limitation of the light field in the lateral direction (layer surface direction). As a method to counteract this diffraction loss, a structure has been proposed that incorporates a concave mirror with a spherical shape as one of the pair of mirrors (see Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: WO 2018 / 083877 Summary of the Invention

[0007] Technical issues

[0008] In the proposal described in Patent Document 1, a method is used to apply heat treatment to a fluid material patterned on a substrate to form a convex spherical shape, and then use this convex spherical shape to form a concave mirror. However, in this method, there is a problem that the shape of the fluid material does not become convex spherical but rather flat or concave due to the tension of the substrate surface and the fluid material, as well as the influence of gravity.

[0009] For example, when the diameter of the patterned fluid material is large, capillary action is disrupted by gravity, resulting in a flat or concave shape. Furthermore, when the fluid material becomes thinner, the surface tension between the substrate and the fluid material prevents the contact angle between them from being less than a specific value, causing the fluid material to become flat or concave. When the fluid material is flat or concave, the concave mirror cannot achieve the desired optical properties.

[0010] In view of the above, the purpose of this technology is to provide a laser element with a concave mirror structure and exhibiting excellent optical properties, a laser element array, and a method for manufacturing the laser element.

[0011] Solution to the problem

[0012] To achieve the above objectives, the laser element according to the present technology includes: a first light-reflecting layer; a second light-reflecting layer; and a laminate.

[0013] The first light-reflecting layer reflects light of a specific wavelength.

[0014] The second light-reflecting layer reflects light of that wavelength.

[0015] The stack includes a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first light-reflecting layer and the second light-reflecting layer. It has a first surface on the side of the first light-reflecting layer and a second surface on the side of the second light-reflecting layer. The first semiconductor layer is formed of a semiconductor material having a first conductivity type, and the second semiconductor layer is formed of a semiconductor material having a second conductivity type. The active layer is disposed between the first semiconductor layer and the second semiconductor layer and emits light through carrier recombination. A lens is disposed on the first surface.

[0016] The lens has a lens shape that protrudes toward the first light-reflecting layer, with a first direction as the longitudinal direction and a second direction as the transverse direction. The first direction is parallel to a plane perpendicular to the optical axis of the emitted light, and the second direction is parallel to the plane and orthogonal to the first direction. The central portion of the lens in the first direction has a first width, which is the shortest width along the second direction. The non-central portion of the lens in the first direction has a second width, which is the maximum width along the second direction. The lens has a shape in which its height from the plane is uniform or the central portion is higher than the end portion. The radius of curvature of the vertex of the lens in the second direction is uniform.

[0017] A first light-reflecting layer is stacked on the first surface to form a concave mirror with a concave shape on the lens. It should be noted that in this specification, the phrase "uniform" for the radius of curvature or height means that the value does not exceed ±20% of the average value at the apex of the predetermined concave mirror in substantially all portions.

[0018] The laminate can have a current-limiting structure that confines the current and forms a current-concentrated current injection region, and

[0019] The current injection region can have a shape in which the planar pattern of the current injection region when viewed from the optical axis overlaps with the lens when viewed from the optical axis, wherein the first direction is the longitudinal direction and the second direction is the transverse direction.

[0020] The length of the lens along the first direction can be greater than the second width.

[0021] The length of the lens along the first direction can be 40 μm or more.

[0022] The second width of the lens can be 10 μm or more.

[0023] The resonator length of the laser element can be the distance between the concave mirror and the second light-reflecting layer, and

[0024] The radius of curvature can be greater than the length of the resonator.

[0025] The surface accuracy of the lens can be below 1.0 nm in RMS (root mean square).

[0026] The first semiconductor layer and the second semiconductor layer can be formed of GaN.

[0027] The first semiconductor layer and the second semiconductor layer can be formed from GaAs.

[0028] The first semiconductor layer and the second semiconductor layer can be formed from InP.

[0029] The laser element may further include a wavelength conversion layer disposed on the side of the second light-reflecting layer opposite to the laminate and formed of a wavelength conversion material.

[0030] The first and second light-reflecting layers can each be DBRs (Distributed Bragg Reflectors) that include multiple layers of light-reflecting films.

[0031] To achieve the above objectives, the laser element array according to this technology is a laser element array in which multiple laser elements, each individually driveable, are arranged, the laser elements comprising:

[0032] The first light-reflecting layer reflects light of a specific wavelength.

[0033] The second light-reflecting layer reflects light of that wavelength, and

[0034] A laminate includes a first semiconductor layer, a second semiconductor layer, and an active layer. The laminate is disposed between a first light-reflecting layer and a second light-reflecting layer, and has a first surface located on one side of the first light-reflecting layer and a second surface located on one side of the second light-reflecting layer. The first semiconductor layer is formed of a semiconductor material having a first conductivity type, and the second semiconductor layer is formed of a semiconductor material having a second conductivity type. The active layer is disposed between the first and second semiconductor layers and emits light through carrier recombination. A lens is disposed on the first surface.

[0035] The lens has a lens shape that protrudes towards a first light-reflecting layer, with a first direction as its longitudinal direction and a second direction as its transverse direction. The first direction is parallel to a plane perpendicular to the optical axis of the emitted light, and the second direction is parallel to the plane and orthogonal to the first direction. The central portion of the lens in the first direction has a first width, which is the shortest width along the second direction. The non-central portion of the lens in the first direction has a second width, which is the maximum width along the second direction. The lens has a shape where its height above the plane is uniform or the central portion is higher than the ends. The radius of curvature of the lens's apex in the second direction is uniform.

[0036] The first light-reflecting layer is stacked on the first surface to form a concave mirror with a concave shape on the lens.

[0037] To achieve the above objectives, a method for manufacturing a laser element according to this technology includes:

[0038] A laminate is prepared, comprising a first semiconductor layer, a second semiconductor layer and an active layer, and having a first surface and a second surface. The first semiconductor layer is formed of a semiconductor material having a first conductivity type, the second semiconductor layer is formed of a semiconductor material having a second conductivity type, and the active layer is disposed between the first semiconductor layer and the second semiconductor layer and emits light through carrier recombination.

[0039] A structure is formed on a first surface. The structure is formed of a fluid material and has a certain thickness. The first direction is the longitudinal direction and the second direction is the transverse direction. The first direction is parallel to a plane perpendicular to the optical axis of the emitted light. The second direction is parallel to the plane and orthogonal to the first direction. The central portion of the structure in the first direction has a first width, which is the shortest width along the second direction. The non-central portion of the structure in the first direction has a second width, which is the maximum width along the second direction.

[0040] The structure is deformed by heating the structure to allow fluid material to flow, and the shape of the structure is used to form a lens on the first surface. The lens has a shape in which its height above the plane is uniform or its central portion is higher than its end portion, and the radius of curvature of the vertex of the lens in the second direction is uniform.

[0041] A first light-reflecting layer that reflects light of a specific wavelength is stacked on a first surface to form a concave mirror with a concave shape on the lens; and

[0042] A second light-reflecting layer that reflects light of that wavelength is formed on the second surface side of the laminate.

[0043] The steps of forming a lens may include: deforming the structure into a lens shape protruding toward one side of the first light-reflecting layer, wherein the first direction is the longitudinal direction and the second direction is the transverse direction, the central portion has a first width, the non-central portion has a second width, the structure has a shape in which its height above the plane is uniform or the central portion is higher than the end portion, and the radius of curvature of the apex of the structure in the second direction is uniform.

[0044] The steps of forming a lens may include: using a structure deformed into the shape as an etching mask to etch the stack to form a lens on a first surface.

[0045] The steps of forming a lens may include using a structure deformed into that shape as a lens.

[0046] The length of the structural component along the first direction can be greater than the second width.

[0047] The length of the structural component along the first direction can be 40 μm or more.

[0048] Etching can be either dry etching or wet etching. Attached Figure Description

[0049] Figure 1 This is a cross-sectional view of a laser element according to a first embodiment of the present technology.

[0050] Figure 2 This is an exploded cross-sectional view of a portion of the laser element configuration.

[0051] Figure 3 This is a schematic diagram showing the current injection region of the laser element.

[0052] Figure 4 This is a schematic diagram showing the current injection region of the laser element.

[0053] Figure 5 It is a plan view of the lens included in the laser element.

[0054] Figure 6 It is a perspective view of the lens included in the laser element.

[0055] Figure 7 It is a plan view of the lens included in the laser element.

[0056] Figure 8 This is a schematic diagram showing the shape of a lens included in a laser element.

[0057] Figure 9 This is a schematic diagram showing the cross-sectional shape of the central and non-central portions of a lens included in a laser element.

[0058] Figure 10This is a schematic diagram showing the length of the resonator in a laser element.

[0059] Figure 11 This is a schematic diagram showing the positional relationship between the current injection region and the concave mirror of the laser element.

[0060] Figure 12 This is a cross-sectional view of a laser element according to a first embodiment of the present technology, wherein the lens includes another component.

[0061] Figure 13 This is a schematic diagram illustrating the operation of a laser element according to a first embodiment of the present technology.

[0062] Figure 14 This is a schematic diagram showing the shape of the lens used for comparison.

[0063] Figure 15 This is a schematic diagram illustrating a method for manufacturing a laser element according to a first embodiment of the present technology.

[0064] Figure 16 This is a schematic diagram illustrating a method for manufacturing laser elements.

[0065] Figure 17 It is a perspective view of the structure in the manufacturing process of laser elements.

[0066] Figure 18 It is a plan view of the structure in the manufacturing method of laser elements.

[0067] Figure 19 This is a schematic diagram showing the shape of the structure in the manufacturing method of a laser element.

[0068] Figure 20 It is a perspective view of the deformed structure in the manufacturing process of laser elements.

[0069] Figure 21 This is a schematic diagram illustrating the etching process in the manufacturing method of laser elements.

[0070] Figure 22 It is a perspective view of the structure in the manufacturing process of laser elements.

[0071] Figure 23 It is a plan view of a lens with another shape included in a laser element.

[0072] Figure 24 In the formation Figure 23 A perspective view of the structure used in the lens process shown.

[0073] Figure 25 It is a plan view of a lens with a different shape included in a laser element.

[0074] Figure 26 In the formation Figure 25 A perspective view of the structure used in the lens process shown.

[0075] Figure 27 This is a cross-sectional view of a laser element including a wavelength conversion layer according to a first embodiment of the present technology.

[0076] Figure 28 This is a cross-sectional view of a laser element array according to a first embodiment of the present technology.

[0077] Figure 29 This is a planar diagram of a laser element array.

[0078] Figure 30 This is a cross-sectional view of a laser element array including a wavelength conversion layer according to a first embodiment of the present technology.

[0079] Figure 31 This is a cross-sectional view of a laser element according to a second embodiment of the present technology.

[0080] Figure 32 This is an exploded cross-sectional view showing a partial configuration of the laser element.

[0081] Figure 33 This is a schematic diagram showing the current-limiting structure of a laser element.

[0082] Figure 34 This is a cross-sectional view of a laser element with another configuration according to a second embodiment of the present technology.

[0083] Figure 35 This is a cross-sectional view of a laser element according to a third embodiment of the present technology.

[0084] Figure 36 This is an exploded cross-sectional view showing a portion of the structure of a laser element.

[0085] Figure 37 This is a schematic diagram showing the current-limiting structure of a laser element. Detailed Implementation

[0086] (First Implementation)

[0087] A laser element according to a first embodiment of the present invention will be described. In the accompanying drawings of this disclosure, the optical axis direction of the light emitted from the laser element is defined as the Z direction, a direction orthogonal to the Z direction is defined as the X direction, and a direction orthogonal to both the Z and X directions is defined as the Y direction. The laser element according to this embodiment has a structure similar to that of a VCSEL (Vertical-Cavity Surface-Emitting Laser) element. However, a VCSEL element has a structure in which the light resonates in the Z direction, and the laser element according to this embodiment differs from a VCSEL element in that the resonance also occurs in another direction (the Y direction) besides the Z direction.

[0088] [Structure of laser components]

[0089] Figure 1 This is a cross-sectional view of the laser element 100 according to this embodiment, and Figure 2 This is an exploded schematic diagram of the laser element 100. As shown, the laser element 100 includes a first semiconductor layer 101, a second semiconductor layer 102, an active layer 103, a first light-reflecting layer 104, a second light-reflecting layer 105, a first electrode 106, and a second electrode 107. The first semiconductor layer 101, the second semiconductor layer 102, and the active layer 103 are collectively referred to as a laminate 150.

[0090] Each of these layers has a surface orientation along the XY plane, and the first electrode 106, the first light-reflecting layer 104, the first semiconductor layer 101, the active layer 103, the second semiconductor layer 102, the second electrode 107, and the second light-reflecting layer 105 are stacked in this order. Therefore, the stack 150 is stacked between the first light-reflecting layer 104 and the second light-reflecting layer 105.

[0091] The first semiconductor layer 101 is formed of a semiconductor having a first conductivity type and is a layer that transports charge carriers to the active layer 103. The first conductivity type may be n-type, and the first semiconductor layer 101 may include, for example, an n-GaN substrate. A lens 160 is disposed in the first semiconductor layer 101. The lens 160 will be described below. The second semiconductor layer 102 is formed of a semiconductor having a second conductivity type and is a layer that transports charge carriers to the active layer 103. The second conductivity type may be p-type, and the second semiconductor layer 102 may be formed of, for example, p-GaN.

[0092] The active layer 103 is disposed between the first semiconductor layer 101 and the second semiconductor layer 102 and emits light through carrier recombination. The active layer 103 has a multiple quantum well structure in which quantum well layers and barrier layers are alternately stacked to obtain multiple layers. The quantum well layers can be formed of, for example, InGaN, and the barrier layers can be formed of, for example, GaN. Furthermore, the active layer 103 only needs to be a layer that emits light through carrier recombination and does not need to be a multiple quantum well structure.

[0093] like Figure 2 As shown, in the surface of the laminate 150, the surface on the side of the first light-reflecting layer 104 is defined as the first surface 151, and the surface on the side of the second light-reflecting layer 105 is defined as the second surface 152. A lens 160 is disposed on the first surface 151. Consequently, the first surface 151 has a main surface 151a and a lens surface 151b. The main surface 151a is a plane (XY plane) perpendicular to the optical axis (Z direction) of the emitted light. The lens surface 151b is the surface of the lens 160 and is a surface that protrudes from the main surface 151a.

[0094] The first light-reflecting layer 104 reflects light of a specific wavelength (hereinafter, wavelength λ) and allows light of other wavelengths to pass through. Wavelength λ is, for example, 445 nm. Figure 1 As shown, the first light-reflecting layer 104 can be a DBR (distributed Bragg reflector) comprising multiple light-reflecting films, in which a high-refractive-index layer 104a and a low-refractive-index layer 104b with an optical film thickness of λ / 4 are alternately stacked to obtain multiple layers. The first light-reflecting layer 104 can, for example, have a layered structure such as Ta2O5 / SiO2, SiO2 / SiN, SiO2 / Nb2O5, etc.

[0095] The first light-reflecting layer 104 includes a concave mirror 104c. The first light-reflecting layer 104 is stacked on the first surface 151 of the laminate 150 to have a certain thickness. Figure 2 As shown, according to the shape of the lens 160, the first light-reflecting layer 104 has a concave surface 104d on one side of the laminate 150 and a convex surface 104e on the surface opposite to the laminate 150. As a result, a concave mirror 104c is formed in the first light-reflecting layer 104.

[0096] The second light-reflecting layer 105 reflects light with wavelength λ, while allowing light of other wavelengths to pass through. For example... Figure 1As shown, the second light-reflecting layer 105 can be a DBR (distributed Bragg reflector), which includes multiple light-reflecting films, wherein a high-refractive-index layer 105a and a low-refractive-index layer 105b with an optical film thickness of λ / 4 are alternately stacked to obtain multiple layers. For example, the second light-reflecting layer 105 can have a layered structure such as Ta2O5 / SiO2, SiO2 / SiN, SiO2 / Nb2O5, etc.

[0097] The first electrode 106 is disposed around the concave mirror 104c on the first light-reflecting layer 104 and serves as an electrode of the laser element 100. The first electrode 106 may include, for example, a single-layer metal film formed of Au, Ni, Ti, etc., or a multilayer metal film formed of Ti / Au, Ag / Pd, Ni / Au / Pt, etc.

[0098] The second electrode 107 is disposed between the second semiconductor layer 102 and the second light-reflecting layer 105, and serves as another electrode of the laser element 100. For example, the second electrode 107 may be formed of a transparent conductive material such as ITO (indium tin oxide), ITiO (indium titanium oxide), TiO, AZO (aluminum-doped zinc oxide), ZnO, SnO, ZSnO, SnO2, SnO3, TiO, TiO2, and graphene.

[0099] In the laser element 100, a current-limiting structure is formed in the laminate 150. Figure 3 and Figure 4 Each is a schematic diagram illustrating the current limiting structure. Figure 3 Part (a) and Figure 4 Part (a) is a plan view of the current limiting structure when viewed from the optical axis direction (Z direction). Figure 3 Part (b) is a cross-sectional view showing the XZ section of the current-limiting structure, and Figure 4 Part (b) is a cross-sectional view showing the YZ section of the current-limiting structure. (See diagram below.) Figure 3 Part (b) and Figure 4 As shown in part (b), the current limiting structure has a current injection region 121 and an insulating region 122 (dashed line region). The current injection region 121 is a region without implanted ions (non-ion implanted region) and is a conductive region.

[0100] The insulating region 122 is the region surrounding the current injection region 121 in the layer surface direction (XY direction), and is an ion-implanted region (ion-implanted region) that is insulated by implanting ions into the semiconductor material forming the laminate 150. The ions to be implanted into the insulating region 122 can be boron (B) ions. Alternatively, ions capable of insulating semiconductor materials, such as oxygen (O) ions and hydrogen (H) ions, can be used instead of boron ions.

[0101] like Figure 3 Part (a) and Figure 4 As shown in part (a), the current injection region 121 has an elongated planar shape, wherein one direction (Y direction) is the longitudinal direction, and the direction orthogonal to the longitudinal direction (X direction) is the transverse direction. Hereinafter, the longitudinal direction (Y direction) of the current injection region 121 will be referred to as the first direction A1, and the transverse direction (X direction) of the current injection region 121 will be referred to as the second direction A2. The first direction A1 and the second direction A2 are orthogonal to the optical axis direction (Z direction) and are mutually orthogonal.

[0102] like Figure 3 Part (a) and Figure 4 As shown in part (a), when the current injection region 121 is defined along the length of the first direction A1 as length L e And the width along the second direction A2 is defined as width d. e At that time, length L e Appropriate width d e More than three times, and more appropriately more than 20 times. Specifically, the length L e Appropriately, it should be 40 μm or larger.

[0103] The current flowing through the laser element 100 cannot pass through the insulating region 122 and is concentrated in the current injection region 121. That is, the current limiting structure is formed by the current injection region 121 and the insulating region 122. Note that the insulating region 122 does not need to be provided in all of the first semiconductor layer 101, the active layer 103 and the second semiconductor layer 102, but only in at least one of these layers.

[0104] Note that, from Figure 3 Part (a) and Figure 4 When viewed along the optical axis (Z direction) as shown in part (a), the planar shape of the current injection region 121 is... Figure 3 Part (b) and Figure 4 The current injection region 121 shown in part (b) has a planar pattern with a minimum diameter in the layer surface direction (XY direction). Since the diameter of the current injection region 121 increases with distance from the interface between the second semiconductor layer 102 and the second electrode 106, the planar shape of the current injection region 121 is the shape of the current injection region 121 at the same interface.

[0105] [Regarding lens shape]

[0106] The shape of lens 160 will be described. Figures 5 to 7 These are schematic diagrams showing the shape of lens 160. Figure 5Part (a) is a cross-sectional view of the first semiconductor layer 101 when viewed from the optical axis direction (Z direction), and Figure 5 Part (b) is a cross-sectional view of the first semiconductor layer 101. Figure 6 This is a perspective view of lens 160. Figure 7 Part (a) is a plan view of lens 160 when viewed from the X direction, and Figure 7 Part (b) is a plan view of lens 160 when viewed from the Y direction. For example... Figures 5 to 7 As shown, lens 160 is configured to protrude from a main surface 151a parallel to the XY plane toward the first light-reflecting layer 104. Hereinafter, the main surface 151a will be referred to as the “plane” that defines the shape of lens 160.

[0107] like Figure 5 As shown, lens 160 has an elongated lens shape, with a longitudinal direction (Y direction) parallel to the main surface 151a and a transverse direction (X direction) orthogonal to the longitudinal direction. The longitudinal direction (Y direction) of lens 160 is parallel to the first direction A1, which is the longitudinal direction of the current injection region 121 (see...). Figure 3 The lens 160 is matched with a second direction A2, which is the transverse direction of the current injection region 121. That is, the lens 160 has a first direction A1 as the longitudinal direction and a second direction A2 as the transverse direction.

[0108] Figure 8 This is a schematic diagram showing the shape of lens 160 when viewed from the optical axis direction (Z direction). As shown, lens 160 includes a central portion 160a and a non-central portion 160b. The central portion 160a is the portion of lens 160 located at the center in the first direction A1. The width of the central portion 160a along the second direction A2 is defined as a first width d. s When 1, the first width d s 1 is the shortest width of lens 160 along the second direction A2. The first width d s 1 can be, for example, 36 μm.

[0109] Furthermore, the non-central portion 160b is the part of the lens 160 positioned away from the central portion 160a in the first direction A1, and is the portion of the lens 160 near both ends. The width of the non-central portion 160b along the second direction A2 is defined as the second width d. s At time 2, the second width d s 2 is the maximum width of lens 160 along the second direction A2. The second width d s 2 is appropriately 10 μm or more, and can be, for example, 40 μm.

[0110] In lens 160, the portion between the central portion 160a and the non-central portion 160b can have a shape in which the width along the second direction A2 gradually decreases from the non-central portion 160b to the central portion 160a, such as... Figure 8 As shown. When viewed from the optical axis direction (Z direction), the angle θ formed between the outer peripheral edge of lens 160 and the first direction A1 can be, for example, 3.8°. Furthermore, as... Figure 8 As shown, when the length of lens 160 along the first direction A1 is defined as length L s At that time, length L s Appropriately larger than the second width d s 2. And appropriately 40 μm or greater. Length L s It can be, for example, 100 μm.

[0111] Figure 9 This is a schematic diagram showing the shape of the central portion 160a and the non-central portion 160b. Figure 9 Part (a) shows a cross-sectional view of the central portion 160a taken along the XZ plane, and Figure 9 Part (b) shows a cross-sectional view of the non-central portion 160b taken along the XZ plane. (See diagram for reference.) Figure 9 Part (a) and Figure 9 As shown in part (b), the central portion 160a and the non-central portion 160b may have a shape in which the outer peripheral edge in the XZ section has a curve, the shape of which differs between the central portion 160a and the non-central portion 160b. In the portion between the central portion 160a and the non-central portion 160b, the curve drawn by the outer peripheral edge in the XZ section has a shape that differs between the central portion 160a and the non-central portion 160b. Figure 9 Part (a) and Figure 9 The intermediate shape between part (b).

[0112] like Figure 7 and Figure 9 As shown, the height of lens 160 from the main surface 151a (in the Z direction) is defined as height H. s .like Figure 9 As shown in parts (a) and (b), both the central part 160a and the non-central part 160b have a height H s Furthermore, the portion between the central portion 160a and the non-central portion 160b also has a height H. s Furthermore, lens 160 has a uniform height H. s ,like Figure 7 As shown. Note the height H. sPreferably, the wavelength is 10 nm or more. Furthermore, the lens 160 may have a shape where the height of the central portion 160a from the main surface 151a is greater than the height of the end portion from the main surface 151a. The end portion is the portion located near both ends of the lens 160a in the first direction A1, and is, for example, a non-central portion 160b.

[0113] Furthermore, in lens 160, the vertex of lens surface 152b (hereinafter referred to as the vertex of the lens) has a radius of curvature (ROC) R in the second direction A2. s .exist Figure 9 In parts (a) and (b), the vertex of the lens is represented by a dashed line, and the radius of curvature R of the vertex of the lens in the second direction A2 is shown. s .like Figure 9 As shown in parts (a) and (b), within the central part 160a and the non-central part 160b, the vertices of the lens have the same radius of curvature R. s Furthermore, the portion between the central part 160a and the non-central part 160b also has a radius of curvature R. s In lens 160, the vertex of the lens has a uniform radius of curvature R in the second direction A2. s .

[0114] The radius of curvature R s The resonator length is appropriately equal to or greater than that of the laser element 100. Figure 10 This is a schematic diagram showing the resonator length K of the laser element 100. As shown, the resonator length K of the laser element 100 is the distance between the concave mirror 104c and the second light-reflecting layer 105. (Radius of curvature R) s The resonator length can be appropriately set to K or greater, either the same as or larger than the resonator length K. This is because when the radius of curvature R... s When the resonator length K is less than the resonator length K, the laser oscillation described below will not occur. The resonator length K can be, for example, 25 μm, and the radius of curvature R... s It could be, for example, 44μm.

[0115] Furthermore, in lens 160, the surface precision (RMS) of lens surface 152b is preferably 1.0 nm or less. This is because if the surface precision (RMS) of lens surface 152b exceeds 1.0 nm, light loss occurs in lens surface 152b. The surface precision (RMS) can be, for example, 0.6 nm.

[0116] Figure 11 This shows lens 160 and current injection region 121 (see...) Figure 3This is a schematic diagram of the positional relationship between lens 160 and current injection region 121 when viewed from the optical axis direction (Z direction). As shown, the position and shape of lens 160 are configured such that current injection region 121 overlaps with lens 160 when viewed from the same direction.

[0117] Note that lens 160 can be used as follows: Figure 2 The structure shown is formed from a portion of the first semiconductor layer 101, but may include components different from the first semiconductor layer 101. Figure 12 This is a cross-sectional view showing a lens 160 bonded to the first semiconductor layer 101. As shown, the lens 160 may include components bonded to the first semiconductor layer 101.

[0118] Furthermore, although in the above description, the main surface 151a parallel to the XY plane is defined as a "plane" for defining the shape of the lens 160, the main surface 151a is not limited to a flat surface parallel to the XY plane, and can be a curved surface, etc. In this case, a virtual plane parallel to the XY plane can be used as a "plane" for defining the shape of the lens 160.

[0119] It should be noted that lens 160 may have a shape in which its outer peripheral edge in the XZ section has a curve as described above. The shape drawn by the outer peripheral edge of lens 160 in the XZ section may be a portion of a circle, a portion of a parabola, a portion of a sine curve, a portion of an ellipse, or a portion of a catenary. In some cases, this shape is not strictly a portion of a circle, not strictly a portion of a parabola, not strictly a portion of a sine curve, not strictly a portion of an ellipse, or not strictly a portion of a catenary. That is, the phrase "the shape is a portion of a circle, a portion of a parabola, a portion of a sine curve, a portion of an ellipse, or a portion of a catenary" includes cases where the shape is essentially a portion of a circle, a fundamental portion of a parabola, a fundamental portion of a sine curve, a fundamental portion of an ellipse, or a fundamental portion of a catenary. These portions of the curve may be replaced by line segments. The shape drawn by the outer peripheral edge of lens 160 in the XZ section can be obtained by measuring the shape of lens surface 152b with a measuring instrument and based on data obtained from least squares analysis.

[0120] [Operation of laser components]

[0121] The operation of laser element 100 will be described. Figure 13 This is a schematic diagram illustrating the operation of the laser element 100. When a voltage is applied between the first electrode 106 and the second electrode 107, current flows between the first electrode 106 and the second electrode 107. The current is limited by a current-limiting structure and injected into the current injection region 121, as shown. Figure 13As shown by arrow C in the diagram.

[0122] The injected current induces spontaneous emission of light F near the current injection region 121 of the active layer 103. The spontaneous emission of light F travels in the stacking direction (Z direction) of the laser element 100 and is reflected by the first light-reflecting layer 104 and the second light-reflecting layer 105.

[0123] Since the first light-reflecting layer 104 and the second light-reflecting layer 105 are configured to reflect light with an oscillating wavelength λ, a component of the spontaneously emitted light with an oscillating wavelength λ forms a standing wave between the first light-reflecting layer 104 and the second light-reflecting layer 105 and is amplified by the active layer 103. When the injected current exceeds a threshold, the light forming the standing wave causes laser oscillation. The resulting laser E is transmitted through the second light-reflecting layer 105 and emitted from the laser element 100 with the Z direction as the optical axis.

[0124] Here, in the laser element 100, the current injection region 121 has an elongated planar shape extending along the first direction A1 (Y direction), and the lens 160 also has an elongated shape extending along the first direction A1 (see...). Figure 11 By forming the current injection region 121 and the lens 160 into an elongated shape along the first direction A1, the light-confining region can be limited in the second direction A2 by the current injection region 121, while the light-confining region can be extended in the first direction A1 by the current injection region 121. Therefore, the width of the laser E emitted from the laser element in the first direction A1 is increased, and the radiation angle of the laser E along the Y direction can be reduced.

[0125] Furthermore, lens 160 induces optical resonance not only in the stacking direction (Z direction) but also in the first direction A1 (Y direction). As a result, the coherence of the laser E can be improved. As described above, since the current injection region 121 and lens 160 have elongated shapes along the first direction A1, the laser element 100 is able to emit a laser E with a large beam diameter and a narrow radiation angle, and operate as a line source emitting a linear beam.

[0126] [Effects of laser components]

[0127] As described above, the laser element 100 includes a lens 160, in which the height H from the main surface 151a is... s It is uniform and the radius of curvature R of the vertex of the lens in the second direction A2. s It is uniform. Figure 14This is a schematic diagram of lens 560 when viewed from various directions, shown for comparison. Lens 560 has an elongated lens shape, with a first direction A1 as the longitudinal direction and a second direction A2 as the transverse direction. Lens 560 has a shape where its height above plane 551a is non-uniform and the central portion is low in height. Furthermore, in lens 560, the radius of curvature of the lens apex in the second direction A2 is also non-uniform.

[0128] When the lens has a shape that is relatively long (specifically, 40 μm or more) in one direction, such as Figure 14 As shown, due to the effects of surface tension and gravity during the manufacturing process, the central portion is compressed, resulting in a non-uniform shape in terms of height from plane 551a and the radius of curvature of the lens apex. If the laser element 100 includes lens 560 instead of lens 160, the resonator length K (see [reference needed]) will be longer due to the non-uniform height of lens 560, specifically, the ends being higher than the central portion. Figure 10 The specific pattern varies depending on which part of the lens 560 the light reaches. Therefore, different longitudinal patterns (repeated states in the Z direction) are established at different locations within the laser element 100.

[0129] Furthermore, because the radius of curvature at the lens apex in lens 560 is non-uniform, different transverse modes (repeating states in the XY direction) are established in laser element 100. For these reasons, when laser element 100 includes lens 560, the brightness of laser E is non-uniform in laser element 100, the light field in laser element 100 does not become coherent, and laser E with a narrow radiation angle cannot be emitted.

[0130] On the other hand, the laser element 100 includes a lens 160, wherein the height H of the lens apex is... s and radius of curvature R s It is uniform. Therefore, by forming a current injection region 121 on the lens 160, modes having resonance in the optical axis direction (Z direction) and the longitudinal direction (Y direction) of the lens 160 can be formed, and a laser element 100 emitting light with high linearity can be realized. Furthermore, in the laser element 100, in some cases, due to the radius of curvature R... s It is uniform, so the lateral pattern can be uniform, and due to the height H s It is uniform, so the longitudinal pattern can be uniform. Therefore, laser E without brightness non-uniformity can be emitted, and thus, laser element 100 can achieve a good line source.

[0131] Furthermore, in shapes with uneven height (specifically, the ends being higher than the center), such as in lens 560, stress is concentrated in the center, making it possible for the center to be damaged by heating or physical contact. On the other hand, when the height is as uniform as in lens 160, durability can be improved by dispersing stress.

[0132] [Manufacturing methods for laser components]

[0133] The method for manufacturing the laser element 100 will be described. Figures 15 to 21 These are schematic diagrams illustrating a method for manufacturing the laser element 100. First, as... Figure 15 As shown, a laminate 150 is fabricated. The laminate 150 can be fabricated by laminating an active layer 103 and a second semiconductor layer 102 on a first semiconductor layer 101 (substrate). The active layer 103 and the second semiconductor layer 102 can be laminated by a metal-organic chemical vapor deposition (MOCVD) method or the like.

[0134] Subsequently, as Figure 16 As shown, an insulating region 122 is formed. The insulating region 122 can be formed by implanting ions into the stack 150 from one side of the second semiconductor layer 102. At this time, by covering a portion of the second semiconductor layer 102 with a mask, a current injection region 121, which is a region where no ions are implanted, can be formed.

[0135] Subsequently, as Figure 17 As shown, a structure 170 is formed on the first surface 151 of the laminate 150. The structure 170 has a certain thickness from the first surface 151 and is patterned into a predetermined shape. Figure 18 This is a plan view showing the shape of structure 170 and is a diagram of structure 170 when viewed from the optical axis direction (Z direction). As shown, structure 170 has an elongated shape, wherein one direction (Y direction) is the longitudinal direction, and a direction orthogonal to the longitudinal direction (X direction) is the transverse direction. The longitudinal direction (Y direction) of structure 170 is perpendicular to the first direction A1, which is the longitudinal direction of the current injection region 121 (see...). Figure 3 The structure 170 is matched with a second direction A2, which is the transverse direction of the current injection region 121. That is, the structure 170 has a first direction A1 as the longitudinal direction and a second direction A2 as the transverse direction.

[0136] Figure 19This is a schematic diagram showing the shape of structure 170 when viewed from the optical axis (Z direction). As shown, structure 170 includes a central portion 170a and a non-central portion 170b. The central portion 170a is the portion of structure 170 located at the center in the first direction A1. The width of the central portion 170a along the second direction A2 is defined as the first width d. p When 1, the first width d p 1 is the shortest width of structure 170 along the second direction A2. First width d p 1 can be, for example, 36 μm.

[0137] Furthermore, the non-central portion 170b is the part of structure 170 located away from the central portion 170a in the first direction A1, and is the part of structure 170 near both ends. The width of the non-central portion 170b along the second direction A2 is defined as the second width d. p At time 2, the second width d p 2 is the maximum width of structure 170 along the second direction A2. The second width d p 2 is appropriately 10 μm or more, and can be, for example, 40 μm.

[0138] In structure 170, the portion between the central portion 170a and the non-central portion 170b can have a shape in which the width along the second direction A2 gradually decreases from the non-central portion 170b to the central portion 170a, such as... Figure 19 As shown. When viewed from the optical axis direction (Z direction), the angle θ formed between the outer peripheral edge of structure 170 and the first direction A1 can be, for example, 3.8°. Furthermore, as... Figure 19 As shown, when the length of structure 170 along the first direction A1 is defined as length L p At that time, length L p Appropriately larger than the second width d p 2, and appropriately 40 μm or greater. Length L p It can be, for example, 100 μm.

[0139] Structure 170 is formed from a fluid material that is fluid at room temperature or during the heating process described below. The fluid material may be an organic material or SOG (silicon on glass), and may be a commercially available photoresist. Structure 170 may be formed by coating the fluid material onto a first surface 151 to a certain thickness and patterning the fluid material.

[0140] The fluid material can be coated by spin coating at a speed of 10 rpm or greater, and for example, 3000 rpm. Patterning can be performed by forming a mask with the aforementioned planar shape of structure 170 on the fluid material and then using the mask to perform etching. The etching can be wet etching or dry etching. Alternatively, reactive ion etching (RIE) can be used. The mask can be formed by photolithography, and a calibrator, stepper, or electron beam writer can be used as the exposure device. As the light source, g-line, i-line, KrF laser, or ArF laser can be used.

[0141] Subsequently, heat treatment (reflux) is performed to heat structure 170 to a temperature equal to or higher than the melting point of the fluid material. The heating temperature may be, for example, 160°C. This heating changes the viscosity of the fluid material and alters the shape of structure 170. Figure 20 This is a schematic diagram showing structure 175, which is deformed from structure 170 through heat treatment. The shape of structure 175 is the same as that of lens 160 described above. That is, the width of the central portion of structure 175 is equal to the first width d of lens 160. s 1 (see) Figure 8 Furthermore, the width of the non-central portion of structure 175 is equal to the second width d of lens 160. s 2. Furthermore, the height of structure 175 is uniform and equal to the height H of lens 160. s Furthermore, the radius of curvature of the vertex of structure 175 in the second direction A2 is equal to the radius of curvature R of the vertex of lens 160 in the second direction A2. s .

[0142] Subsequently, the first semiconductor layer 101 was etched using structure 175 as an etching mask. Figure 21 This is a schematic diagram illustrating the etching process. As indicated by the arrows in the diagram, etchant is provided to the first semiconductor layer 101 from the first surface 151 side. As a result, the first semiconductor layer 101 is etched from the first surface 151 side to form a lens 160. At this time, by making the etching rates of the first semiconductor layer 101 and the structure 175 equal, a lens 160 with the same shape as the structure 175 can be formed. The etching can be wet etching or dry etching. However, anisotropic etching is suitable, and reactive ion etching can be used.

[0143] Furthermore, instead of using structure 175 as an etching mask, structure 175 can be used as lens 160. When structure 175 is used as lens 160, such as Figure 12 The lens 160 shown includes components different from the first semiconductor layer 101. A structure 175 can be used as the lens 160 by forming a structure 170 of a material that is transparent to light at the oscillation wavelength λ.

[0144] In this way, lens 160 can be formed on the first surface 151 (see...) Figure 6 Then, a first light-reflecting layer 104, a second light-reflecting layer 105, a first electrode 106, and a second electrode 107 are formed, thus enabling the fabrication of... Figure 1 The laser element 100 is shown. Each of these layers can be formed by sputtering, vacuum deposition, or the like. When the first light-reflecting layer 104 is stacked on the first semiconductor layer 101, a concave mirror 104c is formed because the lens 160 is disposed on the first surface 151. Note that the second light-reflecting layer 105 and the second electrode 107 can be formed before the lens 160 is formed.

[0145] In this manufacturing method, the structure 170 is made to have a narrow shape with a central portion 170a as described above (see...). Figure 19 This allows the height and radius of curvature of the apex of structure 175 to be uniform, thereby making the height and radius of curvature of the lens 160 uniform as well. If structure 170 has a uniform width when viewed from the Z direction, the deformation of structure 175 results in a shape in which the central portion is concave due to the effects of surface tension and weight (see...). Figure 14 Furthermore, the radius of curvature of the central portion increases. On the other hand, when the structure 170 has a shape with a narrow width of the central portion 170a, surface tension plays a role in reducing the radius of curvature and can make the height of the structure 175 and the radius of curvature of the apex uniform.

[0146] Furthermore, in the step of etching the first semiconductor layer 101 described above, by performing the etching under the condition that the surface accuracy (RMS: root mean square) of the structure 175 is lower than the surface accuracy (RMS) of the first semiconductor layer 101, the surface accuracy (RMS) of the lens 160 after etching can be lower than the surface accuracy before etching. Therefore, scattering loss on the surface of the lens 160 can be suppressed and the performance of the resonator can be improved. In addition, the threshold and power consumption of the laser element 100 can be reduced and the output structure, efficiency, and reliability can be improved.

[0147] The laser element 100 can be manufactured in this manner. Note that the method of manufacturing the laser element 100 is not limited to the method shown herein, and the laser element 100 can be manufactured by another method. Figure 22 This is a schematic diagram illustrating another manufacturing method of the laser element 100. A structure 170 is formed on the first surface 151 (see...). Figure 17After that, heat treatment (reflow) is performed with the first surface 151 facing downwards as shown in the figure. This prevents the height of the central portion of the structure 175 from decreasing due to gravity, and therefore allows the height of the structure 175 to be uniform or for the central portion to be higher than the ends.

[0148] [Another lens configuration]

[0149] The lens 160 included in the laser element 100 may have the configuration shown below, instead of the configuration described above. Figure 23 and Figure 25 Each is a plan view of a lens 160 with another configuration, and each is a diagram of the lens 160 when viewed from the optical axis direction (Z direction).

[0150] like Figure 23 As shown, lens 160 may have a shape in which the width along the second direction A2 decreases in a stepped manner from the non-central portion 160b to the central portion 160a. The height H of lens 160... s and the radius of curvature R of the lens vertex in the second direction A2 s (see Figure 9 The height H is uniform. s It can be, for example, 3.6 μm, and the radius of curvature R s Greater than the resonator length K (see Figure 10 ) and can be, for example, 44μm.

[0151] The central portion 160a has a first width d along the second direction A2. s 1 can be, for example, 36 μm, and the non-central portion 160b has a second width d along the second direction A2. s 2 can be, for example, 40 μm. Furthermore, the length L of lens 160 along the first direction A1... s It can be, for example, 100 μm, with a first width d along the first direction A1. s The length M of part 1 s 1 can be, for example, 10 μm, and has a second width d along the first direction A1. s The length M of part 2 s 2 can be, for example, 30 μm.

[0152] The following structure 170 can be used to prepare Figure 23 The shape of lens 160 shown. Figure 24 This is a plan view of a structure 170 capable of forming the shape of lens 160. Structure 170 has a certain thickness from the first surface 151 (see...). Figure 17 And as shown in the figure, it can have a shape in which the width along the second direction A2 decreases in a stepped manner from the non-central portion 160b to the central portion 160a.

[0153] The central portion 170a has a first width d along the second direction A2. p 1 can be, for example, 36 μm, and the non-central portion 170b has a second width d along the second direction A2. p 2 can be, for example, 40 μm. Furthermore, the length L of structure 170 along the first direction A1... p It can be, for example, 100 μm, with a first width d along the first direction A1. p The length M of part 1 p 1 can be, for example, 10 μm, and has a second width d along the first direction A1. p The length M of part 2 p 2 can be, for example, 30 μm.

[0154] In addition, such as Figure 25 As shown, lens 160 may also have a shape in which rectangular blocks (B1 to B5) whose width narrows from the non-central portion 160b to the central portion 160a are connected. The number of blocks is not particularly limited, and may, for example, be five. The height H of lens 160 is... s and the radius of curvature R of the lens vertex in the second direction A2 s (see Figure 9 The height H is uniform. s It can be, for example, 3.6 μm, and the radius of curvature R s Greater than the resonator length K (see Figure 10 ) and can be, for example, 44μm.

[0155] The central portion 160a has a first width d along the second direction A2. s 1 can be, for example, 36 μm, and the non-central portion 160b has a second width d along the second direction A2. s 2 can be, for example, 40 μm. In the portion between the central portion 160a and the non-central portion 160b, the width along the second direction A2 decreases from the non-central portion 160b to the central portion 160a, and satisfies the second width d. s 2> Third width d s 3> Fourth width d s 4> First width d s The relationship of 1.

[0156] Specifically, for example, the second width d s 2 can be 40μm, and the third width d s 3 can be 39μm, the fourth width d s 4 can be 38μm, the first width d s 1 can be 36μm. Furthermore, the length L of lens 160 along the first direction A1... sIt could be, for example, 100 μm. Regarding the length M of each portion along the first direction A1... s 1 to M s 4. Length M s 2 can be 10μm, length M s 3 can be 10μm, length M s 4 can be 5μm, and the length M s 1 can be 10μm.

[0157] The following structure 170 can be used to prepare Figure 25 The shape of lens 160 shown. Figure 26 This is a plan view of a structure 170 capable of forming the shape of lens 160. Structure 170 has a certain thickness from the first surface 151 (see...). Figure 17 It may also have a shape in which rectangular blocks (B1 to B5) are connected from the non-central portion 160b to the central portion 160a, as shown in the figure. The central portion 170a has a first width d along the second direction A2. p 1 can be, for example, 36 μm, and the non-central portion 170b has a second width d along the second direction A2. p 2 can be, for example, 40 μm.

[0158] In the portion between the central portion 170a and the non-central portion 170b, the width along the second direction A2 decreases from the non-central portion 170b towards the central portion 170a, and satisfies the second width d. p 2> Third width d p 3> Fourth width d p 4> First width d p The relationship is 1. Specifically, for example, the second width d p 2 can be 40μm, and the third width d p 3 can be 39μm, the fourth width d p 4 can be 38μm, and the first width d p 1 can be 36 μm. Furthermore, the length L of lens 160 along the first direction A1... p It could be, for example, 100 μm. Regarding the length M of each portion along the first direction A1... p 1 to Mp4, length M p 2 can be 10μm, length Mp3 can be 10μm, length Mp4 can be 5μm, and length M p 1 can be 10μm.

[0159] Similarly, in lens 160, there is such Figure 23 and Figure 25 In the configuration shown, due to the height H of the lens vertex sand radius of curvature R s It is uniform, thus enabling the emission of a good line source with no uneven brightness in the laser E. Furthermore, instead of the shape shown here, the shape of the lens 160 can be a shape including a central portion 160a and a non-central portion 160b, wherein the height H of the lens apex... s and radius of curvature R s It is uniform.

[0160] [Another configuration for the laser element]

[0161] The configuration of the laser element 100 is not limited to the above configuration, and may include a wavelength conversion layer. Figure 27 This is a cross-sectional view of the laser element 100 including the wavelength conversion layer 181. The wavelength conversion layer 181, formed of a wavelength conversion material, is disposed on the side of the second light-reflecting layer 105 opposite to the laminate 150, and converts the laser E that has entered from the second light-reflecting layer 105 (see...). Figure 13 The wavelength of ).

[0162] The wavelength conversion material forming the wavelength conversion layer 181 can be a wavelength conversion material that is excited by blue light and emits red light. Specifically, red luminescent phosphor particles can be used, more specifically, (ME: Eu)S [however, "ME" refers to at least one atom selected from the group consisting of Ca, Sr, and Ba, and applies equally hereinafter], (M: Sm] X (Si, Al) 12 (O, N) 16 [However, “M” refers to at least one atom selected from the group consisting of Li, Mg and Ca, and applies equally below], ME2Si5N8:Eu, (Ca:Eu)SiN2 and (Ca:Eu)AlSiN3.

[0163] Furthermore, the wavelength conversion material forming the wavelength conversion layer 181 can be a wavelength conversion material that is excited by blue light and emits green light. Specifically, green luminescent phosphor particles can be used, more specifically, (ME: Eu)Ga2S4, (M: RE) X (Si, Al) 12 (O, N) 16 [However, "RE" refers to Tb and Yb], (M: Tb) X (Si, Al) 12 (O, N) 16 (M:Yb) X (Si, Al) 12 (O, N) 16 and Si 6-Z Al Z O Z N 8-ZEu.

[0164] Furthermore, the wavelength conversion material forming the wavelength conversion layer 181 can be a wavelength conversion material that is excited by blue light and emits yellow light. Specifically, yellow luminescent phosphor particles can be used, and more specifically, YAG (yttrium aluminum garnet) phosphor particles can be used. Note that the wavelength conversion material can be of one type, or two or more types can be mixed and used.

[0165] Furthermore, by using a mixture of two or more types of wavelength conversion materials forming the wavelength conversion layer 181, emitted light of colors other than yellow, green, and red can be emitted from the mixture of wavelength conversion materials. Specifically, for example, cyan light can be emitted. In this case, only green luminescent phosphor particles (e.g., LaPO4:Ce, Tb, BaMgAl) are needed. 10 O 17 : Eu, Mn, Zn2SiO4: Mn, MgAl 11 O 19 Ce, Tb, Y₂SiO₅: Ce, Tb or MgAl 11 O 19 (CE, Tb, Mn) and blue luminescent phosphor particles (e.g., BaMgAl) 10 O 17 Eu, BaMg2Al 16 O 27 A mixture of Eu, Sr2P2O7, Eu, Sr5(PO4)3Cl, Eu, (Sr, Ca, Ba, Mg)5(PO4)3Cl, Eu, CaWO4 or CaWO4: Pb.

[0166] Furthermore, the wavelength conversion material forming the wavelength conversion layer 181 can be a wavelength conversion material that is excited by ultraviolet light and emits red light. Specifically, red emitting phosphor particles can be used, and more specifically, Y₂O₃:Eu, YVO₄:Eu, Y(P,V)O₄:Eu, 3.5MgO·0.5MgF₂·Ge₂:Mn, CaSiO₃:Pb,Mn, Mg₆AsO₂ 11 :Mn、(Sr、Mg)3(PO4)3:Sn、La2O2S:Eu or Y2O2S:Eu.

[0167] Furthermore, the wavelength conversion material forming the wavelength conversion layer 181 can be a wavelength conversion material that is excited by ultraviolet light and emits green light. Specifically, green luminescent phosphor particles can be used, and more specifically, LaPO4:Ce,Tb,BaMgAl 10 O 17 : Eu, Mn, Zn2SiO4: Mn, MgAl 11 O 19: Ce, Tb, Y2SiO5: Ce, Tb, MgAl 11 O 19 : CE, Tb, Mn, or Si 6-Z Al Z O Z N 8-Z Eu.

[0168] Furthermore, the wavelength conversion material forming the wavelength conversion layer 181 can be a wavelength conversion material that is excited by ultraviolet light and emits blue light. Specifically, blue light-emitting phosphor particles can be used, and more specifically, BaMgAl 10 O 17 Eu, BaMg2Al 16 O 27 : Eu, Sr2P2O7: Eu, Sr5(PO4)3Cl: Eu, (Sr, Ca, Ba, Mg)5(PO4)3Cl: Eu, CaWO4 or CaWO4: Pb.

[0169] Furthermore, the wavelength conversion material forming the wavelength conversion layer 181 can be a wavelength conversion material that is excited by ultraviolet light and emits yellow light. Specifically, yellow luminescent phosphor particles, and more specifically, YAG phosphor particles, can be used. Note that the wavelength conversion material can be of one type, or two or more types can be mixed and used. Furthermore, by using a mixture of two or more types of wavelength conversion materials, light of colors other than yellow, green, and red can be emitted from the mixture of wavelength conversion materials. Specifically, cyan light can be emitted. In this case, a mixture of the aforementioned green and blue luminescent phosphor particles can be used.

[0170] However, wavelength conversion materials (color conversion materials) are not limited to phosphor particles. Examples of wavelength conversion materials include luminescent particles in which the wavefunction of charge carriers in an indirect transition silicon material is localized to efficiently convert charge carriers into light as in a direct transition material, and quantum effects are used; quantum well structures such as two-dimensional quantum well structures, one-dimensional quantum well structures (quantum wires), and zero-dimensional quantum well structures (quantum dots) are applied to these luminescent particles. Furthermore, it is known that rare-earth atoms added to semiconductor materials emit light rapidly due to intrashell transitions, and luminescent particles employing this technology can also be used.

[0171] Examples of wavelength conversion materials (color conversion materials) forming the wavelength conversion layer 181 include quantum dots as described above. As the size (diameter) of the quantum dot decreases, the band gap energy increases and the wavelength of the light emitted from the quantum dot decreases. That is, the smaller the size of the quantum dot, the shorter the wavelength of the emitted light (light on the blue side), and the larger the size, the longer the wavelength of the emitted light (light on the red side). Therefore, by using the same material used to form the quantum dot and adjusting the size of the quantum dot, quantum dots that emit light with a desired wavelength (convert to a desired color) can be obtained.

[0172] Specifically, quantum dots preferably have a core-shell structure. Examples of materials forming quantum dots include, but are not limited to, Si; Se; CIGS (CuInGaSe), CIS (CuInSe2), CuInS2, CuAlS2, CuAlSe2, CuGaS2, CuGaSe2, AgAlS2, AgAlSe2, AgInS2, AgInSe2 as chalcopyrite compounds; perovskite materials; GaAs, GaP, InP, InAs, InGaAs, AlGaAs, InGaP, AlGaInP, InGaAsP, GaN as III-V compounds; CdSe, CdSeS, CdS, CdTe, In2Se3, In2S3, Bi2Se3, Bi2S3, ZnSe, ZnTe, ZnS, HgTe, HgS, PbSe, PbS, and TiO2.

[0173] Furthermore, although in the above description, the first semiconductor layer 101 is formed of an n-type semiconductor material and the second semiconductor layer 102 is formed of a p-type semiconductor material, the first semiconductor layer 101 may be formed of a p-type semiconductor material and the second semiconductor layer 102 may be formed of an n-type semiconductor material. Additionally, the laser element 100 may have another configuration capable of realizing the operation of the laser element 100 described above.

[0174] [About laser element arrays]

[0175] Laser element 100 can form a laser element array. Figure 28 This is a cross-sectional view of the laser element array 10 according to this embodiment, and Figure 29 This is a schematic plan view of the laser element array 10.

[0176] like Figure 28 and Figure 29 As shown, the laser element array 10 includes a plurality of arrayed laser elements 100. The number of laser elements 100 constituting the laser element array 10 is not particularly limited, but can be, for example, 10. Figure 29As shown, the laser elements 100 can be arranged such that the first direction A1 (the longitudinal direction of the lens 160) of each of the laser elements 100 matches. For example, the array spacing R (the interval between the centers of the lenses 160) can be 20 μm. The arrangement direction of the laser elements 100 is not limited to this, and the lenses 160 can be arranged in a hexagonal close-packed array.

[0177] The first electrode 106 of each laser element 100 is spaced apart from the first electrode 106 of the adjacent laser element 100. Therefore, by independently controlling the voltage between the first electrode 106 and the second electrode 107 of the laser element 100, the laser element 100 can emit light independently. Because each of the laser elements 100 is a good line source emitting laser light E without brightness non-uniformity, the laser element array 10 can have a high output of more than 1W by, for example, arranging the laser elements 100.

[0178] Similarly, in the laser element array 10, the laser element 100 may include a wavelength conversion layer 181. Figure 30 This is a cross-sectional view showing the laser element array 10 including the wavelength conversion layer 181. The wavelength conversion layer 181 may be included in each laser element 100, or may be a continuous layer between multiple laser elements 100.

[0179] (Second Implementation)

[0180] A laser element according to a second embodiment of the present technology will be described. The main difference between the laser element according to this embodiment and the laser element according to the first embodiment lies in the current limiting structure. The laser element according to this embodiment has a structure similar to that of a VCSEL element, but the difference between the laser element according to this embodiment and the VCSEL element is that resonance occurs not only in the Z direction, but also in another direction (Y direction).

[0181] [Structure of laser components]

[0182] Figure 31 This is a cross-sectional view of the laser element 200 according to this embodiment, and Figure 32 This is an exploded cross-sectional view showing a partial configuration of the laser element 200. As shown, the laser element 200 includes a substrate 201, a first semiconductor layer 202, a second semiconductor layer 203, a third semiconductor layer 204, an active layer 205, a tunnel junction layer 206, a first light-reflecting layer 207, a second light-reflecting layer 208, a first electrode 209, a second electrode 210, and an insulating film 211. The substrate 201, the first semiconductor layer 202, the second semiconductor layer 203, the third semiconductor layer 204, the active layer 205, and the tunnel junction layer 206 are collectively referred to as a laminate 250.

[0183] Each of these layers has a surface orientation along the XY plane, and the first light-reflecting layer 207, substrate 201, first semiconductor layer 202, active layer 205, second semiconductor layer 203, third semiconductor layer 204, and second light-reflecting layer 208 are stacked in this order. Therefore, the stack 250 is disposed between the first light-reflecting layer 207 and the second light-reflecting layer 208.

[0184] Substrate 201 supports each layer of laser element 200. Substrate 201 may include, for example, a semi-insulating InP substrate. Figure 32 As shown, lens 260 is disposed on substrate 201. Lens 260 will be described below.

[0185] The first semiconductor layer 202 is formed of a semiconductor having a first conductivity type and is a layer that transports charge carriers to the active layer 205. The first conductivity type can be n-type, and the first semiconductor layer 202 can be a layer formed of, for example, n-InP. The second semiconductor layer 203 is formed of a semiconductor having a second conductivity type and is a layer that transports charge carriers to the active layer 205. The second conductivity type can be p-type, and the second semiconductor layer 203 can be a layer formed of, for example, P-InP. The third semiconductor layer 204 is formed of a semiconductor having a first conductivity type and is a layer that transports charge carriers to the tunnel junction layer 206. The third semiconductor layer 204 can be a layer formed of, for example, n-InP.

[0186] The active layer 205 is disposed between the first semiconductor layer 202 and the second semiconductor layer 203 and emits light through carrier recombination. The active layer 205 has a multiple quantum well structure in which quantum well layers and barrier layers are alternately stacked to obtain multiple layers. The quantum well layers can be formed, for example, by InGaAsP, and the barrier layers can be formed, for example, by InGaAsP having a composition different from that of the quantum well layers. Furthermore, the active layer 205 only needs to be a layer that emits light through carrier recombination, and does not need to be a multiple quantum well structure.

[0187] A tunnel junction layer 206 forms a buried tunnel junction. The tunnel junction layer 206 is disposed between the central portion of the second semiconductor layer 203 and the central portion of the third semiconductor layer 204. The tunnel junction layer 206 includes a first layer 206a on one side of the second semiconductor layer 203 and a second layer 206b on one side of the third semiconductor layer 204. The first layer 206a is a layer of a second conductivity type with a high impurity concentration, and may be, for example, composed of p... + The second layer, 206b, is an AlInGaAs layer. It is a first conductivity type layer with a high impurity concentration and can be, for example, composed of n... + -InP forms the layer.

[0188] like Figure 31As shown, the outer periphery portions of the active layer 205, the second semiconductor layer 203, and the third semiconductor layer 204 are removed to form a mesa (platform structure) M. The tunnel junction layer 206 is arranged in the central portion of the mesa M when viewed from the Z direction.

[0189] like Figure 31 As shown, in the surface of the laminate 250, the surface on the side of the first light-reflecting layer 207 is defined as the first surface 251, and the surface on the side of the second light-reflecting layer 208 is defined as the second surface 252. The lens 260 is disposed on the first surface 251. Therefore, as... Figure 32 As shown, the first surface 251 has a main surface 251a and a lens surface 251b. The main surface 251a is a plane (XY plane) perpendicular to the optical axis (Z direction) of the emitted light. The lens surface 251b is the surface of the lens 260 and is a surface that protrudes from the main surface 251a.

[0190] The first light-reflecting layer 207 reflects light of a specific wavelength (hereinafter, wavelength λ) and allows light of other wavelengths to pass through. Wavelength λ is, for example, a specific wavelength within the range of 1300 nm to 1600 nm. Figure 31 As shown, the first light-reflecting layer 207 can be a DBR (Distributed Bragg Reflector), which includes multiple layers of light-reflecting films. These layers consist of alternating layers of a high-refractive-index layer 207a and a low-refractive-index layer 207b, each with an optical film thickness of λ / 4. For example, the first light-reflecting layer 207 can have a layered structure such as Ta2O5 / SiO2, SiO2 / SiN, or SiO2 / Nb2O5.

[0191] The first light-reflecting layer 207 includes a concave mirror 207c. The first light-reflecting layer 207 is stacked on the second surface 201b of the substrate 201 to have a certain thickness. Its surface on one side of the stack 250 is formed with a concave surface 207d according to the shape of the lens 260 disposed on the first surface 251, and its surface on the side opposite to the stack 250 is formed with a convex surface 207e. As a result, a concave mirror 207c is formed in the first light-reflecting layer 207.

[0192] The second light-reflecting layer 208 reflects light with wavelength λ and allows light of wavelengths other than λ to pass through. For example... Figure 31 As shown, the second light-reflecting layer 208 can be a DBR (distributed Bragg reflector) comprising multiple light-reflecting films. In the multiple light-reflecting films, a high-refractive-index layer 208a and a low-refractive-index layer 208b with an optical film thickness of λ / 4 are alternately stacked to obtain multiple layers. For example, the second light-reflecting layer 208 can have a layered structure such as Ta2O5 / SiO2, SiO2 / SiN, or SiO2 / Nb2O5.

[0193] The first electrode 209 is disposed around the mesa M on the first semiconductor layer 202 and serves as an electrode of the laser element 200. The first electrode 209 may include, for example, a single-layer metal film formed of Au, Ni, Ti, etc., or a multilayer metal film formed of Ti / Au, Ag / Pd, Ni / Au / Pt, etc.

[0194] The second electrode 210 is disposed around the second light-reflecting layer 208 on the third semiconductor layer 204 and serves as another electrode of the laser element 200. The second electrode 210 may comprise, for example, a single-layer metal film formed of Au, Ni, Ti, etc., or a multilayer metal film formed of Ti / Au, Ag / Pd, Ni / Au / Pt, etc. An insulating film 211 is disposed around the second electrode 210 on the side surface and the upper surface of the mesa M to insulate the outer periphery of the mesa M. The insulating film 211 is formed of any insulating material.

[0195] In the laser element 200, a current-limiting structure is formed in the laminate 250 through the tunnel junction layer 206. Figure 33 This is a schematic diagram illustrating the current-limiting structure. As shown, the current-limiting structure has a current injection region 221 and an insulating region 222. The current injection region 221 is the region where a tunnel junction is formed by the tunnel junction layer 206 (tunnel junction region), and current passes through this tunnel junction. The insulating region 222 is the region surrounding the current injection region 221 in the layer surface direction (XY direction) and does not allow current to pass through because no tunnel junction is formed (non-tunnel junction region). Because the current flowing through the laser element 200 cannot pass through the insulating region 222, the current is concentrated in the current injection region 221. That is, the current injection region 221 and the insulating region 222 form a current-limiting structure.

[0196] [Regarding the shape of the current injection area and the lens]

[0197] The shape of the current injection region 221 in the laser element 200 is the same as the shape of the current injection region 121 according to the first embodiment. That is, the current injection region 221 has an elongated planar shape, wherein the first direction A1 is the longitudinal direction and the second direction A2 is the transverse direction (see...). Figure 3 and Figure 4 The first direction A1 and the second direction A2 are orthogonal to the optical axis (Z direction) and are mutually orthogonal.

[0198] Furthermore, the shape of the lens 260 in the laser element 200 is the same as that of the lens 160 according to the first embodiment. That is, the lens 260 has an elongated lens shape, wherein the first direction A1 is the longitudinal direction and the second direction A2 is the transverse direction. Moreover, the length, width, height, radius of curvature of the lens vertex, and surface finish (RMS) of the lens 260 are the same as those of the lens 160.

[0199] Note that, although Figure 32 As shown, lens 260 may be formed from a portion of substrate 201, but lens 260 may include components that are different from substrate 201 and bonded to substrate 201 (see...). Figure 12 ).

[0200] [Operation of laser components]

[0201] Laser element 200 operates similarly to laser element 100 according to the first embodiment. That is, when a voltage is applied between the first electrode 209 and the second electrode 210, current flows between the first electrode 209 and the second electrode 210. The current is limited by a current-limiting structure and injected into the current injection region 221. Spontaneous emission light caused by this injected current is reflected by the first light-reflecting layer 207 and the second light-reflecting layer 208 to induce laser oscillation. The resulting laser light is transmitted through the second light-reflecting layer 208 and emitted from laser element 200 with the Z direction as the optical axis. Laser element 200 is capable of emitting a laser E with a large beam diameter and a narrow radiation angle through the shape of the current injection region 221 and the lens 260, and operates as a line light source emitting a linear beam.

[0202] [Effects of laser components]

[0203] Furthermore, the laser element 200 includes a lens 260, in which the height H from the main surface 251a is... s and the radius of curvature R of the lens vertex in the second direction A2 s (see Figure 9 The light source is uniform. Therefore, by forming a current injection region 221 on the lens 260, modes resonating in the optical axis direction (Z direction) and the longitudinal direction (Y direction) of the lens 260 can be formed, and a laser element 200 emitting light with high linearity can be realized. Furthermore, in the laser element 200, in some cases, because the radius of curvature R... s It is uniform, so the lateral pattern can be consistent, and because of the height H sIt is uniform, so the longitudinal pattern can be uniform. Therefore, laser E without brightness non-uniformity can be emitted, and thus, laser element 200 can achieve a good line light source. In addition, because the height is more uniform and stress is dispersed in lens 260, durability can be improved.

[0204] [Manufacturing methods for laser components]

[0205] In the manufacturing method of laser element 200, after each layer up to the second layer 206b is stacked on substrate 201 by metal-organic chemical vapor deposition or the like, unnecessary portions of the first layer 206a and the second layer 206b are removed by photolithography and etching to form tunnel junction layer 206. The shape of tunnel junction layer 206 can be freely controlled by photolithography.

[0206] Subsequently, a third semiconductor layer 204 is stacked on the tunnel junction layer 206, and a mesa M is formed by photolithography and etching. As a result, a stack 250 is formed on the substrate 201. Furthermore, a lens 260 is disposed on the substrate 201 by a method similar to that in the first embodiment, and a first light-reflecting layer 207, a second light-reflecting layer 208, etc., are stacked, thereby enabling the fabrication of a laser element 200. Alternatively, the laser element 200 can be fabricated by another manufacturing method.

[0207] [Regarding current-limiting structures via ion implantation]

[0208] Although, as described above, the current-limiting structure is provided by the buried tunnel junction in the tunnel junction layer 206 of the laser element 200, as described below, the current-limiting structure can also be provided by ion implantation into the tunnel junction layer 206.

[0209] Figure 34 This is a cross-sectional view of a laser element 200 having an insulating region 223 formed by ion implantation. In this configuration, a tunnel junction layer 206 is disposed entirely between a second semiconductor layer 203 and a third semiconductor layer 204, and the insulating region 223 (dashed region) is disposed in the outer peripheral region of the tunnel junction layer 206.

[0210] like Figure 34 As shown, the current-limiting structure has a current-injection region 221 and an insulating region 223. The current-injection region 221 is formed from a tunnel junction layer 206 without ion implantation. Meanwhile, the insulating region 223 is a region surrounding the current-injection region 221 in the layer surface direction (XY direction) and insulated by ion implantation into the tunnel junction layer 206. The ions implanted into the ion-implantation region can be boron (B) ions. Alternatively, ions capable of insulating semiconductor materials, such as oxygen (O) ions and hydrogen (H) ions, can be used instead of B ions.

[0211] Similarly, in this configuration, because the current flowing through the laser element 200 cannot pass through the insulating region 223, the current is concentrated in the current injection region 221. That is, the current injection region 221 and the insulating region 223 form a current-limiting structure.

[0212] [Another configuration for the laser element]

[0213] Although in the above description, each layer is stacked on substrate 201 to prepare laminate 250, laminate 250 can be formed by stacking each layer on another support substrate, removing the support substrate, and bonding these layers to substrate 201. Furthermore, similar to the first embodiment, laser element 200 may include a wavelength conversion layer (see...). Figure 27 The wavelength conversion layer changes the wavelength of the emitted light on the side of the second light reflective layer 208 opposite to the laminate 250.

[0214] Furthermore, although the first semiconductor layer 202 and the third semiconductor layer 204 are formed of n-type semiconductor material and the second semiconductor layer 203 is formed of p-type semiconductor material, the first semiconductor layer 202 and the third semiconductor layer 204 can be formed of p-type semiconductor material and the second semiconductor layer 203 can be formed of n-type semiconductor material. In this case, the first layer 206a of the tunnel junction layer 206 can be an n-type layer with a high impurity concentration, and the second layer 206b can be a p-type layer with a high impurity concentration. Additionally, instead of the above configuration, the laser element 200 can have another configuration capable of realizing the operation of the laser element 200 described above.

[0215] [About laser element arrays]

[0216] The laser elements 200 can be arranged similarly to those in the first embodiment. Because each laser element 200 is a good line source emitting laser light E without brightness inhomogeneity, the laser element array including the laser elements 200 can, for example, have a high output exceeding 1W by arranging the laser elements 200. The laser element array including the laser elements 200 may include a wavelength conversion layer (see...). Figure 28 ).

[0217] (Third Implementation)

[0218] A laser element according to a third embodiment of the present invention will be described. The main difference between the laser element according to this embodiment and the laser element according to the first embodiment lies in the current limiting structure. The laser element according to this embodiment has a structure similar to that of a VCSEL element, but the difference between the laser element according to this embodiment and the VCSEL element is that resonance occurs not only in the Z direction, but also in another direction (Y direction).

[0219] [Structure of laser components]

[0220] Figure 35 This is a cross-sectional view of the laser element 300 according to this embodiment, and Figure 36 These are exploded cross-sectional views of a portion of the configuration of the laser element 300. As shown in these figures, the laser element 300 includes a substrate 301, a first semiconductor layer 302, a second semiconductor layer 303, an active layer 304, an oxide confinement layer 305, a first light-reflecting layer 306, a second light-reflecting layer 307, a first electrode 308, a second electrode 309, and an insulating film 310. The substrate 301, the first semiconductor layer 302, the second semiconductor layer 303, the active layer 304, and the oxide confinement layer 305 are collectively referred to as a laminate 350.

[0221] Each of these layers has a surface orientation along the XY plane, and the first light-reflecting layer 306, substrate 301, first semiconductor layer 302, active layer 304, second semiconductor layer 303, oxide confinement layer 305, and second light-reflecting layer 307 are stacked in this order. Therefore, the stack 350 is disposed between the first light-reflecting layer 306 and the second light-reflecting layer 307.

[0222] Substrate 301 supports each layer of laser element 300. Substrate 301 may include, for example, a semi-insulating GaAs substrate. Figure 36 As shown, lens 360 is disposed on substrate 301. Lens 360 will be described below.

[0223] The first semiconductor layer 302 is formed of a semiconductor having a first conductivity type and is a layer that transports charge carriers to the active layer 304. The first conductivity type can be n-type, and the first semiconductor layer 302 can be formed of, for example, n-GaAs. The second semiconductor layer 303 is formed of a semiconductor having a second conductivity type and is a layer that transports charge carriers to the active layer 304. The second conductivity type can be p-type, and the second semiconductor layer 303 can be a layer formed of, for example, p-GaAs.

[0224] The active layer 304 is disposed between the first semiconductor layer 302 and the second semiconductor layer 303 and emits light through carrier recombination. The active layer 304 has a multiple quantum well structure in which quantum well layers and barrier layers are alternately stacked to obtain multiple layers. The quantum well layers can be formed of, for example, GaAs, and the barrier layers can be formed of, for example, AlGaAs. Furthermore, the active layer 304 only needs to be a layer that emits light through carrier recombination, and does not need to be a multiple quantum well structure.

[0225] The oxide confinement layer 305 forms a current-limiting structure. The oxide confinement layer 305 has an unoxidized region 305a in which the semiconductor material is not oxidized and an oxidized region 305b in which the semiconductor material is oxidized. The unoxidized region 305a is formed of a material of a second conductivity type with a high impurity concentration, and can be, for example, p-type. + -AlAs. The oxidized region 305b is formed of a material obtained by oxidizing the constituent material of the unoxidized region 305a, and may be, for example, an AlAs oxide.

[0226] like Figure 35 As shown, in the surface of the laminate 350, the surface on the side of the first light-reflecting layer 306 is defined as the first surface 351, and the surface on the side of the second light-reflecting layer 307 is defined as the second surface 352. A lens 360 is disposed on the first surface 351. As a result, as... Figure 36 As shown, the first surface 351 has a main surface 351a and a lens surface 351b. The main surface 351a is a plane (XY plane) perpendicular to the optical axis (Z direction) of the emitted light. The lens surface 351b is the surface of the lens 360 and is a surface that protrudes from the main surface 351a.

[0227] The first light-reflecting layer 306 reflects light of a specific wavelength (hereinafter, wavelength λ) and allows light of other wavelengths to pass through. Wavelength λ is, for example, a specific wavelength within the range of 850 nm to 1400 nm. Figure 35 As shown, the first light-reflecting layer 306 can be a DBR (distributed Bragg reflector) comprising multiple light-reflecting films, in which a high-refractive-index layer 306a and a low-refractive-index layer 306b with an optical film thickness of λ / 4 are alternately stacked to obtain multiple layers. For example, the first light-reflecting layer 306 can have a layered structure such as Ta2O5 / SiO2, SiO2 / SiN, SiO2 / Nb2O5, etc.

[0228] The first light-reflecting layer 306 includes a concave mirror 306c. The first light-reflecting layer 306 is stacked on the second surface 301b of the substrate 301 to have a certain thickness. The surface of the first light-reflecting layer on one side of the stack 350 is formed with a concave surface 306d according to the shape of the lens 360 disposed on the first surface 351, and a convex surface 306e is formed on the surface opposite to the stack 350. As a result, the concave mirror 306c is formed in the first light-reflecting layer 306.

[0229] The second light-reflecting layer 307 reflects light with wavelength λ and allows light of other wavelengths to pass through. For example... Figure 35As shown, the second light-reflecting layer 307 can be a DBR (distributed Bragg reflector) comprising multiple layers of light-reflecting films, wherein a high-refractive-index layer 307a and a low-refractive-index layer 307b with an optical film thickness of λ / 4 are alternately stacked to obtain multiple layers. The second light-reflecting layer 307 can be a semiconductor DBR formed of semiconductor material.

[0230] like Figure 35 As shown, the outer periphery of the active layer 304, the second semiconductor layer 303, the oxide confinement layer 305, and the second light reflective layer 307 are removed to form a mesa (platform structure) M.

[0231] The first electrode 308 is disposed around the mesa M on the first semiconductor layer 302 and serves as an electrode of the laser element 300. The first electrode 308 may include, for example, a single-layer metal film formed of Au, Ni, Ti, etc., or a multilayer metal film formed of Ti / Au, Ag / Pd, Ni / Au / Pt, etc.

[0232] The second electrode 309 is disposed on the second light-reflecting layer 307 and serves as another electrode of the laser element 300. The second electrode 309 may comprise, for example, a single-layer metal film formed of Au, Ni, Ti, etc., or a multilayer metal film formed of Ti / Au, Ag / Pd, Ni / Au / Pt, etc. An insulating film 310 is disposed around the second electrode 309 on the side surface and the upper surface of the mesa M to insulate the outer periphery of the mesa M. The insulating film 310 is formed of any insulating material.

[0233] In the laser element 300, a current-limiting structure is formed in the laminate 350 by means of an oxide limiting layer 305. Figure 37 This is a schematic diagram illustrating the current-limiting structure. As shown, the current-limiting structure has a current-injection region 321 and an insulating region 322. The current-injection region 321 is a conductive region obtained through the unoxidized region 305a. The insulating region 322 is a non-conductive region that surrounds the current-injection region 321 in the layer surface direction (XY direction) and is insulated by the oxidized region 305b. Since the current flowing through the laser element 300 cannot pass through the insulating region 322, the current is concentrated in the current-injection region 321. That is, in the laser element 300, the current-limiting structure is formed by the oxide limiting layer 305.

[0234] [Regarding the shape of the current injection area and the lens]

[0235] The shape of the current injection region 321 in the laser element 300 is the same as that of the current injection region 321 according to the first embodiment. That is, the current injection region 321 has an elongated planar shape, wherein the first direction A1 is the longitudinal direction and the second direction A2 is the transverse direction (see...). Figure 3 and Figure 4 The first direction A1 and the second direction A2 are orthogonal to the optical axis (Z direction) and are mutually orthogonal.

[0236] Furthermore, the shape of the lens 360 in the laser element 300 is the same as that of the lens 160 according to the first embodiment. That is, the lens 360 has an elongated lens shape with the first direction A1 as the longitudinal direction and the second direction A2 as the transverse direction. Moreover, the length, width, height, radius of curvature of the lens vertex, and surface finish (RMS) of the lens 360 are the same as those of the lens 160.

[0237] Note that, although Figure 36 As shown, lens 360 may be formed from a portion of substrate 301, but lens 360 may include components that are different from substrate 301 and are bonded to substrate 301 (see...). Figure 12 ).

[0238] [Operation of laser components]

[0239] The laser element 300 operates similarly to the laser element 100 according to the first embodiment. That is, when a voltage is applied between the first electrode 308 and the second electrode 309, current flows between the first electrode 308 and the second electrode 309. The current is confined by a current-limiting structure and injected into the current injection region 321. Spontaneous emission light generated by this injected current is reflected by the first light-reflecting layer 306 and the second light-reflecting layer 307 to induce laser oscillation. The resulting laser light is transmitted through the second light-reflecting layer 307 and emitted from the laser element 300 with the Z direction as the optical axis. The laser element 300 is capable of emitting a laser E with a large beam diameter and a narrow radiation angle through the shape of the current injection region 321 and the lens 360, and operates as a line light source emitting a linear beam.

[0240] [Effects of laser components]

[0241] Furthermore, the laser element 300 includes a lens 360, in which the height H from the main surface 351a is... s and the radius of curvature R of the lens vertex in the second direction A2 s (see Figure 9 The light emission is uniform. Therefore, by forming a current injection region 321 on the lens 360, a mode resonating in the optical axis direction (Z direction) and also resonating in the longitudinal direction (Y direction) of the lens 360 can be formed, thus realizing a laser element 300 emitting light with high linearity. Furthermore, in the laser element 300, in some cases, because the radius of curvature R of the lens apex... s It is uniform, so the lateral pattern can be consistent, and because of the height H sIt is uniform, so the longitudinal pattern can be uniform. Therefore, laser E without brightness non-uniformity can be emitted, and thus, laser element 300 can achieve a good line light source. In addition, because the height is more uniform and stress is dispersed in the lens 360, durability can be improved.

[0242] [Manufacturing methods for laser components]

[0243] In the method for manufacturing the laser element 300, after stacking layers up to the second light-reflecting layer 307 on the substrate 301 using methods such as metal-organic chemical vapor deposition, a mesa M is formed by photolithography and etching. Subsequently, an oxide region 305b is formed by oxidizing the material of the oxide confinement layer 305 from the outer peripheral side by methods such as heating the laminate 350 in a steam atmosphere. At this time, when viewed from the Z direction, the shape of the unoxidized region 305a can be controlled by the shape of the mesa M when viewed from the Z direction.

[0244] Furthermore, by providing the lens 360 on the substrate 301 using a method similar to that in the first embodiment, and by stacking the first light-reflecting layer 306, the second light-reflecting layer 307, etc., the laser element 300 can be manufactured. Alternatively, the laser element 300 can be manufactured using another manufacturing method.

[0245] [Another configuration for the laser element]

[0246] Although in the above description, each layer is stacked on substrate 301 to prepare laminate 350, laminate 350 can be formed by stacking each layer on another support substrate, removing the support substrate, and bonding these layers to substrate 301. Furthermore, similar to the first embodiment, laser element 300 may include a wavelength conversion layer on the side of the second light-reflecting layer 307 opposite to laminate 350 that modifies the wavelength of the emitted light (see [link to embodiment]). Figure 27 ).

[0247] Furthermore, although the first semiconductor layer 302 is formed of an n-type semiconductor material and the second semiconductor layer 303 is formed of a p-type semiconductor material, the first semiconductor layer 302 can be formed of a p-type semiconductor material and the second semiconductor layer 303 can be formed of an n-type semiconductor material. In this case, the unoxidized region 305a of the oxide confinement layer 305 can be formed of an n-type material with a high impurity concentration. Additionally, instead of the above configuration, the laser element 300 can have another configuration capable of achieving the operation of the laser element 300 described above.

[0248] [About laser element arrays]

[0249] The laser elements 300 can be arranged similarly to those in the first embodiment. Because each of the laser elements 300 is a good line source emitting laser light E without brightness inhomogeneity, the laser element array including the laser elements 300 can, for example, have a high output exceeding 1W by arranging the laser elements 300. The laser element array including the laser elements 300 may include a wavelength conversion layer (see...). Figure 28 ).

[0250] (Regarding this disclosure)

[0251] The effects described in this disclosure are merely examples and are not limiting; other effects may also be achieved. The description of the multiple effects above does not necessarily mean that these effects will occur simultaneously. This means that at least one of the above effects can be achieved depending on conditions, and there is a possibility that effects not described in this disclosure may also occur. Furthermore, at least two of the feature portions described in this disclosure can be arbitrarily combined with each other.

[0252] It should be noted that this technology can also be configured as follows.

[0253] (1) A laser element, comprising:

[0254] The first light-reflecting layer reflects light of a specific wavelength;

[0255] A second light-reflecting layer reflects light of this wavelength; and

[0256] A laminate includes a first semiconductor layer, a second semiconductor layer, and an active layer. The laminate is disposed between a first light-reflecting layer and a second light-reflecting layer, and has a first surface located on one side of the first light-reflecting layer and a second surface located on one side of the second light-reflecting layer. The first semiconductor layer is formed of a semiconductor material having a first conductivity type, and the second semiconductor layer is formed of a semiconductor material having a second conductivity type. The active layer is disposed between the first and second semiconductor layers and emits light through carrier recombination. A lens is disposed on the first surface.

[0257] The lens has a lens shape protruding towards the first light-reflecting layer, with a first direction as its longitudinal direction and a second direction as its transverse direction. The first direction is parallel to a plane perpendicular to the optical axis of the emitted light, and the second direction is parallel to the plane and orthogonal to the first direction. The lens has a first width at its central portion in the first direction, which is the shortest width along the second direction. The lens has a second width at its non-central portion in the first direction, which is the maximum width along the second direction. The lens has a shape where its height from the plane is uniform or the central portion is higher than the ends. The radius of curvature of the lens's apex in the second direction is uniform.

[0258] The first light-reflecting layer is stacked on the first surface to form a concave mirror with a concave shape on the lens.

[0259] (2) According to the laser element described in (1) above, wherein

[0260] The laminate has a current-limiting structure that restricts current and forms a current-injection region with concentrated current.

[0261] The current injection region has a shape in which the planar shape of the current injection region when viewed from the optical axis direction overlaps with the lens when viewed from the optical axis direction, wherein the first direction is the longitudinal direction and the second direction is the transverse direction.

[0262] (3) The laser element according to (1) or (2) above, wherein,

[0263] The length of the lens along the first direction is greater than the second width.

[0264] (4) The laser element according to any one of (1) to (3) above, wherein,

[0265] The length of the lens along the first direction is 40 μm or more.

[0266] (5) The laser element according to any one of (1) to (4) above, wherein,

[0267] The second width of the lens is 10 μm or more.

[0268] (6) The laser element according to any one of (1) to (5) above, wherein,

[0269] The resonator length of the laser element is the distance between the concave mirror and the second light-reflecting layer, and

[0270] The radius of curvature is greater than the length of the resonator.

[0271] (7) The laser element according to any one of (1) to (6) above, wherein,

[0272] The surface accuracy of the lens is less than 1.0 nm in RMS (root mean square).

[0273] (8) The laser element according to any one of (1) to (7) above, wherein,

[0274] The first semiconductor layer and the second semiconductor layer are formed of GaN.

[0275] (9) The laser element according to any one of (1) to (7) above, wherein,

[0276] The first semiconductor layer and the second semiconductor layer are formed of GaAs.

[0277] (10) The laser element according to any one of (1) to (7) above, wherein,

[0278] The first semiconductor layer and the second semiconductor layer are formed of InP.

[0279] (11) The laser element according to any one of (1) to (10) above further comprises:

[0280] A wavelength conversion layer is disposed on the side of the second light-reflecting layer opposite to the laminate and is formed of a wavelength conversion material.

[0281] (12) The laser element according to any one of (1) to (11) above, wherein,

[0282] Both the first light-reflecting layer and the second light-reflecting layer are DBRs (distributed Bragg reflectors) that include multiple light-reflecting films.

[0283] (13) A laser element array, wherein a plurality of individually driveable laser elements are arranged in the laser element array, the laser elements comprising:

[0284] The first light-reflecting layer reflects light of a specific wavelength.

[0285] The second light-reflecting layer reflects light of that wavelength, and

[0286] A laminate includes a first semiconductor layer, a second semiconductor layer, and an active layer. The laminate is disposed between a first light-reflecting layer and a second light-reflecting layer, and has a first surface located on one side of the first light-reflecting layer and a second surface located on one side of the second light-reflecting layer. The first semiconductor layer is formed of a semiconductor material having a first conductivity type, and the second semiconductor layer is formed of a semiconductor material having a second conductivity type. The active layer is disposed between the first and second semiconductor layers and emits light through carrier recombination. A lens is disposed on the first surface.

[0287] The lens has a lens shape that protrudes towards the first light-reflecting layer, with a first direction as its longitudinal direction and a second direction as its transverse direction. The first direction is parallel to a plane perpendicular to the optical axis of the emitted light, and the second direction is parallel to the plane and orthogonal to the first direction. The lens has a first width at its central portion in the first direction, which is the shortest width along the second direction. The lens has a second width at its non-central portion in the first direction, which is the maximum width along the second direction. The lens has a shape where its height from the plane is uniform or the central portion is higher than the ends. The radius of curvature of the lens's apex in the second direction is uniform.

[0288] The first light-reflecting layer is stacked on the first surface to form a concave mirror with a concave shape on the lens.

[0289] (14) A method for manufacturing a laser element, comprising:

[0290] A laminate is prepared, the laminate comprising a first semiconductor layer, a second semiconductor layer and an active layer, and having a first surface and a second surface, wherein the first semiconductor layer is formed of a semiconductor material having a first conductivity type, the second semiconductor layer is formed of a semiconductor material having a second conductivity type, and the active layer is disposed between the first semiconductor layer and the second semiconductor layer and emits light through carrier recombination;

[0291] A structure of fluid material and having a certain thickness is formed on the first surface, with the first direction as the longitudinal direction and the second direction as the transverse direction. The first direction is parallel to a plane perpendicular to the optical axis of the emitted light, and the second direction is parallel to the plane and orthogonal to the first direction. The central portion of the structure in the first direction has a first width, which is the shortest width along the second direction. The non-central portion of the structure in the first direction has a second width, which is the maximum width along the second direction.

[0292] The structure is deformed by heating it to allow the fluid material to flow, and a lens is formed on the first surface using the shape of the structure. The lens has a shape in which its height from the plane is uniform or its central portion is higher than its ends, and the radius of curvature of the vertex of the lens in the second direction is uniform.

[0293] A first light-reflecting layer that reflects light of a specific wavelength is stacked on the first surface to form a concave mirror with a concave shape on the lens; and

[0294] A second light-reflecting layer that reflects light of that wavelength is formed on the second surface side of the laminate.

[0295] (15) The manufacturing method of the laser element according to (14) above, wherein

[0296] The step of forming a lens includes deforming the structure into a lens shape protruding toward one side of the first light-reflecting layer, with a first direction as the longitudinal direction and a second direction as the transverse direction, the central portion having the first width, the non-central portion having the second width, the structure having a shape in which its height from the plane is uniform or the central portion is higher than the ends, and the radius of curvature of the apex of the structure in the second direction is uniform.

[0297] (16) The manufacturing method of the laser element according to (15) above, wherein

[0298] The step of forming the lens includes: using the structure deformed into the shape as an etching mask to etch the stack to form the lens on the first surface.

[0299] (17) The manufacturing method of the laser element according to (15) above, wherein

[0300] The steps of forming a lens include: using the structure that has been deformed into the shape of the lens as the lens.

[0301] (18) A method for manufacturing a laser element according to any one of (14) to (17) above, wherein,

[0302] The length of the structure along the first direction is greater than the second width.

[0303] (19) A method for manufacturing a laser element according to any one of (14) to (18) above, wherein,

[0304] The length of the structure along the first direction is 40 μm or more.

[0305] (20) A method for manufacturing a laser element according to any one of (14) to (19) above, wherein

[0306] The etching is either dry etching or wet etching.

[0307] Reference number list

[0308] 100, 200, 300 laser elements

[0309] 201, 301 substrate

[0310] 101, 202, 302 First semiconductor layer

[0311] 102, 203, 303 Second semiconductor layer

[0312] 204 Third Semiconductor Layer

[0313] 103, 205, 304 active layers

[0314] 206 Tunnel strata

[0315] 305 Oxidation Confinement Layer

[0316] 104, 207, 306 First light-reflecting layer

[0317] 104c, 207c, and 306c concave mirrors

[0318] 105, 208, 307 Second light-reflecting layer

[0319] 106, 209, 308 First Electrode

[0320] 107, 210, 309 Second Electrode

[0321] 121, 221, 321 current injection regions

[0322] Insulation zones 122, 222, and 322

[0323] 150, 250, 350 layered structures

[0324] 160, 260, 360 lenses

[0325] 170, 270, 370 structures

[0326] 175, 275, 375 structures

[0327] 181 wavelength conversion layer.

Claims

1. A laser element, comprising: The first light-reflecting layer reflects light of a specific wavelength; The second light-reflecting layer reflects light of the specified wavelength. as well as A laminate includes a first semiconductor layer, a second semiconductor layer, and an active layer. The laminate is disposed between the first light-reflecting layer and the second light-reflecting layer, and has a first surface located on one side of the first light-reflecting layer and a second surface located on one side of the second light-reflecting layer. The first semiconductor layer is formed of a semiconductor material having a first conductivity type, and the second semiconductor layer is formed of a semiconductor material having a second conductivity type. The active layer is disposed between the first semiconductor layer and the second semiconductor layer and emits light through carrier recombination. A lens is disposed on the first surface. The lens has a lens shape protruding towards the first light-reflecting layer, with a first direction as its longitudinal direction and a second direction as its transverse direction. The first direction is parallel to a plane perpendicular to the optical axis of the emitted light, and the second direction is parallel to the plane and orthogonal to the first direction. The lens has a first width at its central portion in the first direction, which is the shortest width along the second direction. The lens has a second width at its non-central portion in the first direction, which is the maximum width along the second direction. The lens has a shape where the height of the lens from the plane is uniform or the central portion is higher than the ends. The radius of curvature of the lens's apex in the second direction is uniform. The first light-reflecting layer is stacked on the first surface to form a concave mirror with a concave shape on the lens.

2. The laser element according to claim 1, wherein, The laminate has a current-limiting structure that limits the current and forms a current-concentrated current injection region. The current injection region has a shape in which the planar shape of the current injection region when viewed from the optical axis direction overlaps with the lens when viewed from the optical axis direction.

3. The laser element according to claim 1, wherein, The length of the lens along the first direction is greater than the second width.

4. The laser element according to claim 1, wherein, The length of the lens along the first direction is 40 μm or more.

5. The laser element according to claim 1, wherein, The second width of the lens is 10 μm or more.

6. The laser element according to claim 1, wherein, The resonator length of the laser element is the distance between the concave mirror and the second light-reflecting layer, and The radius of curvature is greater than or equal to the length of the resonator.

7. The laser element according to claim 1, wherein, The surface accuracy of the lens is less than 1.0 nm in terms of root mean square (RMS).

8. The laser element according to claim 1, wherein, The first semiconductor layer and the second semiconductor layer are formed of GaN.

9. The laser element according to claim 1, wherein, The first semiconductor layer and the second semiconductor layer are formed of GaAs.

10. The laser element according to claim 1, wherein, The first semiconductor layer and the second semiconductor layer are formed of InP.

11. The laser element according to claim 1, further comprising: A wavelength conversion layer is disposed on the side of the second light-reflecting layer opposite to the laminate and is formed of a wavelength conversion material.

12. The laser element according to claim 1, wherein, Both the first light-reflecting layer and the second light-reflecting layer are distributed Bragg reflectors (DBRs) that include multiple light-reflecting films.

13. An array of laser elements, wherein, Multiple laser elements, each capable of being individually driven, are arranged in the laser element array, the laser elements comprising: The first light-reflecting layer reflects light of a specific wavelength. The second light-reflecting layer reflects light of the specified wavelength, and A laminate includes a first semiconductor layer, a second semiconductor layer, and an active layer. The laminate is disposed between the first light-reflecting layer and the second light-reflecting layer, and has a first surface located on one side of the first light-reflecting layer and a second surface located on one side of the second light-reflecting layer. The first semiconductor layer is formed of a semiconductor material having a first conductivity type, and the second semiconductor layer is formed of a semiconductor material having a second conductivity type. The active layer is disposed between the first semiconductor layer and the second semiconductor layer and emits light through carrier recombination. A lens is disposed on the first surface. The lens has a lens shape protruding towards the first light-reflecting layer, with a first direction as its longitudinal direction and a second direction as its transverse direction. The first direction is parallel to a plane perpendicular to the optical axis of the emitted light, and the second direction is parallel to the plane and orthogonal to the first direction. The lens has a first width at its central portion in the first direction, which is the shortest width along the second direction. The lens has a second width at its non-central portion in the first direction, which is the maximum width along the second direction. The lens has a shape where the height of the lens from the plane is uniform or the central portion is higher than the ends. The radius of curvature of the lens's apex in the second direction is uniform. The first light-reflecting layer is stacked on the first surface to form a concave mirror with a concave shape on the lens.

14. A method for manufacturing a laser element, comprising: A laminate is prepared, the laminate comprising a first semiconductor layer, a second semiconductor layer and an active layer, and the laminate having a first surface and a second surface, the first semiconductor layer being formed of a semiconductor material having a first conductivity type, the second semiconductor layer being formed of a semiconductor material having a second conductivity type, and the active layer being disposed between the first semiconductor layer and the second semiconductor layer and emitting light through carrier recombination; A structure is formed on the first surface. The structure is formed of a fluid material and has a certain thickness. A first direction is the longitudinal direction and a second direction is the transverse direction. The first direction is parallel to a plane perpendicular to the optical axis of the emitted light. The second direction is parallel to the plane and orthogonal to the first direction. The central portion of the structure in the first direction has a first width, which is the shortest width along the second direction. The non-central portion of the structure in the first direction has a second width, which is the maximum width along the second direction. The structure is deformed by heating it to allow the fluid material to flow, and a lens is formed on the first surface using the deformed shape of the structure. The lens has a shape in which the height of the lens from the plane is uniform or the central portion of the lens is higher than the end portion, and the radius of curvature of the vertex of the lens in the second direction is uniform. A first light-reflecting layer that reflects light of a specific wavelength is stacked on the first surface to form a concave mirror with a concave shape on the lens; as well as A second light-reflecting layer that reflects the wavelength of light is formed on the second surface side of the laminate.

15. The method for manufacturing a laser element according to claim 14, wherein, The step of forming the lens includes: deforming the structure into a lens shape protruding toward the first light-reflecting layer, wherein the central portion of the lens shape has a first width, the non-central portion of the lens shape has a second width, the structure has a shape in which the height of the structure from the plane is uniform or the central portion is higher than the end, and the radius of curvature of the vertex of the lens shape in the second direction is uniform.

16. The method for manufacturing a laser element according to claim 15, wherein, The step of forming the lens includes: using the structure deformed into the shape of the lens as an etching mask to etch the stack to form the lens on the first surface.

17. The method for manufacturing a laser element according to claim 15, wherein, The step of forming the lens includes: using the structure deformed into the shape of the lens as the lens.

18. The method for manufacturing a laser element according to claim 14, wherein, The length of the structure along the first direction is greater than the second width.

19. The method of producing a laser element according to claim 14, wherein The length of the structure along the first direction is 40 μm or more.

20. The method of producing a laser element according to claim 16, wherein The etching is either dry etching or wet etching.

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