Light-emitting device

Abstract

[Problem] To perform individual driving more appropriately. [Solution] A light-emitting device which comprises: a layered structure (20) that is obtained by stacking a first conductivity-type first compound semiconductor layer (21) that has a first surface (21a) and a second surface (21b) which is opposite to the first surface, a second conductivity-type second compound semiconductor layer (22) that has a first surface (22a) which is provided on the side facing the second surface of the first compound semiconductor layer and a second surface (22b) which is opposite to the first surface, and a second conductivity-type third compound semiconductor layer (24) that has a second surface (24b) which is provided on the side facing the first surface of the first compound semiconductor layer and a first surface (24a) which is opposite to the second surface; a first light reflection layer (41) that is provided on the first surface side of the third compound semiconductor layer; and a second light reflection layer (42) that is provided on the second surface side of the second compound semiconductor layer. The first light reflection layer has a concave mirror part (43), and at least the first compound semiconductor layer and the second compound semiconductor layer of the layered structure have a plurality of mesa parts (M).

Description

Light-emitting device

[0001] SUMMARY OF THE INVENTION Embodiments according to the present disclosure relate to a light emitting device.

[0002] In a light-emitting device made of a vertical cavity surface-emitting laser (VCSEL), laser oscillation is generally generated by resonating laser light between two light-reflecting layers (distributed Bragg reflector layers, DBR layers) (see Patent Documents 1 to 3).

[0003] JP 2007-158215 A JP 2022-168786 A International Publication No. 2018 / 083877

[0004] However, in a light emitting device such as an array device having a plurality of light emitting elements, it is sometimes difficult to drive them individually.

[0005] Therefore, the present disclosure provides a light emitting device that can be driven individually more appropriately.

[0006] In order to solve the above-described problems, the present disclosure provides a light emitting device including: a stacked structure including: a first compound semiconductor layer of a first conductivity type having a first surface and a second surface opposite to the first surface; a second compound semiconductor layer of a second conductivity type having a first surface provided on the second surface side of the first compound semiconductor layer and a second surface opposite to the first surface; and a third compound semiconductor layer of the second conductivity type having a second surface provided on the first surface side of the first compound semiconductor layer and a first surface opposite to the second surface; a first light reflective layer provided on the first surface side of the third compound semiconductor layer; and a second light reflective layer provided on the second surface side of the second compound semiconductor layer; the first light reflective layer has a concave mirror portion; and at least the first compound semiconductor layer and the second compound semiconductor layer of the stacked structure have a plurality of mesa portions.

[0007] The diameter of the mesa portion in the second compound semiconductor layer may be larger than 3ω0, where ω0 is the beam waist of the concave mirror portion and is expressed by the following equation: where λ: oscillation wavelength, n: refractive index, L: resonator length, R: radius of curvature of the concave mirror.

[0008] The stacked structure may further include an active layer stacked between the second surface of the first compound semiconductor layer and the first surface of the second compound semiconductor layer.

[0009] The third compound semiconductor layer may be located at a distance of (2n+1)λ / 4 (n=1, 2, 3, . . . ) from the active layer in the stacking direction, where λ is the oscillation wavelength.

[0010] The active layer may include InGaN, AlGaN, AlGaInP, InGaP, or AsP based materials.

[0011] The diameter of the mesa portion in the first compound semiconductor layer may be larger than the diameter of the mesa portion in the second compound semiconductor layer.

[0012] The semiconductor device may further include an insulating layer provided around the mesa portion.

[0013] The insulating layer may include epoxy, plastic, ceramic, or glass.

[0014] The refractive index of the insulating layer may be equal to or greater than the refractive index of the material comprising the resonator.

[0015] The device may further include a substrate provided between the first compound semiconductor layer, the first surface, and the first light reflecting layer.

[0016] The substrate may be a GaN substrate, a GaAs substrate, or an InP substrate.

[0017] The radius of curvature of the concave mirror portion may be equal to or greater than the length of the resonator.

[0018] The thickness of the first compound semiconductor layer in the stacking direction may be equal to or greater than the thickness of a depletion layer formed inside the first compound semiconductor layer.

[0019] The thickness W of the depletion layer formed inside the first compound semiconductor layer n may be expressed as the following formula: where ε s : Dielectric constant V D : Diffusion potential V: Applied voltage N d : effective donor density of the first compound semiconductor layer N a : effective acceptor density of the third compound semiconductor layer

[0020] The second conductivity type dopant of the third compound semiconductor layer may include Mg, C, Zn, or Fe.

[0021] Each mesa may further include a wiring provided so as to be electrically conductive.

[0022] The wiring may be arranged in a matrix.

[0023] The first compound semiconductor layer, the second compound semiconductor layer, and the third compound semiconductor layer may include GaN.

[0024] FIG. 1 is a schematic partial end view of a light emitting device of Example 1. FIG. 2 is a schematic plan view of a light emitting device of Example 1. FIG. 3 is a schematic plan view of a light emitting device of Example 2. FIG. 4 is a schematic plan view of a light emitting device of Example 3. FIG. 5 is a schematic plan view of a light emitting device of Example 4. FIG. 6 is a schematic partial end view of a light emitting device of Example 5. FIG. 7 is a schematic partial end view of a light emitting device of Example 6. FIG. 8 is a schematic partial end view of a light emitting device of Example 7. FIG. 9 is a schematic partial end view of a light emitting device of Example 9. FIG. 10 is a schematic partial end view of a light emitting device of Example 11. FIG. 11 is a schematic partial end view of a light emitting device of Example 12.

[0025] Hereinafter, the present disclosure will be described based on examples with reference to the drawings, but the present disclosure is not limited to the examples, and various numerical values ​​and materials in the examples are merely examples. The description will be made in the following order: 1. General Description of the Light-Emitting Device of the Present Disclosure 2. Example 1 (Light-Emitting Device of the Present Disclosure) 3. Example 2 (Modification of Example 1) 4. Example 3 (Modification of Example 1) 5. Example 4 (Modification of Examples 2 to 3) 6. Example 5 (Modification of Examples 1 to 4) 7. Example 6 (Modification of Examples 1 to 5) 8. Example 7 (Modification of Examples 1 to 6) 9. Example 8 (Modification of Examples 1 to 7) 10. Example 9 (Modification of Examples 1 to 7) 11. Example 10 (Modification of Examples 1 to 9) 12. Example 11 (Modification of Examples 1 to 10) 13. Example 12 (Modification of Examples 1 to 11) 14. Other

[0026] <General Description of Light-Emitting Element and Light-Emitting Device of the Present Disclosure> In the light-emitting element of the present disclosure (hereinafter collectively referred to as the "light-emitting element, etc. of the present disclosure"), when the cavity length is LOR, -5 m≦L OR It is preferable to satisfy the following.

[0027] In the light-emitting device and the like of the present disclosure, including the preferred embodiment described above, when the first light-reflecting layer is cut along a virtual plane including the stacking direction of the stacked structure, the figure drawn by the interface of a portion of the concave mirror portion of the first light-reflecting layer facing the stacked structure can be a portion of a circle or a portion of a parabola. The figure may not strictly be a portion of a circle or a parabola. That is, even if the figure is roughly a portion of a circle or a parabola, this is still included in the definition of "a figure being a portion of a circle or a parabola." Such a portion (area) of the first light-reflecting layer that is a portion of a circle or a parabola may be referred to as the "effective area of ​​the concave mirror portion of the first light-reflecting layer." The figure drawn by the interface of a portion of the concave mirror portion facing the stacked structure can be determined by measuring the shape of the interface with a measuring instrument and analyzing the obtained data using the least squares method.

[0028] In the light-emitting device and the like according to the present disclosure, including the preferred embodiment described above, the second compound semiconductor layer is provided with a current injection region and a non-current injection region surrounding the current injection region, and the shortest distance D from the centroid of the current injection region to the boundary between the current injection region and the non-current injection region is CI can be configured to satisfy the following equation. Here, for convenience, a light-emitting element having such a configuration will be referred to as a "light-emitting element of first configuration." For the derivation of the following equation, see, for example, H. Kogelnik and T. Li, "Laser Beams and Resonators," Applied Optics / Vol. 5, No. 10 / October 1966. ω0 is also called the beam waist radius.

[0029] D CI ≧ω0 / 2 (1-1) However, ω0 2 ≡(λ / π){L OR (R DBR -L OR )1 / 2 (1-2) where, λ0: wavelength of the desired light mainly emitted from the light emitting element (oscillation wavelength) L OR :Resonator length R DBR : radius of curvature of the concave mirror portion of the first light-reflecting layer

[0030] Here, the light-emitting element etc. of the present disclosure has a concave mirror portion only in the first light-reflecting layer, but considering the symmetry with respect to the flat mirror of the second light-reflecting layer, the resonator can be expanded to a Fabry-Perot resonator sandwiched between two concave mirror portions having the same radius of curvature. However, a virtual Fabry-Perot resonator having two concave mirror portions has a radius of curvature R DBR is the resonator length L OR If the radius of curvature R is smaller than DBR is the resonator length L OR It is preferable that the distance between the active layer and the second compound semiconductor layer is larger than λ0 / 2. Incidentally, if the active layer is disposed closer to the flatter of the two light reflecting layers, specifically the second light reflecting layer, the optical field is more concentrated in the active layer. That is, the optical field confinement in the active layer is strengthened, facilitating laser oscillation. The position of the active layer, i.e., the distance from the surface of the second light reflecting layer facing the second compound semiconductor layer to the active layer, is not limited to, but can be exemplified as λ0 / 2 to 10λ0.

[0031] However, if the region where the light reflected by the first optical reflective layer is focused is not included in the current injection region corresponding to the region where the active layer has gain due to current injection, stimulated emission of light from carriers may be inhibited, and laser oscillation may be inhibited. By satisfying the above formulas (1-1) and (1-2), it is possible to ensure that the region where the light reflected by the first optical reflective layer is focused is included in the current injection region, and laser oscillation can be reliably achieved.

[0032] The light-emitting element of the first configuration further includes: a mode loss action portion provided on the second surface of the second compound semiconductor layer and constituting a mode loss action region that acts to increase or decrease oscillation mode loss; a second electrode formed from on the second surface of the second compound semiconductor layer over the mode loss action portion; and a first electrode electrically connected to the first compound semiconductor layer; the second light-reflecting layer is formed on the second electrode; and the laminated structure is formed with a current injection region, a non-current injection inner region surrounding the current injection region, and a non-current injection outer region surrounding the non-current injection inner region, and the orthogonal projection image of the mode loss action region and the orthogonal projection image of the non-current injection outer region overlap each other.

[0033] In the light-emitting element of the first configuration including such a preferable configuration, the radius r' of the effective area of ​​the concave mirror portion of the first light-reflecting layer is DBR ω0≦r' DBR ≦20·ω0, preferably ω0≦r′ DBR ≦10·ω0. Alternatively, r' DBR As the value of r' DBR ≦1×10 -4 m, preferably r' DBR ≦5×10 -5 m can be exemplified. DBR As, h DBR ≦5×10 -5 Furthermore, in the light-emitting device of the first configuration including such a preferable configuration, D CI Furthermore, in the light-emitting element of the first configuration including such a preferable configuration, R DBR ≦1×10 -3 m, preferably 1 × 10 -5 m≦R DBR ≦1×10 -3 m, more preferably 1 × 10 -5 m≦R DBR ≦1×10 -4 It is possible to have a configuration that satisfies m.

[0034] Furthermore, the light-emitting device etc. of the present disclosure, including the preferred embodiment described above, further includes a mode loss action portion provided on the second surface of the second compound semiconductor layer and constituting a mode loss action region that acts to increase or decrease oscillation mode loss, a second electrode formed from the second surface of the second compound semiconductor layer over the mode loss action portion, and a first electrode electrically connected to the first compound semiconductor layer, wherein the second light-reflecting layer is formed on the second electrode, and the stacked structure is formed with a current injection region, a non-current injection inner region surrounding the current injection region, and a non-current injection outer region surrounding the non-current injection inner region, and the orthogonal projection images of the mode loss action region and the non-current injection outer region overlap. Here, for convenience, a light-emitting device of this configuration will be referred to as a "light-emitting device of second configuration."

[0035] Alternatively, the light-emitting device etc. of the present disclosure, including the preferred embodiment described above, may further include a second electrode formed on the second surface of the second compound semiconductor layer, a second light-reflecting layer formed on the second electrode, a mode-loss action region provided on the first surface of the first compound semiconductor layer and constituting a mode-loss action region that acts to increase or decrease oscillation mode loss, and a first electrode electrically connected to the first compound semiconductor layer, wherein the first light-reflecting layer is formed from the first surface of the first compound semiconductor layer to the mode-loss action region, and the stacked structure may include a current-injection region, a non-current-injection inner region surrounding the current-injection region, and a non-current-injection outer region surrounding the non-current-injection inner region, and the orthogonal projection images of the mode-loss action region and the non-current-injection outer region overlap. Here, for convenience, a light-emitting device of this configuration will be referred to as a "light-emitting device of a third configuration." The definition of the light-emitting device of the third configuration can also be applied to the light-emitting device of the first configuration.

[0036] In the light-emitting device of the second configuration or the light-emitting device of the third configuration, a current non-injection region (a collective term for the current non-injection inner region and the current non-injection outer region) is formed in the stacked structure, and the current non-injection region may be formed in a region of the second compound semiconductor layer on the second electrode side in the thickness direction, or in the entire second compound semiconductor layer, or in the second compound semiconductor layer and the active layer, or may be formed from the second compound semiconductor layer to a part of the first compound semiconductor layer. The orthogonal projection images of the mode loss effect region and the current non-injection outer region overlap, but in a region sufficiently separated from the current injection region, the orthogonal projection images of the mode loss effect region and the current non-injection outer region do not have to overlap.

[0037] In the light emitting device of the second configuration, the current non-injection outer region may be located below the mode loss active region.

[0038] In a light-emitting element of a second configuration including the above-described preferred configuration, when the area of ​​the orthogonal projection image of the current injection region is S1 and the area of ​​the orthogonal projection image of the current-non-injected inner region is S2, the following relationship can be satisfied: 0.01≦S1 / (S1+S2)≦0.7. Furthermore, in a light-emitting element of a third configuration, when the area of ​​the orthogonal projection image of the current injection region is S1' and the area of ​​the orthogonal projection image of the current-non-injected inner region is S2', the following relationship can be satisfied: 0.01≦S1' / (S1'+S2')≦0.7. However, the ranges of S1 / (S1'+S2) and S1' / (S1'+S2') are not limited or restricted to the above ranges.

[0039] In the light-emitting device of the second configuration or the light-emitting device of the third configuration, which include the above-described preferred configurations, the non-current-injection inner region and the non-current-injection outer region can be configured to be formed by ion implantation into the stacked structure. Light-emitting devices of such configurations are referred to as "light-emitting devices of the 2-A configuration" and "light-emitting devices of the 3-A configuration" for convenience. In this case, the ion species can be at least one type of ion (i.e., one type of ion or two or more types of ions) selected from the group consisting of boron, proton, phosphorus, arsenic, carbon, nitrogen, fluorine, oxygen, germanium, and silicon.

[0040] Alternatively, in the light-emitting device of the second or third configuration, which includes the above-described preferred configuration, the non-current-injection inner and outer regions can be formed by plasma irradiation of the second surface of the second compound semiconductor layer, ashing of the second surface of the second compound semiconductor layer, or reactive ion etching of the second surface of the second compound semiconductor layer. Light-emitting devices of this configuration are referred to as "light-emitting devices of the second-B configuration" and "light-emitting devices of the third-B configuration" for convenience. In these processes, the non-current-injection inner and outer regions are exposed to plasma particles, which deteriorates the conductivity of the second compound semiconductor layer and causes the non-current-injection inner and outer regions to become highly resistive. That is, the non-current-injection inner and outer regions can be formed by exposure of the second surface of the second compound semiconductor layer to plasma particles. Specific examples of plasma particles include argon, oxygen, and nitrogen.

[0041] Alternatively, in the light-emitting device of the second configuration or the light-emitting device of the third configuration, which include the above-described preferred configurations, the second light-reflecting layer can have a region that reflects or scatters light from the first light-reflecting layer toward the outside of the resonator structure formed by the first light-reflecting layer and the second light-reflecting layer. Light-emitting devices of such configurations are conveniently referred to as "light-emitting devices of the 2-C configuration" or "light-emitting devices of the 3-C configuration." Specifically, the region of the second light-reflecting layer located above the sidewall of the mode-loss active region (the sidewall of the opening provided in the mode-loss active region) has a forward tapered slope or a region that is convexly curved toward the first light-reflecting layer. Alternatively, in the light-emitting device of the second configuration or the light-emitting device of the third configuration, which include the above-described preferred configurations, the first light-reflecting layer can have a region that reflects or scatters light from the second light-reflecting layer toward the outside of the resonator structure formed by the first light-reflecting layer and the second light-reflecting layer. Specifically, a partial region of the first light reflecting layer may have a forward tapered slope or a convex curved portion toward the second light reflecting layer, or a region of the first light reflecting layer located above a sidewall of the mode loss action region (a sidewall of an opening provided in the mode loss action region) may have a forward tapered slope or a region that is convexly curved toward the second light reflecting layer.Furthermore, a configuration may be adopted in which light is scattered at the boundary (sidewall edge portion) between the top surface of the mode loss action region and the sidewall of the opening provided in the mode loss action region, thereby scattering light toward the outside of the resonator structure formed by the first light reflecting layer and the second light reflecting layer.

[0042] In the light-emitting device having the 2-A configuration, the 2-B configuration, or the 2-C configuration described above, when the optical distance from the active layer in the current injection region to the second surface of the second compound semiconductor layer is L2 and the optical distance from the active layer in the mode loss action region to the top surface of the mode loss action portion is L0, the following relationship can be satisfied: L0 > L2. Furthermore, in the light-emitting device having the 3-A configuration, the 3-B configuration, or the 3-C configuration described above, when the optical distance from the active layer in the current injection region to the first surface of the first compound semiconductor layer is L1' and the optical distance from the active layer in the mode loss action region to the top surface of the mode loss action portion is L0', the following relationship can be satisfied: L0' > L1'. Furthermore, in the light-emitting device having the 2-A configuration, the light-emitting device having the 3-A configuration, the light-emitting device having the 2-B configuration, the light-emitting device having the 3-B configuration, the light-emitting device having the 2-C configuration, or the light-emitting device having the 3-C configuration described above, including these configurations, the generated light having a higher-order mode can be dissipated by the mode loss effect region toward the outside of the resonator structure formed by the first light reflecting layer and the second light reflecting layer, thereby increasing the oscillation mode loss. That is, due to the presence of the mode loss effect region that acts to increase or decrease the oscillation mode loss, the optical field intensities of the generated fundamental mode and higher-order modes decrease the farther away from the Z-axis in the orthogonal projection image of the mode loss effect region, but the mode loss of the higher-order modes is greater than the decrease in the optical field intensity of the fundamental mode, thereby further stabilizing the fundamental mode and suppressing the mode loss compared to when the current non-injection inner region is not present, thereby reducing the threshold current.

[0043] In the light emitting device having the 2-A configuration, the light emitting device having the 3-A configuration, the light emitting device having the 2-B configuration, the light emitting device having the 3-B configuration, the light emitting device having the 2-C configuration, or the light emitting device having the 3-C configuration described above, the mode loss active portion can be made of a dielectric material, a metal material, or an alloy material. X , SiN X , AlN X , AlO X , TaO X , ZrOX Examples of suitable materials include titanium, gold, platinum, and alloys thereof, but are not limited to these materials. A mode loss effect portion made of these materials can absorb light and increase the mode loss. Alternatively, mode loss can be controlled by disturbing the phase without directly absorbing light. In this case, the mode loss effect portion can be made of a dielectric material, and the optical thickness t0 of the mode loss effect portion can be a value that is not an integer multiple of ¼ of the wavelength λ0 of the light generated in the light-emitting element. In other words, by disturbing the phase of light that circulates within the resonator and forms a standing wave, the standing wave can be destroyed and a corresponding mode loss can be imparted. Alternatively, the mode loss effect portion can be made of a dielectric material, and the optical thickness t0 of the mode loss effect portion (refractive index n0) can be an integer multiple of ¼ of the wavelength λ0 of the light generated in the light-emitting element. That is, the optical thickness t0 of the mode loss effect region can be configured to be a thickness that does not disturb the phase of light generated in the light-emitting element and does not destroy standing waves. However, it does not need to be a strict integer multiple of 1 / 4; it only needs to satisfy the following: (λ0 / 4n0)×m-(λ0 / 8n0)≦t0≦(λ0 / 4n0)×2m+(λ0 / 8n0). Alternatively, by configuring the mode loss effect region from a dielectric material, a metal material, or an alloy material, the phase of light passing through the mode loss effect region can be disturbed or absorbed by the mode loss effect region. Furthermore, by adopting these configurations, it is possible to control the oscillation mode loss with a higher degree of freedom and to further increase the degree of freedom in designing the light-emitting element.

[0044] Alternatively, a light-emitting device of a second configuration including the above-described preferred configuration may have a convex portion formed on the second surface side of the second compound semiconductor layer, and the mode loss effect portion may be formed on a region of the second surface of the second compound semiconductor layer surrounding the convex portion. For convenience, a light-emitting device of this configuration is referred to as a "light-emitting device of 2-D configuration." The convex portion occupies the current injection region and the non-current injection inner region. In this case, when the optical distance from the active layer in the current injection region to the second surface of the second compound semiconductor layer is L2 and the optical distance from the active layer in the mode loss effect region to the top surface of the mode loss effect portion is L0, the following relationship can be satisfied: L0 < L2. Furthermore, in these cases, the generated light having a higher-order mode is confined to the current injection region and the non-current injection inner region by the mode loss effect region, thereby reducing oscillation mode loss. That is, the optical field intensities of the fundamental mode and higher-order modes that are generated are increased in the orthogonal projection images of the current injection region and the non-current injection inner region due to the presence of a mode loss effect region that acts to increase or decrease the oscillation mode loss. Furthermore, in these cases, the mode loss effect region can be made of a dielectric material, a metal material, or an alloy material. Here, examples of the dielectric material, metal material, or alloy material include the various materials described above.

[0045] Alternatively, in a light-emitting device of a third configuration including the above-described preferred configuration, a convex portion is formed on the first surface side of the first compound semiconductor layer, and the mode loss effect portion is formed on a region of the first surface of the first compound semiconductor layer surrounding the convex portion, or alternatively, the mode loss effect portion can be configured to be composed of a region of the first compound semiconductor layer surrounding the convex portion. For convenience, a light-emitting device of this configuration will be referred to as a "light-emitting device of 3-D configuration." The convex portion coincides with the orthogonal projection images of the current injection region and the current non-injection inner region. In this case, when the optical distance from the active layer in the current injection region to the first surface of the first compound semiconductor layer is L1' and the optical distance from the active layer in the mode loss action region to the top surface of the mode loss action portion is L0', a configuration can be achieved in which L0'<L1' is satisfied.Furthermore, in these cases, the generated light having a higher-order mode can be confined to the current injection region and the current non-injection region by the mode loss action region, thereby reducing oscillation mode loss.Furthermore, in these cases, the mode loss action portion can be made of a dielectric material, a metal material, or an alloy material.Here, examples of the dielectric material, metal material, and alloy material include the various materials described above.

[0046] Furthermore, in the light-emitting device etc. of the present disclosure including the preferred forms and configurations described above (including the light-emitting device of the first configuration to the light-emitting device of the third configuration), the stacked structure including the second electrode may be configured such that at least two light-absorbing material layers are formed parallel to the imaginary plane occupied by the active layer. Here, for convenience, a light-emitting device of such a configuration will be referred to as a "light-emitting device of the fourth configuration."

[0047] In the light-emitting element of the fourth configuration, it is preferable that at least four light-absorbing material layers are formed.

[0048] In the light-emitting element of the fourth configuration including the above-described preferred configuration, the oscillation wavelength (the wavelength of light mainly emitted from the light-emitting element, which is the desired oscillation wavelength) is λ0, the equivalent refractive index of the entire two light-absorbing material layers and the portion of the laminated structure located between the light-absorbing material layers is n eq , the distance between the light absorbing material layers is L AbsWhen this is the case, 0.9 × {(m λ0) / (2 n eq )≦L Abs ≦1.1×{(m・λ0) / (2・n eq )} where m is 1 or any integer equal to or greater than 1. The equivalent refractive index n eq The thickness of each of the two light-absorbing material layers and the layers constituting the laminated structure located between the light-absorbing material layers is t i , and the refractive index of each is n i When this is the case, n eq =Σ(t i ×n i ) / Σ(t i ) where i = 1, 2, 3, ..., I, and "I" is the total number of layers constituting the two light absorbing material layers and the layered structure portion located between the light absorbing material layers, and "Σ" means taking the sum from i = 1 to i = I. The equivalent refractive index n eq can be calculated based on the known refractive index and thickness of each constituent material obtained by observing the cross section of the light emitting element using an electron microscope or the like. When m is 1, the distance between adjacent light absorbing material layers is 0.9 × {λ0 / (2.n eq )≦L Abs ≦1.1×{λ0 / (2・n eq )} is satisfied. When m is an arbitrary integer of 2 or more including 1, for example, if m=1 or 2, the distance between adjacent light absorbing material layers in some of the light absorbing material layers satisfies the following: 0.9×{λ0 / (2·n eq )≦L Abs ≦1.1×{λ0 / (2・n eq )}, and in the remaining light absorbing material layers, the distance between adjacent light absorbing material layers is 0.9 × {(2·λ0) / (2·n eq )≦L Abs ≦1.1×{(2・λ0) / (2・n eq Generally, in some light-absorbing material layers, the distance between adjacent light-absorbing material layers satisfies the following: 0.9×{λ0 / (2·n eq )≦L Abs ≦1.1×{λ0 / (2・neq )}, and in the remaining various light-absorbing material layers, the distance between adjacent light-absorbing material layers is 0.9×{(m′·λ0) / (2·n eq )≦L Abs ≦1.1×{(m'・λ0) / (2・n eq )} where m' is any integer equal to or greater than 2. The distance between adjacent light-absorbing material layers is the distance between the centers of gravity of adjacent light-absorbing material layers. In other words, it is actually the distance between the centers of the light-absorbing material layers when the active layer is cut along an imaginary plane along the thickness direction of the active layer.

[0049] Furthermore, in the light-emitting element of the fourth configuration including the various preferable configurations described above, the thickness of the light-absorbing material layer is λ0 / (4·n eq The lower limit of the thickness of the light absorbing material layer is preferably 1 nm or less.

[0050] Furthermore, in a light-emitting element of a fourth configuration including the various preferred configurations described above, the light-absorbing material layer can be located in the minimum amplitude portion of the standing wave of light formed inside the laminated structure.

[0051] Furthermore, in a light-emitting device of a fourth configuration including the various preferred configurations described above, the active layer can be configured to be located in a maximum amplitude portion of a standing wave of light formed inside the laminated structure.

[0052] Furthermore, in a light-emitting element of a fourth configuration including the various preferred configurations described above, the light-absorbing material layer can be configured to have a light absorption coefficient that is at least twice as high as that of the compound semiconductors that constitute the stacked structure. Here, the light absorption coefficients of the light-absorbing material layer and the compound semiconductors that constitute the stacked structure can be determined by observing the constituent materials through electron microscope observation of a cross section of the light-emitting element, for example, and by analogy with known evaluation results observed for each constituent material.

[0053] Furthermore, in the light-emitting device of a fourth configuration including the various preferred configurations described above, the light-absorbing material layer can be configured to be composed of at least one material selected from the group consisting of a compound semiconductor material having a narrower band gap than the compound semiconductor constituting the stacked structure, a compound semiconductor material doped with impurities, a transparent conductive material, and a light-reflecting layer-constituting material having light-absorbing properties. Here, for example, when the compound semiconductor constituting the stacked structure is GaN, an example of the compound semiconductor material having a narrower band gap than the compound semiconductor constituting the stacked structure can be InGaN. An example of the impurity-doped compound semiconductor material can be Si-doped n-GaN or B-doped n-GaN. An example of the transparent conductive material can be a transparent conductive material constituting the electrode described later. An example of the light-reflecting layer-constituting material having light-absorbing properties can be a material constituting the light-reflecting layer described later (e.g., SiO X , SiN X , TaO X Examples of suitable light-absorbing material layers include: (a) a light-absorbing layer formed on a first compound semiconductor layer; (b) a light-absorbing layer formed on a second compound semiconductor layer; (c) a light-absorbing layer formed on a first light-reflecting layer; (d) a light-absorbing layer formed on a second light-reflecting layer; and (e) a light-absorbing layer formed on a first compound semiconductor layer. Alternatively, the light-absorbing material layer may be formed of one of these materials. Alternatively, the light-absorbing material layer may also serve as an electrode formed of a transparent conductive material, as described below.

[0054] Furthermore, in the light-emitting device etc. of the present disclosure including the preferred embodiments and configurations (including the light-emitting device of the first configuration to the light-emitting device of the fourth configuration) described above, a compound semiconductor substrate can be arranged between the first surface of the first compound semiconductor layer and the first light-reflecting layer. Here, for convenience, a light-emitting device of such a configuration will be referred to as a "light-emitting device of the fifth configuration." In this case, the compound semiconductor substrate can be configured to be a GaN substrate. The thickness of the compound semiconductor substrate is 5×10 -5 m to 1×10 -4 Examples of m include, but are not limited to, these values. In a light-emitting device of a fifth configuration including such a configuration, the concave mirror portion of the first light-reflecting layer can be configured to include a base portion formed from a protruding portion of a compound semiconductor substrate and a multilayer light-reflecting film formed on at least a portion of the surface of the base. Here, for convenience, a light-emitting device of this configuration will be referred to as a "light-emitting device of a fifth-A configuration." Alternatively, the concave mirror portion of the first light-reflecting layer can be configured to include a base portion formed on a compound semiconductor substrate and a multilayer light-reflecting film formed on at least a portion of the surface of the base. Here, for convenience, a light-emitting device of this configuration will be referred to as a "light-emitting device of a fifth-B configuration." The material constituting the base in the light-emitting device of the fifth-A configuration is, for example, a GaN substrate. As the GaN substrate, any of polar substrates, antipolar substrates, and nonpolar substrates may be used. On the other hand, examples of materials constituting the base in the light-emitting device of the fifth-B configuration include transparent dielectric materials such as TiO 2 , Ta 2 O 5 , and SiO 2 , silicone-based resins, and epoxy-based resins.

[0055] Alternatively, in the light-emitting device etc. of the present disclosure including the preferred embodiments and configurations described above (including the light-emitting device of the first configuration to the light-emitting device of the fourth configuration), a first light-reflecting layer may be formed on the first surface of the first compound semiconductor layer. Here, for convenience, a light-emitting device of such a configuration will be referred to as a "light-emitting device of the sixth configuration."

[0056] Furthermore, in the light-emitting devices and the like of the present disclosure including the preferred embodiments and configurations described above (including the light-emitting devices of the first to sixth configurations), the thermal conductivity value of the laminated structure can be configured to be higher than the thermal conductivity value of the first light-reflecting layer. The thermal conductivity value of the dielectric material that constitutes the first light-reflecting layer is generally about 10 Watts / (m·K) or less. On the other hand, the thermal conductivity value of the GaN-based compound semiconductor that constitutes the laminated structure is about 50 Watts / (m·K) to 100 Watts / (m·K).

[0057] Furthermore, in the light-emitting element and the like of the present disclosure including the preferred embodiments and configurations (including the light-emitting element of the first configuration to the light-emitting element of the sixth configuration) described above, the concave mirror portion of the light-emitting element (specifically, the radius r' of the concave mirror portion of the first light-reflecting layer DBR The radius of curvature of the effective area of DBR When this is done, R DBR ≦1×10 -3 m, preferably 1 × 10 -5 m≦R DBR ≦1×10 -3 m, more preferably 1 × 10 -5 m≦R DBR ≦1×10 -4 m can be satisfied. -5 m≦L OR However, preferably 1×10 -5 m≦L OR ≦5×10 -4 m, more preferably 1 × 10 -5 m≦L OR ≦1×10 -4 It is desirable to satisfy m.

[0058] Furthermore, in the light-emitting devices and the like of the present disclosure including the preferred embodiments and configurations described above (including the light-emitting devices of the first to sixth configurations), a convex portion is formed around the periphery of the first light reflecting layer, and the first light reflecting layer can be configured not to protrude from the convex portion, thereby protecting the first light reflecting layer. That is, because the first light reflecting layer is provided in a recessed state relative to the convex portion, even if an object comes into contact with the convex portion, the object will not come into contact with the first light reflecting layer, and the first light reflecting layer can be reliably protected.

[0059] Furthermore, in the light-emitting devices and the like of the present disclosure, including the preferred forms and configurations (including the light-emitting devices of the first to sixth configurations) described above, it is preferable that the materials constituting the various compound semiconductor layers (including the compound semiconductor substrate) located between the active layer and the first light-reflecting layer do not have a refractive index modulation of 10% or more (no refractive index difference of 10% or more based on the average refractive index of the laminated structure), which makes it possible to suppress the occurrence of disturbances in the optical field within the resonator.

[0060] The light-emitting element and the like of the present disclosure, including the preferred embodiments and configurations described above, can be used to configure a surface-emitting laser element (vertical cavity laser, VCSEL) that emits laser light through the first optical reflecting layer, or can be used to configure a surface-emitting laser element that emits laser light through the second optical reflecting layer. In some cases, the substrate for manufacturing the light-emitting element may be removed.

[0061] In the light-emitting device etc. of the present disclosure, the stacked structure can specifically be configured to be made of an AlInGaN-based compound semiconductor. More specifically, AlInGaN-based compound semiconductors include GaN, AlGaN, InGaN, and AlInGaN. Furthermore, these compound semiconductors may contain boron (B) atoms, thallium (Tl) atoms, arsenic (As) atoms, phosphorus (P) atoms, and antimony (Sb) atoms, as desired. The active layer desirably has a quantum well structure. Specifically, it may have a single quantum well structure (SQW structure) or a multiple quantum well structure (MQW structure). An active layer having a quantum well structure has a structure in which at least one well layer and one barrier layer are stacked, and the combination of (the compound semiconductor constituting the well layer and the compound semiconductor constituting the barrier layer) may be (In y Ga (1-y) N, GaN), (In y Ga (1-y) N, In z Ga (1-z) N) [where y>z], (In y Ga (1-y) Examples of the compound semiconductor layer include GaN (N, AlGaN). The first compound semiconductor layer can be made of a compound semiconductor of a first conductivity type (e.g., n-type), and the second compound semiconductor layer can be made of a compound semiconductor of a second conductivity type (e.g., p-type) different from the first conductivity type. The first compound semiconductor layer and the second compound semiconductor layer are also called a first cladding layer and a second cladding layer. The first compound semiconductor layer and the second compound semiconductor layer may be layers of a single structure, layers of a multilayer structure, or layers of a superlattice structure. Furthermore, they may be layers having a composition gradient layer or a concentration gradient layer.

[0062] The laminated structure is formed on the second surface of a substrate for manufacturing a light-emitting element, or alternatively, on the second surface of a compound semiconductor substrate. Examples of substrates for manufacturing a light-emitting element include GaN substrates, sapphire substrates, GaAs substrates, SiC substrates, alumina substrates, ZnS substrates, ZnO substrates, AlN substrates, LiMgO substrates, LiGaO substrates, MgAlO substrates, InP substrates, and Si substrates, as well as substrates having an underlayer or buffer layer formed on the surface (main surface) of these substrates. However, GaN substrates are preferred due to their low defect density. Examples of compound semiconductor substrates include GaN substrates. It is known that the properties of GaN substrates vary between polar, nonpolar, and semipolar depending on the growth surface. However, any of the main surfaces (second surfaces) of GaN substrates can be used to form compound semiconductor layers. Furthermore, with regard to the primary surface of the GaN substrate, depending on the crystal structure (e.g., cubic crystal type, hexagonal crystal type, etc.), crystal orientation planes called A-plane, B-plane, C-plane, R-plane, M-plane, N-plane, S-plane, etc., or planes obtained by offsetting these in a specific direction, etc., can also be used. Examples of methods for forming various compound semiconductor layers that constitute the light-emitting element include, but are not limited to, metal organic chemical vapor deposition (MOCVD, Metal Organic-Chemical Vapor Deposition, MOVPE, Metal Organic-Vapor Phase Epitaxy), molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HVPE) in which halogen contributes to transport or reaction, atomic layer deposition (ALD), migration-enhanced epitaxy (MEE), and plasma-assisted physical vapor deposition (PPD).

[0063] Here, examples of organic gallium source gases in the MOCVD method include trimethylgallium (TMG) gas and triethylgallium (TEG) gas, and examples of nitrogen source gases include ammonia gas and hydrazine gas. When forming a GaN-based compound semiconductor layer having n-type conductivity, for example, silicon (Si) may be added as an n-type impurity (n-type dopant), and when forming a GaN-based compound semiconductor layer having p-type conductivity, for example, magnesium (Mg) may be added as a p-type impurity (p-type dopant). When aluminum (Al) or indium (In) is included as a constituent atom of the GaN-based compound semiconductor layer, trimethylaluminum (TMA) gas may be used as the Al source, and trimethylindium (TMI) gas may be used as the In source. Furthermore, monosilane gas (SiH gas) may be used as the Si source, and biscyclopentadienyl magnesium gas, methylcyclopentadienyl magnesium, or biscyclopentadienyl magnesium (CpMg) may be used as the Mg source. Examples of n-type impurities (n-type dopants) include Ge, Se, Sn, C, Te, S, O, Pd, and Po, in addition to Si, and examples of p-type impurities (p-type dopants) include Zn, Cd, Be, Ca, Ba, C, Hg, and Sr, in addition to Mg.

[0064] The support substrate may be composed of, for example, any of the various substrates exemplified as substrates for manufacturing light-emitting elements, or may be composed of an insulating substrate such as AlN, a semiconductor substrate such as Si, SiC, or Ge, or a metal or alloy substrate. However, it is preferable to use a conductive substrate, or alternatively, a metal or alloy substrate from the viewpoints of mechanical properties, elastic deformation, plastic deformability, heat dissipation, etc. Examples of the thickness of the support substrate include 0.05 mm to 1 mm. Known methods for fixing the second light-reflecting layer to the support substrate can be used, such as solder bonding, room-temperature bonding, bonding using adhesive tape, wax bonding, and adhesive bonding. However, from the viewpoint of ensuring conductivity, it is preferable to use solder bonding or room-temperature bonding. For example, when a conductive silicon semiconductor substrate is used as the support substrate, it is preferable to use a method that allows bonding at a low temperature of 400°C or less to suppress warping due to differences in thermal expansion coefficients. When a GaN substrate is used as the support substrate, the bonding temperature may be 400°C or higher.

[0065] In the manufacture of the light-emitting element and the like according to the present disclosure, the substrate for light-emitting element manufacture may be left in place, or the substrate for light-emitting element manufacture may be removed after sequentially forming an active layer, a second compound semiconductor layer, a second electrode, and a second light-reflecting layer on the first compound semiconductor layer. Specifically, the active layer, the second compound semiconductor layer, the second electrode, and the second light-reflecting layer may be sequentially formed on the first compound semiconductor layer, and then the second light-reflecting layer may be fixed to a support substrate. The substrate for light-emitting element manufacture may be removed to expose the first compound semiconductor layer (the first surface of the first compound semiconductor layer). The substrate for light-emitting element manufacture may be removed by wet etching using an alkaline aqueous solution such as a sodium hydroxide solution or a potassium hydroxide solution, an ammonia solution plus hydrogen peroxide, a sulfuric acid solution plus hydrogen peroxide, a hydrochloric acid solution plus hydrogen peroxide, a phosphoric acid solution plus hydrogen peroxide, or the like, chemical mechanical polishing (CMP), mechanical polishing, dry etching, a laser-based lift-off method, or a combination thereof.

[0066] When the substrate for light-emitting element production remains, the first electrode may be formed on the first surface opposite the second surface of the substrate for light-emitting element production, or on the first surface opposite the second surface of the compound semiconductor substrate. Furthermore, when the substrate for light-emitting element production remains, the first electrode may be formed on the first surface of the first compound semiconductor layer constituting the laminated structure. In this case, a first light-reflecting layer is formed on the first surface of the first compound semiconductor layer, and therefore, the first electrode may be formed to surround the first light-reflecting layer, for example. The first electrode preferably has a single-layer or multilayer structure containing at least one metal (including alloys) selected from the group consisting of gold (Au), silver (Ag), palladium (Pd), platinum (Pt), nickel (Ni), titanium (Ti), vanadium (V), tungsten (W), chromium (Cr), aluminum (Al), copper (Cu), zinc (Zn), tin (Sn), and indium (In). Specific examples include Ti / Au, Ti / Al, Ti / Al / Au, Ti / Pt / Au, Ni / Au, Ni / Au / Pt, Ni / Pt, Pd / Pt, and Ag / Pd. Note that the layer before the " / " in the multilayer structure is located closer to the active layer. This also applies to the following description. The first electrode can be formed by a physical vapor deposition (PVD) method such as vacuum deposition or sputtering.

[0067] When the first electrode is formed to surround the first light-reflecting layer, the first light-reflecting layer and the first electrode may be in contact with each other. Alternatively, the first light-reflecting layer and the first electrode may be spaced apart, i.e., offset, with a separation distance of 1 mm or less. If the current injection region located in the first light-reflecting layer and the first electrode are spaced apart in plan view, the current will flow a long distance through the first compound semiconductor layer. Therefore, to keep the electrical resistance in this current path low, it is preferable that the separation distance be 1 mm or less. In some cases, the first electrode may be formed up to the edge of the first light-reflecting layer, or the first light-reflecting layer may be formed up to the edge of the first electrode. Here, when the first light-reflecting layer is formed up to the edge of the first electrode, the first electrode needs to have an opening of a certain size to minimize absorption of fundamental mode light of laser oscillation. The size of the opening is not limited since it varies depending on the wavelength of the fundamental mode and the light confinement structure in the lateral direction (in-plane direction of the first compound semiconductor layer), but it is preferable that it is on the order of several times the oscillation wavelength λ or more.

[0068] The second electrode may be made of a transparent conductive material. Examples of the transparent conductive material constituting the second electrode include indium-based transparent conductive materials [specifically, for example, indium-tin oxide (ITO, Indium Tin Oxide, Sn-doped In2O3, including crystalline ITO and amorphous ITO), indium-zinc oxide (IZO, Indium Zinc Oxide, Sn-doped In2O3, crystalline ITO, and amorphous ITO], and the like. Oxide), indium-gallium oxide (IGO), indium-doped gallium-zinc oxide (IGZO, In—GaZnO), IFO (F-doped In2O3), ITiO (Ti-doped In2O3), InSn, InSnZnO], tin-based transparent conductive materials [specifically, for example, tin oxide (SnO2), ATO (Sb-doped SnO2), FTO (F-doped SnO2)], zinc-based transparent conductive materials [specifically, for example, zinc oxide (including ZnO, Al-doped ZnO (AZO) and B-doped ZnO), gallium-doped zinc oxide (GZO), AlMgZnO (aluminum oxide and magnesium oxide-doped zinc oxide)], and NiO can be listed as examples. Alternatively, the second electrode may be a transparent conductive film having a base layer made of gallium oxide, titanium oxide, niobium oxide, antimony oxide, nickel oxide, or the like. Transparent conductive materials such as spinel oxides and oxides having a YbFe2O4 structure may also be used. However, depending on the arrangement of the second light-reflecting layer and the second electrode, the material constituting the second electrode is not limited to transparent conductive materials. Metals such as palladium (Pd), platinum (Pt), nickel (Ni), gold (Au), cobalt (Co), and rhodium (Rh) may also be used. The second electrode may be composed of at least one of these materials. The second electrode may be formed, for example, by a physical vapor deposition (PVD) method such as vacuum deposition or sputtering. Alternatively, a low-resistance semiconductor layer may be used as the transparent electrode layer. In this case, specifically, an n-type GaN-based compound semiconductor layer may be used. Furthermore, when the layer adjacent to the n-type GaN-based compound semiconductor layer is p-type, the electrical resistance at the interface can be reduced by joining the two via a tunnel junction.By forming the second electrode from a transparent conductive material, the current can be spread laterally (in the in-plane direction of the second compound semiconductor layer), and the current can be efficiently supplied to the current injection region.

[0069] A pad electrode may be provided on the first electrode or the second electrode for electrical connection to an external electrode or circuit. The pad electrode preferably has a single-layer or multilayer structure containing at least one metal selected from the group consisting of Ti (titanium), aluminum (Al), Pt (platinum), Au (gold), Ni (nickel), and Pd (palladium). Alternatively, the pad electrode may have a multilayer structure such as a Ti / Pt / Au multilayer structure, a Ti / Au multilayer structure, a Ti / Pd / Au multilayer structure, a Ti / Pd / Au multilayer structure, a Ti / Ni / Au multilayer structure, or a Ti / Ni / Au / Cr / Au multilayer structure. When the first electrode is composed of an Ag layer or an Ag / Pd layer, it is preferable to form a cover metal layer, for example, made of Ni / TiW / Pd / TiW / Ni, on the surface of the first electrode, and to form a pad electrode, for example, made of a multilayer structure of Ti / Ni / Au or a multilayer structure of Ti / Ni / Au / Cr / Au, on the cover metal layer.

[0070] The light reflecting layers (distributed Bragg reflector layers, DBR layers) constituting the first light reflecting layer and the second light reflecting layer are made of, for example, a semiconductor multilayer film or a dielectric multilayer film. Examples of dielectric materials include oxides and nitrides of Si, Mg, Al, Hf, Nb, Zr, Sc, Ta, Ga, Zn, Y, B, Ti, etc. (e.g., SiN X , AlN X , AlGaN X , GaN X , B.N. X ) or fluorides, etc. Specifically, SiO X , TiO X , NbO X , ZrO X , TaO X , ZnO X , AlO X , HfO X , SiN X , AlN XAmong these dielectric materials, a light reflective layer can be obtained by alternately laminating two or more types of dielectric films made of dielectric materials with different refractive indices. X / SiN Y , SiO X / TaO X , SiO X / NbO Y , SiO X / ZrO Y , SiO X / AlN Y Multilayer films such as SiO 2 are preferred. In order to obtain a desired light reflectance, the material, film thickness, number of layers, etc. constituting each dielectric film may be selected as appropriate. The thickness of each dielectric film can be adjusted as appropriate depending on the material used, etc., and is determined by the oscillation wavelength (emission wavelength) λ0 and the refractive index n of the material used at the oscillation wavelength λ0. Specifically, it is preferable to make the thickness an odd multiple of λ0 / (4n). For example, in a light emitting device with an oscillation wavelength λ0 of 410 nm, the light reflective layer may be made of SiO 2 X / NbO Y When the light-reflecting layer is made up of a plurality of layers, the thickness can be approximately 40 nm to 70 nm. The number of layers can be 2 or more, preferably 5 to 20. The total thickness of the light-reflecting layer can be approximately 0.6 μm to 1.7 μm. The light reflectance of the light-reflecting layer is preferably 95% or more.

[0071] The light-reflecting layer can be formed based on a well-known method, and specific examples thereof include PVD methods such as vacuum deposition, sputtering, reactive sputtering, ECR plasma sputtering, magnetron sputtering, ion beam assisted deposition, ion plating, and laser ablation; various CVD methods; coating methods such as spraying, spin coating, and dipping; methods combining two or more of these methods; and methods combining these methods with one or more of full or partial pretreatment, irradiation with inert gas (Ar, He, Xe, etc.) or plasma, irradiation with oxygen gas, ozone gas, or plasma, oxidation treatment (heat treatment), and exposure treatment.

[0072] The size and shape of the light-reflecting layer are not particularly limited as long as it covers the current injection region or the element region. The shape of the boundary between the current injection region and the non-current injection inner region, the shape of the boundary between the non-current injection inner region and the non-current injection outer region, and the planar shape of the opening provided in the element region or current confinement region can be specifically circular, elliptical, rectangular, or polygonal (triangle, square, hexagon, etc.). It is desirable that the shapes of the boundary between the current injection region and the non-current injection inner region, and the shape of the boundary between the non-current injection inner region and the non-current injection outer region are similar. When the shape of the boundary between the current injection region and the non-current injection inner region is circular, it is preferable that the diameter is approximately 5 μm to 100 μm. Here, the term "element region" refers to a region into which a confined current is injected, or a region into which light is confined due to a refractive index difference or the like, or a region sandwiched between the first light reflecting layer and the second light reflecting layer where laser oscillation occurs, or a region sandwiched between the first light reflecting layer and the second light reflecting layer that actually contributes to laser oscillation.

[0073] The side surfaces and exposed surfaces of the laminated structure may be covered with a covering layer (insulating film). The covering layer (insulating film) can be formed based on a well-known method. The refractive index of the material constituting the covering layer (insulating film) is preferably smaller than the refractive index of the material constituting the laminated structure. The material constituting the covering layer (insulating film) is preferably SiO2 containing SiO2. X based material, SiN X based material, SiO Y N Z based material, TaO X , ZrO X , AlN X , AlO X , GaO X Alternatively, an organic material such as a polyimide resin can be used. The coating layer (insulating film) can be formed by a PVD method such as a vacuum deposition method or a sputtering method, or a CVD method, or can be formed by a coating method.

[0074] Example 1 relates to a light-emitting device of the present disclosure. More specifically, the light-emitting device of Example 1 or Examples 2 to 12 described below is composed of a surface-emitting laser element (vertical cavity laser, VCSEL) that emits laser light from the top surface of the second compound semiconductor layer via the second optical reflecting layer. A schematic partial end view of the light-emitting device of Example 1 is shown in FIG.

[0075] The light emitting device has a plurality of light emitting elements, and is, for example, an array device in which a plurality of light emitting elements are arranged in a predetermined array.

[0076] The light emitting device of Example 1 or the light emitting devices of Examples 2 to 12 described below comprises: (A) a stacked structure 20 in which a first compound semiconductor layer 21 of a first conductivity type (specifically, n-type) having a first surface 21 a and a second surface 21 b facing the first surface 21 a, a second compound semiconductor layer 22 of a second conductivity type (specifically, p-type) having a first surface 22 a provided on the second surface 21 b side of the first compound semiconductor layer 21 and a second surface 22 b facing the first surface 22 a, and a third compound semiconductor layer 24 of the second conductivity type having a second surface 24 b provided on the first surface 21 a side of the first compound semiconductor layer 21 and a first surface 24 a facing the second surface 24 b, (B) a first light reflecting layer 41 provided on the first surface 24 a side of the third compound semiconductor layer 24, and (C) a second light reflecting layer 42 provided on the second surface 22b side of the second compound semiconductor layer 22. The first light reflecting layer 41 has a concave mirror portion 43, and at least the first compound semiconductor layer 21 and the second compound semiconductor layer 22 of the stacked structure 20 have a plurality of mesa portions M.

[0077] A resonator is formed by the region of the first light reflecting layer 41 extending from the first surface 21a of the first compound semiconductor layer 21 to a certain depth, the stacked structure 20 (the first compound semiconductor layer 21, the active layer 23, the second compound semiconductor layer 22, and the third compound semiconductor layer 24), and the region of the second light reflecting layer 42 extending from the second surface 22b of the second compound semiconductor layer 22 to a certain depth. OR When this is done, 1 x 10 -5 m≦L OR Satisfy.

[0078] In the light-emitting element of Example 1, when the first light-reflecting layer 41 is cut along an imaginary plane including the stacking direction of the stacked structure 20, the figure drawn by the interface 43a of a part of the concave mirror portion 43 of the first light-reflecting layer 41 (effective area 44 of the concave mirror portion 43 of the first light-reflecting layer 41) facing the stacked structure 20 is a part of a circle or a part of a parabola. Note that the shape (cross-sectional figure) of the part of the concave mirror portion 43 located outside the effective area 44 does not have to be a part of a circle or a part of a parabola.

[0079] Furthermore, a compound semiconductor substrate 11 made of a GaN substrate is disposed between the first surface 24a of the third compound semiconductor layer 24 and the first light-reflecting layer 41. The surface of the compound semiconductor substrate (substrate for manufacturing a light-emitting element) 11 facing the third compound semiconductor layer 24 is referred to as the "second surface 11b," and the surface opposite to the second surface 11b is referred to as the "first surface 11a." That is, the stacked structure 20 is formed on the second surface 11b of the conductive compound semiconductor substrate 11. The concave mirror portion 43 of the first light-reflecting layer 41 is composed of a base portion 45A made of the protruding portion 11a' of the first surface 11a of the compound semiconductor substrate 11, and a multilayer light-reflecting film 46 formed on at least a portion of the surface of the base portion 45A (specifically, the surface of the base portion 45A). Furthermore, the concave mirror portion 43 (specifically, the radius r' of the concave mirror portion 43 of the first light-reflecting layer 41) is formed on the concave mirror portion 43 of the first light-reflecting layer 41. DBR The radius of curvature of the effective area 44) is R DBR When this is done, R DBR ≦1×10 -3 m. Specifically, but not limited to, L OR = 50 μm R DBR = 70 μm r′ DBR In addition, the wavelength (oscillation wavelength) λ0 of the desired light mainly emitted from the light emitting element can be λ0=450 nm, for example.

[0080] Here, if the distance from the active layer 23 to the interface between the base 45A and the multilayer optical reflecting film 46 is T0, the ideal parabolic function x=f(z) is expressed as follows: 2 / t0 h DBR = r' DBR 2 / 2T0, but when the figure drawn by the interface 43a is taken as a part of a parabola, it goes without saying that the figure may deviate from such an ideal parabola.

[0081] Furthermore, the thermal conductivity of the laminated structure 20 is higher than that of the first light reflecting layer 41. The thermal conductivity of the dielectric material constituting the first light reflecting layer 41 is about 10 watts / (m·K) or less. On the other hand, the thermal conductivity of the GaN-based compound semiconductor constituting the laminated structure 20 is about 50 watts / (m·K) to 100 watts / (m·K).

[0082] The first compound semiconductor layer 21 is made of an n-GaN layer, and the active layer 23 is made of In 0.04 Ga 0.96 N layer (barrier layer) and In 0.16 Ga 0.84 The semiconductor device has a five-layer multiple quantum well structure in which an N layer (well layer) is stacked, and the second compound semiconductor layer 22 is made of a p-GaN layer. The third compound semiconductor layer 24 is made of a p-GaN layer. The first electrode 31 is formed on the first compound semiconductor layer 21. Meanwhile, the second electrode 32 is formed on the second compound semiconductor layer 22, and the second light-reflecting layer 42 is formed on the second electrode 32. The second light-reflecting layer 42 on the second electrode 32 has a flat shape. The first electrode 31 is made of Ti / Pt / Au, and the second electrode 32 is made of a transparent conductive material, specifically ITO. A pad electrode (not shown), made of, for example, Ti / Pt / Au or V / Pt / Au, is formed or connected on the edge of the first electrode 31 for electrical connection to an external electrode or circuit. A pad electrode 33 made of, for example, Pd / Ti / Pt / Au, Ti / Pd / Au, or Ti / Ni / Au is formed or connected on the edge of the second electrode 32 for electrical connection to an external electrode or circuit. The first light-reflecting layer 41 and the second light-reflecting layer 42 have a laminated structure of Ta2O5 layers and SiO2 layers (total number of dielectric film layers: 20). Although the first light-reflecting layer 41 and the second light-reflecting layer 42 have this multilayer structure, they are represented as a single layer for simplicity of illustration. The first electrode 31, the first light-reflecting layer 41, and the second light-reflecting layer 42 each have a circular planar shape.

[0083] The stacked structure 20 includes a stacked body in which a third compound semiconductor layer 24 of a second conductivity type (e.g., p-type), a first compound semiconductor layer 21 of a first conductivity type (e.g., n-type), and a second compound semiconductor layer 22 of the second conductivity type are stacked in this order from a first light reflecting layer 41 onwards.

[0084] The second conductivity type dopant of the third compound semiconductor layer 24 includes, for example, Mg, C, Zn, or Fe.

[0085] The second compound semiconductor layer 22 contains, for example, 1×10 Mg. 19 cm -3 The first compound semiconductor layer 21 is doped with, for example, 2×10 Si. 18 cm -3 The third compound semiconductor layer 24 is doped with, for example, 1×10 Mg. 18 cm -3 It's doped.

[0086] At least the first compound semiconductor layer 21 and the second compound semiconductor layer 22 of the stacked structure 20 have a plurality of mesa portions M (mesa regions) (four in the drawing). The mesa portions M have, for example, a cylindrical shape. The mesa portions M are arranged side by side along the substrate surface of the compound semiconductor substrate 11. Each of the four mesa portions M functions as a light-emitting element. By providing the mesa portions M, it is possible to further suppress the flow of current to other adjacent light-emitting elements, and to more appropriately drive the plurality of light-emitting elements individually.

[0087] The mesa structure of the mesa portion M has two or more stages. That is, the diameter (mesa diameter) of the mesa portion M in the first compound semiconductor layer 21 is larger than the diameter of the mesa portion M in the second compound semiconductor layer 22. The diameter of the mesa portion M in the first compound semiconductor layer 21 is, for example, 50 μm. The diameter of the mesa portion M in the second compound semiconductor layer 22 is, for example, 20 μm.

[0088] The diameter of the mesa portion M in the second compound semiconductor layer 22 is larger than the beam waist of the concave mirror portion 43. This makes it possible to suppress optical loss. More specifically, the diameter of the mesa portion M in the second compound semiconductor layer 22 is larger than the beam waist (1 / e ２ ) is ω0, which is greater than 3ω0. ω0 is expressed by Equation 2. where λ: oscillation wavelength, n: refractive index, L: resonator length, R: radius of curvature of the concave mirror.

[0089] By providing the third compound semiconductor layer 24, an np reverse bias can be formed by the first compound semiconductor layer 21 and the third compound semiconductor layer 24. This makes it possible to suppress current from flowing from the first compound semiconductor layer 21 to the third compound semiconductor layer 24. The third compound semiconductor layer 24 further suppresses current from flowing to other adjacent light-emitting elements, allowing for more appropriate individual driving of a plurality of light-emitting elements.

[0090] The compound semiconductor substrate 11, the first compound semiconductor layer 21, the second compound semiconductor layer 22, and the third compound semiconductor layer 24 are not limited to GaN, and may contain GaAs or InP.

[0091] The active layer 23 is stacked between the second surface 21b of the first compound semiconductor layer 21 and the first surface 22a of the second compound semiconductor layer 22. The active layer 23 is included in the mesa portion M. The active layer 23 includes, for example, an InGaN, AlGaN, AlGaInP, InGaP, or AsP-based material.

[0092] The first light reflecting layer 41 and the second light reflecting layer 42 are made of a dielectric material, and include, for example, Ti2O5 / SiO2.

[0093] The radius of curvature of the concave mirror portion 43 (the lens top) is OR The radius of curvature is, for example, 50 μm. The cavity length L OR is, for example, 1 μm or more, and may be, for example, 20 μm.

[0094] The light emitting device further includes an insulating layer 82. The insulating layer 82 is provided around the mesa portion M. By providing the insulating layer 82, the first electrode 31 and the pad electrode 33 can be arranged separately on different layers. That is, the pad electrode 33 can be arranged almost directly above the first electrode 31. The refractive index of the insulating layer 82 is equal to or higher than the refractive index of the material constituting the resonator. The insulating layer 82 includes, for example, epoxy resin, plastic, ceramics, or glass. The insulating layer 82 may include, for example, BCB (benzocyclobutene).

[0095] The light-emitting device further includes a current confinement layer 81. The current confinement layer 81 is provided around the active layer 23 and has a predetermined thickness in the Z direction. The current confinement layer 81 is provided between the active layer 23 and the insulating layer 82. The current confinement layer 81 is formed by, for example, B+ ion implantation.

[0096] Next, the first electrode 31, the pad electrode 33, and the wiring structure will be described.

[0097] 2 is a schematic plan view of the light emitting device of Example 1. FIG. 2 is a diagram showing the first electrode 31 and the pad electrode 33 as viewed from the Z direction.

[0098] 2 shows an array device including, for example, 4×4 light emitting elements (mesa portions M). In the example shown in FIG. 2, the first electrode 31 and the pad electrode 33 are provided in a circular ring shape.

[0099] The light emitting device further includes an electrode (n-side power supply part) 91 , an electrode (p-side power supply part) 92 , and wirings 93 and 94 .

[0100] The wiring 93 is connected between the electrode 91 and the first electrode 31 .

[0101] The wiring 94 is connected between the electrode 92 and the pad electrode 33 .

[0102] The wirings 93 and 94 are provided so as to be electrically conductive for each mesa portion M. That is, it is possible to drive the light emitting element in any mesa portion M. In the example shown in FIG. 2 , electrodes 91 and 92 and wirings 93 and 94 are provided individually for each mesa portion M.

[0103] In the light emitting device of Example 1, the first light reflecting layer 41 has a concave mirror portion 43. Therefore, the cavity length L OR is 1 x 10 -5 Even if the resonator length is longer than L m, an increase in diffraction loss can be avoided, and as a result, laser oscillation can be reliably performed. OR is 1 x 10 -5 Since the resonator length L can be set to 1.5 m or more, the problem of thermal saturation can be alleviated. OR is 1 x 10 -5 Since the thickness can be set to m or more, the tolerance of the manufacturing process for the light emitting device is increased, and as a result, the yield can be improved.

[0104] Furthermore, in the light-emitting device of Example 1, the stacked structure 20 has a PNP structure in which a third compound semiconductor layer 24, a first compound semiconductor layer 21, and a second compound semiconductor layer 22 are stacked in this order. At least the first compound semiconductor layer 21 and the second compound semiconductor layer 22 of the stacked structure 20 have multiple mesa portions M. Furthermore, the mesa portions M and the PNP structure can prevent current from flowing between multiple light-emitting elements in the light-emitting device. This can prevent unintended light-emitting elements from emitting light, allowing for more appropriate individual driving of multiple light-emitting elements. Furthermore, in the light-emitting device, the light-emitting intensity of each light-emitting element can be made more uniform even in a long cavity.

[0105] The light emitting element is not limited to a VCSEL, but may be an LED (Light Emitting Diode) or an SLD (Super Luminescent Diode), or the like.

[0106] Example 2 is a modification of Example 1. A schematic plan view of the light emitting device of Example 2 is shown in FIG.

[0107] The light emitting device includes four electrodes 91 and four electrodes 92 .

[0108] The wirings 93 and 94 are each arranged in a comb shape.

[0109] In the example shown in FIG. 3 , a plurality of electrodes 91, 92 are commonly wired. One electrode 91 is shared by four light-emitting elements (mesa portions M). One electrode 92 is shared by four light-emitting elements (mesa portions M). For example, when driving the upper left light-emitting element (mesa portion M), the topmost electrode 91 and the leftmost electrode 92 are energized. Therefore, the structure of the wires 93, 94 is a matrix type. As described in Example 1, the insulating layer 82 allows the pad electrode 33 to be positioned almost directly above the first electrode 31, making a matrix type wiring structure possible.

[0110] Except for the above points, the configuration and structure of the light emitting device of Example 2 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0111] Example 3 is a modification of Example 1. A schematic plan view of the light emitting device of Example 3 is shown in FIG.

[0112] The light emitting elements (mesa portions M) are arranged in a hexagonal close-packed pattern, which allows for a larger number of light emitting elements (mesa portions M) to be provided, thereby enabling higher output.

[0113] Except for the above points, the configuration and structure of the light emitting device of Example 3 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0114] Example 4 is a modification of Example 2 or Example 3. Example 4 is also a combination of Example 2 and Example 3. A schematic plan view of the light emitting device of Example 4 is shown in FIG.

[0115] As in Example 3, the light-emitting elements (mesa portions M) are arranged in a hexagonal close-packed pattern. Also, as in Example 2, multiple electrodes 91 and 92 are commonly wired. One electrode 91 is shared by multiple light-emitting elements (mesa portions M). One electrode 92 is shared by multiple light-emitting elements (mesa portions M).

[0116] Except for the above points, the configuration and structure of the light emitting device of Example 4 can be the same as the configuration and structure of the light emitting device of Example 2 or Example 3, so detailed description will be omitted.

[0117] Example 5 is a modification of Examples 1 to 4. A schematic partial end view of the light emitting device of Example 5 is shown in FIG.

[0118] The third compound semiconductor layer 24 of the stacked structure 20 has a mesa portion M. That is, the third compound semiconductor layer 24 is also included in the mesa portion M. The mesa portion M has a three-tiered mesa structure. This further suppresses current flow to other adjacent light-emitting elements, enabling more appropriate individual driving. The diameter of the mesa portion M in the third compound semiconductor layer 24 is larger than the diameter of the mesa portion M in the first compound semiconductor layer 21. The diameter of the mesa portion M in the third compound semiconductor layer 24 is, for example, 70 μm.

[0119] Except for the above points, the configuration and structure of the light emitting device of Example 5 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0120] Example 6 is a modification of Examples 1 to 5. A schematic partial end view of the light emitting device of Example 6 is shown in FIG.

[0121] The third compound semiconductor layer 24 is located (2n+1)λ / 4 (n=1, 2, 3, ...) away from the active layer 23 in the Z direction, where λ is the oscillation wavelength. While the active layer 23 is a gain region, the third compound semiconductor layer 24 is highly doped, resulting in high optical loss and light absorption. By positioning the active layer 23 at an antinode of the optical field and the third compound semiconductor layer 24 at a node of the optical field, it is possible to achieve a lower threshold value and higher efficiency. In addition, wavelength stability is improved.

[0122] Except for the above points, the configuration and structure of the light emitting device of Example 6 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0123] Example 7 is a modification of Examples 1 to 6. A schematic partial end view of the light emitting device of Example 7 is shown in FIG.

[0124] When a reverse bias is applied, a depletion layer 23 is formed at the pn junction interface between the first compound semiconductor layer 21 and the third compound semiconductor layer 24. Under conditions in which the third compound semiconductor layer 24 is completely depleted, no current flows from the first compound semiconductor layer 21 to the third compound semiconductor layer 24. On the other hand, the first compound semiconductor layer 21 is provided thick so that a current flows between the first electrode 31 and the second electrode 32.

[0125] The thickness (film thickness) of the third compound semiconductor layer 24 in the Z direction is the width (thickness in the Z direction) W of the depletion layer formed inside the third compound semiconductor layer 24. p The depletion layer width W p (nm) is expressed by Equation 3. where ε s : Dielectric constant V D : Diffusion potential V: Applied voltage N d : effective donor density of the first compound semiconductor layer N a : effective acceptor density of the third compound semiconductor layer, and dielectric constant ε s is the dielectric constant ε of GaN s (=8.9 x vacuum dielectric constant).

[0126] For example, when the forward voltage is 5 V, the effective donor density (N d ) is 1 x 10 １８ cm －３ and the effective acceptor density (N a ) is 2 x 10 １８ cm －３ The thickness of the third compound semiconductor layer 24 is 50 nm.

[0127] The thickness (film thickness) of the first compound semiconductor layer 21 in the Z direction is a width (thickness in the Z direction) W of a depletion layer formed inside the first compound semiconductor layer 21. n That's all. Depletion layer width W n (nm) is expressed by Equation 4.

[0128] For example, when the forward applied voltage is −5 V, the effective donor density (N d ) is 1 x 10 １８ cm －３and the effective acceptor density (N a ) is 2 x 10 １８ cm －３ The thickness of the first compound semiconductor layer 21 is 5 μm.

[0129] The above-described depletion layer width can suppress current from flowing from the first compound semiconductor layer 21 to the third compound semiconductor layer 24. This allows the plurality of light-emitting elements to be driven individually more appropriately.

[0130] Except for the above points, the configuration and structure of the light emitting device of Example 7 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0131] The eighth embodiment is a modification of the first to seventh embodiments.

[0132] The insulating layer 82 is filled with a high thermal conductivity material (>1 W / m·K). ２ O ３ The material contains a thermosetting resin material with a thermal conductivity of 30 W / m·K, to which filler powder of 1000 ppm has been added. This improves heat dissipation and enables higher output.

[0133] Except for the above points, the configuration and structure of the light emitting device of Example 8 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0134] Example 9 is a modification of Examples 1 to 7. A schematic partial end view of the light emitting device of Example 9 is shown in FIG.

[0135] Instead of the insulating layer 82, a conductive layer 83 and an insulating layer 84 are provided.

[0136] The conductive layer 83 has a higher thermal conductivity than insulating layers such as the insulating layer 84. The insulating layer 84 is provided to prevent unintended electrical connection with the conductive layer 83.

[0137] For example, the insulating layer 84 contains SiN and is provided to a thickness of 200 nm. For example, the conductive layer 83 is provided on the insulating layer 84, contains Ni / Cu, and is laminated to a thickness of 1 μm. This improves heat dissipation and enables high output.

[0138] Except for the above points, the configuration and structure of the light emitting device of Example 9 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0139] The tenth embodiment is a modification of the first to ninth embodiments.

[0140] The third compound semiconductor layer 24 contains In. The third compound semiconductor layer 24 contains, for example, InGaN. The mesa portion M is formed, for example, by etching. When the third compound semiconductor layer 24 contains In, the etching rate decreases, making it easier to stop etching at a targeted position. This makes it easier to form a desired mesa structure, and stabilizes the process. As a result, the characteristics can be further stabilized.

[0141] Except for the above points, the configuration and structure of the light emitting device of Example 10 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0142] Example 11 is a modification of Examples 1 to 10. A schematic partial end view of the light emitting device of Example 11 is shown in FIG.

[0143] The light emitting device further includes a fourth compound semiconductor layer 25 .

[0144] The fourth compound semiconductor layer 25 is provided in a region where the mesa portion M is not provided. The fourth compound semiconductor layer 25 is provided in the first compound semiconductor layer 21, the third compound semiconductor layer 24, or both layers. The fourth compound semiconductor layer 25 is formed by, for example, ion implantation. The ions implanted are, for example, B+.

[0145] The high-resistance fourth compound semiconductor layer 25 can prevent current from flowing to other adjacent light-emitting elements, and the plurality of light-emitting elements can be driven individually more appropriately. In Example 11, when the fourth compound semiconductor layer 25 is formed deep, the mesa portion M does not need to be formed.

[0146] Except for the above points, the configuration and structure of the light emitting device of Example 11 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0147] Example 12 is a modification of Examples 1 to 11. A schematic partial end view of the light emitting device of Example 12 is shown in FIG.

[0148] The first light reflecting layer 41 may be separated for each light emitting element (mesa portion M), that is, for each concave mirror portion 43. Therefore, the first light reflecting layer 41 does not have to be provided on the entire first surface 11 a of the compound semiconductor substrate 11.

[0149] Except for the above points, the configuration and structure of the light emitting device of Example 12 can be the same as the configuration and structure of the light emitting device of Example 1, so detailed description will be omitted.

[0150] The present technology can be configured as follows: (1) A light-emitting device including: a stacked structure including: a first compound semiconductor layer of a first conductivity type having a first surface and a second surface opposite to the first surface; a second compound semiconductor layer of a second conductivity type having a first surface provided on the second surface side of the first compound semiconductor layer and a second surface opposite to the first surface; and a third compound semiconductor layer of the second conductivity type having a second surface provided on the first surface side of the first compound semiconductor layer and a first surface opposite to the second surface; a first light-reflecting layer provided on the first surface side of the third compound semiconductor layer; and a second light-reflecting layer provided on the second surface side of the second compound semiconductor layer, wherein the first light-reflecting layer has a concave mirror portion, and at least the first compound semiconductor layer and the second compound semiconductor layer of the stacked structure have a plurality of mesa portions. (2) The light emitting device according to (1), wherein the diameter of the mesa portion in the second compound semiconductor layer is greater than 3ω0, where ω0 is the beam waist of the concave mirror portion and is expressed by the following formula: where λ: oscillation wavelength, n: refractive index, L: cavity length, and R: radius of curvature of the concave mirror portion. (3) The light-emitting device according to (1) or (2), wherein the stacked structure further includes an active layer stacked between the second surface of the first compound semiconductor layer and the first surface of the second compound semiconductor layer. (4) The light-emitting device according to (3), wherein the third compound semiconductor layer is located (2n+1)λ / 4 (n=1, 2, 3, ...) away from the active layer in the stacking direction, where λ is the oscillation wavelength. (5) The light-emitting device according to (3) or (4), wherein the active layer contains an InGaN, AlGaN, AlGaInP, InGaP, or AsP-based material. (6) The light-emitting device according to any one of (1) to (5), wherein the diameter of the mesa portion in the first compound semiconductor layer is larger than the diameter of the mesa portion in the second compound semiconductor layer. (7) The light emitting device according to any one of (1) to (6), further comprising an insulating layer provided around the mesa portion. (8) The light emitting device according to (7), wherein the insulating layer includes epoxy resin, plastic, ceramic, or glass. (9) The light emitting device according to (7) or (8), wherein the refractive index of the insulating layer is equal to or greater than the refractive index of the material constituting the resonator. (10) The light emitting device according to any one of (1) to (9), further comprising a substrate provided between the first compound semiconductor layer, the first surface, and the first light reflecting layer. (11) The light emitting device according to (10), wherein the substrate is a GaN substrate, a GaAs substrate, or an InP substrate. (12) The light emitting device according to any one of (1) to (11), wherein the radius of curvature of the concave mirror portion is equal to or greater than the length of the resonator. (13) The light-emitting device according to any one of (1) to (12), wherein the thickness of the first compound semiconductor layer in the stacking direction is equal to or greater than the thickness of a depletion layer formed inside the first compound semiconductor layer. n The light-emitting device according to (13), wherein is represented by the following formula: where ε s : Dielectric constant V D : Diffusion potential V: Applied voltage N d : effective donor density of the first compound semiconductor layer N a: effective acceptor density of the third compound semiconductor layer (15) The light emitting device according to any one of (1) to (14), wherein a second conductivity type dopant of the third compound semiconductor layer contains Mg, C, Zn, or Fe. (16) The light emitting device according to any one of (1) to (15), further comprising wiring provided to enable conduction to each mesa portion. (17) The light emitting device according to (16), wherein the wiring is provided in a matrix format. (18) The light emitting device according to any one of (1) to (17), wherein the first compound semiconductor layer, the second compound semiconductor layer, and the third compound semiconductor layer contain GaN.

[0151] The aspects of the present disclosure are not limited to the individual embodiments described above, but include various modifications that may be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the above-described contents. In other words, various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and spirit of the present disclosure, which is derived from the contents defined in the claims and their equivalents.

[0152] 11... compound semiconductor substrate (substrate for manufacturing light-emitting element), 11a... first surface of compound semiconductor substrate (substrate for manufacturing light-emitting element) facing first compound semiconductor layer, 11a'... protruding portion of first surface of compound semiconductor substrate, 11a"... recess, 11b... second surface of compound semiconductor substrate (substrate for manufacturing light-emitting element) facing first compound semiconductor layer, 11A... convex portion, 20... stacked structure, 21... first compound semiconductor layer, 21a... first surface of first compound semiconductor layer, 21b... second surface of first compound semiconductor layer, 21d, 21e... protruding portion of first surface of first compound semiconductor layer, 22... second compound semiconductor layer, 22a... first surface of second compound semiconductor layer, 22b... second surface of second compound semiconductor layer, 23... active layer (light-emitting layer), 31... first electrode, 32... second electrode, 33... pad electrode, 34... insulating layer (current confinement layer), 34A... insulating layer (current confinement layer) a concave mirror portion formed on the concave mirror portion of the first light reflecting layer; a recess formed on the concave mirror portion of the first light reflecting layer; a base portion formed on the concave mirror portion of the first light reflecting layer; a protrusion formed on the concave mirror portion of the first light reflecting layer; a forward tapered inclined portion formed on the second light reflecting layer; a concave mirror portion formed on the concave mirror portion of the first light reflecting layer; a recess formed on the concave mirror portion of the first light reflecting layer; a base portion formed on the concave mirror portion of the first light reflecting layer; a protrusion formed on the concave mirror portion of the first light reflecting layer; a projection ... Planarization film, 48... bonding layer, 49... supporting substrate, 51, 61... current injection region, 52, 62... current non-injection inner region, 53, 63... current non-injection outer region, 54, 64... mode loss effect region (mode loss effect layer), 54A, 54B, 64A... openings formed in the mode loss effect region, 55, 65... mode loss effect region, 71... light absorbing material layer, 93... wiring, 94... wiring, M... mesa portion, W n ...depletion layer width, W p ...Depletion layer width

Claims

1. A light emitting device comprising: a laminated structure including: a first compound semiconductor layer of a first conductivity type having a first surface and a second surface opposite to the first surface; a second compound semiconductor layer of a second conductivity type having a first surface provided on the second surface side of the first compound semiconductor layer and a second surface opposite to the first surface; and a third compound semiconductor layer of the second conductivity type having a second surface provided on the first surface side of the first compound semiconductor layer and a first surface opposite to the second surface; a first light reflective layer provided on the first surface side of the third compound semiconductor layer; and a second light reflective layer provided on the second surface side of the second compound semiconductor layer; wherein the first light reflective layer has a concave mirror portion; and at least the first compound semiconductor layer and the second compound semiconductor layer of the laminated structure have multiple mesas.

2. The light emitting device according to claim 1, wherein the diameter of the mesa portion in the second compound semiconductor layer is greater than 3ω0, where ω0 is the beam waist of the concave mirror portion and is expressed by the following formula: where λ: oscillation wavelength, n: refractive index, L: resonator length, R: radius of curvature of the concave mirror.

3. The light emitting device according to claim 1, wherein the laminated structure further comprises an active layer laminated between the second surface of the first compound semiconductor layer and the first surface of the second compound semiconductor layer.

4. The light emitting device according to claim 3, wherein the third compound semiconductor layer is positioned (2n+1)λ / 4 (n=1, 2, 3, ...) away from the active layer in the stacking direction, where λ is the oscillation wavelength.

5. The light emitting device according to claim 3, wherein the active layer comprises an InGaN, AlGaN, AlGaInP, InGaP, or AsP based material.

6. The light emitting device according to claim 1, wherein the diameter of the mesa portion in the first compound semiconductor layer is larger than the diameter of the mesa portion in the second compound semiconductor layer.

7. The light emitting device according to claim 1, further comprising an insulating layer provided around the mesa portion.

8. The light emitting device of claim 7, wherein the insulating layer comprises an epoxy resin, a plastic, a ceramic, or a glass.

9. The light emitting device according to claim 7, wherein the refractive index of the insulating layer is equal to or greater than the refractive index of the material of the resonator.

10. The light emitting device of claim 1, further comprising a substrate disposed between the first compound semiconductor layer, the first surface, and the first light reflecting layer.

11. The light-emitting device according to claim 10, wherein the substrate is a GaN substrate, a GaAs substrate, or an InP substrate.

12. The light emitting device according to claim 1, wherein the radius of curvature of the concave mirror portion is equal to or greater than the length of the resonator.

13. The light-emitting device according to claim 1, wherein the thickness of the first compound semiconductor layer in the stacking direction is equal to or greater than the thickness of a depletion layer formed inside the first compound semiconductor layer.

14. Thickness W of the depletion layer formed inside the first compound semiconductor layer n The light emitting device according to claim 13 , wherein is represented by the following formula: where ε s : Dielectric constant V D : Diffusion potential V: Applied voltage N d : effective donor density of the first compound semiconductor layer N a : effective acceptor density of the third compound semiconductor layer 15. The light-emitting device according to claim 1, wherein the second conductivity type dopant of the third compound semiconductor layer includes Mg, C, Zn, or Fe.

16. The light emitting device according to claim 1, further comprising wiring provided for each mesa portion so as to be electrically conductive.

17. The light emitting device according to claim 16, wherein the wiring is arranged in a matrix.

18. The light emitting device of claim 1, wherein the first compound semiconductor layer, the second compound semiconductor layer, and the third compound semiconductor layer comprise GaN.

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