Light emitting device

Abstract

[Problem] To provide a light emitting device in which the uniformity of the in-plane distribution of optical output is increased and the exhaust heat efficiency is improved. [Solution] A light emitting device comprising: a first reflecting mirror constituted by laminating a plurality of semiconductor materials having different refractive indexes in a first direction; an active layer provided on a second surface side of the first reflecting mirror and that emits light through application of power; a second reflecting mirror constituted by laminating a plurality of non-conductive materials having different refractive indexes in the first direction or laminating a non-conductive material and an amorphous semiconductor material having different refractive indexes in the first direction; a plurality of protrusions provided between a fourth surface and a sixth surface and protruding in the first direction toward the second reflecting mirror, or a plurality of recesses recessed in the first direction from the second reflecting mirror; a first electrode electrically connected to one surface of the active layer; and a second electrode electrically connected to the other surface of the active layer.

Description

Light-emitting device

[0001] The present disclosure relates to a light emitting device.

[0002] Distance measurement sensors such as d-ToF (Direct Time of Flight) use light-emitting devices such as VCSELs (Vertical-Cavity Surface-Emitting Lasers). In order to extend the distance measurement range of a distance measurement sensor, it is desirable to increase the optical output of the light-emitting device. The optical output of a light-emitting device can be increased by increasing the ratio of the light-emitting area.

[0003] The ratio of the light-emitting area can be increased by narrowing the spacing between the light-emitting devices arranged in an array. To maintain ease of manufacturing while narrowing the spacing between the light-emitting devices, it is effective to reduce the height of the light-emitting device. To reduce the height of the light-emitting device, it is possible to construct the reflector from a dielectric material.

[0004] JP 2013-084909 A JP 2008-251718 A JP 2010-080571 A

[0005] However, if the reflector is made of a dielectric material, the current distribution to the light-emitting layer will be poor, and the in-plane distribution of light output will be poor. Furthermore, reflectors made of dielectric materials have lower thermal conductivity than semiconductor materials, which reduces the efficiency of heat dissipation from the light-emitting layer to the electrodes.

[0006] Therefore, the present disclosure provides a light emitting device that has an in-plane distribution of light output that is closer to uniform and has improved heat dissipation efficiency.

[0007] A light emitting device according to one aspect of the present disclosure includes a first reflecting mirror configured by stacking a plurality of semiconductor materials having refractive indices different from one another in a first direction, the first reflecting mirror having a first surface and a second surface opposite the first surface, an active layer provided on the second surface side of the first reflecting mirror, the active layer having a third surface facing the first reflecting mirror and a fourth surface opposite the third surface, the active layer emitting light when power is applied to the third and fourth surfaces, and a plurality of non-conductive materials having refractive indices different from one another and provided on the fourth surface side of the active layer, stacked in the first direction; The second reflector is constructed by stacking a non-conductive material and an amorphous semiconductor material having different refractive indices in a first direction, and includes a second reflector having a fifth surface facing the active layer and a sixth surface opposite the fifth surface, a plurality of protrusions provided between the fourth surface and the sixth surface and protruding in the first direction toward the second reflector, or a plurality of recesses recessed in the first direction from the second reflector, a first electrode electrically connected to the fourth surface of the active layer, and a second electrode electrically connected to the third surface of the active layer.

[0008] The second reflector is divided into a plurality of second reflector portions by grooves that penetrate the second reflector in a first direction and extend in the first direction, and the first electrode is provided in the grooves so as to surround the peripheries of the plurality of second reflector portions.

[0009] The light emitting device further includes a third reflector provided between the fourth surface and the sixth surface and constructed by stacking a plurality of semiconductor materials having different refractive indices in a first direction, and the third reflector is shared by a plurality of second reflector portions and is not divided.

[0010] The light emitting device further includes a third reflector that is provided between the fourth surface and the sixth surface or between the sixth surface and the plurality of protrusions or the plurality of recesses, and that is constructed by stacking a plurality of semiconductor materials having different refractive indices in a first direction, and the third reflector is divided into a plurality of third reflector portions by grooves.

[0011] The light emitting device further includes a third reflector that is provided between the fourth surface and the sixth surface or between the sixth surface and the plurality of protrusions or the plurality of recesses, and that is constructed by stacking a plurality of semiconductor materials having different refractive indices in a first direction, and the upper layer of the third reflector is divided into a plurality of parts by grooves, and the lower layer of the third reflector is shared by the plurality of second reflector parts and the upper layer and is not divided.

[0012] The plurality of protrusions or recesses are provided between the second reflecting mirror and the third reflecting mirror.

[0013] The plurality of protrusions are part of a step layer having a first film thickness in the region of the plurality of second reflecting mirror portions and a second film thickness thinner than the first film thickness in the region of the grooves, or the plurality of recesses are part of a step layer having a first film thickness in the region of the plurality of second reflecting mirror portions and a second film thickness thicker than the first film thickness in the region of the grooves.

[0014] A plurality of protrusions or recesses are provided for each corresponding second reflecting mirror portion.

[0015] The plurality of protrusions or the plurality of recesses are made of one of the plurality of semiconductor materials that make up the third reflecting mirror.

[0016] Between the first reflecting mirror and the second reflecting mirror, in a first region of the multiple protrusions or multiple recesses, light resonates at a wavelength equal to the wavelength of the output light to the outside, and in regions other than the first region, light does not resonate at a wavelength equal to the wavelength of the output light.

[0017] A first electrode is provided in the groove and on the plurality of second reflector portions, and the light emitting device further includes a connection portion provided on the first electrode.

[0018] The light emitting device further includes a non-conductive semiconductor layer doped with impurities and disposed in the active layer in a first direction relative to the groove.

[0019] When viewed from the first direction, the plurality of protrusions or the plurality of recesses have a substantially circular or substantially polygonal shape.

[0020] The second reflector is arranged around the plurality of protrusions or recesses and has a hole penetrating the second reflector in the first direction, and the first electrode is in electrical contact with the active layer on a fourth surface exposed within the hole.

[0021] The first electrode covers at least a portion of the top surface of the second reflector.

[0022] The spacing between the centers of gravity of adjacent protrusions or adjacent depressions is 4×σ or less, where σ is the standard deviation of the light intensity distribution corresponding to one protrusion or one depression.

[0023] The light intensity distribution of the light emitted from each of the plurality of protrusions or the plurality of depressions has a single peak.

[0024] When viewed from the first direction, the plurality of protrusions or recesses have the same shape and are arranged at equal intervals.

[0025] When viewed from the first direction, the spacing between adjacent protrusions or the spacing between adjacent recesses becomes narrower or wider as one approaches the center of the second reflecting mirror, or when viewed from the first direction, the sides of the multiple protrusions or multiple recesses extending in the second direction become shorter or longer as one moves away from the center of the second reflecting mirror in the second direction.

[0026] The light emitting device further comprises an insulating layer at the edge of the active layer by introducing impurities into the edge of the active layer or by oxidizing the edge of the active layer.

[0027] 10 is a cross-sectional view showing an example of the configuration of a light emitting device according to the first embodiment; 11 is a cross-sectional view showing an example of a method for manufacturing a light emitting device according to the first embodiment; 12 is a cross-sectional view showing an example of a method for manufacturing a light emitting device subsequent to FIG. 2; 13 is a cross-sectional view showing an example of a method for manufacturing a light emitting device subsequent to FIG. 3; 14 is a cross-sectional view showing an example of a method for manufacturing a light emitting device subsequent to FIG. 4; 15 is a cross-sectional view showing an example of a method for manufacturing a light emitting device subsequent to FIG. 5; 16 is a cross-sectional view showing an example of a method for manufacturing a light emitting device subsequent to FIG. 6; 17 is a cross-sectional view showing an example of a method for manufacturing a light emitting device subsequent to FIG. 7; 18 is a cross-sectional view showing an example of a method for manufacturing a light emitting device subsequent to FIG. 8; 19 is a cross-sectional view showing an example of a configuration of a light emitting device according to the second embodiment; 20 is a cross-sectional view showing an example of a configuration of a light emitting device according to the third embodiment; 21 is a cross-sectional view showing an example of a configuration of a light emitting device according to the fourth embodiment; 22 is a cross-sectional view showing an example of a configuration of a light emitting device according to the fifth embodiment; 23 is a cross-sectional view showing an example of a configuration of a light emitting device according to the sixth embodiment; 24 is a cross-sectional view showing an example of a configuration of a light emitting device according to the seventh embodiment; 25 is a plan view showing an example of a configuration of a step layer and a second reflecting mirror according to the eighth embodiment; 26 is a plan view showing an example of a configuration of a step layer and a second reflecting mirror according to the ninth embodiment; 27 is a plan view showing an example of a configuration of a step layer and a second reflecting mirror according to the tenth embodiment 12. A plan view showing an example of the configuration of a step layer and a second reflecting mirror according to a 12th embodiment. A plan view showing an example of the configuration of a step layer and a second reflecting mirror according to a 13th embodiment. A plan view showing an example of the configuration of a step layer and a second reflecting mirror according to a 14th embodiment. A cross-sectional view showing an example of the configuration of a light-emitting device according to a 15th embodiment. A cross-sectional view showing an example of the configuration of a light-emitting device according to a 16th embodiment. A block diagram showing an example of the schematic configuration of a vehicle control system. An explanatory diagram showing an example of the installation positions of a vehicle outside information detection unit and an imaging unit. A cross-sectional view showing an example of the configuration of a light-emitting device according to a 17th embodiment. A plan view showing an example of the configuration of a mesa, a step layer, a second reflecting mirror, and a first electrode according to an 18th embodiment. A diagram showing the light intensity distribution of single-peak laser light emitted from one protrusion. A plan view showing an example of the configuration of a mesa, a step layer, a second reflecting mirror, and a first electrode according to a 19th embodiment. A plan view showing an example of the configuration of a mesa, a step layer, a second reflecting mirror, and a first electrode according to a 20th embodiment. A plan view showing an example of the configuration of a mesa, a step layer, a second reflecting mirror, and a first electrode according to a 21st embodiment. 22. A plan view showing an example of the configuration of a mesa, a step layer, a second reflector, and a first electrode according to a 22nd embodiment.24 is a cross-sectional view showing a configuration example of a light emitting device according to a twenty-fourth embodiment;

[0028] Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings. The drawings are schematic or conceptual, and the proportions of each part are not necessarily the same as those in reality. In the specification and drawings, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0029] 1 is a cross-sectional view showing an example of the configuration of a light-emitting device according to Embodiment 1. The light-emitting device 1 includes a substrate 10, a first semiconductor layer 20, a first reflecting mirror 30, an active layer 40, a third reflecting mirror 50, a step layer 60, a second reflecting mirror 70, a first electrode 80, a second electrode 90, a protective film 100, and connecting portions 110 and 120.

[0030] The light emitting device 1 is, for example, a surface-emitting laser such as a VCSEL. The light emitting device 1 emits light by applying power between the first electrode 80 and the second electrode 90 to inject electrons and holes into the active layer 40 and recombine the electrons and holes in the active layer 40. The light is reflected and resonates between the first reflecting mirror 30 and the second reflecting mirror 70, and is emitted as laser light L from the substrate 10 side. In other words, the light emitting device 1 is a back-emitting laser.

[0031] The substrate 10 is, for example, a semiconductor substrate such as a GaAs substrate.

[0032] The first semiconductor layer 20 is, for example, a semiconductor layer such as n-type GaAs. The first semiconductor layer 20 is provided on the substrate 10 and functions as an n-type contact layer that is in electrical contact with the second electrode 90 with low resistance.

[0033] The first reflecting mirror 30 is a so-called semiconductor DBR (Distributed Bragg Reflector) and is configured by alternately stacking multiple semiconductor materials with different refractive indices in the Z direction. For example, the first reflecting mirror 30 has a layered structure of multiple epitaxially grown n-type semiconductor materials (e.g., a layered structure of n-type GaAs and n-type AlGaAs or n-type AlAs). The first reflecting mirror 30 has a first face F1 and a second face F2 opposite the first face F1. The first reflecting mirror 30 is electrically connected to the second electrode 90 on the first face F1 side via the first semiconductor layer 20.

[0034] The active layer 40 is provided on the second surface F2 side of the first reflecting mirror 30, and is provided between the first reflecting mirror 30 and the third reflecting mirror 50. The active layer 40 has a third surface F3 facing the first reflecting mirror and a fourth surface F4 on the opposite side of the third surface F3. The active layer 40 emits light when electrons and holes recombine inside the active layer 40 upon application of power to the first reflecting mirror 30 and the third reflecting mirror 50. The active layer 40 is made of, for example, GaAs, InGaAs, AlGaInAs, or InGaAsP, and has a multiple quantum well (MQW) structure.

[0035] The third reflecting mirror 50 is provided on the fourth face F4 side of the active layer 40, between the active layer 40 and the second reflecting mirror 70 or between the active layer 40 and the step layer 60. The third reflecting mirror 50 is configured by alternately stacking multiple semiconductor materials with different refractive indices in the Z direction. For example, the third reflecting mirror 50 has a layered structure of multiple epitaxially grown p-type semiconductor materials (e.g., a layered structure of p-type GaAs and p-type AlGaAs or p-type AlAs). The third reflecting mirror 50 has a seventh face F7 and an eighth face F8 opposite the seventh face F7. The third reflecting mirror 50 is electrically connected to the first electrode 80 on the eighth face F8 side. The third reflecting mirror 50 is shared by the multiple second reflecting mirror portions 70a to 70c of the second reflecting mirror 70 and is not divided into multiple parts for the first reflecting mirror 30 or the active layer 40.

[0036] The step layer 60 is provided between the active layer 40 and the second reflector 70, and is sandwiched, for example, between the third reflector 50 and the second reflector 70 or the first electrode 80. The step layer 60 may be made of, for example, one of the semiconductor materials that make up the third reflector 50. For example, the step layer 60 is made of any one of p-type GaAs, p-type AlGaAs, and p-type AlAs. The step layer 60 includes a plurality of protrusions 60a-60c. The plurality of protrusions 60a-60c are provided corresponding to the plurality of second reflector portions 70a-70c of the second reflector 70, respectively, and protrude in the Z direction toward the second reflector portions 70a-70c. The thickness of the step layer 60 in the Z direction at the protruding portions 60a to 60c is a first thickness T1, and the thickness of the step layer 60 in the Z direction in the region other than the protruding portions 60a to 60c is a second thickness T2 that is thinner than the first thickness T1. That is, the step layer 60 has the first thickness T1 in the region R60 of the multiple protruding portions 60a to 60c, and has the second thickness T2 that is thinner than the first thickness T1 in the other regions R70 and RTR of the second reflecting mirror 70 and the trench TR.

[0037] The multiple protrusions 60a-60c are provided between the second reflecting mirror 70 and the third reflecting mirror 50, one for each of the multiple second reflecting mirror portions 70a-70c of the second reflecting mirror 70. The protrusions 60a-60c protrude in the Z direction by a distance T1-T2 relative to the other regions of the step layer 60. That is, the length of each side surface F60 of the protrusions 60a-60c (the height of the protrusions 60a-60c in the Z direction) is T1-T2. The height of the protrusions 60a-60c in the Z direction is set so that light generated in the active layer 40 resonates in the first region of the protrusions 60a-60c between the first reflecting mirror 30 and the second reflecting mirror 70. On the other hand, in the thinner regions of the step layer 60 other than the protrusions 60a-60c, light generated in the active layer 40 does not resonate between the first reflecting mirror 30 and the second reflecting mirror 70. In this manner, the film thickness of the step layer 60 (ie, the height of the protrusions 60a to 60c) is set.

[0038] The second reflecting mirror 70 is provided on the step layer 60 so as to cover the upper surfaces and side surfaces F60 of the protrusions 60a to 60c. The second reflecting mirror 70 is provided between the first electrode 80 and the step layer 60. The second reflecting mirror 70 is a dielectric DBR formed by stacking multiple non-conductive materials with different refractive indices in the Z direction. Alternatively, the second reflecting mirror 70 is a dielectric-amorphous semiconductor DBR formed by stacking non-conductive materials and amorphous semiconductor materials with different refractive indices in the Z direction. The second reflecting mirror 70 is, for example, a stacked film of a silicon oxide film and a silicon nitride film, or a stacked film of a silicon oxide film and amorphous silicon. The second reflecting mirror 70 has a fifth surface F5 facing the active layer 40 and a sixth surface F6 on the opposite side of the fifth surface F5.

[0039] The second reflecting mirror 70 is divided into a plurality of second reflecting mirror portions 70a to 70c by grooves TR extending in the Z direction. The grooves TR penetrate the second reflecting mirror 70 in the Z direction. The plurality of second reflecting mirror portions 70a to 70c are separated from one another by the grooves TR.

[0040] The refractive index of the protrusions 60a to 60c is different from the refractive index of the second reflecting mirror 70 that contacts the protrusions 60a to 60c at the side surface F60. This allows the protrusions 60a to 60c to have an optical confinement effect that enables the formation of a transverse mode required to achieve laser oscillation.

[0041] The first electrode 80 is provided on the sixth face F6 of the second reflector 70 and in the trench TR, and is electrically connected to the fourth face F4 of the active layer 40 via the step layer 60 and the third reflector 50. The first electrode 80 is provided in the trench TR so as to surround the periphery of the plurality of second reflector portions 70a to 70c. The first electrode 80 is electrically connected as a whole to the connection portion 110. The first electrode 80 is made of a conductive metal, for example, a single layer film containing Ti, Pt, or Au, a laminated film of AuGe, Ni, and Au, or a laminated film of PdGe, Ni, and Au.

[0042] The second electrode 90 is provided on the first semiconductor layer 20 and is electrically connected to the third face F3 of the active layer 40 via the first semiconductor layer 20 and the first reflecting mirror 30. The second electrode 90 is also made of a conductive metal such as a single layer film containing Ti, Pt, or Au, a laminated film of AuGe, Ni, and Au, or a laminated film of PdGe, N, and Au.

[0043] The protective film 100 covers the side surfaces of the first reflector 30, the active layer 40, the third reflector 50, the step layer 60, the second reflector 70, the first electrode 80, and the second electrode 90, and also covers part of the upper surfaces of the first electrode 80 and the second electrode 90. As a result, the protective film 100 protects the structure of the first reflector 30, the active layer 40, the third reflector 50, the step layer 60, and the second reflector 70, and can prevent the first and second electrodes 80, 90 from short-circuiting to an unintended configuration. The protective film 100 is made of, for example, SiO ２ The insulating material is SiN or the like.

[0044] The connection portion 110 is provided on the first electrode 80 and is electrically connected to the first electrode 80. The connection portion 110 is made of a conductive material such as gold or solder. The connection portion 110 functions as a bump that electrically connects to a wiring board, a semiconductor chip, or the like (not shown).

[0045] The connection portion 120 is provided on the second electrode 90 and is electrically connected to the second electrode 90. The connection portion 120 is made of a conductive material such as gold or solder. The connection portion 120 functions as a pad that is electrically connected to a bonding wire or the like (not shown).

[0046] The anti-reflection film 130 is provided on the back surface side of the substrate 10. The anti-reflection film 130 is provided so that the laser light generated by the light emitting device 1 is emitted without being reflected on the back surface of the substrate 10. The anti-reflection film 130 is made of, for example, a silicon oxide film or a silicon nitride film.

[0047] When power is applied between the first electrode 80 and the second electrode 90, electrons and holes are injected into the active layer 40, and light is emitted by recombining the electrons and holes in the active layer 40. The light is reflected and resonates between the first reflecting mirror 30 and the second reflecting mirror 70, and is emitted from the back surface side of the substrate 10 as laser light.

[0048] In the light-emitting device 1 according to the present disclosure, a second reflector 70 containing a non-conductive material is divided into multiple second reflector portions 70a-70c. The multiple second reflector portions 70a-70c are formed on a common first reflector 30 and active layer 40 made of a semiconductor material. Non-conductive materials (dielectric materials) can achieve high reflectivity with fewer layers than semiconductor materials. Therefore, the second reflector 70 can be made thinner. By reducing the thickness of the second reflector 70, the height of the multiple second reflector portions 70a-70c is reduced, allowing the multiple second reflector portions 70a-70c to be formed with narrower spacing during the semiconductor manufacturing process.

[0049] On the other hand, the multiple protrusions 60a-60c and the multiple second reflector portions 70a-70c are provided for the mesa structure of one first reflector 30 and one active layer 40. In this manner, in the present disclosure, the multiple divided protrusions 60a-60c and the multiple second reflector portions 70a-70c are formed for the common, undivided first reflector 30 and active layer 40. In other words, although the second reflector 70 containing a non-conductive material is divided, the first reflector 30 and active layer 40 made of a semiconductor material are not divided. Therefore, as described above, the intervals between the multiple second reflector portions 70a-70c can be formed narrow.

[0050] Since the plurality of protrusions 60a-60c are provided corresponding to the plurality of second reflecting mirror portions 70a-70c, narrowing the spacing between the plurality of second reflecting mirror portions 70a-70c also narrows the spacing between the plurality of protrusions 60a-60c. This increases the area (light-emitting area) of the region R60 of the protrusions 60a-60c that emits the laser light. Furthermore, in the plurality of regions R60, the laser light is mode-controlled by each of the protrusions 60a-60c and each of the second reflecting mirror portions 70a-70c, so the in-plane distribution of the light-emitting intensity can be made uniform.

[0051] The first electrode 80 is also provided in the grooves TR between the multiple second reflector portions 70a-70c, and is provided so as to surround not only the periphery of the second reflector 70 but also the periphery of each of the second reflector portions 70a-70c. The first electrode 80 is electrically connected to the step layer 60 around the periphery of the second reflector 70 and around each of the second reflector portions 70a-70c. This allows the first electrode 80 to supply power not only to the periphery of the second reflector 70 but also to its intermediate portion, even if the second reflector 70 includes a non-conductive material. This makes it easier for the first electrode 80 to inject current into the entire active layer 40, further homogenizing the in-plane distribution of light emission intensity.

[0052] Furthermore, the heat generated in the active layer 40 when light is emitted is difficult to dissipate from the second reflecting mirror 70, which is made of a non-conductive material with low thermal conductivity. Therefore, if the second reflecting mirror 70 is not divided into multiple second reflecting mirror portions 70a to 70c, the heat of the active layer 40 cannot be efficiently dissipated.

[0053] However, in the present disclosure, the second reflecting mirror 70 is divided into a plurality of second reflecting mirror portions 70a to 70c, and the groove TR is provided with a first electrode 80 made of a conductive material with high thermal conductivity. This allows the heat of the active layer 40 to be efficiently dissipated via the first electrode 80.

[0054] The second reflecting mirror 70 and the step layer 60, which are in contact with each other at the side surface F60 of each protrusion 60, have different refractive indices. For example, the refractive index (e.g., 3.5) of the step layer 60 (e.g., GaAs) is different from the refractive index (e.g., 3.5) of the second reflecting mirror 70 (e.g., SiO２ ) is higher than the refractive index (e.g., 1.45). Furthermore, the height (T1-T2) of the protrusions 60a-60c is determined so that light from the active layer 40 resonates between the first reflecting mirror 30 and the second reflecting mirror 70 in region R60, generating laser light. Light from the active layer 40 does not resonate in regions R70 and RTR other than the protrusions 60a-60c. This allows the second reflecting mirror 70 and the step layer 60 to confine the laser light to the protrusions 60a-60c. Thus, in the present disclosure, the step layer 60 functions to confine the laser light, and no current-confining layer made of a non-conductive material is provided within the third reflecting mirror 50. A current-confining layer made of a non-conductive material not only blocks current but also has low thermal conductivity. Therefore, the light-emitting device 1 according to the present disclosure, which does not have a current-confining layer, can further expand the effective light-emitting area and more efficiently dissipate heat.

[0055] As a result, the light emitting device 1 according to the present disclosure can increase the density of the light emitting region of the mode-controlled laser light, make the light emitting intensity of the light emitting region substantially uniform, and keep the thermal resistance low. As a result, the light emitting device 1 according to the present disclosure can improve the near-field pattern and the far-field pattern, and can form a high-output light source with a small chip size and low cost.

[0056] Next, a method for manufacturing the light emitting device 1 of the present disclosure will be described.

[0057] 2 to 9 are cross-sectional views showing an example of a method for manufacturing the light emitting device according to the first embodiment.

[0058] First, as shown in FIG. 2 , a first semiconductor layer (GaAs), a first reflecting mirror 30 (a laminated film of n-type GaAs and n-type AlGaAs), an active layer (a multi-quantum well layer of GaAs and InGaAs) 40, a third reflecting mirror (a laminated film of p-type GaAs and p-type AlGaAs) 50, and a step layer (of GaAs, for example) 60 are epitaxially grown in this order on a substrate (of GaAs, for example) 10 using a MOCVD (Metal Organic Chemical Vapor Deposition) method.

[0059] Next, using lithography and etching techniques, the step layer 60 is processed to form protrusions 60a to 60c on its surface, as shown in Figure 3. The step layer 60 may be made of the same material as the high refractive index material among the multiple semiconductor materials of the third reflecting mirror 50. Alternatively, the step layer 60 may be made of a semiconductor material different from the multiple semiconductor materials of the third reflecting mirror 50.

[0060] By forming the protrusions 60a to 60c in this manner, steps are provided on the surface of the step layer 60.

[0061] Next, as shown in FIG. 4, the material of the second reflecting mirror 70 is epitaxially grown on the step layer 60. The material of the second reflecting mirror 70 includes a non-conductive material, such as a laminated film of a silicon oxide film and a silicon nitride film, or a laminated film of a silicon oxide film and an amorphous silicon film. In the figure, for convenience, the thickness of each layer of the second reflecting mirror 70 is shown thin, but the film thickness of the first layer (e.g., silicon oxide film) of the second reflecting mirror 70 is formed thicker than the height (T1-T2) of the protrusions 60a to 60c (e.g., GaAs). For example, the thickness of each layer of the second reflecting mirror 70 is several tens to several hundreds of nanometers, while the height (T1-T2) of the protrusions 60a to 60c is several nanometers to several tens of nanometers. As a result, the side surfaces F60 of the protrusions 60a to 60c come into contact with the first layer of the second reflecting mirror 70, and the interface (e.g., SiO ２ The difference in effective refractive index at the interface between the SiO2 and GaAs reflects light, thereby confining the laser light.

[0062] Next, as shown in FIG. 5, the second reflecting mirror 70 is processed using lithography and etching techniques. As a result, trenches TR are formed between the protruding portions 60a to 60c, dividing the second reflecting mirror 70 into multiple second reflecting mirror portions 70a to 70c. The multiple second reflecting mirror portions 70a to 70c are formed so as to cover the top and side surfaces of the protruding portions 60a to 60c, respectively. The trenches TR are formed so as to reach the step layer 60. In this case, the step layer 60 is made of a semiconductor material so that the first electrode 80, which will be formed later, is electrically connected to the active layer 40.

[0063] Next, as shown in FIG. 6 , a first electrode 80 is formed around the second reflector portions 70a-70c and in the trenches TR. The first electrode 80 covers the top and side surfaces of the second reflector portions 70a-70c. The first electrode 80 is electrically connected to the fourth face F4 of the active layer 40 via the step layer 60 and the third reflector 50, allowing a positive voltage to be applied to the fourth face F4 of the active layer 40. By forming the first electrode 80 also in the trenches TR between the divided second reflector portions 70, as described above, the in-plane distribution of the current flowing through the active layer 40 can be made uniform and heat can be efficiently dissipated from the active layer 40.

[0064] 7 , the step layer 60, the third reflecting mirror 50, the active layer 40, and the first reflecting mirror 30 are processed into a mesa shape using lithography and etching. Next, a second electrode 90 is formed on the exposed first semiconductor layer 20. The second electrode 90 is electrically connected to the third face F3 of the active layer 40 via the first semiconductor layer 20 and the first reflecting mirror 30, and a negative voltage can be applied to the third face F3 of the active layer 40.

[0065] 8, a protective film 100 is deposited on the first electrode 80, the second electrode 90, the step layer 60, the third reflecting mirror 50, the active layer 40, and the first reflecting mirror 30. Next, the protective film 100 is processed using lithography and etching techniques to expose the upper surfaces of the first electrode 80 and the second electrode 90.

[0066] Next, as shown in FIG. 9, the connecting portions 110, 120 are formed on the exposed upper surfaces of the first electrode 80 and the second electrode 90 using electrolytic plating or the like.

[0067] Next, the rear surface of the substrate 10 is polished, and an anti-reflection film 130 is formed on the rear surface of the substrate 10. In this way, the light emitting device 1 of FIG.

[0068] 10 is a cross-sectional view showing an example of the configuration of a light emitting device according to Embodiment 2. In the first embodiment, the protrusions 60a to 60c are integrally formed with the step layer 60, but in the second embodiment, the protrusions 60a to 60c and the step layer 60 are formed from different materials.

[0069] 2, the material for the protrusions 60a-60c is deposited on the step layer 60, and the material for the protrusions 60a-60c is processed using lithography and etching techniques to form the protrusions 60a-60c. The refractive index of the protrusions 60a-60c is different from the refractive index of the second reflecting mirror 70 that contacts the protrusions 60a-60c at their side surface F60. The step layer 60 is made of, for example, GaAs. The protrusions 60a-60c may be made of, for example, a non-conductive material such as silicon nitride film, or a semiconductor material such as amorphous silicon.

[0070] Other configurations of the second embodiment may be the same as those of the first embodiment, and therefore the second embodiment can achieve the same effects as the first embodiment.

[0071] Third Embodiment FIG. 11 is a cross-sectional view showing an example of the configuration of a light-emitting device according to a third embodiment. In the third embodiment, the trench TR penetrates the step layer 60 and extends to the middle of the third reflector 50. Accordingly, the first electrode 80 also penetrates the step layer 60 and extends to the middle of the third reflector 50. The upper layer of the third reflector 50 is divided into multiple parts by the trench TR. The lower layer of the third reflector 50 is shared by the multiple second reflector portions 70a to 70c and the upper layer of the third reflector 50 and is not divided. In this way, by providing the first electrode 80 deep enough to the middle of the third reflector 50, the in-plane distribution of the current flowing through the active layer 40 is more uniform and heat can be dissipated from the active layer 40 more efficiently.

[0072] Other configurations of the third embodiment may be the same as those of the first embodiment, and therefore the third embodiment can achieve the same effects as the first embodiment.

[0073] 12 is a cross-sectional view showing an example of the configuration of a light-emitting device according to a fourth embodiment. In the fourth embodiment, a trench TR penetrates the step layer 60 and the third reflector 50. Accordingly, a first electrode 80 also penetrates the step layer 60 and the third reflector 50. The third reflector 50 is divided into a plurality of reflector portions 50a to 50c by the trench TR, but the trench TR does not reach the active layer 40. By providing the first electrode 80 so as to penetrate the step layer 60 and the third reflector 50 in this way, the in-plane distribution of the current flowing through the active layer 40 is made more uniform, and heat can be dissipated from the active layer 40 more efficiently.

[0074] Other configurations of the fourth embodiment may be the same as those of the first embodiment, and therefore the fourth embodiment can achieve the same effects as the first embodiment.

[0075] Fifth Embodiment Fig. 13 is a cross-sectional view showing an example of the configuration of a light-emitting device according to a fifth embodiment. In the fifth embodiment, the first electrode 80 is provided on the bottom of the trench TR and on the lower side surface of the second reflector portion 70, but is not provided on the upper surface or upper side surface of the second reflector portions 70a to 70c. A connection portion 110 extends into the upper portion of the trench TR and is connected to the first electrode 80. As a result, the first electrode 80 is electrically connected as a single electrode on the step layer 60. In this way, the film thickness of the first electrode 80 may be relatively thin.

[0076] Other configurations of the fifth embodiment may be the same as those of the first embodiment, and therefore the fifth embodiment can achieve the same effects as the first embodiment.

[0077] Sixth Embodiment FIG. 14 is a cross-sectional view showing an example of the configuration of a light-emitting device according to a sixth embodiment. In the sixth embodiment, the first electrode 80 around the second reflector 70 has a thin film thickness. On the other hand, the first electrode 80 in the groove TR is formed thick. The first electrode 80 is provided on the top surface of the second reflector portion 70 at the center of the second reflector 70, but is not provided on the top surface of the second reflector portion 70 at the end of the second reflector 70. The first electrode 80 in the groove TR extends in a direction perpendicular to the Z direction and is connected to the first electrode 80 around the second reflector 70. Therefore, the first electrodes 80 are electrically connected as a single electrode.

[0078] Other configurations of the sixth embodiment may be the same as those of the first embodiment, and therefore the sixth embodiment can achieve the same effects as the first embodiment.

[0079] Seventh Embodiment Fig. 15 is a cross-sectional view showing an example of the configuration of a light-emitting device according to a seventh embodiment. In the above-described embodiments, one mesa MS is provided on the substrate 10 and the first semiconductor layer 20. However, in the seventh embodiment, multiple mesas MS are provided on the substrate 10 and the first semiconductor layer 20. Each mesa MS is a structure including the components 30 to 120 in Fig. 1. The electrode 90 and the connection portion 120 may be provided in common to multiple mesas MS. According to the seventh embodiment, the light-emitting area can be further increased.

[0080] Next, the planar shapes of the step layer 60 and the second reflecting mirror 70 will be described.

[0081] Eighth Embodiment Fig. 16 is a plan view showing an example of the configuration of a step layer and a second reflector according to an eighth embodiment. Fig. 16 shows an example of the configuration of a step layer 60 and a second reflector 70 for one mesa MS. Other configurations are not shown.

[0082] A plurality of protrusions 60a to 60c and a plurality of second reflecting mirror portions 70a to 70c are two-dimensionally arranged in a matrix for one mesa MS. Figure 1 corresponds to a cross-sectional view taken along line 1-1 in Figure 16.

[0083] Ninth Embodiment FIG. 17 is a plan view showing an example of the configuration of a step layer and a second reflector according to a ninth embodiment. In the ninth embodiment, similar to the eighth embodiment, a plurality of protrusions 60a-60c and a plurality of second reflector portions 70a-70c are two-dimensionally arranged in a matrix for one mesa MS. In the ninth embodiment, each of the protrusions 60a-60b is further divided into a plurality of portions for the corresponding second reflector portions 70a-70c. FIG. 1 corresponds to the cross-sectional view taken along line 1-1 in FIG. 16. For example, a plurality of protrusions 60a are provided for one second reflector portion 70a. A plurality of protrusions 60b are provided for one second reflector portion 70b. A plurality of protrusions 60c are provided for one second reflector portion 70c. Thus, even if a plurality of each of the protrusions 60a-60c is provided for each of the second reflector portions 70a-70c, the effect of the present technology is not lost.

[0084] Tenth Embodiment FIG. 18 is a plan view showing a configuration example of a step layer and a second reflector according to a tenth embodiment. In the tenth embodiment, a plurality of second reflector portions 70a, 70b are two-dimensionally arranged in a matrix for one mesa MS. Furthermore, each of the protrusions 60a, 60b is divided into a plurality of portions for the corresponding second reflector portion 70a, 70b. In the tenth embodiment, the protrusion 60a is divided vertically in the second reflector portion 70a. The protrusion 60b is divided horizontally in the second reflector portion 70b. In this way, even if a plurality of protrusions 60a, 60b are provided for each of the corresponding second reflector portions 70a, 70b, the effect of the present technology is not lost.

[0085] 11th Embodiment Fig. 19 is a plan view showing an example of the configuration of a step layer and second reflector according to an 11th embodiment. In the 11th embodiment, in a plan view seen from the Z direction, multiple protrusions 60a-60c and multiple second reflector portions 70a-70c are provided on a single mesa MS, each having a substantially circular shape. Fig. 1 corresponds to a cross-sectional view taken along line 1-1 in Fig. 19.

[0086] 12th Embodiment Fig. 20 is a plan view showing an example of the configuration of a step layer and second reflector according to a 12th embodiment. In the 12th embodiment, in a plan view seen from the Z direction, multiple protrusions 60a-60c and multiple second reflector portions 70a-70c are provided on a single hexagonal mesa MS, each having a substantially hexagonal shape. Fig. 1 corresponds to a cross-sectional view taken along line 1-1 in Fig. 20.

[0087] 13th Embodiment Fig. 21 is a plan view showing an example of the configuration of a step layer and second reflector according to a 13th embodiment. In the 13th embodiment, in a plan view seen from the Z direction, multiple protrusions 60a-60c and multiple second reflector portions 70a-70c are provided on a single triangular mesa MS, each having a substantially triangular shape. Fig. 1 corresponds to a cross-sectional view taken along line 1-1 in Fig. 21.

[0088] The step layer 60 and the second reflecting mirror 70 may have other substantially polygonal shapes as long as they correspond to each other.

[0089] 22 is a plan view showing an example of the configuration of a step layer and a second reflector according to a fourteenth embodiment. In the fourteenth embodiment, in a plan view seen from the Z direction, a plurality of protrusions 60 a, 60 b and a plurality of second reflector portions 70 a, 70 b are provided on a single mesa MS, each having a substantially rectangular outer shape and a substantially circular or substantially polygonal hole in the center. In this way, the step layer 60 and the second reflector 70 may have various shapes as long as they correspond to each other.

[0090] 23 is a cross-sectional view showing a configuration example of a light-emitting device according to a fifteenth embodiment. The fifteenth embodiment further includes a non-conductive semiconductor layer 140 containing impurities provided in the active layer 40 below the trench TR. After the trench TR is formed, the semiconductor layer 140 may be formed by ion-implanting impurities through the trench TR using the second reflecting mirror 70 as a mask. The impurities may be, for example, boron, hydrogen, or oxygen. The semiconductor layer 140 functions as a current confinement layer.

[0091] The semiconductor layer 140 can be formed using lithography and ion implantation techniques after the active layer 40 is formed.

[0092] The semiconductor layer 140 may be formed by using lithography and ion implantation techniques after the formation of the third reflecting mirror 50. In this case, the semiconductor layer 140 is formed below the trench TR so as to extend from the eighth face F8 of the third reflecting mirror 50 to the third face F3 of the active layer 40.

[0093] Other configurations of the fifteenth embodiment may be similar to those of the first embodiment, and therefore the fifteenth embodiment can achieve the same effects as the first embodiment.

[0094] Sixteenth Embodiment Fig. 24 is a cross-sectional view showing a configuration example of a light-emitting device according to a sixteenth embodiment. In the sixteenth embodiment, the side surface F60 of the protrusion 60 is inclined with respect to the Z direction. Even if the side surface F60 of the protrusion 60 has a tapered shape in this way, the effect of the present technology is not lost. Note that, although the side surface F60 of the protrusion 60 has a forward tapered shape in Fig. 24, it may have a reverse tapered shape.

[0095] (Application Example to a Mobile Body) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0096] FIG. 25 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0097] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 25, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (Interface) 12053.

[0098] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0099] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0100] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0101] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0102] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0103] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the distance between vehicles, maintaining vehicle speed, vehicle collision warning, vehicle lane departure warning, etc.

[0104] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0105] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0106] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying the passengers of the vehicle or the outside of the vehicle of information. In the example of Fig. 25, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0107] FIG. 26 is a diagram showing an example of the installation position of the imaging unit 12031.

[0108] In FIG. 26, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0109] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0110] 26 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0111] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0112] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation.

[0113] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0114] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0115] An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described. The technology according to the present disclosure can be applied to, for example, a light-emitting element of a distance measuring unit used in the image capturing unit 12031 or the like, among the above-described configurations.

[0116] 27 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the seventeenth embodiment. In the seventeenth embodiment, the step layer 60 includes a plurality of recesses 60d, 60e, and 60f. The recesses 60d, 60e, and 60f are provided corresponding to the plurality of second reflecting mirror portions 70d, 70e, and 70f of the second reflecting mirror 70, respectively, and are recessed in the −Z direction from the second reflecting mirror portions 70d, 70e, and 70f. A first thickness T1 in the Z direction of the step layer 60 in the recesses 60d, 60e, and 60f is thinner than a second thickness T2 in the Z direction of the step layer 60 in regions other than the recesses 60d, 60e, and 60f. That is, the step layer 60 has a first thickness T1 in a region R60 of the plurality of recesses 60d, 60e, 60f that is thinner than a second thickness T2 in the other regions R70 and RTR of the second reflector 70 and trench TR.

[0117] The plurality of recesses 60d-60f are provided between the second reflecting mirror 70 and the third reflecting mirror 50, and each recess corresponds to one of the plurality of second reflecting mirror portions 70d-70f of the second reflecting mirror 70. The recesses 60d-60f are recessed in the Z direction by a distance T2-T1 relative to the other regions of the step layer 60. That is, the length of each side surface F60 of the recesses 60d-60f (the depth of the recesses 60d-60f in the Z direction) is T2-T1. The depth of the recesses 60d-60f in the Z direction is set so that light generated in the active layer 40 resonates in the regions of the recesses 60d-60f between the first reflecting mirror 30 and the second reflecting mirror 70. On the other hand, in the thick regions of the step layer 60 other than the recesses 60d to 60f, the light generated in the active layer 40 does not resonate between the first reflecting mirror 30 and the second reflecting mirror 70. The film thickness of the step layer 60 (i.e., the depth of the recesses 60d to 60f) is set in this manner.

[0118] The second reflecting mirror 70 is provided on the step layer 60 so as to cover the upper surfaces and side surfaces F60 of the recessed portions 60d to 60f. Therefore, the second reflecting mirror portions 70d to 70f are recessed in the −Z direction corresponding to the recessed portions 60d to 60f, respectively. The configuration and material of the second reflecting mirror 70 may be the same as those in the first embodiment. The configuration of the trenches TR may also be the same as those in the first embodiment.

[0119] The refractive index of the recesses 60d to 60f is different from the refractive index of the second reflecting mirror 70 that contacts the recesses 60d to 60f at the side surface F60. This allows the recesses 60d to 60f to have an optical confinement effect that enables the formation of a transverse mode required to achieve laser oscillation.

[0120] The first electrode 80 and the connecting portion 110 are recessed in the regions corresponding to the recessed portions 60d-60f and the second reflecting mirror portions 70d-70f. The other configurations of the first electrode 80 and the connecting portion 110 may be the same as those in the first embodiment. The first electrode 80 and the connecting portion 110 cover part or all of the upper surface of the second reflecting mirror 70.

[0121] The second reflecting mirror 70 and the step layer 60, which are in contact with each other at the side surface F60 of each of the recesses 60d to 60f, have different refractive indices. For example, the refractive index (e.g., 3.5) of the step layer 60 (e.g., GaAs) is different from the refractive index (e.g., 3.5) of the second reflecting mirror 70 (e.g., SiO ２ ) (e.g., 1.45). The depth (T2-T1) of the recesses 60d-60f is formed so that light from the active layer 40 resonates between the first reflecting mirror 30 and the second reflecting mirror 70 in the region R60 to oscillate laser light. In the regions R70 and RTR other than the recesses 60d-60f, the light from the active layer 40 does not resonate. As a result, the second reflecting mirror 70 and the step layer 60 function to confine the laser light to the recesses 60d-60f. The other configurations of the seventeenth embodiment may be the same as those of the first embodiment. Therefore, the seventeenth embodiment can achieve the same effects as those of the first embodiment.

[0122] The recessed portions 60d to 60f of the seventeenth embodiment may be applied to any of the second to sixteenth embodiments, thereby enabling the seventeenth embodiment to obtain the effects of any of the second to sixteenth embodiments.

[0123] Furthermore, the planar shapes of the step layer 60 and the second reflecting mirror 70 will be described.

[0124] 28 is a plan view showing a configuration example of a mesa, a step layer, a second reflecting mirror, and a first electrode according to the 18th embodiment. Fig. 28 shows a configuration example for one mesa MS. The illustration of other configurations is omitted.

[0125] A single mesa MS is provided with a plurality of protrusions 60a to 60c (or a plurality of recesses 60d to 60f) and two second reflectors 70. Furthermore, a plurality of protrusions 60a to 60c (or a plurality of recesses 60d to 60f) is provided for each second reflector 70. The following description will be given assuming that a plurality of protrusions 60a to 60c is provided, but the same can be said for a plurality of recesses 60d to 60f.

[0126] The multiple protrusions 60a to 60c are two-dimensionally arranged in a matrix with respect to the mesa MS or the second reflecting mirror 70 when viewed from above in the Z direction. The multiple protrusions 60a to 60c each have a substantially circular or elliptical shape and are substantially the same size. The adjacent multiple protrusions 60a to 60c are spaced apart substantially equally and are evenly spaced. The spacing Wcg between the centers of gravity of the adjacent multiple protrusions 60a to 60c is 4×σ or less, where σ is the standard deviation of the light intensity distribution of light emitted from one protrusion 60a.

[0127] As shown in FIG. 29, each of the multiple protrusions 60a-60c emits laser light having a single peak. FIG. 29 illustrates the light intensity distribution of single-peak laser light emitted from one protrusion. The horizontal axis represents distance, and the vertical axis represents light intensity. The light intensity distribution corresponding to one protrusion (e.g., 60a) has a Gaussian distribution with a single peak, and its standard deviation is σ. In this case, when the spacing Wcg between the centers of gravity of adjacent multiple protrusions 60a-60c is 4×σ or less, the laser light from the multiple protrusions 60a-60c undergoes so-called evanescent light interaction, i.e., evanescent coupling, making it easier to control the wavelength and phase, and improving directivity. As a result, the resolution of the far-field pattern is improved. This also applies to the multiple recesses 60d-60f.

[0128] Referring again to Figure 28, two second reflectors 70 are provided for one mesa MC. The two second reflectors 70 have approximately the same shape (e.g., a substantially rectangular shape) and approximately the same size. Each second reflector 70 has protruding portions in areas corresponding to the multiple protrusions 60a to 60c.

[0129] Two first electrodes 80 are provided corresponding to the two second reflectors 70. The two first electrodes 80 have substantially the same shape (e.g., substantially rectangular) and substantially the same size. Each first electrode 80 has protruding portions in regions corresponding to the multiple protrusions 60a to 60c.

[0130] The other configurations of the eighteenth embodiment may be the same as those of the other embodiments.

[0131] 30 is a plan view showing a configuration example of a mesa, a step layer, a second reflecting mirror, and a first electrode according to the 19th embodiment. Fig. 30 shows the configuration example for one mesa MS. The illustration of the other configurations is omitted.

[0132] A plurality of protrusions 60a to 60c are provided for each second reflecting mirror 70.

[0133] One second reflecting mirror 70 and one first electrode 80 are provided for each mesa MS. Therefore, in the nineteenth embodiment, no trenches TR are provided. Instead, a plurality of holes HL are provided in the second reflecting mirror 70 around the plurality of protrusions 60a to 60c. The holes HL penetrate the second reflecting mirror 70 in the Z direction and reach the step layer 60. A first electrode 80 is buried in the holes HL.

[0134] The multiple protrusions 60a to 60c are two-dimensionally arranged in a matrix with respect to the mesa MS when viewed from the Z direction. Furthermore, the multiple protrusions 60a to 60c are arranged in a staggered pattern when viewed from the Z direction, with a half-pitch offset. The shapes and sizes of the protrusions 60a to 60c may be the same as those of the eighteenth embodiment. Furthermore, the spacing Wcg between the centers of gravity of adjacent multiple protrusions 60a to 60c is 4×σ or less, where σ is the standard deviation of the light intensity distribution of light emitted from one protrusion 60a. As a result, similar to the eighteenth embodiment, the laser light from the multiple protrusions 60a to 60c interacts with each other through evanescent light, i.e., evanescent coupling, improving the resolution of the far-field pattern.

[0135] One second reflecting mirror 70 is provided corresponding to one mesa MC. One second reflecting mirror 70 has substantially the same shape as the mesa MC (for example, a substantially rectangular shape) and is slightly smaller than the mesa MC. The second reflecting mirror 70 has protruding portions in areas corresponding to the multiple protrusions 60a to 60c.

[0136] One first electrode 80 is provided corresponding to one second reflector 70 and one mesa MC. One first electrode 80 has substantially the same shape (e.g., a substantially rectangular shape) as the second reflector 70, and is slightly larger than the second reflector 70. The first electrode 80 has protruding portions in regions corresponding to the multiple protrusions 60a to 60c.

[0137] The first electrode 80 is embedded in the multiple holes HL and is provided as pillar portions PL within the second reflecting mirror 70 around the multiple protrusions 60a to 60c. The multiple pillars PL are portions of the first electrode 80 that extend in the Z direction within the second reflecting mirror 70. In a plan view from the Z direction, the holes HL, i.e., the pillars PL, may be substantially circular or substantially elliptical. The multiple pillars PL enable efficient dissipation of heat from the active layer 40.

[0138] The other configurations of the eighteenth embodiment may be the same as those of the other embodiments.

[0139] 31 is a plan view showing a configuration example of a mesa, a step layer, a second reflecting mirror, and a first electrode according to a 20th embodiment. Fig. 31 shows a configuration example for one mesa MS. Other configurations are not shown.

[0140] A plurality of protrusions 60a to 60c and two second reflectors 70 are provided for one mesa MS.

[0141] The multiple protrusions 60a to 60c each have a substantially square or rectangular shape and are substantially the same size. The spacing between adjacent protrusions 60a to 60c is substantially equal. The spacing Wcg between the centers of gravity of adjacent protrusions 60a to 60c is 4×σ or less, where σ is the standard deviation of the light intensity distribution of light emitted from one protrusion 60a. As a result, similar to the eighteenth embodiment, the laser light from the multiple protrusions 60a to 60c interacts with each other through evanescent light, i.e., evanescent coupling, thereby improving the resolution of the far-field pattern.

[0142] Two second reflectors 70 are provided for one mesa MC. The second reflectors 70 may have the same configuration as that of the eighteenth embodiment. The second reflectors 70 have protruding portions in regions corresponding to the plurality of protrusions 60a to 60c.

[0143] One first electrode 80 is provided in common to the two second reflecting mirrors 70. One first electrode 80 is provided on the two second reflecting mirrors 70 across the groove TR. The first electrode 80 has protruding portions in regions corresponding to the plurality of protrusions 60a to 60c.

[0144] A plurality of holes HL are arranged between a plurality of diagonally adjacent protrusions 60a to 60c in a plan view from the Z direction. The plurality of holes HL penetrate the second reflecting mirror 70 in the Z direction and reach the step layer 60. A first electrode 80 is embedded in the holes HL to form pillar portions PL. The plurality of pillars PL are portions of the first electrode 80 that extend in the Z direction within the second reflecting mirror 70. In a plan view from the Z direction, the holes HL, i.e., the pillars PL, may be approximately square or approximately rectangular. The plurality of pillars PL can efficiently dissipate heat from the active layer 40.

[0145] The other configurations of the twentieth embodiment may be the same as those of the other embodiments.

[0146] 21st Embodiment Fig. 32 is a plan view showing a configuration example of a mesa, a step layer, a second reflecting mirror, and a first electrode according to the 21st embodiment. Fig. 32 shows a configuration example for one mesa MS. The illustration of other configurations is omitted.

[0147] In the 21st embodiment, the arrangement of the multiple protrusions 60a-60c differs from that of the 20th embodiment in plan view from the Z direction. The spacing between the multiple protrusions 60a-60c is not equal, but narrows toward the center of the second reflecting mirror 70. The spacing Wcg between the centers of gravity of adjacent multiple protrusions 60a-60c is equal to or less than 4×σ, where σ is the standard deviation of the light intensity distribution of light emitted from one protrusion 60a. As a result, similar to the 18th embodiment, the laser light from the multiple protrusions 60a-60c interacts with each other through evanescent light, i.e., evanescent coupling, improving the resolution of the far-field pattern. The shapes and sizes of the multiple protrusions 60a-60c may be substantially equal to each other.

[0148] Furthermore, the first electrode 80 is not provided on the second reflecting mirror 70 but is provided around it. The first electrode 80 is also embedded in the groove TR between adjacent second reflecting mirrors 70. This allows heat from the active layer 40 to be dissipated efficiently.

[0149] The other configurations of the 21st embodiment may be the same as those of the other embodiments.

[0150] 22nd Embodiment Fig. 33 is a plan view showing a configuration example of a mesa, a step layer, a second reflecting mirror, and a first electrode according to a 22nd embodiment. Fig. 33 shows a configuration example for one mesa MS. Other configurations are not shown.

[0151] In the twenty-second embodiment, the shape and size of the multiple protrusions 60a to 60c differ from those of the twentieth embodiment in plan view from the Z direction. The spacing between the multiple protrusions 60a to 60c may be approximately equal. The size of the multiple protrusions 60a to 60c increases as they approach the center of the second reflecting mirror 70. The multiple protrusions 60a to 60c are elongated in a direction perpendicular to the second direction, with the sides extending in the direction of distance (second direction) becoming shorter as they move away from the center of the second reflecting mirror 70. The spacing Wcg between the centers of gravity of adjacent multiple protrusions 60a to 60c is 4×σ or less, where σ is the standard deviation of the light intensity distribution of light emitted from one protrusion 60a. As a result, similar to the eighteenth embodiment, the laser light from the multiple protrusions 60a to 60c interacts with each other through evanescent light, i.e., evanescent coupling, improving the resolution of the far-field pattern. Furthermore, the first electrode 80 is not provided on the second reflecting mirror 70 but is provided around it. The first electrode 80 is also embedded in the groove TR between adjacent second reflecting mirrors 70. This allows heat from the active layer 40 to be dissipated efficiently.

[0152] The other configurations of the 22nd embodiment may be the same as those of the other embodiments.

[0153] In the twenty-first and twenty-second embodiments, the first electrode 80 may cover at least a part of the Noh surface of the second reflecting mirror 70 .

[0154] 23rd Embodiment FIG. 34 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the 23rd embodiment. In the 23rd embodiment, an insulating layer 105 is provided on the side surfaces of the first reflecting mirror 30, the active layer 40, and the third reflecting mirror 50. The insulating layer 105 may be formed by ion-implanting impurities into the side surfaces of the first reflecting mirror 30, the active layer 40, and the third reflecting mirror 50 to make them electrically non-conductive. The impurities may be, for example, boron, hydrogen, or oxygen. The semiconductor layer 140 functions as a current confinement layer. The other configurations of the 23rd embodiment may be the same as those of the first embodiment.

[0155] 24th Embodiment Fig. 35 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the 24th embodiment. In the 24th embodiment, an insulating layer 105 is provided on the side surface of the active layer 40. The insulating layer 105 may be made electrically non-conductive by ion-implanting impurities into the end portion of the active layer 40 using lithography and implantation techniques. The impurities may be, for example, boron, hydrogen, or oxygen. The semiconductor layer 140 functions as a current confinement layer. The other configurations of the 24th embodiment may be the same as those of the first embodiment.

[0156] 25th Embodiment FIG. 36 is a cross-sectional view showing a configuration example of a light-emitting device according to a 25th embodiment. In the 25th embodiment, the side surfaces of the recesses 60d to 60f are inclined with respect to the Z direction. Even if the side surfaces of the recesses 60d to 60f have a tapered shape, the effect of the present technology is not lost. Note that in FIG. 36, the side surfaces of the recesses 60d to 60f have a forward tapered shape, but they may also have a reverse tapered shape. Furthermore, the side surfaces of the holes HL, i.e., the side surfaces of the pillars PL, may have a tapered shape that is inclined with respect to the Z direction. For example, the side surfaces of the holes HL and the pillars PL are tapered so that the areas of the holes HL and the pillars PL, as viewed from the Z direction, become smaller as they approach the step layer 60.

[0157] The present technology can be configured as follows.

[0158] (1) A first reflecting mirror configured by stacking a plurality of semiconductor materials having refractive indices different from one another in a first direction, and having a first surface and a second surface opposite to the first surface; an active layer provided on the second surface side of the first reflecting mirror, having a third surface facing the first reflecting mirror and a fourth surface opposite to the third surface, and emitting light when power is applied to the third and fourth surfaces; a second reflecting mirror provided on the fourth surface side of the active layer, configured by stacking a plurality of non-conductive materials having refractive indices different from one another in the first direction, or by stacking a non-conductive material and an amorphous semiconductor material having refractive indices different from one another in the first direction, and having a fifth surface facing the active layer and a sixth surface opposite to the fifth surface; a plurality of protrusions provided between the fourth surface and the sixth surface, protruding in the first direction toward the second reflecting mirror, or a plurality of recesses recessed from the second reflecting mirror in the first direction; and a first electrode electrically connected to the fourth surface of the active layer. a second electrode electrically connected to the third surface of the active layer.

[0159] (2) The light-emitting device according to (1), wherein the second reflector is divided into a plurality of second reflector portions by grooves that penetrate the second reflector in the first direction and extend in the first direction, and the first electrode is provided in the grooves so as to surround the peripheries of the plurality of second reflector portions.

[0160] (3) The light emitting device according to (2), further comprising a third reflector provided between the fourth surface and the sixth surface and configured by stacking a plurality of semiconductor materials having different refractive indices in the first direction, wherein the third reflector is shared by the plurality of second reflector portions and is not divided.

[0161] (4) The light emitting device according to (2), further comprising a third reflector provided between the fourth surface and the sixth surface or between the sixth surface and the plurality of protrusions or the plurality of recesses, the third reflector being configured by stacking a plurality of semiconductor materials having different refractive indices in the first direction, the third reflector being divided into a plurality of third reflector portions by the grooves.

[0162] (5) The light emitting device according to (2), further comprising a third reflector provided between the fourth surface and the sixth surface or between the sixth surface and the plurality of protrusions or the plurality of recesses, and configured by stacking a plurality of semiconductor materials having different refractive indices in the first direction, wherein an upper layer of the third reflector is divided into a plurality of parts by the grooves, and a lower layer of the third reflector is shared by the plurality of second reflector portions and the upper layer and is not divided.

[0163] (6) The light emitting device according to (3), wherein the plurality of protrusions or the plurality of recesses are provided between the second reflecting mirror and the third reflecting mirror.

[0164] (7) The light emitting device according to any one of (2) to (6), wherein the plurality of protrusions are part of a step layer having a first film thickness in the region of the plurality of second reflecting mirror portions and a second film thickness thinner than the first film thickness in the region of the groove, or the plurality of recesses are part of a step layer having a first film thickness in the region of the plurality of second reflecting mirror portions and a second film thickness thicker than the first film thickness in the region of the groove.

[0165] (8) The light emitting device according to any one of (2) to (7), wherein a plurality of the protrusions or recesses are provided for each of the second reflecting mirror portions.

[0166] (9) The light-emitting device according to any one of (3) to (6), wherein the plurality of protrusions or the plurality of recesses are made of one semiconductor material among the plurality of semiconductor materials that make up the third reflecting mirror.

[0167] (10) The light emitting device according to any one of (1) to (9), wherein, between the first reflecting mirror and the second reflecting mirror, in a first region of the plurality of protrusions or the plurality of recesses, light resonates at a wavelength equal to the wavelength of output light to the outside, and in a region other than the first region, light does not resonate at a wavelength equal to the wavelength of the output light.

[0168] (11) The light-emitting device according to any one of (2) to (10), wherein the first electrode is provided in the groove and on the plurality of second reflecting mirror portions, and further includes a connection portion provided on the first electrode.

[0169] (12) The light-emitting device according to any one of (2) to (11), further comprising a non-conductive semiconductor layer into which an impurity is introduced, the non-conductive semiconductor layer being provided in the active layer in the first direction relative to the groove.

[0170] (13) The light emitting device according to any one of (1) to (12), wherein the plurality of protrusions or the plurality of recesses have a substantially circular or substantially polygonal shape in a plan view from the first direction.

[0171] (14) The light-emitting device according to any one of (1) to (13), wherein the second reflector is provided around the plurality of protrusions or the plurality of recesses and has holes penetrating the second reflector in the first direction, and the first electrode is in electrical contact with the active layer on the fourth surface exposed in the holes.

[0172] (15) The light-emitting device according to any one of (1) to (14), wherein the first electrode covers at least a part of an upper surface of the second reflecting mirror.

[0173] (16) The light emitting device according to any one of (1) to (15), wherein the distance between the centers of gravity of the adjacent protrusions or the distance between the centers of gravity of the adjacent recesses is 4 × σ or less, where σ is the standard deviation of the light intensity distribution corresponding to one of the protrusions or one of the recesses.

[0174] (17) The light emitting device according to (16), wherein the light intensity distribution of the light emitted from each of the plurality of protrusions or the plurality of recesses has a single peak.

[0175] (18) The light-emitting device according to any one of (1) to (17), wherein the plurality of protrusions or the plurality of recesses have the same shape and are arranged at equal intervals when viewed from the first direction.

[0176] (19) The light emitting device according to any one of (1) to (17), wherein, when viewed from the first direction, the spacing between adjacent protrusions or the spacing between adjacent recesses becomes narrower or wider as one approaches the center of the second reflecting mirror, or when viewed from the first direction, the sides of the protrusions or the recesses extending in the second direction become shorter or longer as one moves away from the center of the second reflecting mirror in the second direction.

[0177] (20) The light-emitting device according to any one of (1) to (19), further comprising an insulating layer at the end of the active layer, the insulating layer being formed by introducing impurities into the end of the active layer or by oxidizing the end of the active layer.

[0178] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present disclosure. Furthermore, the effects described in this specification are merely examples and are not intended to be limiting, and other effects may also be obtained.

[0179] REFERENCE SIGNS LIST 1 Light emitting device 10 Substrate 20 First semiconductor layer 30 First reflector 40 Active layer 50 Third reflector 60 Step layer 60a to 60c Protrusion 70 Second reflector 70a to 70c Second reflector portion 80 First electrode 90 Second electrode 100 Protective film 110, 120 Connection portion

Claims

1. A first reflecting mirror constructed by laminating a plurality of semiconductor materials having different refractive indices in a first direction, and having a first surface and a second surface opposite the first surface; an active layer provided on the second surface side of the first reflecting mirror, having a third surface facing the first reflecting mirror and a fourth surface opposite the third surface, and emitting light when power is applied to the third and fourth surfaces; a second reflecting mirror provided on the fourth surface side of the active layer, constructed by laminating a plurality of non-conductive materials having different refractive indices in the first direction, or by laminating a non-conductive material and an amorphous semiconductor material having different refractive indices in the first direction, and having a fifth surface facing the active layer and a sixth surface opposite the fifth surface; a plurality of protrusions provided between the fourth surface and the sixth surface, protruding in the first direction toward the second reflecting mirror, or a plurality of recesses recessed from the second reflecting mirror in the first direction; and a first electrode electrically connected to the fourth surface of the active layer. a second electrode electrically connected to the third surface of the active layer.

2. The light-emitting device described in claim 1, wherein the second reflector is divided into a plurality of second reflector portions by grooves that penetrate the second reflector in the first direction and extend in the first direction, and the first electrode is provided in the grooves so as to surround the peripheries of the plurality of second reflector portions.

3. The light emitting device according to claim 2, further comprising a third reflector provided between the fourth surface and the sixth surface and constructed by stacking a plurality of semiconductor materials having different refractive indices in the first direction, wherein the third reflector is shared by the plurality of second reflector portions and is not divided.

4. The light emitting device according to claim 2, further comprising a third reflector configured by stacking a plurality of semiconductor materials having different refractive indices in the first direction, the third reflector being provided between the fourth surface and the sixth surface or between the plurality of protrusions or the plurality of recesses and the sixth surface, the third reflector being divided into a plurality of third reflector portions by the grooves.

5. The light emitting device of claim 2, further comprising a third reflector provided between the fourth surface and the sixth surface or between the sixth surface and the plurality of protrusions or the plurality of depressions, and constructed by stacking a plurality of semiconductor materials having different refractive indices in the first direction, wherein an upper layer of the third reflector is divided into a plurality of parts by the grooves, and a lower layer of the third reflector is shared by the plurality of second reflector portions and the upper layer and is not divided.

6. The light emitting device according to claim 3, wherein the plurality of protrusions or the plurality of recesses are provided between the second reflecting mirror and the third reflecting mirror.

7. The light-emitting device according to claim 2, wherein the plurality of protrusions are part of a step layer having a first film thickness in the region of the plurality of second reflecting mirror portions and a second film thickness thinner than the first film thickness in the region of the groove, or the plurality of recesses are part of a step layer having a first film thickness in the region of the plurality of second reflecting mirror portions and a second film thickness thicker than the first film thickness in the region of the groove.

8. The light emitting device according to claim 2, wherein a plurality of said protrusions or said recesses are provided for each of said second reflecting mirror portions.

9. The light emitting device according to claim 3, wherein the plurality of protrusions or the plurality of recesses are made of one of the plurality of semiconductor materials that make up the third reflector.

10. A light emitting device as described in claim 1, wherein, between the first reflecting mirror and the second reflecting mirror, in a first region of the plurality of protrusions or the plurality of recesses, light resonates at a wavelength equal to the wavelength of the output light to the outside, and in regions other than the first region, light does not resonate at a wavelength equal to the wavelength of the output light.

11. The light emitting device according to claim 2, wherein the first electrode is provided in the groove and on the plurality of second reflector portions, and further comprising a connection portion provided on the first electrode.

12. The light emitting device according to claim 2, further comprising a non-conductive semiconductor layer doped with impurities, the non-conductive semiconductor layer being disposed in the active layer in the first direction relative to the groove.

13. The light emitting device according to claim 1, wherein the plurality of protrusions or the plurality of recesses have a substantially circular or substantially polygonal shape when viewed in a plan view from the first direction.

14. The light-emitting device described in claim 1, wherein the second reflector is provided around the plurality of protrusions or the plurality of recesses and has holes penetrating the second reflector in the first direction, and the first electrode is in electrical contact with the active layer on the fourth surface exposed within the holes.

15. The light emitting device according to claim 1, wherein the first electrode covers at least a portion of an upper surface of the second reflector.

16. The light-emitting device according to claim 1, wherein the spacing between the centers of gravity of adjacent said plurality of protrusions or the spacing between the centers of gravity of adjacent said plurality of recesses is 4 x σ or less, where σ is the standard deviation of the light intensity distribution corresponding to one said protrusion or one said recess.

17. The light emitting device according to claim 16, wherein the light intensity distribution of the light emitted from each of the plurality of protrusions or the plurality of depressions has a single peak.

18. The light emitting device according to claim 1, wherein the plurality of protrusions or the plurality of recesses have the same shape and are arranged at equal intervals when viewed from the first direction.

19. The light emitting device of claim 1, wherein, when viewed from the first direction, the spacing between adjacent protrusions or the spacing between adjacent recesses becomes narrower or wider as one approaches the center of the second reflector, or, when viewed from the first direction, the sides of the plurality of protrusions or the plurality of recesses extending in the second direction become shorter or longer as one moves away from the center of the second reflector in the second direction.

20. The light emitting device according to claim 1, further comprising an insulating layer at the edge of the active layer, the insulating layer being formed by introducing impurities into the edge of the active layer or by oxidizing the edge of the active layer.

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