Light-emitting device

Abstract

[Problem] To provide a light-emitting device capable of achieving a high polarization ratio at low cost. [Solution] A light-emitting device (1) comprises: a first reflection part (20) that has a first surface (F1) and a second surface (F2) on the side opposite of that of the first surface; a second reflection part (90) that is provided on the second surface side of the first reflection part and has a third surface (F3) facing the first reflection part and a fourth surface (F4) on the side opposite of that of the third surface; an active layer (40) that is provided between the second surface of the first reflection part and the third surface of the second reflection part, has a fifth surface (F5) facing the second surface and a sixth surface (F6) facing the third surface, and emits light when electric power is applied thereto; and a first electrode (100) that is provided on the sixth surface side and is electrically connected to the sixth surface of the active layer, the first electrode (100) including a plurality of first electrode parts (100a) linked to each other and provided at the periphery of a plurality of light emission regions (Remt) on the first surface of the first reflection part or the fourth surface of the second reflection part when viewed from the stacking direction of the first and second reflection parts and the active layer.

Description

Light-emitting device

[0001] This disclosure relates to a light-emitting device.

[0002] Surface-emitting lasers such as VCSELs (Vertical-Cavity Surface-Emitting Lasers) have been developed. VCSELs for eye-safe applications require low cost and a high polarization ratio. To control the polarization of such VCSELs, methods such as using a tilted substrate or adding a grating to the light-emitting surface are being considered.

[0003] Japanese Patent Publication No. 2008-028120

[0004] However, using inclined substrates or adding gratings requires special materials and manufacturing processes, resulting in higher costs.

[0005] Therefore, this disclosure provides a light-emitting device that can achieve a high polarization ratio at low cost.

[0006] A light-emitting device according to one aspect of the present disclosure includes: a first reflector having a first surface and a second surface opposite to the first surface; a second reflector provided on the second surface side of the first reflector and having a third surface facing the first reflector and a fourth surface opposite to the third surface; an active layer provided between the second surface of the first reflector and the third surface of the second reflector and having a fifth surface facing the second surface and a sixth surface facing the third surface, which emits light when power is applied; and a first electrode provided on the sixth surface side and electrically connected to the sixth surface of the active layer, the first electrode including a plurality of interconnected first electrode portions, provided around a plurality of light-emitting regions on the first surface of the first reflector or on the fourth surface of the second reflector when viewed from the stacking direction of the first, second reflector and active layer.

[0007] The first electrode covers almost the entire sixth surface, excluding the multiple light-emitting regions, when viewed from the stacking direction.

[0008] The first electrode further comprises a plurality of second electrode portions connecting a plurality of adjacent first electrode portions in a plane intersecting the stacking direction in the first direction, and a plurality of third electrode portions connecting a plurality of adjacent first electrode portions in a fourth plane intersecting the first direction in the second direction.

[0009] The multiple first electrode portions, when viewed from the stacking direction, form annular shapes surrounding each of the multiple light-emitting regions.

[0010] Multiple light-emitting regions are arranged two-dimensionally on a first or fourth surface, with multiple first electrode portions corresponding to each of the multiple light-emitting regions, and multiple adjacent first electrode portions are in direct contact with each other.

[0011] The first electrode further includes an outer frame portion that surrounds the outer circumference of the outermost of the multiple first electrode portions when viewed from the stacking direction.

[0012] The light-emitting device further comprises a first semiconductor layer of a first conductivity type provided between the second surface of the first reflecting section and the fifth surface of the active layer; a second semiconductor layer of a second conductivity type provided between the sixth surface of the active layer and the third surface of the second reflecting section; a third semiconductor layer of a first conductivity type provided between the second semiconductor layer and the third surface of the second reflecting section; and a plurality of junctions provided between the second and third semiconductor layers corresponding to a plurality of light-emitting regions, which are formed by contacting a fourth semiconductor layer of a second conductivity type having a higher impurity concentration than the second semiconductor layer and a fifth semiconductor layer of a first conductivity type having a higher impurity concentration than the third semiconductor layer.

[0013] The light-emitting device further comprises a second electrode electrically connected to the first semiconductor layer.

[0014] The junction is a constricted layer that selectively passes current to the active layer, focusing the light into the light-emitting region.

[0015] When viewed from the stacking direction, the regions of the active layer, junction, and second semiconductor layer other than the light-emitting region are impurity regions with higher resistance than the light-emitting region.

[0016] The light-emitting device further includes a transparent electrode provided between the first electrode and the third semiconductor layer.

[0017] Light from the active layer is emitted from the fourth surface side of the second reflector.

[0018] Light from the active layer is emitted from the first surface side of the first reflecting section.

[0019] The first reflective section is constructed by stacking multiple semiconductor layers or multiple dielectric layers with different refractive indices, and the second reflective section is constructed by stacking multiple dielectric layers with different refractive indices.

[0020] The first reflective section is provided on a substrate containing Group III-V elements or Group IV elements.

[0021] A light-emitting device in another aspect of the present disclosure includes: a first reflector having a first surface and a second surface opposite to the first surface; a second reflector provided on the second surface side of the first reflector and having a third surface facing the first reflector and a fourth surface opposite to the third surface; an active layer provided between the second surface of the first reflector and the third surface of the second reflector and having a fifth surface facing the second surface and a sixth surface facing the third surface, which emits light when power is applied; and a first electrode provided on the sixth surface side and electrically connected to the sixth surface of the active layer, the first electrode including a first electrode portion provided around a light-emitting region on the first surface of the first reflector or on the fourth surface of the second reflector when viewed from the stacking direction of the first, second reflector and active layer, and a wiring portion drawn out from the first electrode portion in the direction of at least the crystal orientation

[011] of the active layer.

[0022] The first electrode covers almost the entire sixth surface, excluding the multiple light-emitting regions, when viewed from the stacking direction.

[0023] The light-emitting device further comprises: a first semiconductor layer of a first conductivity type provided between the second surface of the first reflecting section and the fifth surface of the active layer; a second semiconductor layer of a second conductivity type provided between the sixth surface of the active layer and the third surface of the second reflecting section; a third semiconductor layer of a first conductivity type provided between the second semiconductor layer and the third surface of the second reflecting section; and a junction provided between the second and third semiconductor layers corresponding to the light emission region, which is formed by contacting a fourth semiconductor layer of a second conductivity type having a higher impurity concentration than the second semiconductor layer and a fifth semiconductor layer of a first conductivity type having a higher impurity concentration than the third semiconductor layer.

[0024] This is a cross-sectional view showing an example of the configuration of a light-emitting device according to the first embodiment. This is a plan view showing an example of the configuration of a light-emitting device according to the first embodiment. This is a graph showing the polarization ratio, etc., of the light-emitting device according to the first embodiment. This is a plan view showing an example of the configuration of a light-emitting device according to a comparative example. This is a graph showing the polarization ratio, etc., of the light-emitting device according to a comparative example. This is a cross-sectional view showing an example of a method for manufacturing a light-emitting device according to the first embodiment. This is a cross-sectional view showing an example of a method for manufacturing a light-emitting device, following Figure 6. This is a cross-sectional view showing an example of a method for manufacturing a light-emitting device, following Figure 7. This is a cross-sectional view showing an example of a method for manufacturing a light-emitting device, following Figure 8. This is a cross-sectional view showing an example of a method for manufacturing a light-emitting device, following Figure 9. This is a cross-sectional view showing an example of a method for manufacturing a light-emitting device, following Figure 10. This is a cross-sectional view showing an example of a method for manufacturing a light-emitting device, following Figure 11. This is a plan view showing an example of the configuration of a light-emitting device according to the second embodiment. This is a plan view showing an example of the configuration of a light-emitting device according to a modified version of the second embodiment. This is a plan view showing an example of the configuration of a light-emitting device according to the third embodiment. This is a plan view showing an example of the configuration of a light-emitting device according to the fourth embodiment. This is a graph showing the intensity of the laser light L from the light-emitting device according to the fourth embodiment. This is a graph showing the intensity of the laser light L from the light-emitting device according to a comparative example. This is a plan view showing an example of the configuration of a light-emitting device according to the fifth embodiment. This is a cross-sectional view showing an example of the configuration of a light-emitting device according to the sixth embodiment. This is a cross-sectional view showing an example of the configuration of a light-emitting device according to the seventh embodiment. This is a cross-sectional view showing an example of the configuration of a light-emitting device according to the eighth embodiment. This is a cross-sectional view showing an example of the configuration of a light-emitting device according to the ninth embodiment. This is a cross-sectional view showing an example of the configuration of a light-emitting device according to the tenth embodiment. This is a cross-sectional view showing an example of the configuration of a light-emitting device according to the eleventh embodiment. This is a cross-sectional view showing an example of the application of the first embodiment to a back-facing VCSEL. This is a block diagram showing an example of the schematic configuration of a vehicle control system. This is an explanatory diagram showing an example of the installation positions of the external information detection unit and the imaging unit.

[0025] The following describes specific embodiments of this technology with reference to the drawings. The drawings are schematic or conceptual, and the proportions of each part may not necessarily be the same as those of actual objects. In the specification and drawings, elements similar to those described above are denoted by the same reference numerals with respect to previously shown drawings, and detailed explanations are omitted as appropriate.

[0026] (First Embodiment) FIG. 1 is a cross-sectional view showing a configuration example of a light-emitting device according to the first embodiment. FIG. 2 is a plan view showing a configuration example of the light-emitting device according to the first embodiment. FIG. 1 shows a cross section taken along line 1-1 of FIG. 2.

[0027] The light-emitting device 1 includes a substrate 10, a first reflecting mirror 20, a first semiconductor layer 30, an active layer 40, a second semiconductor layer 50, a third semiconductor layer 60, a fourth semiconductor layer 70, a fifth semiconductor layer 80, a second reflecting mirror 90, a first electrode 100, a pad 101, a second electrode 110, and a pad 111. The light-emitting device 1 is, for example, a semiconductor light-emitting device such as a VCSEL used in a ranging device such as ToF (Time of Flight).

[0028] The light-emitting device 1 injects electrons and holes from the first and second semiconductor layers 30 and 50 into the active layer 40 by applying electric power between the first electrode 100 and the second electrode 110, and emits light by causing the electrons and holes to recombine in the active layer 40. Light L of a certain wavelength is reflected and resonated between the first reflecting mirror 20 and the second reflecting mirror 90, and is emitted from the fourth surface F4 of the second reflecting mirror 90 as laser light. That is, the present embodiment is a surface-emitting VCSEL.

[0029] The substrate 10 contains a group III-V element or a group IV element. The substrate 10 may be, for example, a semiconductor substrate such as an n-type InP substrate. However, the substrate 10 is not limited, and may be a GaAs substrate.

[0030] The first reflecting mirror 20 is a so-called DBR (Distributed Bragg Reflector), and is configured by alternately laminating a plurality of materials having different refractive indexes. For example, the first reflecting mirror 20 has a laminated structure of a plurality of types of semiconductor materials with different refractive indexes epitaxially grown on the substrate 10 (for example, a laminated structure of n-type InP and n-type AlGaInAs). The first reflecting mirror 20 has a first surface F1 and a second surface F2 on the opposite side to the first surface F1.

[0031] The first semiconductor layer 30 is located between the second surface F2 of the first reflecting mirror 20 and the fifth surface F5 of the active layer 40, and is a spacer layer provided on the first reflecting mirror 20. The first semiconductor layer 30 is composed of n-type InP or an n-type material lattice-matched to InP (for example, n-type InGaAsP, n-type AlGaInAs, etc.). The first semiconductor layer 30 may be a single layer of the above materials, or may be a laminated film of a plurality of materials among the above materials.

[0032] The active layer 40 is provided between the second surface F2 of the first reflecting mirror 20 and the third surface F3 of the second reflecting mirror 90, and has a fifth surface F5 facing the second surface F2 and a sixth surface F6 facing the third surface F3. More specifically, the active layer 40 is provided between the first semiconductor layer 30 and the second semiconductor layer 50. The active layer 40 receives electric power from the first and second semiconductor layers 30 and 50, and emits light by recombining electrons from the first semiconductor layer 30 and holes from the second semiconductor layer 50 therein. The active layer 40 has, for example, a multiple quantum well (MQW (Multiple Quantum Well)) structure composed of AlGaInAs, InGaAs or InGaAsP, and generates light with a wavelength of, for example, 1.2 μm to 2 μm.

[0033] The second semiconductor layer 50 is provided between the sixth surface F6 of the active layer 40 and the third surface F3 of the second reflecting mirror 90, and more specifically, is a spacer layer provided between the active layer 40 and the third semiconductor layer 60. The second semiconductor layer 50 is composed of p-type InP having a conductivity type opposite to that of the first semiconductor layer 30. Therefore, by applying a positive voltage to the first electrode 100 and a negative voltage to the second electrode 110, electrons are supplied from the first semiconductor layer 30 to the active layer 40, and holes are supplied from the second semiconductor layer 50 to the active layer 40.

[0034] The third semiconductor layer 60 is a spacer layer provided between the second semiconductor layer 50 and the third surface F3 of the second reflecting mirror 90. The third semiconductor layer 60 is composed of n-type InP having a conductivity type opposite to that of the second semiconductor layer 50.

[0035] The fourth semiconductor layer 70 is provided between the second semiconductor layer 50 and the third semiconductor layer 60 so as to correspond to the light emission region Remt. The fourth semiconductor layer 70 is composed of a p-type semiconductor with a high impurity concentration, for example, p＋＋ It is composed of type AlGaInAs. The p-type impurity concentration of the fourth semiconductor layer 70 is higher than that of the second semiconductor layer 50, for example, 5 × 10⁻⁶ １９ / cm －３ That's all.

[0036] The fifth semiconductor layer 80 is provided on the fourth semiconductor layer 70 between the second semiconductor layer 50 and the third semiconductor layer 60. The fifth semiconductor layer 80 is also provided corresponding to the light emission region Remt. The fifth semiconductor layer 80 is composed of an n-type semiconductor with a high impurity concentration, for example, n ＋＋ It is composed of type InP. The n-type impurity concentration of the fifth semiconductor layer 80 is higher than that of the third semiconductor layer 60, for example, 5 × 10⁻⁶ １９ / cm －３ That's all.

[0037] The fourth and fifth semiconductor layers 70 and 80 are in contact with each other and form a pn junction. The fourth and fifth semiconductor layers 70 and 80 form a buried tunnel junction (BTJ) with a high impurity concentration. Hereinafter, the fourth and fifth semiconductor layers 70 and 80 will also be referred to as BTJ70 and 80. BTJ70 and 80 have a higher impurity concentration than the second semiconductor layer 50 and the third semiconductor layer 60. Therefore, the current between the first and second electrodes 100 and 110 flows concentrated in BTJ70 and 80, and is constricted. BTJ70 and 80 function as constricting layers that selectively allow current to flow to the active layer 40, concentrating light in the light-emitting region Remt. As a result, BTJ70 and 80 can promote light emission in the active layer 40 directly beneath them. Furthermore, BTJ70 and 80 also have the function of focusing light into the light-emitting region Remt due to the refractive index difference with the third semiconductor layer 60 on their sides. Therefore, BTJ70 and 80 combine the functions of current constriction and light constriction.

[0038] The plurality of BTJs 70 and 80 are provided corresponding to the light emission region Remt of the second reflecting mirror 90, as shown in FIG. 2, when viewed from the stacking direction (Z direction). The plurality of BTJs 70 and 80 are provided for one active layer 40, one second semiconductor layer 50, one third semiconductor layer 60, and one first electrode 100 (that is, one plateau structure PLT). Note that the stacking direction (Z direction) is also the direction in which current flows through the BTJs 70 and 80, and is also the direction in which light resonates between the first reflecting mirror 20 and the second reflecting mirror 90.

[0039] In the first embodiment, as shown in FIG. 2, a plurality of BTJs 70 and 80 are provided for one active layer 40, and laser light is emitted from each of the BTJs 70 and 80. That is, the light emitting device 1 of the first embodiment is a multi-aperture (multi-emitter) VCSEL. Note that the number of BTJs 70 and 80 is not limited.

[0040] As shown in FIG. 1, the third semiconductor layer 60 is provided on the second semiconductor layer 50 and the BTJs 70 and 80. The third semiconductor layer 60 covers the BTJs 70 and 80. The third semiconductor layer 60 is composed of an n-type semiconductor, for example, composed of n-type InP. The n-type impurity concentration of the third semiconductor layer 60 is lower than that of the fifth semiconductor layer 80, for example, 5×10 １７ to 1×10 １８ / cm －３ . A reverse bias is applied to the pn junction portion between the second semiconductor layer 50 and the third semiconductor layer 60 when a positive voltage is applied to the first electrode 100 and a negative voltage is applied to the second electrode 110. Therefore, no current flows through the pn junction portion between the second semiconductor layer 50 and the third semiconductor layer 60.

[0041] A semiconductor layer 61 is provided over the third semiconductor layer 60. The semiconductor layer 61 is composed of, for example, InGaAs. The semiconductor layer 61 functions as a contact layer that connects the first electrode 100 to the third semiconductor layer 60 with low resistance.

[0042] The second reflector 90 is located above the BTJs 70 and 80 (in the Z direction). The second reflector 90 is a dielectric DBR and is constructed by alternately stacking multiple types of dielectric materials with different refractive indices. For example, the second reflector 90 has a stacked structure of multiple dielectric materials (for example, SiO ２ , MgO and TiO ２ Ta ２ O ３ It has a laminated structure with either SiN or amorphous silicon. That is, the second reflector 90 is a dielectric DBR. The dielectric material in this disclosure is a single-crystal non-semiconductor dielectric material obtained by epitaxial growth on a semiconductor substrate such as GaAs or InP, for example SiO ２ , TiO ２ Ta ２ O ３ This includes SiN, MgO, amorphous semiconductor materials, and the like. The second reflecting mirror 90 also has a third surface F3 and a fourth surface F4 that is opposite to the third surface F3.

[0043] The first electrode 100 is provided on a semiconductor layer 61 on the third semiconductor layer 60 and is electrically connected to the third semiconductor layer 60 via the semiconductor layer 61. The first electrode 100 is provided on the sixth surface F6 side of the active layer 40 and is electrically connected to the sixth surface F6 of the active layer 40 via the third semiconductor layer 60 and BTJs 70 and 80. The first electrode 100 is made of a conductive metal such as Ti, Pt, or Au, an AuGe / Ni / Au multilayer film, or a PdGe / Ni / Au multilayer film. The first electrode 100 is provided around the second reflector 90. The first electrode 100 may be in contact with the second reflector 90. A pad 101 is provided on the first electrode 100. The pad 101 functions as a bonding pad for wire bonding, etc. The pad 101 is made of a conductive metal such as Ti, Pt, or Au.

[0044] The active layer 40, the second semiconductor layer 50, and the third semiconductor layer 60 constitute a plate structure PLT that protrudes from the first semiconductor layer 30. A second reflector 90 is provided on the plate structure PLT. A light emission region Remt is provided on the plate structure PLT, and a first electrode 100 is provided around the light emission region Remt. The light emission region Remt is an aperture from which laser light L is emitted, and its diameter (diameter of BTJ 70, 80) is, for example, about 6 μm. If the diameter of each aperture is a size that allows for transverse single-mode lasers, then, as in this embodiment, the polarization components can be aligned by covering everything except the light emission region Remt with the first electrode 100.

[0045] The second electrode 110 is provided on the first semiconductor layer 30 and is electrically connected to the first semiconductor layer 30. The second electrode 110 is made of a conductive metal such as Ti, Pt, or Au, an AuGe / Ni / Au multilayer film, or a PdGe / Ni / Au multilayer film. The second electrode 110 may be made of the same material as the first electrode 100. A pad 111 is provided on the second electrode 110. The pad 111 functions as a bonding pad for wire bonding, etc. The pad 111 is made of a conductive metal such as Ti, Pt, or Au.

[0046] The first and second electrodes 100 and 110 do not overlap with the BTJs 70 and 80 (i.e., the light emission region Remt) when viewed from the Z direction. Therefore, the first and second electrodes 100 and 110 do not obstruct the laser light emitted from the second reflector 90.

[0047] Here, as shown in Figure 2, the first electrode 100 is provided around each of the multiple light emission regions Remt on the fourth surface F4 of the second reflector 90 when viewed from the stacking direction (Z direction) of the first and second reflectors 20, 90 and the active layer 40. The electrode portions of the first electrode 100 around each of the multiple light emission regions Remt (any portion of the first electrode 100 around each light emission region Remt) are continuously connected to one another. Therefore, the first electrode 100 is provided in a solid, gapless manner over almost the entire third semiconductor layer 60 or semiconductor layer 61 other than the light emission regions Remt on the sixth surface F6 side of the active layer 40. That is, when viewed from the Z direction, the first electrode 100 covers almost the entire sixth surface F6 other than the light emission regions Remt.

[0048] Figure 3 is a graph showing the polarization ratio and other parameters of the light-emitting device according to the first embodiment. The horizontal axis of this graph shows the current value supplied to the active layer 40. The vertical axis shows the intensity OP, OP_0, OP_90 of the laser light L, and the orthogonal polarization suppression ratio (OPSR) (hereinafter also referred to as the polarization ratio). The vertical axis is displayed on a logarithmic scale.

[0049] OP is the total intensity of the laser light L. OP_0 is the intensity of the laser light L with a polarization direction of 0 degrees (hereinafter referred to as 0-degree polarization). OP_90 is the intensity of the laser light L with a polarization direction of 90 degrees (hereinafter referred to as 90-degree polarization). The polarization ratio OPSR indicates the ratio (OP_0 / OP_90) of the intensity of the 0-degree polarization OP_0 to the intensity of the 90-degree polarization OP_90.

[0050] As shown in Figure 3, increasing the current supplied to the active layer 40 gradually increases the overall intensity OP of the laser light L. The intensity OP_0 of 0-degree polarization also increases as the current supplied to the active layer 40 increases. The intensity OP_90 of 90-degree polarization does not increase much even when the current supplied to the active layer 40 is increased. The intensity OP_90 of 90-degree polarization rises slightly when the supply current exceeds 90 mA. Therefore, the polarization ratio OPSR maintains a relatively high value and gradually decreases when the supply current exceeds 90 mA.

[0051] Figure 4 is a plan view showing an example of the configuration of a light-emitting device according to a comparative example. In this comparative example, the first electrode 100 includes annular portions provided in a substantially ring shape around each of the light-emitting regions Remt, and wiring portions connecting these annular portions in the X direction. Adjacent annular portions in the X direction are connected to each other, but adjacent annular portions in the Y direction are not directly connected. The other configurations of the comparative example may be the same as those of the first embodiment.

[0052] Figure 5 is a graph showing the polarization ratio, etc., of the light-emitting device according to a comparative example. It is the same as the first embodiment in that increasing the supply current to the active layer 40 gradually increases the overall intensity OP of the laser light L.

[0053] However, in this comparative example, the intensity of 90-degree polarization OP_90 increases as the supply current to the active layer 40 increases, while the increase in the intensity of 0-degree polarization OP_0 is slower. For example, the intensity of 90-degree polarization OP_90 increases when the supply current exceeds 30 mA, while the intensity of 0-degree polarization OP_0 does not increase much when the supply current exceeds 90 mA. Therefore, the polarization ratio OPSR peaks near a supply current of 30 mA and decreases as the supply current is further increased.

[0054] Comparing Figures 3 and 5, it can be seen that the light-emitting device 1 according to this embodiment has a clearly higher polarization ratio (OPSR) compared to the comparative example. That is, according to this embodiment, by simply changing the planar shape of the first electrode 100, it is possible to selectively increase the intensity of 0-degree polarization (OP_0) while suppressing the increase in the intensity of 90-degree polarization (OP_90). As a result, this embodiment can maintain a high polarization ratio (OPSR). This embodiment can be realized simply by changing the planar layout of the first electrode 100, without using special processing or special materials. Therefore, this embodiment can easily control polarization at low cost.

[0055] (Method of manufacturing the light-emitting device) Next, the method of manufacturing the light-emitting device 1 will be explained.

[0056] Figures 6 to 12 are cross-sectional views showing an example of a method for manufacturing a light-emitting device according to the first embodiment.

[0057] First, as shown in Figure 6, using the MOCVD (Metal Organic Chemical Vapor Deposition) method, an n-type InP buffer layer (not shown), a first reflector 20 (for example, a laminated film of n-type InP and n-type AlGaInAs), a first semiconductor layer 30 (n-type InP), an active layer 40 (for example, a multi-quantum well layer with the well layer being AlGaInAs and the barrier layer being AlGaInAs), a second semiconductor layer 50 (for example, p-type InP), and a fourth semiconductor layer 70 (for example, p ＋＋ (Type AlGaInAs), fifth semiconductor layer 80 (n ＋＋ The n-type InP (InP) and the semiconductor layer 81 (n-type InP) are epitaxially grown in this order. ＋＋ This indicates a high concentration of impurities.

[0058] Next, as shown in Figure 7, the BTJ 70 and 80 materials are processed using lithography and a wet etching method. In the etching process, the BTJ 70 and 80 are wet-etched with a mixed aqueous solution containing sulfuric acid and hydrogen peroxide. The shape of the BTJ 70 and 80 as viewed from the Z direction may be circular, elliptical, or polygonal. The size of the BTJ 70 and 80 as viewed from the Z direction, for example, if it is circular, has a diameter of approximately 10 μm. The spacing between multiple BTJ 70 and 80 is preferably 50 μm or more to suppress thermal interference. In Figure 7, one BTJ 70 or 80 is shown, but in this embodiment, multiple BTJ 70 and 80 are provided for one active layer 40.

[0059] Next, as shown in Figure 8, a third semiconductor layer 60 and a semiconductor layer 61 are formed on the second semiconductor layer 50 and the fifth semiconductor layer 80 using the MOCVD method. The third semiconductor layer 60 is, for example, n-type InP. The semiconductor layer 61 is, for example, InGaAs.

[0060] Next, as shown in Figure 9, the semiconductor layer 61, the third semiconductor layer 60, the second semiconductor layer 50, and a portion of the active layer 40 are etched using lithography and dry etching techniques to expose the first semiconductor layer 30 and a portion of the upper surface of the substrate 10. This forms a platen lithograph (PLT).

[0061] Next, the materials for the first and second electrodes 100 and 110 are deposited on the first semiconductor layer 30 and the semiconductor layer 61. The materials for the first and second electrodes 100 and 110 are conductive metals such as Ti, Pt, or Au, AuGe / Ni / Au multilayer films, or PdGe / Ni / Au multilayer films.

[0062] Next, the materials for the first and second electrodes 100 and 110 are processed using lithography and etching techniques. As a result, as shown in Figure 10, the first electrode 100 is formed on the semiconductor layer 61 and the second electrode 110 is formed on the first semiconductor layer 30. At this time, the material of the first electrode 100 located above the MTJs 70 and 80 (light emission region Remt) is removed. The light emission region Remt from which the material of the first electrode 100 has been removed becomes an aperture (opening) from which light L is emitted. If the diameter of each aperture is of a size that allows for transverse single-mode emission, the polarization components can be aligned by covering everything except the light emission region Remt with the first electrode 100. The diameter of each aperture (the diameter of the light emission region Remt or BTJ) is, for example, about 6 μm.

[0063] As shown in Figure 2, the planar layout of the first electrode 100 is such that it is provided in a solid, gapless manner around the light-emitting region Remt, covering almost the entire third semiconductor layer 60 or semiconductor layer 61 other than the light-emitting region Remt. That is, when viewed from the Z direction, the first electrode 100 covers almost the entire sixth surface F6 other than the light-emitting region Remt.

[0064] Next, as shown in Figure 11, pads 101 and 111 are formed on the first and second electrodes 100 and 110. The material of the pads 111 is, for example, a conductive metal such as Ti, Pt, or Au.

[0065] Next, as shown in Figure 12, the material for the second reflector 90 (for example, SiO2) is placed on the third semiconductor layer 60 and the first electrode 100. ２ and Ti ２ O ２ It forms a laminated film.

[0066] Subsequently, the substrate 10 is diced into individual semiconductor chips and mounted on a heat sink or wiring board. Metal wires are bonded to the first and second electrodes 100 and 110 to complete the light-emitting device 1.

[0067] According to this embodiment, when viewed from the Z direction, the first electrode 100 is provided around each of the multiple light emission regions Remt, and furthermore, it is continuously connected between adjacent multiple light emission regions Remt in a solid, gapless manner. That is, when viewed from the Z direction, the first electrode 100 covers almost the entire sixth surface F6 other than the light emission regions Remt. As a result, this embodiment can maintain a high polarization ratio OPSR, as explained with reference to Figure 3. Moreover, this embodiment can be easily realized by changing the planar layout of the first electrode 100 without using special processing or special materials. Therefore, this embodiment can easily control polarization at low cost.

[0068] (Second Embodiment) Figure 13A is a plan view showing an example of the configuration of a light-emitting device according to the second embodiment. In the second embodiment, the first electrode 100 includes a plurality of annular first electrode portions 100a that surround each of the plurality of light-emitting regions Remt when viewed from the Z direction. When viewed from the Z direction, the first electrode portions 100a are, for example, substantially annular, but are not limited to annular shapes, and may be substantially elliptical or polygonal annular shapes. The plurality of light-emitting regions Remt are arranged in a two-dimensional array on the fourth plane F4. The plurality of first electrode portions 100a are provided so as to surround each of the plurality of light-emitting regions Remt. The plurality of first electrode portions 100a that are adjacent to each other in the X-Y plane are in direct contact with each other. That is, not only the plurality of first electrode portions 100a adjacent in the X direction, but also the plurality of first electrode portions 100a adjacent in the Y direction or in the inclined direction are in direct contact with each other. The first electrode portion 100a is made of the same material as the first electrode 100 in the first embodiment. The other components of the second embodiment may be the same as those of the first embodiment.

[0069] In this way, multiple first electrode portions 100a adjacent to each other in the X-Y plane are in direct contact. As a result, the second embodiment has characteristics substantially similar to those shown in Figure 3, and can maintain a high polarization ratio OPSR. Furthermore, the second embodiment can also be easily realized by changing the planar layout of the first electrode 100. Therefore, the second embodiment can obtain the same effects as the first embodiment.

[0070] Figure 13B is a plan view showing an example of the configuration of a light-emitting device according to a modification of the second embodiment. In this modification, when viewed from the Z direction, the first electrode 100 includes a plurality of second electrode portions 100_1 that connect a plurality of adjacent first electrode portions 100a in the D1 direction within the X-Y plane intersecting the Z direction, a plurality of third electrode portions 100_2 that connect a plurality of adjacent first electrode portions 100a in the D2 direction, and a plurality of fourth electrode portions 100_3 that connect a plurality of adjacent first electrode portions 100a in the D3 direction (X direction). The D1 direction is a direction inclined with respect to the X and Y directions. The D2 direction is inclined with respect to the X and Y directions, similar to the D1 direction, but intersects (for example, is orthogonal to) the D1 direction. The D3 direction is the X direction.

[0071] If the first electrode portion 100a is small and multiple adjacent first electrode portions 100a cannot directly contact each other, second to fourth electrode portions 100_1 to 100_3 may be provided to connect the multiple first electrode portions 100a, as shown in this modified example. This will result in the first electrode 100 being connected in the same way as in the second embodiment. Although not shown, additional electrode portions connecting the multiple first electrode portions 100a in the Y direction may be added. The other configurations of this modified example may be the same as those of the second embodiment. Thus, this modified example can obtain the same effects as the second embodiment.

[0072] (Third Embodiment) Figure 14 is a plan view showing an example of the configuration of a light-emitting device according to the third embodiment. In the third embodiment, the first electrode 100 includes, when viewed from the Z direction, a plurality of annular first electrode portions 100a surrounding each of the plurality of light emission regions Remt, and an outer frame portion 100b surrounding the outer circumference of the plurality of first electrode portions 100a that are the outermost of the plurality of first electrode portions 100a. When viewed from the Z direction, the planar layout of the first electrode portions 100a may be the same as that of the first embodiment.

[0073] The outer frame portion 100b is provided on the outer circumference of the multiple first electrode portions 100a so as to surround them. The outer frame portion 100b is provided on the entire outer circumference of the platen structure PLT. The outer frame portion 100b is made of the same material as the first electrode portions 100a.

[0074] Thus, the outer frame portion 100b may be provided. The other configurations of the third embodiment may be the same as those of the second embodiment. Therefore, the third embodiment can obtain the same effects as the second embodiment.

[0075] (Fourth Embodiment) Figure 15 is a plan view showing an example of the configuration of a light-emitting device according to the fourth embodiment. In the fourth embodiment, one light-emitting region Remt and one BTJ 70, 80 are provided for each active layer 40. Laser light is emitted from one BTJ 70, 80. That is, the light-emitting device 1 of the fourth embodiment is a single-aperture type (single-emitter type) VCSEL.

[0076] In this case, when viewed from the Z direction, the first electrode 100 includes a first electrode portion 100a provided around a light emission region Remt on the fourth surface F4, and a wiring portion 100c drawn out from the first electrode portion 100a in the direction of the crystal orientation

[011] of the active layer 40 (±Y direction). The other configurations of the fourth embodiment may be the same as those of the first embodiment.

[0077] Figure 16 is a graph showing the intensity of the laser light L from the light-emitting device according to the fourth embodiment. The horizontal axis indicates the polarization direction. The vertical axis indicates the intensity of the normalized laser light L. It is assumed that the supply current to the active layer 40 is constant.

[0078] Referring to Figure 16, the intensity of 0-degree polarization (180-degree polarization) is highest, and the intensity of 90-degree polarization is lowest. Therefore, the polarization ratio OPSR is high.

[0079] Figure 17 is a graph showing the intensity of laser light L from a light-emitting device in a comparative example. In this comparative example, the wiring portion 100c is drawn out from the first electrode portion 100a in a direction tilted with respect to the crystal orientation

[011] of the active layer 40 (for example, in a direction tilted 45 degrees with respect to X and Y) (not shown). In this case, as shown in Figure 17, the intensity of 150-degree polarization is the highest, and the intensity of 60-degree polarization is the lowest. The intensity of 0-degree polarization is approximately 0.75, and the intensity of 90-degree polarization is approximately 0.35. Therefore, the polarization ratio OPSR is relatively low.

[0080] In other words, by extending the wiring portion 100c from the first electrode portion 100a in the direction of the crystal orientation

[011] of the active layer 40 (±Y direction), a high polarization ratio OPSR can be obtained. Furthermore, the fourth embodiment can also be easily realized by changing the planar layout of the first electrode 100. Therefore, the fourth embodiment can obtain the same effects as the first embodiment.

[0081] (Fifth Embodiment) Figure 18 is a plan view showing an example of the configuration of a light-emitting device according to the fifth embodiment. The fifth embodiment is a single-emitter type VCSEL, but the first electrode 100 covers almost the entire sixth surface F6 other than the light emission region Remt when viewed from the Z direction. That is, the first electrode 100 is provided in a solid form without any gaps other than the light emission region Remt when viewed from the Z direction.

[0082] Even in this configuration, the characteristics described with reference to Figure 16 can be obtained. The other configurations of the fifth embodiment may be the same as those of the fourth embodiment. Therefore, the fifth embodiment can obtain the same effects as the fourth embodiment.

[0083] (Sixth Embodiment) Figure 19 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the sixth embodiment. In the sixth embodiment, the semiconductor layer 61 is omitted. Other configurations of the sixth embodiment may be the same as those of the first embodiment. Therefore, the sixth embodiment can obtain the same effects as the first embodiment. The sixth embodiment may be combined with any of the second to fifth embodiments.

[0084] (Seventh Embodiment) Figure 20 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the seventh embodiment. In the seventh embodiment, the areas of the active layer 40, TJs 70 and 80, and the second semiconductor layer 50 other than the light-emitting region Remt are impurity regions 95 with higher resistance than the light-emitting region Remt. The impurity regions 95 narrow the current to the active layer 40. The fourth and fifth semiconductor layers 70 and 80 are not processed and are not embedded by the third semiconductor layer 60. Therefore, the fourth and fifth semiconductor layers 70 and 80 are called TJs (Tunnel Junctions) 70 and 80.

[0085] The impurity region 95 is formed by implanting impurities such as H, He, O, and B in areas other than the light-emitting region Remt, which does not allow current or light to pass through, among the lower part of the third semiconductor layer 60, the fourth and fifth semiconductor layers 70 and 80, the active layer 40, the second semiconductor layer 50, and the upper part of the first semiconductor layer 30. The impurity region 95 is in a non-conductive or high-resistance state due to the introduction of crystal defects by the implantation of impurities.

[0086] According to the seventh embodiment, the current is narrowed by the impurity region 95. The current between electrodes 100 and 110 flows concentrated in TJs 70 and 80 and is narrowed. As a result, TJs 70 and 80 can promote luminescence in the active layer 40 directly beneath them.

[0087] The other configurations of the seventh embodiment may be the same as those of the first embodiment. Therefore, the seventh embodiment can obtain the same effects as the first embodiment. The seventh embodiment may be combined with any of the second to sixth embodiments.

[0088] (Eighth Embodiment) Figure 21 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the eighth embodiment. In the eighth embodiment, transparent electrodes 96 are provided between the third semiconductor layer 60 and the second reflector 90, and between the third semiconductor layer 60 and the first electrode 100. The transparent electrodes 96 are, for example, TiO ２ It consists of ITiO, etc.

[0089] In the eighth embodiment, the impurity region 95 is provided in areas other than the active layer 40, the second semiconductor layer 50, the third semiconductor layer 60, and the light emission regions Remt of the TJs 70 and 80. As a result, the impurity region 95 more effectively narrows the current to the active layer 40. On the other hand, the transparent electrode 96 is provided to maintain the electrical connection between the third semiconductor layer 60 and the first electrode 100.

[0090] The other configurations of the eighth embodiment may be the same as those of the seventh embodiment. Therefore, the eighth embodiment can obtain the same effects as the seventh embodiment.

[0091] (Ninth Embodiment) Figure 22 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the ninth embodiment. In the ninth embodiment, the first reflector 20 is constructed by laminating dielectric layers in the same manner as the second reflector 90. The dielectric layer of the first reflector 20 is made of the same dielectric material as the second reflector 90 (for example, SiO ２ , MgO and TiO ２ Ta ２ O ３ The same structure as the laminated structure of either SiN or amorphous silicon is acceptable. However, in order to emit the laser light L from the second reflector 90 side, the number of dielectric layers in the first reflector 20 is greater than the number of dielectric layers in the second reflector 90.

[0092] Other configurations of the ninth embodiment may be the same as those of the first embodiment. Therefore, the ninth embodiment can obtain the same effects as the first embodiment. The ninth embodiment may be combined with any of the second to eighth embodiments.

[0093] (Tenth Embodiment) Figure 23 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the tenth embodiment. In the tenth embodiment, the first reflector 20 has a hybrid structure of a dielectric layer and a metal part. The dielectric layer of the first reflector 20 may be the same as the dielectric material of the second reflector 90. The metal part of the first reflector 20 may be the same material as the first electrode 100 or the second electrode 110 (for example, a conductive metal such as Ti, Pt or Au, an AuGe / Ni / Au laminate, or a PdGe / Ni / Au laminate). Even if the number of dielectric layers of the first reflector 20 is small, the laser light L can be emitted from the second reflector 90 side because the metal part reflects the laser light L. In this case, the overall thickness of the first reflector 20 can be reduced.

[0094] Other configurations of the tenth embodiment may be the same as those of the first embodiment. Therefore, the tenth embodiment can obtain the same effects as the first embodiment. The tenth embodiment may be combined with any of the second to eighth embodiments.

[0095] (Eleventh Embodiment) Figure 24 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the eleventh embodiment. In the eleventh embodiment, the first reflector 20 is constructed by stacking GaAs-based semiconductor materials. The first reflector 20 may be, for example, a stacked structure of GaAs and AlGaAs.

[0096] When the first reflector 20 is made of a GaAs-based semiconductor material, the first reflector 20 can be epitaxially grown on a GaAs substrate and then bonded to the first semiconductor layer 30. This makes it possible to form a first reflector 20 using a GaAs-based semiconductor material with high heat dissipation properties on an InP-based body.

[0097] Other configurations of the 11th embodiment may be the same as those of the first embodiment. Therefore, the 11th embodiment can obtain the same effects as the first embodiment. The 11th embodiment may be combined with any of the second to eighth embodiments.

[0098] (Modifications) In the first to eleventh embodiments, the laser beam L is emitted from the second reflector 90 side. That is, the above embodiments are surface-emitting VCSELs. However, the first to eleventh embodiments can also be applied to back-side-emitting VCSELs. Figure 25 is a cross-sectional view showing an example of the first embodiment being applied to a back-side-emitting VCSEL. In this case, the number of layers or material of the first reflector 20 is adjusted to emit the laser beam L from the first reflector 20 side. In a back-side-emitting VCSEL, the light emission region Remt is located on the first surface F1 of the first reflector 20. However, in a plan view from the Z direction, the relationship between the light emission region Remt and the first electrode 100 is the same as in a surface-emitting VCSEL. Therefore, this technology can be effective even when applied to a back-side-emitting VCSEL. The second to eleventh embodiments can also be applied to back-side-emitting VCSELs.

[0099] (Examples of application to mobile devices) The technology disclosed herein (the technology) can be applied to various products. For example, the technology disclosed herein may be implemented as a device mounted on any type of mobile device such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, and robots.

[0100] Figure 26 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0101] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 26, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0102] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0103] The body system control unit 12020 controls the operation of various devices mounted on 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 system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0104] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0105] The imaging unit 12031 is a light 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.

[0106] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0107] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal 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 ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0108] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0109] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0110] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 26, the output devices include 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 onboard display and a head-up display.

[0111] Figure 27 shows an example of the installation position of the imaging unit 12031.

[0112] In Figure 27, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0113] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0114] Figure 27 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0115] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0116] For example, the microcomputer 12051, based on distance information obtained from the imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0117] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies 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 the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0118] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0119] The above describes an example of a vehicle control system to which the technology described herein may be applied. The technology described herein may be applied to, for example, the imaging unit 12031, among the configurations described above.

[0120] Furthermore, this technology can be configured as follows:

[0121] (1) A light-emitting device comprising: a first reflective portion having a first surface and a second surface opposite to the first surface; a second reflective portion provided on the second surface side of the first reflective portion and having a third surface facing the first reflective portion and a fourth surface opposite to the third surface; an active layer provided between the second surface of the first reflective portion and the third surface of the second reflective portion and having a fifth surface facing the second surface and a sixth surface facing the third surface, which emits light when power is applied; and a first electrode provided on the sixth surface side and electrically connected to the sixth surface of the active layer, the first electrode including a plurality of interconnected first electrode portions provided around a plurality of light-emitting regions on the first surface of the first reflective portion or on the fourth surface of the second reflective portion when viewed from the stacking direction of the first, second reflective portions and the active layer.

[0122] (2) The light-emitting device according to (1), wherein the first electrode covers substantially the entire sixth surface other than the plurality of light-emitting regions when viewed from the stacking direction.

[0123] (3) The light-emitting device according to (1), wherein the first electrode further comprises a plurality of second electrode portions connecting the plurality of first electrode portions adjacent to each other in the first direction in a plane intersecting the stacking direction, and a plurality of third electrode portions connecting the plurality of first electrode portions adjacent to each other in the second direction intersecting the first direction in the fourth plane.

[0124] (4) The light-emitting device according to (1) or (3), wherein the plurality of first electrode portions are annular in shape when viewed from the stacking direction, surrounding each of the plurality of light-emitting regions.

[0125] (5) The light-emitting device according to (4), wherein the plurality of light-emitting regions are arranged in two dimensions on the first or fourth surface, the plurality of first electrode portions are provided corresponding to each of the plurality of light-emitting regions, and the plurality of adjacent first electrode portions are in direct contact with each other.

[0126] (6) The light-emitting device according to any one of (1), (3) to (5), wherein the first electrode further includes an outer frame portion that surrounds the outer circumference of the outermost of the plurality of first electrode portions when viewed from the stacking direction.

[0127] (7) The light-emitting device according to any one of (1) to (6), further comprising: a first semiconductor layer of a first conductivity type provided between the second surface of the first reflecting portion and the fifth surface of the active layer; a second semiconductor layer of a second conductivity type provided between the sixth surface of the active layer and the third surface of the second reflecting portion; a third semiconductor layer of a first conductivity type provided between the second semiconductor layer and the third surface of the second reflecting portion; and a plurality of junctions provided between the second semiconductor layer and the third semiconductor layer corresponding to the plurality of light-emitting regions, which are formed by contacting a fourth semiconductor layer of a second conductivity type having a higher impurity concentration than the second semiconductor layer and a fifth semiconductor layer of a first conductivity type having a higher impurity concentration than the third semiconductor layer.

[0128] (8) The light-emitting device according to (7), further comprising a second electrode electrically connected to the first semiconductor layer.

[0129] (9) The light-emitting device according to (7) or (8), wherein the junction is a constriction layer that selectively passes current to the active layer and concentrates light into the light-emitting region.

[0130] (10) The light-emitting apparatus according to (7) or (8), wherein, when viewed from the stacking direction, the regions other than the light-emitting region of the active layer, the junction, and the second semiconductor layer are impurity regions with higher resistance than the light-emitting region.

[0131] (11) The light-emitting device according to any one of (7) to (10), further comprising a transparent electrode provided between the first electrode and the third semiconductor layer.

[0132] (12) The light-emitting device according to any one of (1) to (11), wherein the light from the active layer is emitted from the fourth surface side of the second reflector.

[0133] (13) The light-emitting device according to any one of (1) to (11), wherein the light from the active layer is emitted from the first surface side of the first reflector.

[0134] (14) The light-emitting device according to any one of (1) to (13), wherein the first reflecting portion is constructed by stacking a plurality of semiconductor layers or a plurality of dielectric layers having different refractive indices, and the second reflecting portion is constructed by stacking a plurality of dielectric layers having different refractive indices.

[0135] (15) The light-emitting device according to any one of (1) to (14), wherein the first reflecting portion is provided on a substrate containing a group III-V element or a group IV element.

[0136] (16) A light-emitting device comprising: a first reflecting portion having a first surface and a second surface opposite to the first surface; a second reflecting portion provided on the second surface side of the first reflecting portion and having a third surface facing the first reflecting portion and a fourth surface opposite to the third surface; an active layer provided between the second surface of the first reflecting portion and the third surface of the second reflecting portion and having a fifth surface facing the second surface and a sixth surface facing the third surface, which emits light when power is applied; and a first electrode provided on the sixth surface side and electrically connected to the sixth surface of the active layer, the first electrode including a first electrode portion provided around a light-emitting region on the first surface of the first reflecting portion or on the fourth surface of the second reflecting portion when viewed from the stacking direction of the first, second reflecting portions and the active layer, and a wiring portion drawn out from the first electrode portion in the direction of the crystal orientation

[011] of the active layer.

[0137] (17) The light-emitting device according to (16), wherein the first electrode covers substantially the entire sixth surface other than the plurality of light-emitting regions when viewed from the stacking direction.

[0138] (18) The light-emitting device according to (16) or (17), further comprising: a first semiconductor layer of a first conductivity type provided between the second surface of the first reflecting portion and the fifth surface of the active layer; a second semiconductor layer of a second conductivity type provided between the sixth surface of the active layer and the third surface of the second reflecting portion; a third semiconductor layer of a first conductivity type provided between the second semiconductor layer and the third surface of the second reflecting portion; and a junction provided between the second semiconductor layer and the third semiconductor layer corresponding to the light emission region, which is formed by contacting a fourth semiconductor layer of a second conductivity type having a higher impurity concentration than the second semiconductor layer and a fifth semiconductor layer of a first conductivity type having a higher impurity concentration than the third semiconductor layer.

[0139] Furthermore, this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the gist of this disclosure. Also, the effects described herein are merely illustrative and not limiting, and other effects may exist.

[0140] 1. Light-emitting device 10. Substrate 20. First reflector 30. First semiconductor layer 40. Active layer 50. Second semiconductor layer 60. Third semiconductor layer 70. Fourth semiconductor layer 80. Fifth semiconductor layer 90. Second reflector 100. First electrode 110. Second electrode

Claims

1. A light-emitting device comprising: a first reflective portion having a first surface and a second surface opposite to the first surface; a second reflective portion provided on the second surface side of the first reflective portion and having a third surface facing the first reflective portion and a fourth surface opposite to the third surface; an active layer provided between the second surface of the first reflective portion and the third surface of the second reflective portion and having a fifth surface facing the second surface and a sixth surface facing the third surface, which emits light when power is applied; and a first electrode provided on the sixth surface side and electrically connected to the sixth surface of the active layer, the first electrode including a plurality of interconnected first electrode portions provided around a plurality of light-emitting regions on the first surface of the first reflective portion or on the fourth surface of the second reflective portion when viewed from the stacking direction of the first, second reflective portions and the active layer.

2. The light-emitting device according to claim 1, wherein the first electrode covers substantially the entire sixth surface other than the plurality of light-emitting regions when viewed from the stacking direction.

3. The light-emitting device according to claim 1, wherein the first electrode further comprises a plurality of second electrode portions connecting adjacent first electrode portions in a plane intersecting the stacking direction in a first direction, and a plurality of third electrode portions connecting adjacent first electrode portions in a fourth plane intersecting the first direction in a second direction.

4. The light-emitting device according to claim 1, wherein the plurality of first electrode portions are annular in shape when viewed from the stacking direction, surrounding each of the plurality of light-emitting regions.

5. The light-emitting device according to claim 4, wherein the plurality of light-emitting regions are arranged two-dimensionally on the first or fourth surface, the plurality of first electrode portions are provided corresponding to each of the plurality of light-emitting regions, and the plurality of adjacent first electrode portions are in direct contact with each other.

6. The light-emitting device according to claim 1, wherein the first electrode further includes an outer frame portion that surrounds the outer circumference of the outermost of the plurality of first electrode portions when viewed from the stacking direction.

7. The light-emitting device according to claim 1, further comprising: a first semiconductor layer of a first conductivity type provided between the second surface of the first reflecting portion and the fifth surface of the active layer; a second semiconductor layer of a second conductivity type provided between the sixth surface of the active layer and the third surface of the second reflecting portion; a third semiconductor layer of a first conductivity type provided between the second semiconductor layer and the third surface of the second reflecting portion; and a plurality of junctions provided between the second semiconductor layer and the third semiconductor layer corresponding to the plurality of light-emitting regions, which are formed by contacting a fourth semiconductor layer of a second conductivity type having a higher impurity concentration than the second semiconductor layer and a fifth semiconductor layer of a first conductivity type having a higher impurity concentration than the third semiconductor layer.

8. The light-emitting device according to claim 7, further comprising a second electrode electrically connected to the first semiconductor layer.

9. The light-emitting device according to claim 7, wherein the junction is a constriction layer that selectively passes current to the active layer and concentrates light into the light-emitting region.

10. The light-emitting device according to claim 7, wherein, when viewed from the stacking direction, the regions of the active layer, the junction, and the second semiconductor layer other than the light-emitting region are impurity regions with higher resistance than the light-emitting region.

11. The light-emitting device according to claim 7, further comprising a transparent electrode provided between the first electrode and the third semiconductor layer.

12. The light-emitting device according to claim 1, wherein light from the active layer is emitted from the fourth surface side of the second reflecting portion.

13. The light-emitting device according to claim 1, wherein the light from the active layer is emitted from the first surface side of the first reflecting portion.

14. The light-emitting device according to claim 1, wherein the first reflective portion is constructed by stacking a plurality of semiconductor layers or a plurality of dielectric layers having different refractive indices, and the second reflective portion is constructed by stacking a plurality of dielectric layers having different refractive indices.

15. The light-emitting device according to claim 1, wherein the first reflective portion is provided on a substrate containing a group III-V element or a group IV element.

16. A light-emitting device comprising: a first reflective portion having a first surface and a second surface opposite to the first surface; a second reflective portion provided on the second surface side of the first reflective portion and having a third surface facing the first reflective portion and a fourth surface opposite to the third surface; an active layer provided between the second surface of the first reflective portion and the third surface of the second reflective portion and having a fifth surface facing the second surface and a sixth surface facing the third surface, which emits light when power is applied; and a first electrode provided on the sixth surface side and electrically connected to the sixth surface of the active layer, the first electrode including a first electrode portion provided around a light-emitting region on the first surface of the first reflective portion or on the fourth surface of the second reflective portion when viewed from the stacking direction of the first, second reflective portions and the active layer, and a wiring portion drawn out from the first electrode portion in the direction of the crystal orientation [011] of the active layer.

17. The light-emitting device according to claim 16, wherein the first electrode covers substantially the entire sixth surface other than the plurality of light-emitting regions when viewed from the stacking direction.

18. The light-emitting device according to claim 16, further comprising: a first semiconductor layer of a first conductivity type provided between the second surface of the first reflecting portion and the fifth surface of the active layer; a second semiconductor layer of a second conductivity type provided between the sixth surface of the active layer and the third surface of the second reflecting portion; a third semiconductor layer of a first conductivity type provided between the second semiconductor layer and the third surface of the second reflecting portion; and a junction provided between the second semiconductor layer and the third semiconductor layer corresponding to the light emission region, formed by contacting a fourth semiconductor layer of a second conductivity type having a higher impurity concentration than the second semiconductor layer and a fifth semiconductor layer of a first conductivity type having a higher impurity concentration than the third semiconductor layer.

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