Light-emitting device and method for manufacturing same

Abstract

[Problem] To provide a light-emitting device having high heat dissipation while achieving a decrease in the length of a resonator, and a method for manufacturing the same. [Solution] A light-emitting device according to the present technology includes: a first reflecting mirror; a second reflecting mirror; a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type which are provided between the first reflecting mirror and the second reflecting mirror; and an active layer which is provided between the first semiconductor layer and the second semiconductor layer, and emits light when electric power is applied to the first and second semiconductor layers. The first semiconductor layer includes a first material layer of the first conductivity type, and a second material layer of the first conductivity type which is provided within the first material layer and has a smaller band gap than the first material layer.

Description

Light emitting device and method for manufacturing the same

[0001] The present disclosure relates to a light emitting device and a method for manufacturing the same.

[0002] In order to dissipate heat during oscillation in a vertical cavity surface emitting laser (VCSEL) using InP, it has been considered to increase the length of the cavity or to attach a GaAs-based distributed Bragg reflector (DBR) with high thermal conductivity.

[0003] Japanese Patent Application Laid-Open No. 2018-064061

[0004] However, increasing the length of the resonator can cause diffraction loss or lead to variations in the thickness of the material layers of the resonator, which can reduce yields. Also, when a GaAs-based DBR is bonded, when a current flows through the junction interface between the DBR and other material layers of the resonator, the interaction between light and current within the resonator generates crystal defects, which poses a reliability problem.

[0005] Therefore, the present disclosure provides a light emitting device that has a short cavity length and high heat dissipation properties, and a method for manufacturing the same.

[0006] A light emitting device according to one aspect of the present disclosure includes a first reflector, a second reflector, a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type provided between the first reflector and the second reflector, an active layer provided between the first semiconductor layer and the second semiconductor layer and emitting light when power is applied to the first and second semiconductor layers, and the first semiconductor layer includes a first material layer of the first conductivity type and a second material layer of the first conductivity type provided within the first material layer and having a smaller band gap than the first material layer.

[0007] The first material layer is an InP layer, and the second material layer is a material layer made of InGaAs containing a Group 3 element or a Group 5 element.

[0008] The second material layer is a material layer containing any one of InGaAsP, InGaAs, and AlGaInAs.

[0009] The second material layer is disposed at a position shifted by λ / 4 (λ is the wavelength of the laser light) from the maximum value of the intensity of the laser light resonating between the first reflecting mirror and the second reflecting mirror.

[0010] A plurality of layers of a second material are disposed within the first layer of material.

[0011] The first reflector is made of a semiconductor material, and the second reflector is made of a dielectric material.

[0012] The light emitting device further includes a third semiconductor layer provided on the second semiconductor layer between the second reflector and the second semiconductor layer, the third semiconductor layer having a higher concentration of impurities of the second conductivity type than the second semiconductor layer, and a fourth semiconductor layer of the first conductivity type provided on the third semiconductor layer and forming a tunnel junction with the third semiconductor layer.

[0013] The first reflecting mirror is provided on a GaAs substrate or a Ge substrate, and is made of a laminated film of GaAs and AlGaAs or AlAs.

[0014] The first reflecting mirror is provided on a silicon substrate, and is made of a laminated film of single crystal silicon, amorphous silicon, and silicon oxide film.

[0015] The second semiconductor layer includes a conductive region sandwiched between the first reflector and the second reflector, and an impurity implant region provided around the conductive region.

[0016] The light emitting device further includes a first electrode electrically connected to the first semiconductor layer, a second electrode electrically connected to the second semiconductor layer provided around the second reflector, and a transparent electrode provided between the second reflector and the second semiconductor layer and electrically connected to the second electrode.

[0017] The third semiconductor layer includes a semiconductor region sandwiched between the first reflecting mirror and the second reflecting mirror, and an oxide region provided around the semiconductor region.

[0018] The third semiconductor layer includes a semiconductor region sandwiched between the first reflecting mirror and the second reflecting mirror, and an air gap region provided around the semiconductor region.

[0019] The active layer includes quantum dots.

[0020] A second electrode is coated on the second reflector.

[0021] The first semiconductor layer is provided between the second reflector and the active layer, and the second semiconductor layer is provided between the first reflector and the active layer. The light emitting device further includes a third semiconductor layer provided between the first reflector and the second semiconductor layer and having a higher p-type impurity concentration than the second semiconductor layer, and an n-type fourth semiconductor layer provided between the first reflector and the third semiconductor layer and forming a tunnel junction with the third semiconductor layer.

[0022] A plurality of laminated structures each made up of first to fourth semiconductor layers and an active layer are laminated between the first reflector and the second reflector.

[0023] A plurality of second reflectors are provided for one first reflector, and a plurality of third semiconductor layers and a plurality of fourth semiconductor layers are provided corresponding to each of the plurality of second reflectors and the second semiconductor layer.

[0024] The first reflector is disposed on a silicon substrate having an image sensor.

[0025] A method for manufacturing a light emitting device according to one aspect of the present disclosure includes forming a first semiconductor layer above a first substrate, the first semiconductor layer including a first material layer of a first conductivity type semiconductor and a second material layer of the first conductivity type semiconductor sandwiched within the first material layer and having a smaller band gap than the first material layer; forming an active layer on the first semiconductor layer that emits light when power is applied; forming a second semiconductor layer of a second conductivity type on the active layer; forming a third semiconductor layer of the second conductivity type on the second semiconductor layer, the third semiconductor layer having an impurity concentration higher than that of the second semiconductor layer; forming a fourth semiconductor layer of a first conductivity type on the third semiconductor layer to form a tunnel junction with the third semiconductor layer; forming a first electrode on a portion of a surface of the first semiconductor layer that is electrically connected to the first semiconductor layer and a second electrode that is electrically connected to the fourth semiconductor layer; and forming a second reflecting mirror above the third and fourth semiconductor layers.

[0026] The method for manufacturing a light emitting device further includes forming a first reflector on the second substrate, and bonding the first substrate and the second substrate together so that the first reflector is bonded to the first semiconductor layer.

[0027] 1 is a cross-sectional view showing an example of the configuration of a light-emitting device according to the first embodiment; a plan view showing an example of the configuration of a light-emitting device according to the first embodiment; a graph showing the relationship between the position of a resonator in the light-emitting device and the intensity waveform of laser light; a cross-sectional view showing an example of a method for manufacturing a light-emitting device according to the first embodiment; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 4; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 5; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 6; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 7; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 8; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 9; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 10; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 11; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 12; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 13; a cross-sectional view showing another example of the method for manufacturing a light-emitting device according to the first embodiment; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 15; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 16; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 17; a cross-sectional view showing an example of a method for manufacturing a light-emitting device subsequent to FIG. 30 is a cross-sectional view showing an example of a configuration of a light-emitting device according to a third embodiment. 31 is a cross-sectional view showing an example of a manufacturing method of a light-emitting device according to the third embodiment. 32 is a cross-sectional view showing an example of a configuration of a light-emitting device according to a fourth embodiment. 33 is a cross-sectional view showing an example of a configuration of a light-emitting device according to a fifth embodiment. 34 is a cross-sectional view showing an example of a manufacturing method of a light-emitting device according to the fifth embodiment. 35 is a cross-sectional view showing an example of a configuration of a light-emitting device according to a sixth embodiment. 36 is a cross-sectional view showing an example of a manufacturing method of a light-emitting device according to the sixth embodiment. 37 is a cross-sectional view showing an example of a configuration of a light-emitting device according to a seventh embodiment. 38 is a cross-sectional view showing an example of a configuration of a light-emitting device according to an eighth embodiment. 39 is a cross-sectional view showing an example of a configuration of a light-emitting device according to a ninth embodiment. 39 is a cross-sectional view showing an example of a manufacturing method of a light-emitting device according to the ninth embodiment. 30 is a cross-sectional view showing an example of a manufacturing method of a light-emitting device following FIG. 31. 32 is a cross-sectional view showing an example of a manufacturing method of a light-emitting device following FIG. 33. 34 is a cross-sectional view showing an example of a manufacturing method of a light-emitting device according to a tenth embodiment. 35 is a cross-sectional view showing an example of a configuration of a light-emitting device according to an eleventh embodiment. 36 is a plan view showing an example of a configuration of a light-emitting device according to an eleventh embodiment. 37 is a cross-sectional view showing an example of a configuration of a light-emitting device according to a twelfth embodiment.42. A cross-sectional view showing an example of a method for manufacturing a light emitting device according to a twelfth embodiment. A cross-sectional view showing an example of a method for manufacturing a light emitting device, following FIG. 39. A cross-sectional view showing an example of a configuration of a light emitting device according to a thirteenth embodiment. A cross-sectional view showing an example of a method for manufacturing a light emitting device according to the thirteenth embodiment. A cross-sectional view showing an example of a method for manufacturing a light emitting device, following FIG. 42. 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. A diagram showing an example of an installation position of an imaging unit 12031.

[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] First Embodiment FIG. 1 is a cross-sectional view showing an example of the configuration of a light-emitting device according to a first embodiment. 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 second electrode 110, and a protective film 120. The light-emitting device 1 is a semiconductor light-emitting device such as a VCSEL. The light-emitting device 1 emits light by applying power between the first electrode 100 and the second electrode 110 to inject electrons and holes from the first and second semiconductor layers 30 and 50 into the active layer 40, causing the electrons and holes to recombine in the active layer 40. Light is reflected and resonates between the first reflecting mirror 20 and the second reflecting mirror 90, and is emitted as laser light from the second reflecting mirror 90 side.

[0030] The substrate 10 may be a semiconductor substrate such as a GaAs substrate or a Ge substrate.

[0031] The first reflecting mirror 20 is a so-called Distributed Bragg Reflector (DBR), and is configured by alternately stacking multiple materials with different refractive indices. For example, the first reflecting mirror 20 has a layered structure of multiple epitaxially grown semiconductor materials (e.g., a layered structure of GaAs and AlGaAs or AlAs).

[0032] The first semiconductor layer 30 is located between the first reflecting mirror 20 and the second reflecting mirror 90 and is a cladding layer provided on the first reflecting mirror 20. The first semiconductor layer 30 has a stacked structure of an n-type first material layer 31 and an n-type second material layer 32. Here, the second material layer 32 is sandwiched between multiple first material layers 31 and is made of a material with a smaller band gap than the first material layer 31. The first material layer 31 is made of, for example, n-type InP as an n-type semiconductor. The second material layer 32 is made of, for example, n-type InGaAsP as an n-type semiconductor with a smaller band gap than n-type InP. The second material layer 32 may be made of n-type InGaAs, n-type AlGaInAs, or the like, in addition to n-type InGaAsP. In this way, the second material layer 32 may be a material layer containing a Group 3 element or a Group 5 element in InGaAs. The second material layer 32 may be a material that is lattice-mismatched to the first material layer 31 .

[0033] In this embodiment, the first semiconductor layer 30 is configured by alternately stacking a plurality of first material layers 31 and a plurality of second material layers 32. That is, a plurality of second material layers 32 are embedded in the first material layer 31. However, one second material layer 32 may be embedded in the first material layer 31. Furthermore, three or more second material layers 32 may be embedded in the first material layer 31.

[0034] The active layer 40 is provided between the first semiconductor layer 30 and the second semiconductor layer 50. When power is applied to the first and second semiconductor layers 30, 50, electrons from the first semiconductor layer 30 and holes from the second semiconductor layer 50 recombine inside the active layer 40, causing the active layer 40 to emit light. The active layer 40 is made of, for example, AlGaInAs, InGaAs, or InGaAsP, and has a multiple quantum well (MQW) structure.

[0035] The second semiconductor layer 50 is a cladding layer located between the first reflecting mirror 20 and the second reflecting mirror 90 and provided on the active layer 40. The second semiconductor layer 50 is made of p-type InP, which has the opposite conductivity type to the first semiconductor layer 30. Therefore, by applying a negative voltage to the first electrode 100 and a positive 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.

[0036] The third semiconductor layer 60 is provided on the second semiconductor layer 50. The third semiconductor layer 60 is located between the second reflecting mirror 90 and the second semiconductor layer 50. The third semiconductor layer 60 is made of a p-type semiconductor, for example, p-type AlInAs. The p-type impurity concentration of the third semiconductor layer 60 is higher than that of the second semiconductor layer 50.

[0037] The fourth semiconductor layer 70 is provided on the third semiconductor layer 60. The fourth semiconductor layer 70 is also located between the second reflecting mirror 90 and the second semiconductor layer 50. The fourth semiconductor layer 70 is made of an n-type semiconductor, for example, n-type InP. The n-type impurity concentration of the fourth semiconductor layer 70 is higher than that of the fifth semiconductor layer 80.

[0038] The third and fourth semiconductor layers 60 and 70 form a buried tunnel junction (BTJ) with a high impurity concentration. Hereinafter, the third and fourth semiconductor layers 60 and 70 are also referred to as BTJs 60 and 70. The current between the electrodes 100 and 110 flows concentratedly in the BTJs 60 and 70 and is constricted. This allows the BTJs 60 and 70 to promote light emission in the active layer 40 directly below them.

[0039] When viewed from the stacking direction (Z direction), the BTJs 60 and 70 overlap with the second reflecting mirror 90. The stacking direction (Z direction) is also the direction in which current flows through the BTJs 60 and 70 and the direction in which light resonates between the first reflecting mirror 20 and the second reflecting mirror 90.

[0040] The fifth semiconductor layer 80 is provided on the second semiconductor layer 50 and the BTJs 60 and 70. The fifth semiconductor layer 80 covers the BTJs 60 and 70. The fifth semiconductor layer 80 is made of an n-type semiconductor, for example, n-type InP. The n-type impurity concentration of the fifth semiconductor layer 80 is lower than that of the fourth semiconductor layer 70. Therefore, no current flows at the junction between the fifth semiconductor layer 80 and the second semiconductor layer 50.

[0041] The second reflecting mirror 90 is provided above (in the Z direction) the BTJs 60 and 70. The second reflecting mirror 90 is a DBR, and is configured by alternately laminating a plurality of materials having different refractive indices. For example, the second reflecting mirror 90 has a laminated structure of a plurality of dielectric materials (e.g., SiO ２ and TiO ２ The first reflecting mirror 20 has a laminated structure with a semiconductor DBR made of a semiconductor material, and the second reflecting mirror 90 is a dielectric DBR made of a dielectric material. In this embodiment, the laser light generated in the resonator between the first reflecting mirror 20 and the second reflecting mirror 90 is emitted from the second reflecting mirror 90.

[0042] The first electrode 100 is provided on the first semiconductor layer 30 and is electrically connected to the first semiconductor layer 30. The first electrode 100 is made of a conductive metal such as Ti, Pt, or Au, a laminated film of AuGe / Ni / Au, or a laminated film of PdGe / Ni / Au. The first electrode 100 is provided around the active layer 40 via a protective film 120. The first electrode 100 is electrically insulated from components other than the first semiconductor layer 30 by the protective film 120.

[0043] The second electrode 110 is provided on the fifth semiconductor layer 80 and is electrically connected to the fourth semiconductor layer 70 via the fifth semiconductor layer 80. The second electrode 110 is also made of a conductive metal such as Ti, Pt, or Au, an AuGe / Ni / Au stacked film, or a PdGe / Ni / Au stacked film. The second electrode 110 may be made of the same material as the first electrode 100. The second electrode 110 is provided around the second reflecting mirror 90. The second electrode 110 may be in contact with the second reflecting mirror 90. The second electrode 110 is electrically insulated from components other than the fifth semiconductor layer 80 by a protective film 120.

[0044] When viewed from the Z direction, the first and second electrodes 100, 110 do not overlap the second reflecting mirror 90 and the BTJs 60, 70. Therefore, the first and second electrodes 100, 110 do not block the laser light emitted from the second reflecting mirror 90.

[0045] The protective film 120 covers the side surfaces of the active layer 40, the second semiconductor layer 50, and the fifth semiconductor layer 80, and also covers a portion of the upper surface of the fifth semiconductor layer 80. This allows the protective film 120 to protect the structure of the active layer 40, the second semiconductor layer 50, and the fifth semiconductor layer 80, and to prevent the first and second electrodes 100, 110 from short-circuiting to an unintended configuration. The protective film 120 is made of, for example, SiO ２ The insulating material is SiN or the like.

[0046] 2 is a plan view showing an example of the configuration of the light-emitting device according to the first embodiment. When viewed from the Z direction, the outer edges of the active layer 40, the second semiconductor layer 50, the fifth semiconductor layer 80, the second reflecting mirror 90, and the BTJs 60 and 70 may be substantially circular, although there is no particular limitation thereto. The second reflecting mirror 90 is located inside the active layer 40, the second semiconductor layer 50, and the fifth semiconductor layer 80. The BTJs 60 and 70 are located inside the second reflecting mirror 90. In the first embodiment, one second reflecting mirror 90 and one BTJ 60 and 70 are provided for one light-emitting device 1 or one active layer 40.

[0047] The second electrode 110 is provided in a substantially circular ring shape around the second reflecting mirror 90. The shape of the first electrode 100 is not particularly limited. The first electrode 100 may be provided in any shape as long as it is electrically connected to the first semiconductor layer 30.

[0048] FIG. 3 is a graph showing the relationship between the position of the resonator of the light-emitting device and the intensity waveform of the laser light. The horizontal axis of this graph represents the depth (-Z direction) of the resonator from the first reflecting mirror 20 to the active layer 40. The bonding surface between the first reflecting mirror 20 and the first semiconductor layer 30 (i.e., the cladding layer) is indicated by B. In this case, the substrate 10 and the first reflecting mirror 20 are formed on a second semiconductor wafer separate from the first semiconductor wafer, which includes the first semiconductor layer 30 and other components, and the second semiconductor wafer is bonded to the first semiconductor layer 30 by bonding it to the first semiconductor wafer. The vertical axis represents the intensity of the laser light. The resonator of the light-emitting device 1 is the structure between the first reflecting mirror 20 and the second reflecting mirror 90, and is the region where light generated in the active layer 40 reflects and resonates between the first reflecting mirror 20 and the second reflecting mirror 90, generating laser light. L represents the waveform of the laser light.

[0049] Here, the position (depth) and thickness of the second material layer 32 in the Z direction will be described. The second material layer 32 is a semiconductor material having a smaller band gap than the first material layer 31, such as InGaAsP, InGaAs, or AlGaInAs. The second material layer 32 is disposed at a position shifted by λ / 4 (λ is the wavelength of the laser light) from the maximum intensity value (antinode of the standing wave) MAX of the laser light resonating between the first reflecting mirror 20 and the second reflecting mirror 90. In other words, the second material layer 32 is disposed at a position close to the minimum intensity value (node ​​of the standing wave) MIN of the laser light.

[0050] The second material layer 32 (e.g., InGaAsP) absorbs light more easily than the first material layer 31 (e.g., InP). Therefore, if the second material layer 32 is disposed at a position corresponding to the maximum value MAX of the intensity of the laser light, the second material layer 32 will absorb the laser light, resulting in a decrease in optical output.

[0051] In contrast to this, in this embodiment, by arranging the second material layer 32 at a position shifted by λ / 4 from the maximum value MAX of the intensity of the laser light and at a position close to the minimum value MIN, it is possible to suppress absorption of the laser light and suppress a decrease in the optical output.

[0052] Furthermore, the film thickness of the second material layer 32 is thinner than the wavelength λ / 2 of the laser light, and more preferably, λ / 4 or less. By making the film thickness of the second material layer 32 thinner than the wavelength λ / 4 of the laser light, it is possible to prevent the second material layer 32 from overlapping the position of the maximum value MAX of the laser light intensity. Furthermore, by making the film thickness of the second material layer 32 further λ / 8 or less, it is possible to separate the second material layer 32 from the position of the maximum value MAX and appropriately position it at the position of the minimum value MIN. For example, when the wavelength λ of the laser light is 1300 nm to 1550 nm, the film thickness of the second material layer 32 is less than 100 nm, and more preferably, 50 nm or less.

[0053] On the other hand, materials with a small band gap tend to confine carriers and increase carrier mobility, which is expected to reduce resistance. Therefore, the second material layer 32 has lower electrical resistance than the first material layer 31 (e.g., InP) and can function as a path (current diffusion layer) through which current flows between the first electrode 100 and the second electrode 110. In this case, if the second material layer 32 is too thin, the resistance of the first semiconductor layer 30 increases, so the second material layer 32 needs to be thick to a certain extent. For example, regardless of the thickness of the first semiconductor layer 30, the thickness of each of the two second material layers 32 is 10 nm or more, more preferably 20 nm or more. That is, considering the loss of laser light and the resistance value of the current, the thickness of the second material layer 32 is 10 nm to 100 nm, more preferably 20 nm to 50 nm. In this case, the n-type impurity concentration (carrier concentration) of the second material layer 32 is 1×10 １８ ~5 x 10 １９ / cm ３ It is preferable that:

[0054] In the first semiconductor layer 30, most of the current flows through the multiple second material layers 32. Therefore, the current does not concentrate at the junction interface between the first reflecting mirror 20 and the first semiconductor layer 30, and the proliferation of defects at the junction interface can be suppressed.

[0055] The light-emitting device 1 according to this embodiment is configured by stacking a first material layer 31 (e.g., InP) and a second material layer 32 (e.g., nGaAsP, InGaAs, or AlGaInAs) having a smaller bandgap than the first material layer 31 on a first semiconductor layer 30 serving as a cladding layer. The provision of the second material layer 32 reduces the resistance of the first semiconductor layer 30. Alternatively, the thickness of the first semiconductor layer 30 can be reduced compared to when the first semiconductor layer 30 is configured solely from the first material layer 31, thereby shortening the length of the resonator in the Z direction. This reduces the diffraction loss of laser light and improves efficiency. Furthermore, the shorter length of the resonator in the Z direction brings the first reflector 20 (a DBR made of GaAs or AlGaAs, which has good heat dissipation properties) and the substrate 10 (a GaAs or Ge substrate, which has good heat dissipation properties) closer to the active layer 40 and the BTJs 60 and 70, improving heat dissipation. This allows the light emitting device 1 to function as a VCSEL that generates laser light in the eye-safe band, which is capable of high output and high temperature operation. Furthermore, by reducing the thickness of the first semiconductor layer 30, the variation in film thickness is reduced, improving in-plane uniformity and improving yield.

[0056] Next, a method for manufacturing the light emitting device 1 according to the first embodiment will be described.

[0057] 4 to 14 are cross-sectional views showing an example of a method for manufacturing the light emitting device 1 according to the first embodiment.

[0058] An InGaAs film 21 is deposited on an n-type InP substrate 11 serving as a first substrate shown in FIG.

[0059] Next, the materials for the first semiconductor layer 30 (a stacked structure of a first material layer 31 and a second material layer 32), the active layer 40, the second semiconductor layer 50, and the BTJs 60 and 70 are epitaxially grown in this order on the InGaAs film 21.

[0060] The material of the first material layer 31 is, for example, n-type InP. The second material layer 32 is a semiconductor material having a smaller band gap than the first material layer 31, such as InGaAsP, InGaAs, or AlGaInAs. The thickness of the second material layer 32 is, for example, 10 nm to 100 nm, and more preferably 20 nm to 50 nm. By alternately stacking the first material layers 31 and the second material layers 32, the second material layers 32 are sandwiched and embedded within the first material layers 31. This forms a first semiconductor layer having the second material layers 32 embedded within the first material layers 31.

[0061] The material of the active layer 40 is, for example, AlGaInAs or InGaAsP. A second semiconductor layer 50 is formed on the active layer 40. The material of the second semiconductor layer 50 is, for example, p-type InP. A third semiconductor layer 60 is formed on the second semiconductor layer 50. The material of the third semiconductor layer 60 is, for example, p-type AlInAs. A fourth semiconductor layer 70 is formed on the third semiconductor layer 60. The material of the fourth semiconductor layer 70 is, for example, n-type InP.

[0062] Next, the material of the BTJs 60 and 70 is processed using lithography and etching techniques. At this time, the material of the fourth semiconductor layer 70 is HCl, H ３ P.O. ４ , C.H. ３ COOH, H ２ The third semiconductor layer 60 is processed by wet etching using a chlorine-based mixed solution of H ３ P.O. ４ , H ２ O ２ , H ２ The etching is performed by wet etching using a chlorine-based mixed solution such as O. As a result, BTJs 60 and 70 are formed in the region where the resonator is formed, as shown in FIG.

[0063] 6, a material for a fifth semiconductor layer 80 is deposited on the second semiconductor layer 50 and the BTJs 60 and 70 so as to cover the BTJs 60 and 70. The material for the fifth semiconductor layer 80 is formed by epitaxially growing n-type InP, for example.

[0064] Next, a hard mask (e.g., a silicon oxide film) is formed in the resonator pattern using lithography and etching techniques. Furthermore, using the hard mask (not shown) as a mask, the materials of the fifth semiconductor layer 80, the second semiconductor layer 50, and the active layer 40 are processed using a reactive ion etching (RIE) method or the like. This results in the structure shown in FIG. 7 .

[0065] 8 , a material for the protective film 120 is deposited by chemical vapor deposition (CVD) so as to cover the upper surfaces of the fifth semiconductor layer 80 and the first semiconductor layer 30, and the side surfaces of the fifth semiconductor layer 80, the second semiconductor layer 50, and the active layer 40. The material for the protective film 120 is, for example, a silicon nitride film.

[0066] Next, the material of the protective film 120 is processed using lithography and etching techniques, thereby opening regions where the first electrode 100, the second electrode 110, and the second reflector 90 are to be formed, as shown in FIG.

[0067] Next, the material of the first and second electrodes 100, 110 is deposited on the first semiconductor layer 30, the fifth semiconductor layer 80, and the protective film 120. The material of the first and second electrodes 100, 110 is, for example, a conductive metal such as Ti, Pt, or Au.

[0068] Next, the material of the first and second electrodes 100, 110 is processed using lithography and etching techniques. As a result, as shown in Fig. 10, the first electrode 100 is formed on the first semiconductor layer 30, and the second electrode 110 is formed on the fifth semiconductor layer 80. At this time, the material of the second electrode 110 in the region where the second reflector 90 is to be formed is removed.

[0069] 11, a second reflecting mirror 90 is formed on the fifth semiconductor layer 80. The second reflecting mirror 90 is made of, for example, SiO ２ and TiO ２ It is a laminated film of

[0070] Next, as shown in FIG. 12, wax 121 is applied onto the second reflecting mirror 90 , the first and second electrodes 100 , 110 , etc., and a support substrate 122 is adhered onto the second reflecting mirror 90 .

[0071] Next, the InP substrate 11 is ground by a BG (Back Grinding) method or the like using the InGaAs layer 21 as an etching stopper. ３ P.O. ４ The InGaAs layer 21 is etched using a mixed solution of H ３ P.O. ４ , H ２ O ２ , H ２ 13, the InP substrate 11 and the InGaAs layer 21 are removed from the first semiconductor layer 30.

[0072] Next, a first reflecting mirror 20 is formed on a GaAs substrate 10 as a second substrate, separate from the InP substrate 11. The first reflecting mirror 20 may have, for example, a layered structure of GaAs and AlGaAs or AlAs. Next, as shown in FIG. 14 , the GaAs substrate 10 is wafer-bonded to the first semiconductor layer 30 so as to bond the first reflecting mirror 20 on the GaAs substrate 10 to the first semiconductor layer 30.

[0073] Next, the support substrate 122 and the wax 121 are removed by thermal melting or organic cleaning, etc. This completes the light emitting device 1 shown in FIG.

[0074] 15 to 18 are cross-sectional views showing another example of the method for manufacturing the light emitting device according to the first embodiment.

[0075] After the steps described with reference to FIGS. 4 to 6 are performed, wax 121 is applied onto the fifth semiconductor layer 80, and a support substrate 122 is adhered onto the fifth semiconductor layer 80, as shown in FIG.

[0076] Next, as described with reference to FIG. 13, the InP substrate 11 and the InGaAs layer 21 are removed (see FIG. 16).

[0077] Next, as described with reference to FIG. 14, the first reflecting mirror 20 and the first semiconductor layer 30 on the GaAs substrate 10 are wafer-bonded (see FIG. 17).

[0078] Next, the wax 121 and the support substrate 122 are removed, resulting in the structure shown in FIG.

[0079] Thereafter, the light emitting device 1 shown in FIG. 1 is completed through the steps described with reference to FIGS.

[0080] In this way, the GaAs substrate 10 and the first reflector 20 may be bonded to the first semiconductor layer 30 side after the second reflector 90 and the electrodes 100, 110 are formed, or may be bonded to the first semiconductor layer 30 side before the second reflector 90 and the electrodes 100, 110 are formed.

[0081] 19 is a cross-sectional view showing a configuration example of a light emitting device according to Embodiment 2. In the second embodiment, instead of the GaAs substrate 10 and the GaAs-based first reflecting mirror 20, a silicon substrate 12 and a silicon-based first reflecting mirror 22 are bonded to the first semiconductor layer 30 side.

[0082] The first reflecting mirror 22 is provided on the silicon substrate 12. The first reflecting mirror 22 is composed of a silicon single crystal layer 22a and a laminated film (DBR) 22b of amorphous silicon and a silicon oxide film. The laminated film 22b is provided on the silicon substrate 12. The silicon single crystal layer 22a is provided on the laminated film 22b.

[0083] The silicon substrate 12 and the silicon-based first reflecting mirror 22 have better heat dissipation properties than the GaAs substrate 10 and the GaAs-based first reflecting mirror 20. Therefore, the light-emitting device 1 according to the second embodiment is capable of higher output and higher temperature operation. The silicon substrate 12 has few defects and allows for a large wafer size, thereby reducing manufacturing costs. Furthermore, by using the silicon substrate 12 as in the twelfth embodiment, the light-emitting device 1 can be easily modularized with optical photonics.

[0084] Other configurations of the second embodiment may be similar to those of the first embodiment, and therefore the second embodiment can achieve the same effects as the first embodiment.

[0085] The material of the substrate 12 is not limited to single crystal silicon, but may be any material that has low light absorption and excellent heat dissipation properties, such as SiC or single crystal diamond.

[0086] Third Embodiment FIG. 20 is a cross-sectional view showing a configuration example of a light-emitting device according to a third embodiment. In the third embodiment, the second semiconductor layer 50, the BTJs 60 and 70, and the fifth semiconductor layer 80 each include a conductive region 130 sandwiched between the first reflecting mirror 20 and the second reflecting mirror 90, and an impurity implant region 131 surrounding the conductive region 130. The conductive region 130 has a stacked structure of the second semiconductor layer 50, the BTJs 60 and 70, and the fifth semiconductor layer 80. The impurity implant region 131 is formed by implanting impurities such as H, He, O, or B into the second semiconductor layer 50, the BTJs 60 and 70, and the fifth semiconductor layer 80 around the conductive region 130. The impurity implant region 131 is in a non-conductive or high-resistance state due to the introduction of crystal defects by the impurity implantation.

[0087] According to the third embodiment, the BTJs 60 and 70 are not processed by etching, but are confined by the impurity implant region 131. The current between the electrodes 100 and 110 flows concentratedly in the conductive region 130 and is confined. This allows the BTJs 60 and 70 to promote light emission in the active layer 40 directly below them.

[0088] Although not shown, a lens mirror may be formed on the back surface side of the substrate 10. This allows the light emitting device 1 to have a light confinement function.

[0089] Other configurations of the third embodiment may be similar to those of the first or second embodiment, and therefore the third embodiment can achieve the same effects as the first or second embodiment.

[0090] Fig. 21 is a cross-sectional view showing an example of a method for manufacturing a light-emitting device according to the third embodiment. The impurity implant region 131 may be formed by selectively implanting impurities around the BTJs 60 and 70 using lithography and implantation techniques after the steps shown in Fig. 4. This results in the structure shown in Fig. 21. At this time, the processing of the BTJs 60 and 70 using lithography and etching techniques described with reference to Fig. 5 is no longer necessary. Thereafter, the structure shown in Fig. 20 is obtained through the steps from Fig. 7 onwards.

[0091] 22 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 transparent electrode 140 is provided between the second reflecting mirror 90 and the fifth semiconductor layer 80. The transparent electrode 140 is provided between the second reflecting mirror 90 and the conductive region 130 of the second semiconductor layer 50, the BTJs 60 and 70, and the fifth semiconductor layer 80. In a plan view seen from the Z direction, the transparent electrode 140 protrudes from the outer edge of the second reflecting mirror 90 and is electrically connected to the second electrode 110. The transparent electrode 140 is preferably made of, for example, ITiO, which has low light absorption.

[0092] Other configurations of the fourth embodiment may be the same as those of any of the first to third embodiments, and therefore the fourth embodiment can achieve the same effects as any of the first to third embodiments.

[0093] 4, the transparent electrode 140 may be formed by depositing a material for the transparent electrode 140 (e.g., ITiO) on the fifth semiconductor layer 80 and processing the material for the transparent electrode 140 using lithography and etching techniques. The transparent electrode 140 may be left directly above the BTJs 60 and 70 in the conductive region. Other steps may be the same as those in any of the manufacturing methods according to the third embodiment.

[0094] 23 is a cross-sectional view showing a configuration example of a light-emitting device according to a fifth embodiment. In the fifth embodiment, the third semiconductor layer 60 of the BTJs 60 and 70 includes a conductive region 61 provided at a position sandwiched between the first reflecting mirror 20 and the second reflecting mirror 90, and an oxide region 62 provided around the conductive region 61. The conductive region 61 is made of the material of the third semiconductor layer 60, for example, p-type AlInAs. The oxide region 62 is formed by oxidizing the material of the third semiconductor layer 60 from the lateral direction (perpendicular to the Z direction). The oxide region 62 is made of, for example, Al ２ O ３ and is in a non-conducting or high resistance state.

[0095] According to the fifth embodiment, the BTJs 60 and 70 are not processed by etching, but the current is more reliably confined by the oxide region 62. As a result, the current between the electrodes 100 and 110 flows and is confined intensively in the conductive region 61. This allows the BTJs 60 and 70 to further promote light emission in the active layer 40 directly below them.

[0096] Other configurations of the fifth embodiment may be the same as those of the first or second embodiment. Therefore, the fifth embodiment can achieve the same effects as those of the first or second embodiment. The fifth embodiment may include a transparent electrode 140. In this case, the fifth embodiment can also achieve the effects of the fourth embodiment.

[0097] 24 is a cross-sectional view showing an example of a method for manufacturing a light-emitting device according to the fifth embodiment. The oxide region 62 undergoes the deposition step of the fifth semiconductor layer 80 shown in FIG. 6 without undergoing the processing of the BTJs 60 and 70 shown in FIG. 5. Then, the third semiconductor layer 60 is selectively oxidized laterally using a steam oxidation method. This results in the structure shown in FIG. 24. Then, the steps from FIG. 7 onward are performed to obtain the structure shown in FIG. 23.

[0098] 25 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 third semiconductor layer 60 of the BTJs 60 and 70 includes a conductive region 61 located between the first reflecting mirror 20 and the second reflecting mirror 90, and an air gap 63 located around the conductive region 61. The conductive region 61 is made of the material of the third semiconductor layer 60, for example, p-type AlInAs. The air gap 63 is formed by etching the material of the third semiconductor layer 60 laterally (perpendicular to the Z direction).

[0099] According to the sixth embodiment, the BTJs 60 and 70 are not processed by etching, but the air gap 63 more reliably confines the current. As a result, the current between the electrodes 100 and 110 flows and is confined in the conductive region 61. This allows the BTJs 60 and 70 to more efficiently promote light emission in the active layer 40 directly below them.

[0100] Other configurations of the sixth embodiment may be the same as those of the first or second embodiment. Therefore, the sixth embodiment can achieve the same effects as those of the first or second embodiment. The sixth embodiment may include a transparent electrode 140. In this case, the sixth embodiment can also achieve the effects of the fourth embodiment.

[0101] 26 is a cross-sectional view showing an example of a method for manufacturing the light emitting device according to the sixth embodiment. The air gap 63 is formed by depositing the fifth semiconductor layer 80 shown in FIG. 6 without undergoing the processing of the BTJs 60 and 70 shown in FIG. 5. ３ P.O. ４ , H ２ O ２ , H ２ The third semiconductor layer 60 is selectively etched laterally using a wet etching method using a mixed solution of O etc. As a result, the structure shown in Fig. 26 is obtained. After that, the steps from Fig. 7 onwards are performed to obtain the structure shown in Fig. 25.

[0102] Seventh Embodiment Fig. 27 is a cross-sectional view showing an example of the configuration of a light-emitting device according to a seventh embodiment. In the seventh embodiment, an active layer 40 includes quantum dots 41 provided on a first semiconductor layer 30 and a burying layer 42 provided on the quantum dots 41. The quantum dots 41 are, for example, InAs epitaxially grown on the first material layer 31. The burying layer 42 is, for example, AlGaInAs. The active layer 40 can emit light even when configured with quantum dots 41 in this manner.

[0103] Other configurations of the seventh embodiment may be the same as those of any of the first to sixth embodiments, and therefore the seventh embodiment can achieve the same effects as any of the first to sixth embodiments.

[0104] 4, the quantum dots 41 are formed by epitaxially growing, for example, InAs on the first material layer 31 when forming the active layer 40. The buried layer 42 is formed by epitaxially growing, for example, AlGaInAs on the quantum dots 41 and the first material layer 31. The other steps may be the same as those in the manufacturing method according to any one of the first to sixth embodiments.

[0105] 28 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, a second electrode 110 covers the second reflecting mirror 90. As a result, the laser light is not emitted from the second reflecting mirror 90, but is emitted in the −Z direction from the back surface of the light-emitting device 1. In other words, the light-emitting device 1 is a back-illuminated VCSEL.

[0106] Other configurations of the eighth embodiment may be similar to those of any of the first to seventh embodiments, and therefore the eighth embodiment can achieve the same effects as any of the first to seventh embodiments.

[0107] Ninth Embodiment FIG. 29 is a cross-sectional view showing a configuration example of a light-emitting device according to a ninth embodiment. In the ninth embodiment, the configuration of the resonator between the first reflecting mirror 20 and the second reflecting mirror 90 is reversed in the Z direction. That is, the first semiconductor layer 30 is provided between the second reflecting mirror 90 and the active layer 40. The second semiconductor layer 50 is provided on the first reflecting mirror 20 side between the first reflecting mirror 20 and the active layer 40. The third semiconductor layer 60 is provided between the first reflecting mirror 20 and the second semiconductor layer 50. The fourth semiconductor layer 70 is provided between the first reflecting mirror 20 and the third semiconductor layer 60. The third and fourth semiconductor layers 60 and 70 constitute BTJs 60 and 70. Furthermore, a fifth semiconductor layer 80 is provided between the BTJs 60 and 70 and the first reflecting mirror 20.

[0108] In the ninth embodiment, similar to the third embodiment, the second semiconductor layer 50, the BTJs 60 and 70, and the fifth semiconductor layer 80 include a conductive region 130 provided at a position sandwiched between the first reflecting mirror 20 and the second reflecting mirror 90, and an impurity implant region 131 provided around the conductive region 130. That is, in the ninth embodiment, current is confined by the impurity implant region 131. The other configurations of the ninth embodiment may be the same as those of the third embodiment. As a result, the ninth embodiment can obtain the same effects as those of the third embodiment.

[0109] According to the ninth embodiment, the active layer 40 and the BTJs 60 and 70 are located close to the substrate 10, which has high heat dissipation properties. Therefore, the light emitting device 1 according to the ninth embodiment has excellent heat dissipation properties.

[0110] The method of current confinement is not limited to this. Therefore, the ninth embodiment can be combined with any of the configurations of the first to eighth embodiments. Therefore, the ninth embodiment can obtain the same effects as any of the first to eighth embodiments.

[0111] 30 to 34 are cross-sectional views showing an example of a method for manufacturing a light-emitting device according to the ninth embodiment. After the steps shown in FIG. 4 are performed, impurities are selectively implanted around the BTJs 60 and 70 using lithography and implantation techniques. This results in the structure shown in FIG. 30. In this case, the processing of the BTJs 60 and 70 using lithography and etching techniques described with reference to FIG. 5 is no longer necessary.

[0112] 31, the structure of FIG. 30 is turned upside down, and the first reflecting mirror 20 on the GaAs substrate 10 is bonded to the fifth semiconductor layer 80. This results in the structure of FIG.

[0113] Next, the InP substrate 11 is ground by a BG method or the like using the InGaAs layer 21 as an etching stop. ３ P.O. ４ The InGaAs layer 21 is etched using a mixed solution of H ３ P.O. ４ , H ２ O ２ and H ２ 33, the InP substrate 11 and the InGaAs layer 21 are removed from the first semiconductor layer 30.

[0114] Next, a hard mask (e.g., a silicon oxide film) is formed in the resonator pattern using lithography and etching techniques. Furthermore, using the hard mask (not shown) as a mask, the materials of the first semiconductor layer 30, the active layer 40, and the second semiconductor layer 50 are processed using RIE or the like. This results in the structure shown in FIG. 34. After that, the steps shown in FIG. 8 and subsequent steps are performed to obtain the structure shown in FIG. 29.

[0115] Tenth Embodiment FIG. 35 is a cross-sectional view showing a configuration example of a light-emitting device according to a tenth embodiment. In the tenth embodiment, a plurality of stacked structures, each including an active layer and a BTJ, are stacked. That is, in the tenth embodiment, a first stacked structure ST1 including an active layer 40, a second semiconductor layer 50, BTJs 60 and 70, and a fifth semiconductor layer 80 is provided on a first semiconductor layer 30. Furthermore, a second stacked structure ST2 including an active layer 45, a second semiconductor layer 55, BTJs 65 and 75, and a fifth semiconductor layer 85 is provided on the first stacked structure ST1. The materials of the active layer 45, the second semiconductor layer 55, the BTJs 65 and 75, and the fifth semiconductor layer 85 may be the same as the materials of the active layer 40, the second semiconductor layer 50, the BTJs 60 and 70, and the fifth semiconductor layer 80, respectively. However, for the purpose of current confinement, the BTJs 65 and 75 close to the second electrode 110 on the positive side are provided only below the second reflecting mirror 90 .

[0116] The substrate 10, the first and second reflecting mirrors 20 and 90, the electrodes 100 and 110, and the protective film 120 are common to the first and second stacked structures ST1 and ST2. The first and second stacked structures ST1 and ST2 are provided between the first reflecting mirror 20 and the second reflecting mirror 90.

[0117] As such, the present technology can also be applied to multi-junction VCSELs. The method of current confinement is not limited to this. Therefore, the tenth embodiment can also be combined with any of the configurations of the first to eighth embodiments. The tenth embodiment can achieve the same effects as any of the first to eighth embodiments. Furthermore, the multi-junction structure of the tenth embodiment may be reversed as in the ninth embodiment. This allows the tenth embodiment to achieve the same effects as the ninth embodiment.

[0118] 36 is a cross-sectional view showing a configuration example of a light emitting device according to an eleventh embodiment. FIG. 37 is a plan view showing a configuration example of a light emitting device according to an eleventh embodiment. In the eleventh embodiment, a plurality of BTJs 60, 70 and a plurality of second reflectors 90 are provided for one first reflector 20. The plurality of BTJs 60, 70 are provided between the second semiconductor layer 50 and each of the plurality of second reflectors 90.

[0119] 37 , the multiple BTJs 60, 70 and the multiple second reflectors 90 are arranged in an array in a plane perpendicular to the Z direction. The multiple BTJs 60, 70 and the multiple second reflectors 90 are arranged corresponding to one another. The stacked structure of the active layer 40, the second semiconductor layer 50, and the fifth semiconductor layer 80 may be, but is not particularly limited to, a substantially rectangular shape in a plan view seen from the Z direction. The multiple second reflectors 90 are located inside the active layer 40, the second semiconductor layer 50, and the fifth semiconductor layer 80. The BTJs 60, 70 are located inside each second reflector 90.

[0120] Other configurations of the eleventh embodiment may be the same as those of the first embodiment, so that the eleventh embodiment can obtain the same effects as those of the first embodiment.

[0121] Furthermore, the eleventh embodiment can be combined with any of the configurations of the second to tenth embodiments, and therefore the eleventh embodiment can achieve the same effects as any of the second to tenth embodiments.

[0122] 12th Embodiment FIG. 38 is a cross-sectional view showing a configuration example of a light-emitting device according to a 12th embodiment. In the 12th embodiment, a light-emitting device 1 is provided on a silicon substrate 12. Other semiconductor elements are also provided on the same silicon substrate 12. The light-emitting device 1 is modularized with the other semiconductor elements. For example, the other semiconductor elements may be a CIS (CMOS (Complementary Metal Oxide Semiconductor) Image Sensor) made up of a photodiode PD and other IC circuits. By configuring the light-emitting device 1 and the CIS as an integrated module, the light-emitting device 1 can configure a TOF (Time Of Flight) device together with the CIS.

[0123] The light emitting device 1 may have the same configuration as any of the first to eleventh embodiments, and therefore the twelfth embodiment can achieve the same effects as any of the first to eleventh embodiments.

[0124] 39 and 40 are cross-sectional views showing an example of a method for manufacturing the light-emitting device according to the twelfth embodiment. For the structure of Fig. 36, wax 121 is applied onto the second reflecting mirror 90, the first and second electrodes 100, 110, etc., and a support substrate 122 is adhered above the second reflecting mirror 90, as shown in Fig. 39. Next, the GaAs substrate 10 is removed from the first reflecting mirror 20.

[0125] Next, the photodiode PD is formed on another silicon substrate 12, and the silicon substrate 12 is wafer-bonded to the first reflecting mirror 20. As a result, the structure shown in FIG.

[0126] 41 is a cross-sectional view showing an example of the configuration of a light-emitting device according to a thirteenth embodiment. The thirteenth embodiment is an embodiment in which the twelfth embodiment is combined with the second embodiment. Therefore, in the thirteenth embodiment, instead of the GaAs substrate 10 and the GaAs-based first reflecting mirror 20 of the twelfth embodiment, a silicon substrate 12 and a silicon-based first reflecting mirror 22 are bonded to the first semiconductor layer 30 side.

[0127] Other configurations of the thirteenth embodiment may be similar to those of the twelfth embodiment, and therefore the thirteenth embodiment can achieve the same effects as the second and twelfth embodiments.

[0128] 42 and 43 are cross-sectional views showing an example of a method for manufacturing the light-emitting device according to the 13th embodiment. In the middle of the manufacturing process of the 12th embodiment, as shown in Fig. 42, wax 121 is applied onto the second reflector 90, the first and second electrodes 100, 110, etc., and the InP substrate 11 and the InGaAs layer 21 are removed from the first semiconductor layer 30 as described with reference to Fig. 13.

[0129] Next, the photodiode PD and the silicon-based first reflecting mirror 22 are formed on another silicon substrate 12, and the silicon substrate 12 is wafer-bonded to the first reflecting mirror 20. This results in the structure shown in FIG.

[0130] (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.

[0131] FIG. 44 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.

[0132] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 44, 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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 information to vehicle occupants or the outside of the vehicle. In the example of Fig. 44, 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.

[0142] FIG. 45 is a diagram showing an example of the installation position of the imaging unit 12031.

[0143] In FIG. 45, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0144] 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.

[0145] 45 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] The above describes an example of a vehicle control system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to, for example, the image capturing unit 12031 and the like among the above-described components.

[0151] The present technology can be configured as follows.

[0152] (1) A light-emitting device comprising: a first reflecting mirror; a second reflecting mirror; a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type provided between the first reflecting mirror and the second reflecting mirror; an active layer provided between the first semiconductor layer and the second semiconductor layer, the active layer emitting light by applying power to the first and second semiconductor layers; and the first semiconductor layer including a first material layer of the first conductivity type and a second material layer of the first conductivity type provided within the first material layer and having a band gap smaller than that of the first material layer.

[0153] (2) The light-emitting device according to (1), wherein the first material layer is an InP layer, and the second material layer is a material layer made of InGaAs containing a Group 3 element or a Group 5 element.

[0154] (3) The light emitting device according to (2), wherein the second material layer is a material layer containing any one of InGaAsP, InGaAs, and AlGaInAs.

[0155] (4) The light-emitting device according to any one of (1) to (3), wherein the second material layer is disposed at a position shifted by λ / 4 (λ is the wavelength of the laser light) from a maximum value of the intensity of the laser light resonating between the first reflecting mirror and the second reflecting mirror.

[0156] (5) The light-emitting device according to any one of (1) to (4), wherein a plurality of the second material layers are provided within the first material layer.

[0157] (6) The light-emitting device according to any one of (1) to (5), wherein the first reflecting mirror is made of a semiconductor material, and the second reflecting mirror is made of a dielectric material.

[0158] (7) The light-emitting device according to any one of (1) to (6), further comprising: a third semiconductor layer provided on the second semiconductor layer between the second reflector and the second semiconductor layer, the third semiconductor layer having a higher impurity concentration of the second conductivity type than the second semiconductor layer; and a fourth semiconductor layer of the first conductivity type provided on the third semiconductor layer and forming a tunnel junction with the third semiconductor layer.

[0159] (8) The light-emitting device according to any one of (1) to (7), wherein the first reflecting mirror is provided on a GaAs substrate or a Ge substrate, and the first reflecting mirror is configured by a stacked film of GaAs and AlGaAs or AlAs.

[0160] (9) The light-emitting device according to any one of (1) to (7), wherein the first reflecting mirror is provided on a silicon substrate, and the first reflecting mirror is configured with a stacked film of single crystal silicon, amorphous silicon, and a silicon oxide film.

[0161] (10) The light-emitting device according to any one of (1) to (9), wherein the second semiconductor layer includes a conductive region sandwiched between the first reflecting mirror and the second reflecting mirror, and an impurity implant region provided around the conductive region.

[0162] (11) The light-emitting device according to any one of (1) to (10), further comprising: a first electrode electrically connected to the first semiconductor layer; a second electrode electrically connected to the second semiconductor layer provided around the second reflector; and a transparent electrode provided between the second reflector and the second semiconductor layer and electrically connected to the second electrode.

[0163] (12) The light-emitting device according to (7), wherein the third semiconductor layer includes a semiconductor region sandwiched between the first reflecting mirror and the second reflecting mirror, and an oxide region provided around the semiconductor region.

[0164] (13) The light-emitting device according to (7), wherein the third semiconductor layer includes a semiconductor region sandwiched between the first reflecting mirror and the second reflecting mirror, and an air gap region provided around the semiconductor region.

[0165] (14) The light-emitting device according to any one of (1) to (13), wherein the active layer includes quantum dots.

[0166] (15) The light emitting device according to (11), wherein the second electrode covers the second reflector.

[0167] (16) The light emitting device according to any one of (1) to (6), further comprising: the first semiconductor layer is provided between the second reflecting mirror and the active layer; the second semiconductor layer is provided between the first reflecting mirror and the active layer; a third semiconductor layer is provided between the first reflecting mirror and the second semiconductor layer and has a higher p-type impurity concentration than the second semiconductor layer; and an n-type fourth semiconductor layer is provided between the first reflecting mirror and the third semiconductor layer and forms a tunnel junction with the third semiconductor layer.

[0168] (17) The light emitting device according to (7), wherein a plurality of stacked structures each made up of the first to fourth semiconductor layers and the active layer are stacked between the first reflecting mirror and the second reflecting mirror.

[0169] (18) The light emitting device according to (7), wherein a plurality of the second reflectors are provided for one of the first reflectors, and a plurality of the third semiconductor layers and a plurality of the fourth semiconductor layers are provided corresponding to each of the second reflectors and the second semiconductor layer.

[0170] (19) The light emitting device according to any one of (1) to (18), wherein the first reflecting mirror is provided on a silicon substrate having an image sensor.

[0171] (20) A method for manufacturing a light emitting device, comprising: forming a first semiconductor layer above a first substrate, the first semiconductor layer including a first material layer of a first conductivity type semiconductor and a second material layer of the first conductivity type semiconductor sandwiched within the first material layer and having a band gap smaller than that of the first material layer; forming an active layer on the first semiconductor layer that emits light when power is applied; forming a second semiconductor layer of a second conductivity type on the active layer; forming a third semiconductor layer of the second conductivity type on the second semiconductor layer, the third semiconductor layer having an impurity concentration higher than that of the second semiconductor layer; forming a fourth semiconductor layer of a first conductivity type on the third semiconductor layer to form a tunnel junction with the third semiconductor layer; forming a first electrode on a part of a surface of the first semiconductor layer that is electrically connected to the first semiconductor layer, and forming a second electrode that is electrically connected to the fourth semiconductor layer; and forming a second reflecting mirror above the third and fourth semiconductor layers.

[0172] (21) The method for manufacturing a light-emitting device according to (20), further comprising: forming a first reflector on a second substrate; and bonding the first substrate and the second substrate together so as to bond the first reflector to the first semiconductor layer.

[0173] 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.

[0174] REFERENCE SIGNS LIST 1 Light emitting device 10 Substrate 20 First reflecting mirror 30 First semiconductor layer 31 First material layer 32 Second material layer 40 Active layer 50 Second semiconductor layer 60 Third semiconductor layer 70 Fourth semiconductor layer 80 Fifth semiconductor layer 90 Second reflecting mirror 100 First electrode 110 Second electrode 120 Protective film

Claims

1. A light-emitting device comprising: a first reflector; a second reflector; a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type provided between the first reflector and the second reflector; an active layer provided between the first semiconductor layer and the second semiconductor layer and emitting light when power is applied to the first and second semiconductor layers; and the first semiconductor layer including a first material layer of the first conductivity type and a second material layer of the first conductivity type provided within the first material layer and having a smaller band gap than the first material layer.

2. The light emitting device according to claim 1, wherein the first material layer is an InP layer, and the second material layer is a material layer of InGaAs containing a Group 3 element or a Group 5 element.

3. The light emitting device according to claim 2, wherein the second material layer is a material layer containing any one of InGaAsP, InGaAs, and AlGaInAs.

4. The light emitting device described in claim 1, wherein the second material layer is positioned at a position shifted by λ / 4 (λ is the wavelength of the laser light) from the maximum value of the intensity of the laser light resonating between the first reflector and the second reflector.

5. The light emitting device of claim 1, wherein a plurality of said second material layers are disposed within said first material layer.

6. The light emitting device according to claim 1, wherein the first reflector is made of a semiconductor material, and the second reflector is made of a dielectric material.

7. The light emitting device according to claim 1, further comprising: a third semiconductor layer provided on the second semiconductor layer between the second reflector and the second semiconductor layer, the third semiconductor layer having a higher concentration of second conductivity type impurities than the second semiconductor layer; and a fourth semiconductor layer of the first conductivity type provided on the third semiconductor layer and forming a tunnel junction with the third semiconductor layer.

8. The light emitting device according to claim 1, wherein the first reflector is provided on a GaAs substrate or a Ge substrate, and the first reflector is composed of a laminated film of GaAs and AlGaAs or AlAs.

9. The light emitting device according to claim 1, wherein the first reflector is provided on a silicon substrate, and the first reflector is made of a laminated film of single crystal silicon, amorphous silicon, and a silicon oxide film.

10. The light emitting device of claim 1, wherein the second semiconductor layer includes a conductive region sandwiched between the first reflector and the second reflector, and an impurity implant region provided around the conductive region.

11. The light emitting device described in claim 1, further comprising: a first electrode electrically connected to the first semiconductor layer; a second electrode electrically connected to the second semiconductor layer provided around the second reflector; and a transparent electrode provided between the second reflector and the second semiconductor layer and electrically connected to the second electrode.

12. The light emitting device according to claim 7, wherein the third semiconductor layer includes a semiconductor region sandwiched between the first reflector and the second reflector, and an oxide region provided around the semiconductor region.

13. The light emitting device according to claim 7, wherein the third semiconductor layer includes a semiconductor region sandwiched between the first reflector and the second reflector, and an air gap region provided around the semiconductor region.

14. The light emitting device of claim 1, wherein the active layer comprises quantum dots.

15. The light emitting device of claim 11, wherein the second electrode is coated on the second reflector.

16. The light emitting device of claim 1, further comprising: a third semiconductor layer provided between the first reflector and the second semiconductor layer and having a higher p-type impurity concentration than the second semiconductor layer; and an n-type fourth semiconductor layer provided between the first reflector and the third semiconductor layer and forming a tunnel junction with the third semiconductor layer.

17. The light emitting device according to claim 7, wherein a plurality of laminated structures each composed of the first to fourth semiconductor layers and the active layer are laminated between the first reflector and the second reflector.

18. The light emitting device according to claim 7, wherein a plurality of the second reflectors are provided for one of the first reflectors, and a plurality of the third semiconductor layers and a plurality of the fourth semiconductor layers are provided correspondingly between each of the plurality of second reflectors and the second semiconductor layer.

19. The light emitting device according to claim 1, wherein the first reflector is provided on a silicon substrate having an image sensor.

20. A method for manufacturing a light emitting device, comprising: forming a first semiconductor layer above a first substrate, the first semiconductor layer including a first material layer of a first conductivity type semiconductor, and a second material layer of the first conductivity type semiconductor sandwiched within the first material layer and having a smaller band gap than the first material layer; forming an active layer on the first semiconductor layer that emits light when power is applied thereto; forming a second semiconductor layer of a second conductivity type on the active layer; forming a third semiconductor layer of a second conductivity type having a higher impurity concentration than the second semiconductor layer on the second semiconductor layer; forming a fourth semiconductor layer of a first conductivity type on the third semiconductor layer and forming a tunnel junction with the third semiconductor layer; forming a first electrode on a portion of a surface of the first semiconductor layer that is electrically connected to the first semiconductor layer, and forming a second electrode that is electrically connected to the fourth semiconductor layer; and forming a second reflector above the third and fourth semiconductor layers.

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