Light emitting device

Abstract

The light emitting device includes: a first compound semiconductor layer of a first conductivity type; an active layer laminated on the first compound semiconductor layer; a second compound semiconductor layer of a second conductivity type opposite to the first conductivity type, and laminated to the active layer on a side opposite to the first compound semiconductor layer; a first reflective layer disposed on an opposite side from the active layer separately from a surface of the second compound semiconductor layer, and reflecting light emitted from the active layer; and a first electrode disposed between the second compound semiconductor layer and the first reflective layer and electrically connecting corresponding portions of the second compound semiconductor layer and the first reflective layer.

Description

Technical Field

[0001] The present disclosure relates to a support member for supporting a display unit and a display device including the display unit and the support member. Background Art

[0002] Patent document 1 discloses a micro light-emitting element. The micro light-emitting element includes a compound semiconductor stacked on a driving circuit board. The compound semiconductor is formed by sequentially stacking a p-type layer, a light-emitting layer, and an n-type layer on the driving circuit board. The p-type layer is electrically coupled to a p-electrode, and the n-type layer is electrically coupled to an n-electrode.

[0003] The micro light-emitting element configured in this manner allows light from the light-emitting layer to be emitted through the n-type layer, thereby constituting an image display element.

[0004] Reference List

[0005] Patent Literature

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-204823 Summary of the invention

[0007] The micro light emitting element includes a transparent electrode formed on the entire surface of the P-type layer of the compound semiconductor facing the driving circuit board, and the P-type layer is electrically coupled to the p-electrode via the transparent electrode. The p-electrode is formed on most of the entire surface of the p-type layer.

[0008] However, for the above-mentioned micro light emitting elements, no consideration is given to the leakage of light emitted from the light emitting layer to the driving circuit board. Therefore, with the further miniaturization of light emitting devices, it is desired to improve light extraction efficiency and realize an image display device with higher image quality.

[0009] A light-emitting device according to a first embodiment of the present disclosure includes: a first compound semiconductor layer having a first conductivity type; an active layer stacked on the first compound semiconductor layer; a second compound semiconductor layer stacked on the active layer on a side opposite to the first compound semiconductor layer, the second compound semiconductor layer having a second conductivity type opposite to the first conductivity type; a first reflective layer arranged away from a surface of the second compound semiconductor layer on a side opposite to the active layer, the first reflective layer reflecting light emitted from the active layer; and a first electrode disposed between the second compound semiconductor layer and the first reflective layer, the first electrode electrically connecting a portion of the second compound semiconductor layer and a portion of the first reflective layer.

[0010] In the light emitting device according to the first embodiment, the light emitting device according to the second embodiment of the present disclosure further includes an insulator between the second compound semiconductor layer and the first reflective layer, the insulator being light-transmissive and insulating.

[0011] In a light-emitting device according to a third embodiment of the present disclosure, in the light-emitting device according to the first embodiment or the second embodiment, the first compound semiconductor layer, the active layer, and at least a portion of the second compound semiconductor layer have a mesa shape, and the light-emitting device further includes a second reflective layer disposed along a side surface of the mesa shape, and the second reflective layer reflects light emitted from the active layer and light reflected from the first reflective layer toward the first compound semiconductor layer.

[0012] The light-emitting device according to the fourth embodiment of the present disclosure also includes: in the light-emitting device according to any one of the first to third embodiments, a second electrode on the first reflective layer on the side opposite to the second compound semiconductor layer, the second electrode including a barrier metal layer, an Al alloy layer and a barrier metal layer stacked in sequence. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic cross-sectional view of a light emitting device according to a first embodiment of the present disclosure.

[0014] Figure 2 yes Figure 1 An enlarged plan view of a main portion of the light emitting device shown in FIG.

[0015] Figure 3 It is composed Figure 1 and Figure 2 An enlarged cross-sectional view of a light emitting element of the light emitting device shown in FIG.

[0016] Figure 4 yes Figure 3 0 is a bottom view of a main part of the light emitting element shown in , showing the configuration of the first reflective layer and the first electrode of the light emitting element.

[0017] Figure 5 is a diagram for explaining a method for manufacturing a light emitting device according to a first embodiment, and Figure 3 Corresponding cross-sectional view of the first process.

[0018] Figure 6 is a cross-sectional view of the second process.

[0019] Figure 7 It is a cross-sectional view of the third process.

[0020] Figure 8 It is a cross-sectional view of the fourth process.

[0021] Fig. 9 is a cross-sectional view of the fifth process.

[0022] Fig.10 is a cross-sectional view of the sixth process.

[0023] Fig.11 is a cross-sectional view of the seventh process.

[0024] Fig.12 is a cross-sectional view of the eighth process.

[0025] Fig.13 It is a bottom view of a main part of a light emitting element constituting a light emitting device according to a second embodiment of the present disclosure, and illustrates the arrangement of a first reflective layer and a first electrode of the light emitting element.

[0026] Fig.14 It is a bottom view of a main part of a light emitting element constituting a light emitting device according to a first modification of the second embodiment, and shows the arrangement of a first reflective layer and a first electrode of the light emitting element.

[0027] Fig.15 It is a bottom view of a main part of a light emitting element constituting a light emitting device according to a second modification of the second embodiment, and shows the arrangement of a first reflective layer and a first electrode of the light emitting element.

[0028] Fig.16 is corresponding to Figure 3 An enlarged cross-sectional view of a light emitting element constituting a light emitting device according to a third embodiment of the present disclosure.

[0029] Fig.17 is Fig.16 , which is a bottom view of the main part of the light emitting element shown in FIG. 1 , shows the configuration of the first reflective layer and the first electrode of the light emitting element, and corresponds to Figure 4 .

[0030] Fig.18 is corresponding to Figure 3 An enlarged cross-sectional view of a light emitting element constituting a light emitting device according to a fourth embodiment of the present disclosure.

[0031] Fig.19 yes Fig.18 , which is a bottom view of the main part of the light emitting element shown in FIG. 1 , shows the configuration of the first reflective layer and the first electrode of the light emitting element, and corresponds to Figure 4 .

[0032] Fig. 20 is corresponding to Figure 3 An enlarged cross-sectional view of a light emitting element constituting a light emitting device according to a fifth embodiment of the present disclosure.

[0033] Fig.21 It is a block diagram showing an embodiment of a schematic configuration of a vehicle control system.

[0034] Fig. 22 The diagram is a diagram for explaining an embodiment of the installation positions of the vehicle exterior information detection unit and the imaging unit. DETAILED DESCRIPTION

[0035] The embodiments of the present disclosure are described in detail below in conjunction with the accompanying drawings. Note that the explanation will be given in the following order.

[0036] 1. First Implementation

[0037] First Embodiment A first example in which the present technology is applied to a light emitting device and a method for manufacturing the same is described.

[0038] 2. Second Implementation

[0039] Second Embodiment A second example in which the arrangement of the light emitting elements in the light emitting device according to the first embodiment is changed will be described.

[0040] 3. Third Implementation

[0041] Third Embodiment A third example in which the arrangement of the light emitting element in the light emitting device according to the first embodiment or the second embodiment is changed is described.

[0042] 4. Fourth Implementation

[0043] Fourth Embodiment A fourth embodiment in which the arrangement of the light emitting element in the light emitting apparatus according to the first to third embodiments is changed is described.

[0044] 5. Fifth Implementation

[0045] Fifth Embodiment A fifth example in which the arrangement of the light emitting element in the light emitting device according to the first to fourth embodiments is changed is described.

[0046] 6. Example of application to moving objects

[0047] This application embodiment describes an embodiment in which the present technology is applied to a vehicle control system which is an embodiment of a mobile body control system.

[0048] 7. Other Implementation Methods

[0049] <1. First Embodiment>

[0050] See also Figures 1 to 12 , a light emitting device 1 and a method for manufacturing the same according to a first embodiment of the present disclosure are described below.

[0051] Here, for convenience, the direction of arrow X in the drawings shown appropriately indicates one plane direction when the light emitting device 1 is placed on a plane. The direction of arrow Y indicates another plane direction orthogonal to the direction of arrow X. The direction of arrow Z indicates an upward direction orthogonal to the direction of arrow X and the direction of arrow Y. The direction of arrow X, the direction of arrow Y, and the direction of arrow Z are precisely consistent with the direction of X axis, the direction of Y axis, and the direction of Z axis of the three-dimensional coordinate system, respectively.

[0052] It should be noted that these directions are shown to help understand the present technology and do not limit the directions of the present technology.

[0053] [Configuration of Light Emitting Device 1]

[0054] (1) Overall Configuration of Light Emitting Device 1

[0055] Figure 1 An example of a schematic cross-sectional configuration of the light emitting device 1 according to the first embodiment is shown. Figure 2 An example of a planar arrangement of the light emitting element 30 and the color conversion layer 40 of the light emitting device 1 is shown.

[0056] like Figure 1 As shown, the light emitting device 1 according to the first embodiment includes a substrate region 2, a light emitting region 3, a color conversion region 4, a filter region 5, and an optical system region 6 in the longitudinal cross-sectional direction (i.e., the arrow Z direction). The light emitting device 1 also includes an element array region 7 and a peripheral region 8 in the planar direction of the arrow X and arrow Y directions.

[0057] The light emitting device 1 includes, as main components thereof, a substrate 20 located in the substrate region 2 and a light emitter 35 located in the light emitting region 3 and including a plurality of light emitting elements 30 arranged in the element array region 7 .

[0058] (2) Configuration of substrate region 2

[0059] The substrate region 2 includes a substrate 20 and a driving circuit 21 mounted on a main surface of the substrate 20. The main surface of the substrate 20 refers to one main surface of the substrate 20 on which a semiconductor element (not shown) such as a driving transistor is manufactured and on which the driving circuit 21 is further formed.

[0060] For example, the substrate 20 may include a single crystal silicon (Si) substrate. The substrate 20 has a back surface and a side surface opposite to the main surface, and an insulator 201 is formed on these back surfaces and side surfaces. In practice, for example, the insulator 201 may include a silicon nitride (SiN) film or a silicon oxide (SiO) film.

[0061] (2-1) Configuration of the driving circuit 21

[0062] The drive circuit 21 includes a semiconductor element (not shown) formed on the main surface of the substrate 20. The drive transistor as the semiconductor element includes, for example, a complementary insulated gate field effect transistor (IGFET). The insulated gate field effect transistor includes at least a field effect transistor (MISFET) having a metal / insulator / semiconductor structure and a field effect transistor (MOSFET) having a metal / oxide film / semiconductor structure.

[0063] (2-2) Configuration of Wiring Layer 24

[0064] The drive circuit 21 is electrically coupled to the first terminal 281 through the wiring layer 24. The wiring layer 24 in the present embodiment includes a plug wiring 240, a first layer wiring 241, a second layer wiring 242, a third layer wiring 243, a fourth layer wiring 244, and a plug wiring 245.

[0065] For example, the plug wiring 240 is formed on a main electrode of an insulated gate field effect transistor (not shown) and is electrically coupled to the main electrode. For example, the plug wiring 240 includes tungsten (W).

[0066] The first layer wiring 240 is formed on the plug wiring 241 to be electrically coupled to the plug wiring 240. The second layer wiring 242 is formed on the first layer wiring 241 to be electrically coupled to the first layer wiring 241. The third layer wiring 243 is formed on the second layer wiring 242 to be electrically coupled to the second layer wiring 242. The fourth layer wiring 244 is formed on the third layer wiring 243 to be electrically coupled to the third layer wiring 243. The first wiring layer 241 to the fourth wiring layer 244 mainly include, for example, aluminum (Al).

[0067] The plug wiring 245 is formed on the fourth layer wiring 244 to be electrically connected to the fourth layer wiring 244. For example, the plug wiring 245 includes a material similar to that of the plug wiring 240.

[0068] The wiring layer 24 also includes an insulator 29. The insulator 29 is formed around the plug wiring 240 and the plug wiring 245. For example, the insulator 29 is also formed between the first layer wiring 241 and the second layer wiring 242, between the second layer wiring 242 and the third layer wiring 243, and between the third layer wiring 243 and the fourth layer wiring 244. The insulator 29 includes, for example, a SiO film or a SiN film.

[0069] (2-3) Arrangement of the Light Shielding Film 26 and the Light Absorption Film 27

[0070] In the wiring layer 24 , the first terminal 281 is electrically coupled to the plug wiring 245 through the light absorbing film 27 and the light shielding film 26 in sequence.

[0071] The light shielding film 26 is provided closer to the driving circuit 21 than the light absorbing film 27. Here, for example, the light shielding film 26 covers the driving transistor of the driving circuit 21. In other words, the light shielding film 26 serves as a circuit electrically connecting the driving circuit 21 and the first terminal 281, and is configured to block leakage light emitted from the light emitting element 30 to the driving circuit 21.

[0072] The light shielding film 26 includes a single layer of metal whose main component is, for example, Al, copper (Cu), W, or titanium (Ti).

[0073] The light absorbing film 27 is placed on the light absorbing film 26 to be opposite to the light emitting element 30. When viewed from the direction of arrow Z, the light absorbing film 27 has the same planar shape (hereinafter referred to as "plan view") as the light shielding film 26. The light absorbing film 27 absorbs leakage light emitted from the light emitting element 30 to the driving circuit 21, and also serves as an electrical path that electrically connects the driving circuit 21 and the first terminal 281.

[0074] The light absorbing film 27 includes a single layer of a metal or a metal compound whose main component is, for example, titanium nitride (TiN), cobalt (Co), nitrogen-doped titanium oxide (TiON), tantalum nitride (TaN), or amorphous carbon (aC).

[0075] (2-4) Configuration of the First Terminal 281

[0076] The first terminal 281 is electrically coupled to the light absorbing film 27 and is placed on the insulator 29. The first terminal 281 is electrically coupled to one end of the light emitting element 30 (specifically, to the second compound semiconductor layer 32). For example, the first terminal 281 includes Cu having a low resistance value.

[0077] In the peripheral region 8, the second terminal 282 is placed in the insulator 29. The second terminal 282 is electrically coupled to the other end of the light emitting element 30 (specifically, to the first compound semiconductor layer 31) or to the outside of the light emitting device 1.

[0078] In the present embodiment, the second terminal 282 is formed in the same conductive layer as the light shielding film 26 and the light absorbing film 27 and includes the same conductive material.

[0079] (3) Configuration of light-emitting area 3

[0080] like Figure 1 and Figure 2 As shown, the light emitting region 3 includes a light emitter 35 disposed on the substrate region 2 and the insulator 29. In this embodiment, the light emitter 35 includes an array of a plurality of light emitting elements 30 including a compound semiconductor layer, and these light emitting elements 30 are arranged along the direction of the light emitting surface of the light emitting element 30 (the direction of arrows X and Y).

[0081] The configuration is described in detail below. In this embodiment, Figure 2 As shown, the light emitting elements 30 each have a hexagonal shape in a plan view. These light emitting elements 30 are arranged in the direction of arrow X, and are also arranged in a direction inclined 30 degrees to the direction of arrow X relative to the direction of arrow Y (the direction of arrow Y). The light emitting elements 30 include a light emitting element 30 (R) emitting red light, a light emitting element 30 (B) emitting blue light, and a light emitting element 30 (G) emitting green light, wherein red, blue, and green are the three primary colors of light.

[0082] The light emitting elements 30(R), 30(B) and 30(G) are arranged so that their centers exactly coincide with the vertices of an equilateral triangle. That is, the light emitting elements 30(R), 30(B) and 30(G) in the first embodiment are in a triangular arrangement.

[0083] The light emitter 35 includes, in addition to the light emitting surface, an insulator 34 surrounding the plurality of light emitting elements 30. The insulator 34 mainly includes a SiO film or a SiN film.

[0084] (3-1) Arrangement of Light Emitting Elements 30

[0085] Figure 3 An example of an enlarged cross-sectional configuration of the light emitting element 30 constituting the light emitting device 1 is shown. Figure 4 An example of the configuration of the first reflective layer 361 and the first electrode 363 of the light emitting element 30 is shown. Figure 4 It is viewed from the direction opposite to the direction of arrow Z. Figure 3 Bottom view taken along line AA in the figure.

[0086] It should be noted that the corresponding Figure 4 The bottom view of is taken at a similar position.

[0087] like Figure 1 and Figure 3 As shown in FIG. , each light emitting element 30 is configured as a light emitting diode (LED) including a first compound semiconductor layer 31, a second compound semiconductor layer 32, and an active layer 33. Note that Figure 1 and Figure 3 , the direction of arrow Z of the light emitting element 30 is opposite.

[0088] For example, each light emitting element 30 mainly includes a group III-V compound semiconductor. The first compound semiconductor layer 31 is placed closer to the color conversion region 4 and is located on the light emitting side. For example, the first compound semiconductor layer 31 includes n-type gallium nitride (n-GaN). Here, "n-type" refers to the "first conductivity type" according to the present technology.

[0089] The second compound semiconductor layer 32 is disposed closer to the substrate region 2. For example, the second compound semiconductor layer 32 includes p-type gallium nitride (p-GaN). Here, "p-type" refers to a "second conductivity type" opposite to the first conductivity type according to the present technology.

[0090] The active layer 33 is placed between the first compound semiconductor layer 31 and the second compound semiconductor layer 32. In other words, the active layer 33 is stacked on the first compound semiconductor layer 31, and the second compound semiconductor layer 32 is stacked on the active layer 33 on the side opposite to the first compound semiconductor layer 31. The active layer 33 serves as a light-emitting layer that emits light. Although not limited to this, the light-emitting element 30 in the first embodiment emits blue light.

[0091] In each light emitting element 30, at least a portion of the first compound semiconductor layer 31, the active layer 33, and the second compound semiconductor layer 32 is a mesa shape in cross section. That is, as described above, the light emitting element 30 has a hexagonal shape in a plan view, and has a mesa shape when viewed in the direction of arrow Y (hereinafter referred to as a "side view").

[0092] Note that the planar shape of the light emitting element 30 is not limited to a hexagon, and the planar shape of the light emitting element 30 may be a circle, a rectangle, or the like.

[0093] (3-2) Configuration of Transparent Electrode 321

[0094] In the light emitting element 30, a transparent electrode 321 is placed on the surface (closer to the substrate region 2) of the second compound semiconductor layer 32. The transparent electrode 321 is electrically coupled to substantially the entire surface of the second compound semiconductor layer 32. The transparent electrode 321 formed for each light emitting element 30 has the same planar shape as the second compound semiconductor layer 32 in a plan view. For example, the transparent electrode 321 includes indium tin oxide (ITO). With this configuration, the transparent electrode 321 is connected to the second compound semiconductor layer 32 through an ohmic contact.

[0095] (3-3) Configuration of the First Reflective Layer 361

[0096] like Figures 1 to 4 As shown, each of the plurality of light emitting elements 30 has a first reflective layer 361 , a first electrode 363 , an insulator 364 , a second reflective layer 362 , and a second electrode 37 .

[0097] First, the first reflective layer 361 will be described in detail. The first reflective layer 361 is placed on the entire second compound semiconductor layer 32 (on the surface of the second compound semiconductor layer closer to the substrate region 2), and the transparent electrode 321 is interposed therebetween to be spaced apart from the second compound semiconductor layer 32. In other words, the first reflective layer 361 is placed on the entire surface of the transparent electrode 321 (on the surface of the transparent electrode closer to the substrate region 2) to be spaced apart from the transparent electrode 321.

[0098] For example, the first reflective layer 361 includes a metal material that is conductive and has a high light reflectivity of 75% or more for blue light having a wavelength of 400 nm. That is, the first reflective layer 361 is configured to provide the second compound semiconductor layer 32 with a current required for light emission of the light emitting element 30 and ensure reflection of light emitted from the active layer 33.

[0099] For example, the first reflective layer 361 includes Al (preferably pure Al). For example, when the thickness of Al is 75nm, its reflectivity for blue light is 92.5%. When the thickness of Al is less than 50nm, the reflectivity of the layer begins to decrease for blue light. For this reason, the thickness of the first reflective layer 361 can be more than 50nm, and from the manufacturing point of view, it is less than 100nm.

[0100] Note that the first reflective layer 361 may include one or more materials selected from Al alloy, Ag, and Ag alloy, in addition to Al.

[0101] In the light emitting element 30 in this embodiment, light emitted from the active layer 33 reaches the first reflective layer 361 through the second compound semiconductor layer 32, and is reflected by the first reflective layer 361. The reflected light then passes through the second compound semiconductor layer 32, the active layer 33, and the first compound semiconductor layer 31, and is then output. Therefore, the thickness of the second compound semiconductor layer 32 is set to a thickness in which the light before and after the reflection at the first reflective layer 361 is not disturbed and attenuated, but is instead amplified to ultimately enhance the light extraction efficiency.

[0102] (3-4) Configuration of the First Electrode 363

[0103] The first electrode 363 is placed between the second compound semiconductor layer 32 and the first reflective layer 361. In the first embodiment, the first electrode 363 is placed between the transparent electrode 321 and the first reflective layer 361. The first electrode 363 electrically connects the second compound semiconductor layer 32 or a portion of the transparent electrode 321 and the first reflective layer 361.

[0104] The first electrode 363 serves as a contact metal. In contrast to a direct connection between the first reflective layer 361 and the transparent electrode 321, the connection of the first reflective layer 361 to the transparent electrode 321 via the first electrode 363 results in good electrical conduction.

[0105] For example, the first electrode 363 includes Ti or a Ti alloy. The first electrode 363 has a thickness of, for example, 10 nm or more and 100 nm or less.

[0106] like Figure 4 As described in FIG. 1 , this embodiment has seven first electrodes 363 for one first reflective layer 361 in a plan view. Specifically, the first electrodes 363 each have a circular shape in a plan view. One of these first electrodes 363 is placed in the middle of the first reflective layer 361 having a hexagonal shape in a plan view, and six are equally spaced at peripheral positions corresponding to the corners of the first reflective layer 361.

[0107] The total area of ​​the seven electrodes when viewed from the thickness direction of the first electrode 363 is smaller than the area of ​​the first reflective layer 361 when viewed from the same direction. Specifically, the total area of ​​the first electrode 363 is 1% to 30% of the area of ​​the first reflective layer 361.

[0108] Such an area ratio of the first electrode 363 suppresses the voltage drop caused by the first electrode 363 to, for example, 10 mV or less, which does not affect the driving current of the light emitting element 30. The reflectivity of the first electrode 363 is lower than the reflectivity of the first reflective layer 361. That is, the area of ​​the first electrode 363 covering the first reflective layer 361 is small. This increases the area of ​​the first reflective layer 361 that contributes to reflection, and suppresses the reduction in light extraction efficiency to 30% or less.

[0109] Note that the planar shape of the first electrode 363 is not limited to a circular shape, and the planar shape of the first electrode 363 may be an ellipse, a triangle, a rectangle, a polygon including a pentagon or more, a slit shape, or the like.

[0110] (3-5) Configuration of Insulator 364

[0111] like Figure 3 As shown, the insulator 364 is placed around the first electrode 363 between the first reflective layer 361 and the transparent electrode 321. In other words, the insulator 364 is arranged between the first reflective layer 361 and the transparent electrode 321 except for the region where the first electrode 363 is arranged. The insulator 364 is light-transmitting and insulating, and serves as a barrier layer separating the first reflective layer 361 and the transparent electrode 321.

[0112] For example, the insulator 364 includes aluminum oxide (AlO) or SiO. The insulator 364 has a thickness that is effectively the same as that of the first electrode 363. For example, the insulator 364 is formed by atomic layer deposition (ALD).

[0113] (3-5) Configuration of the Second Reflective Layer 362

[0114] like Figure 1 and Figure 3 As shown in FIG. 1 , in a side view, the second reflective layer 362 is along and surrounds the side surfaces of the mesa shape of the first compound semiconductor layer 31, the active layer 33, and the second compound semiconductor layer 32. An insulator 341 is formed between the second reflective layer 362 and the first compound semiconductor layer 31, the active layer 33, and the second compound semiconductor layer 32. For example, the insulator 341 includes SiO or SiN.

[0115] The second reflective layer 362 reflects light emitted from the active layer 33 and light reflected from the first reflective layer 361 toward the first compound semiconductor layer 31 to improve light extraction efficiency.

[0116] In the first embodiment, the second reflective layer 362 is formed in the same layer as the first reflective layer 361 and includes the same material as the first reflective layer 361. The second reflective layer 362 is continuous with the first reflective layer 361 and is integrated with the first reflective layer 361.

[0117] (3-6) Configuration of the Second Electrode 37

[0118] like Figure 1 and 3 As shown in FIG. 3 , the second electrode 37 , the plug wiring 38 , and the wiring 39 are sequentially placed on the first reflective layer 361 .

[0119] First, the second electrode 37 is described. The second electrode 37 is placed on the opposite side of the second compound semiconductor layer 32 on the second reflective layer 361. Figure 3 As shown, the second electrode 37 is formed over the entire first reflective layer 361 in plan view and side view and has an area slightly larger than that of the first reflective layer 361. The second electrode 37 is electrically coupled to the second compound semiconductor layer 32 through the first reflective layer 361, the first electrode 363 and the transparent electrode 321.

[0120] In the first embodiment, the second electrode 37 is formed by stacking the barrier metal layer 371 , the Al alloy layer 372 , and the barrier metal layer 373 .

[0121] For example, the barrier metal layer 371 includes titanium nitride (TiN) and has a thickness of 10 nm or more and 100 nm or less.

[0122] For example, the Al alloy layer 372 is made of AlCu in which Cu is added to Al or AlSi in which Si is added to Al. The amount of Cu added is, for example, 1% or more and 3% or less. The amount of Si added is, for example, 1% or more and 5% or less. For example, the Al alloy layer 372 has a thickness of 300 nm or more and 800 nm or less.

[0123] Similar to the barrier metal layer 371 , the barrier metal layer 373 includes, for example, TiN, and has a thickness of 10 nm or more and 100 nm or less.

[0124] (3-7) Arrangement of plug wiring 38

[0125] One end of the plug wiring 38 is electrically connected to the second electrode 37, and the other end is electrically connected to the wiring 39. The plug wiring 38 is placed at a middle position of the first reflective layer 361 and passes through the insulator 34.

[0126] For example, the plug wiring 38 includes W.

[0127] (3-8) Structure of Wiring 39

[0128] The wiring 39 is formed by sequentially stacking a barrier metal layer 391 , an Al alloy layer 392 , and a barrier metal layer 393 .

[0129] The barrier metal layer 391 includes, for example, TiN, similarly to the barrier metal layer 391. For example, the barrier metal layer 391 has a thickness of 10 nm or more and 100 nm or less.

[0130] For example, the Al alloy layer 392 includes AlCu or AlSi. The thickness of the Al alloy layer 392 is, for example, not less than 500 nm and not more than 600 nm.

[0131] Similar to the barrier metal layer 371 , the barrier metal layer 393 includes, for example, TiN, and has a thickness of 10 nm or more and 100 nm or less.

[0132] The barrier metal layers 391 and 393 of the wiring 39 may each include a composite film in which Ti, TiN, and Ti are sequentially stacked instead of TiN. In this case, Ti is formed to have a thickness of, for example, 30 nm or less. TiN is formed to have a thickness of, for example, 10 nm or more and 100 nm or less.

[0133] like Figure 1 As shown, the wiring 39 is connected to a third terminal 390 of the light emitting region 3. The third terminal 390 is formed on the surface of the insulator 34 (closer to the substrate region 2). Like the first terminal 281 described above, the third terminal 390 includes, for example, Cu.

[0134] The third terminal 390 is joined to the first terminal 281 to be electrically coupled to the first terminal 281 .

[0135] (3-9) Configuration of Element Isolation Region 300

[0136] like Figure 1 As shown, the insulator 34 is filled between adjacent light emitting elements 30, and the second reflective layer 362 is placed between each light emitting element 30 and the insulator 34. These insulator 34 and the second reflective layer 362 constitute an element isolation region 300 that optically isolates adjacent light emitting elements 30.

[0137] (3-10) Configuration of Transparent Electrode 311

[0138] like Figure 1 As shown, a transparent electrode 311 is placed on the first compound semiconductor layer 31 of each light emitting element 30 on the opposite side of the second compound semiconductor layer 32. The transparent electrode 311 is electrically coupled to the first compound semiconductor layer 31. The transparent electrode 311 includes a material similar to that of the transparent electrode 321 described above.

[0139] The first electrode 311 is electrically coupled to a wiring 312, and the wiring 312 supplies current to the first compound semiconductor layer 31 through the transparent electrode 311. The wiring 312 includes W, for example.

[0140] (4) Configuration of color conversion area 4

[0141] like Figure 1 As shown, the color conversion region 4 includes a color conversion layer 40 , a third reflective layer 401 and partition walls 41 .

[0142] The color conversion layer 40 is placed on the light emitting surface of the light emitting element 30, that is, placed on the transparent electrode 311 via an insulator without a reference number. The color conversion layer 40 is configured corresponding to each light emitting element 30. The color conversion layer 40 converts the light emitted from the light emitting element 30 into a specific color. In this embodiment, the light emitting element 30 is configured to emit blue light, as described above. Thus, the color conversion layer 40 includes a color conversion layer 40 (R) that converts blue light into red light, a color conversion layer 40 (G) that converts blue light into green light, and a transparent color conversion layer 40 (B, T) that allows blue light to pass as it is. For example, the color conversion layer 40 includes a resin material.

[0143] With this configuration, the light emitting device 1 according to the first embodiment operates as a color light emitting device. Actually, the light emitting device 1 functions as a color image display device or a micro light emitting device (micro LED).

[0144] The third reflective layer 401 is disposed along the periphery of the side of the color conversion layer 40. The third reflective layer 401 reflects light emitted from the light emitting element 30 and light diffused from the color conversion layer 40 to improve light extraction efficiency. For example, the third reflective layer 401 includes a material similar to the first reflective layer 361.

[0145] In the color conversion region 4, partition walls 41 are formed between adjacent color conversion layers 40 in the planar direction and between adjacent third reflective layers 401. The partition walls 41 are configured to optically separate the color conversion layers 40 and to hold the color conversion layers 40. For example, the partition walls 41 include SiO or SiN.

[0146] (5) Configuration of filter area 5

[0147] A filter region 5 is arranged on the color conversion region 4. The filter region 51 in this embodiment includes a distributed Bragg reflector (DBR) 50 and a color filter 5 sequentially stacked on the color conversion region 4. The DBR 50 reflects light of a specific color. The color filter 51 absorbs light of a specific color. In this embodiment, the specific emission color is, for example, blue light.

[0148] (6) Configuration of Optical System Area 6

[0149] The optical system region 6 is placed on the filter region 5. In the optical system region 6, an on-chip lens 60 is placed. The on-chip lens 60 includes a plurality of optical lenses, each of which is placed for a corresponding light emitting element 30 and formed integrally. These optical lenses each have a cross-sectional shape that protrudes and curves in the light emission direction. For example, the on-chip lens 60 includes a resin material or an inorganic material.

[0150] [Method for manufacturing light emitting device 1]

[0151] Next, a method for manufacturing the light emitting device 1 according to the first embodiment will be briefly described.

[0152] Figures 5 to 12 2 is a cross-sectional view of an example of steps of the method for manufacturing the light emitting device 1 according to the first embodiment.

[0153] First, prepare a supporting substrate 90 (see Figure 5 ). For example, a sapphire substrate may be used for the support substrate 90. On the support substrate 90, a first compound semiconductor layer (n-GaN) 31, an active layer 33, and a second compound semiconductor layer (p-GaN) 32 are sequentially formed (see Figure 5 ). Subsequently, a transparent electrode 321 is formed on the second compound semiconductor layer 32 (see Figure 5 ).

[0154] like Figure 5As shown, a mask 901 is formed on the transparent electrode 321. The mask 901 is used as an etching mask to form a mesa shape. For example, the mask 901 includes a single layer film of SiO or SiN or a composite film including them.

[0155] like Figure 6 As shown in FIG. 9 , the transparent electrode 321, the second compound semiconductor layer 32, the active layer 33, and the first compound semiconductor layer 31 are etched using a mask 901. The etching forms a mesa shape of the transparent electrode 321, the second compound semiconductor layer 32, the active layer 33, and the first compound semiconductor layer 31. For example, the etching is dry etching. Afterwards, the mask 901 is removed.

[0156] like Figure 7 As shown, the insulator 341 is formed along the top and side surfaces of the mesa shape. For example, the insulator 341 is formed by a chemical vapor deposition (CVD) method.

[0157] Next, an opening 341H is formed in a portion of the insulator 341 on the top surface of the mesa shape to expose the surface of the transparent electrode 321 (see Figure 8 ). The opening 341H is formed by photolithography and etching techniques.

[0158] Subsequently, an insulator 364 is formed on the transparent electrode 321 in the opening 341H (see Fig. 9 and Figure 3 ). For example, the insulator 364 includes AlO or SiO as described above. For example, the insulator 364 is formed by ALD.

[0159] Next, an opening 364H is formed in the insulator 364 at a region where the first electrode 363 is to be formed, thereby exposing the surface of the transparent electrode 321 (see Fig. 9 and Figure 3 ). For example, the opening 364H is formed by photolithography and etching techniques.

[0160] like Figure 8 As shown, the first electrode 363 is formed in the opening 341H to be electrically coupled to a portion of the surface of the transparent electrode 321 through the opening 364H. For example, as described above, the first electrode 363 includes Ti or a Ti alloy. For example, the first electrode 363 is formed by sputtering and then patterned using an etching technique to form a predetermined shape.

[0161] Figures 8 to 12 The first electrode 363 is shown as a single one to simplify the cross-sectional shape. However, in reality, as described above Figure 4 As shown in FIG. 1 , seven first electrodes 363 are placed in this first embodiment.

[0162] like Fig. 9As shown, the first reflective layer 361 is formed on the first electrode 363 and on the insulator 364 in the opening 341H. In the same manufacturing step as the first reflective layer 361, the second reflective layer 362 is formed on the insulator 341 along the side wall of the mesa shape. These first reflective layer 361 and the second reflective layer 362 include, for example, an Al film formed by a CVD method.

[0163] like Fig.10 As shown, the second electrode 37 is formed on the first reflective layer 361. The second electrode 37 is formed as described above by sequentially stacking a barrier metal layer 371, an Al alloy layer 372, and a barrier metal layer 373. These films are formed by, for example, sputtering and then patterned by etching technology.

[0164] like Fig.11 As shown, the insulator 34 is formed to embed the second electrode 37 therein. Fig.12 As shown, plug wiring 38 is then formed in the insulator 34 , and wiring 39 is formed on the insulator 34 .

[0165] Once these steps are completed, the light emitting element 30 is basically completed. Figure 1 As shown, a third terminal 390 is formed on the light emitting element 30. After bonding the substrate region 2, the light emitting element 30 is peeled off from the supporting substrate 90. After peeling, the color conversion region 4, the filter region 5 and the optical system region 6 are sequentially formed to complete the light emitting device 1 according to the first embodiment.

[0166] [Effects and beneficial effects]

[0167] like Figure 1 , Figure 3 and Figure 4 As shown, the light emitting device 1 according to the first embodiment includes a first compound semiconductor layer 31 , an active layer 33 , a second compound semiconductor layer 32 , a first reflective layer 361 , and a first electrode 363 .

[0168] The first compound semiconductor layer 31 has a first conductivity type. The active layer 33 is stacked on the first compound semiconductor layer 31. The second compound semiconductor layer 32 is stacked on the active layer 33 on the side opposite to the first compound semiconductor layer 31, and has a second conductivity type opposite to the first conductivity type.

[0169] The first reflective layer 361 is disposed over a surface of the second compound semiconductor layer 32 spaced apart therefrom on a side opposite to the active layer 33, and reflects light emitted from the active layer 33. The first electrode 363 is disposed between the second compound semiconductor layer 32 and the first reflective layer 361, and electrically connects the second compound semiconductor layer 32 and a portion of the first reflective layer 361.

[0170] The light emitting device 1 configured in this manner includes the first reflective layer 361 on the surface of the second compound semiconductor layer 32, thereby effectively suppressing or preventing the light emitted from the active layer 33 from leaking to the driving circuit 21. Specifically, the first reflective layer 361 is placed on the entire surface of the second compound semiconductor layer 32, so that light leakage does not occur. The first reflective layer 361 can effectively reflect light, thereby improving the light extraction efficiency of the light emitting device 1.

[0171] Due to the improved light extraction efficiency, the image display devices have enhanced image quality even if their light emitting elements are further miniaturized.

[0172] In addition, the first reflective layer 361 is coupled to the second compound semiconductor layer 32 via the first electrode 363 , and thus current supply from the first reflective layer 361 is improved, thereby improving light emission efficiency of the light emitting element 30 .

[0173] In addition, the first electrode 363 is electrically coupled to the first reflective layer 361 and a portion of the second compound semiconductor layer 32, thereby sufficiently ensuring a reflective region of the first reflective layer 361. Thus, the light emitting device 1 can further improve light extraction efficiency.

[0174] Furthermore, the first reflective layer 361 enables blocking of light leakage to the drive circuit 21, which effectively suppresses or prevents malfunction of the drive circuit 21 caused by the light leakage. This enhances the operational reliability of the light emitting device 1.

[0175] like Figures 1 to 4 As shown, the first reflective layer 361 in the light emitting device 1 includes one or more materials selected from Al, Al alloy, Ag and Ag alloy.

[0176] For example, when the thickness of the first reflective layer 361 is 75 nm, the reflectivity of blue light with a wavelength of 400 nm is 92.5% for Al, 91.5% for Al alloy (AlCu), 86.2% for Ag, and 84.0% for Ag alloy. This means that the reflectivity of the first reflective layer 361 is 75% or more, which further enhances the light extraction efficiency of the light emitting device 1.

[0177] In addition, as in Figure 3 As specifically shown in FIG. 1 , the light emitting device 1 further includes a transparent electrode 321 between the second compound semiconductor layer 32 and the first electrode 363 , and the first electrode 363 is electrically coupled to the second compound semiconductor layer 32 via the transparent electrode 321 .

[0178] This enables good electrical connection between the second compound semiconductor layer 32 and the transparent electrode 321 , thereby resulting in good electrical connection between the first reflective layer 361 and the second compound semiconductor layer 32 .

[0179] In addition, if Figure 3 As specifically shown in FIG. 1 , the first electrode 363 of the light emitting device 1 includes Ti or a Ti alloy. This enables good electrical connection between the first reflective layer 361 and the transparent electrode 321 .

[0180] like Figure 3 and Figure 4 As shown, the light emitting device 1 is configured such that the total area of ​​the first electrode 363 viewed from the thickness direction is smaller than the area of ​​the first reflective layer 361 viewed from the same direction. Specifically, the total area of ​​the first electrode 363 is greater than 1% and less than 30% of the area of ​​the first reflective layer 361.

[0181] The first electrode 363 having such an area ratio suppresses a voltage drop caused by the first electrode 363, which does not affect the driving current of the light emitting element 30. In addition, the area of ​​the first electrode 363 covering the first reflective layer 361 is small, thereby increasing the reflection area of ​​the first reflective layer 361 and improving light extraction efficiency.

[0182] In addition, as in Figure 3 As specifically shown in FIG. 1 , the light emitting device 1 includes an insulator 364 between the second compound semiconductor layer 32 and the first reflective layer (specifically, between the transparent electrode 321 and the first reflective layer 361 except for the region of the first electrode 363). The insulator 364 is light-transmissive and insulating.

[0183] Therefore, the insulator 364 can effectively suppress or prevent the composition change of the first reflective layer 361 caused by the transparent electrode 321, thereby maintaining the reflectivity of the first reflective layer 361 and improving the light extraction efficiency.

[0184] As in Figure 3 As specifically shown in FIG. 1 , the second compound semiconductor layer 32 in the light emitting device 1 has a thickness that amplifies the light extraction efficiency. That is, the second compound semiconductor layer 32 is formed to have an appropriate thickness so that the light emitted from the active layer 33 to the first compound semiconductor layer 31 is not attenuated by the light reflected by the first reflective layer 361 to the active layer 33.

[0185] The light emitting device 1 configured in this manner can improve light extraction efficiency.

[0186] In addition, as in Figure 3 As specifically shown in FIG. 1 , at least a portion of the first compound semiconductor layer 31, the active layer 33, and the second compound semiconductor layer 32 in this light emitting device 1 have a mesa shape. Then, the light emitting device 1 includes a second reflective layer 362 arranged along the side of the mesa shape. The second reflective layer 362 reflects the light emitted from the active layer 33 and the light reflected from the first reflective layer 361 toward the first compound semiconductor layer 31.

[0187] Therefore, the light emitting device 1 can effectively extract reflected light due to the second reflective layer 362, thereby further improving light extraction efficiency.

[0188] like Figure 3 As particularly shown in FIG. 1 , the second reflective layer 362 of the light emitting device 1 is formed in the same layer as the first reflective layer 361 and includes the same material as the first reflective layer 361. In addition, the second reflective layer 362 is integrally formed with the first reflective layer 361.

[0189] Thus, the configuration of the light emitting device 1 becomes simple.

[0190] In addition, if Fig. 9 As shown, the manufacturing method of the light emitting device 1 forms the first reflective layer 361 and the second reflective layer 362 in the same step.

[0191] This allows one of the steps originally required to form the first reflective layer 361 and the second reflective layer 362 to be omitted, thereby reducing the number of steps in the method of manufacturing the light emitting device 1 .

[0192] In addition, if Figure 1 and Figure 3 As shown, the light emitting device 1 includes a second electrode 37. The second electrode 37 is placed on the second reflective layer 361 on the side opposite to the second compound semiconductor layer 32. The second electrode 37 is formed by sequentially stacking a barrier metal layer 371, an Al alloy layer 372, and a barrier metal layer 373. The second electrode 37 configured in this manner can enhance the electrical reliability of the electrode.

[0193] <2. Second Embodiment>

[0194] See also Figures 13 to 15 , a light emitting device 1 according to a second embodiment of the present disclosure is described below. Note that for the second embodiment and subsequent embodiments, components identical or substantially identical to those of the light emitting device 1 according to the first embodiment are denoted by the same reference numerals, and repeated descriptions will be omitted.

[0195] [Configuration of Light Emitting Device 1]

[0196] Fig.13 An example of the configuration of the first reflective layer 361 and the first electrode 363 of the light emitting element 30 in the light emitting device 1 according to the second embodiment is shown.

[0197] like Fig.13As shown, in a plan view, the light emitting element 30 of the light emitting device 1 has one first electrode 363 placed in the middle of the first reflective layer 361. The total area ratio of the first electrode 363 to the first reflective layer 361 is the same as that of the light emitting device 1 according to the first embodiment. The planar shape of the first electrode 363 is the same as that of the first electrode 363 of the light emitting device 1 according to the first embodiment.

[0198] Components other than these are the same as those of the light emitting device 1 according to the first embodiment, and description thereof will be omitted.

[0199] [Effects and beneficial effects]

[0200] According to the light emitting device 1 of the second embodiment, the same actions and advantageous effects as those obtained from the light emitting device 1 according to the first embodiment can be obtained.

[0201] [First Modification]

[0202] Fig.14 An example of the configuration of the first reflective layer 361 and the first electrode 363 of the light emitting element 30 in the light emitting device 1 according to the first modification example of the second embodiment is shown.

[0203] like Fig.14 As shown, the light emitting device 1 according to the first modification example includes a total of four first electrodes 363 , which are placed two in the arrow X direction and two in the arrow Y direction in the first reflective layer 361 .

[0204] Components other than these are the same as those of the light emitting device 1 according to the first embodiment, and description thereof will be omitted.

[0205] [Effects and beneficial effects]

[0206] With the light emitting device 1 according to the first embodiment, the same actions and advantageous effects as those obtained from the light emitting device 1 according to the first embodiment can be obtained.

[0207] [Second Modification]

[0208] Fig.15 An example of the configuration of the first reflective layer 361 and the first electrode 363 of the light emitting element 30 in the light emitting device 1 according to the second modification example of the second embodiment is shown.

[0209] like Fig.15 As shown, the light emitting device 1 according to the second modification includes six first electrodes 363 each of which is equally spaced apart at peripheral positions corresponding to corners of a first reflective layer 361 having a hexagonal shape in a plan view.

[0210] Components other than these are the same as those of the light emitting device 1 according to the first embodiment, and description thereof will be omitted.

[0211] [Effects and beneficial effects]

[0212] With the light emitting device 1 according to the second modification, the same actions and advantageous effects as those obtained with the light emitting device 1 according to the first embodiment can be obtained.

[0213] <3. Third Embodiment>

[0214] See also Fig.16 and Fig.17 , a light emitting device 1 according to a third embodiment of the present disclosure is described below.

[0215] Fig.16 An example of an enlarged cross-sectional configuration of the light emitting element 30 constituting the light emitting device 1 according to the third embodiment is shown. Fig.17 An example of the configuration of the first reflective layer 361 and the first electrode 363 of the light emitting element 30 is shown.

[0216] [Configuration of Light Emitting Device 1]

[0217] like Fig.16 and Fig.17 As shown in FIG. 1 , the light emitting device 1 of the third embodiment does not include a transparent electrode 321 between the second compound semiconductor layer 32 of the light emitting element 30 and the first reflective layer 361 (see FIG. 1 ). Figure 3 ). The first reflective layer 361 is directly coupled to the second compound semiconductor layer 32 with the first electrode 363 interposed therebetween.

[0218] The transparent electrode 321 is not disposed, and thus the first electrode 363 includes, for example, Ni, Pd, or Cr. These materials can be electrically coupled to the second compound semiconductor layer 32 with low resistance. In other words, the first electrode 363 achieves good conductivity with the second compound semiconductor layer 32.

[0219] like Fig.17 As shown, the first electrode 363 has the same Figure 4 Note that the first electrode 363 may have the same arrangement and number of electrodes as the first electrode 363 shown in the second embodiment. Fig.13 , Fig.14 and Fig.15 The arrangement and number of electrodes are the same as the first electrode 363 shown in FIG.

[0220] Components other than these are the same as those of the light emitting device 1 according to the first embodiment, and description thereof will be omitted.

[0221] [Effects and beneficial effects]

[0222] With the light emitting device 1 according to the third embodiment, the same actions and advantageous effects as those obtained from the light emitting device 1 according to the first embodiment can be obtained.

[0223] <4. Fourth Embodiment>

[0224] See also Fig.18 and Fig.19 , a light emitting device 1 according to a fourth embodiment of the present disclosure is described below.

[0225] Fig.18 An example of an enlarged cross-sectional configuration of the light emitting element 30 constituting the light emitting device 1 according to the fourth embodiment is shown. Fig.19 An example of the configuration of the first reflective layer 361 and the first electrode 363 of the light emitting element 30 is shown.

[0226] [Configuration of Light Emitting Device 1]

[0227] like Fig.18 and Fig.19 As shown, the second reflective layer 362 in the light emitting device 1 according to the fourth embodiment is electrically isolated from the first reflective layer 361. Specifically, an insulator 342 is formed between the second reflective layer 362 and the first reflective layer 361. The second reflective layer 362 is electrically floating.

[0228] Similar to the second reflective layer 362 of the light emitting device 1 according to the first embodiment described above, the second reflective layer 362 is formed in the same layer as the first reflective layer 361 and includes the same material as the first reflective layer 361. The second reflective layer 362 may be formed in a different layer from the first reflective layer 361 and include a material different from that of the first reflective layer 361.

[0229] Components other than these are the same as those of the light emitting device 1 according to the first embodiment, and description thereof will be omitted.

[0230] [Effects and beneficial effects]

[0231] According to the light emitting device 1 of the fourth embodiment, the same actions and advantageous effects as those obtained by the light emitting device 1 according to the first embodiment can be obtained.

[0232] like Fig.18As shown, the second reflective layer 362 in the light emitting device 1 is electrically isolated from the first reflective layer 361. With this configuration, no parasitic capacitance is added to the current path from the first reflective layer 361 to the second compound semiconductor layer 32, the second compound semiconductor layer 32, the active layer 33, and the first compound semiconductor layer 31 as one electrode, the insulator 341 as a dielectric, and the second reflective layer 362 as another electrode. This increases the driving operation speed of the light emitting element 30.

[0233] <5. Fifth embodiment>

[0234] See also Fig. 20 , a light emitting device 1 according to a fifth embodiment of the present disclosure is described below.

[0235] Fig. 20 An example of an enlarged cross-sectional configuration of the light emitting element 30 constituting the light emitting device 1 according to the fifth embodiment is shown.

[0236] [Configuration of Light Emitting Device 1]

[0237] like Fig. 20 As shown, similar to the light emitting device 1 according to the first embodiment, the second electrode 37 is placed on the first reflective layer 361 in the light emitting device 1 according to the fifth embodiment. Unlike the second electrode 37 of the light emitting device 1 according to the first embodiment, the second electrode 37 includes a single-layer barrier metal layer. For example, the barrier metal layer includes TiN.

[0238] Components other than these are the same as those of the light emitting device 1 according to the first embodiment, and description thereof will be omitted.

[0239] Note that the first reflective layer 361 in the fifth embodiment may be made of an Al alloy, but this may result in a slight decrease in reflectivity. In practice, AlCu may be used as the Al alloy.

[0240] [Effects and beneficial effects]

[0241] According to the light emitting device 1 of the fifth embodiment, the same actions and advantageous effects as those obtained by the light emitting device 1 according to the first embodiment can be obtained.

[0242] In addition, the second electrode 37 in the light emitting device 1 includes a single barrier metal layer, such as Fig. 20 This simplifies the configuration of the device.

[0243] <6. Example of application to moving objects>

[0244] The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology of the present disclosure can be embodied in the form of a device installed on any type of mobile object, 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.

[0245] Fig.21 is a block diagram depicting an example of a schematic configuration of a vehicle control system as an example of a moving body control system to which the technology according to an embodiment of the present disclosure can be applied.

[0246] The vehicle control system 12000 includes a plurality of electronic control units connected to each other via a communication network 12001. Fig.21 In the example shown, 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. In addition, as a functional configuration of the integrated control unit 12050, a microcomputer 12051, a sound / image output unit 12052, and an in-vehicle network interface (I / F) 12053 are exemplified.

[0247] The drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the drive system control unit 12010 serves as a control device for a drive force generating device (such as an internal combustion engine, a drive motor, etc.) for generating a drive force of the vehicle, a drive force transmitting mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, a braking device for generating a braking force of the vehicle, and the like.

[0248] The body system control unit 12020 controls the operation of various devices provided on the vehicle body according to various programs. For example, the body system control unit 12020 is used as a control device for a keyless entry system, a smart key system, a power window device, or various lights such as a headlight, a backup light, a brake light, a turn signal, a fog light, etc. In this case, a radio wave transmitted from a mobile device as a substitute for a key or a signal of various switches may be input to the body system control unit 12020. The body system control unit 12020 receives these input radio waves or signals, and controls the door lock device, the power window device, the lights, etc. of the vehicle.

[0249] The vehicle exterior information detection unit 12030 detects information outside the vehicle including the vehicle control system 12000. For example, the vehicle exterior information detection unit 12030 is connected to an imaging unit 12031. The vehicle exterior information detection unit 12030 causes the imaging unit 12031 to capture an image outside the vehicle and receive the captured image. In addition, the vehicle exterior information detection unit 12030 may also detect objects such as people, vehicles, obstacles, signs, and text on the road surface, or detect their distances, based on the received image.

[0250] 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 may output the electrical signal as an image, or may output the electrical signal as information about the measured distance. In addition, the light received by the imaging unit 12031 may be visible light, or may be invisible light such as infrared rays.

[0251] The in-vehicle information detection unit 12040 detects information about the interior of the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver state detection unit 12041 that detects the state of the driver. The driver state detection unit 12041 includes, for example, a camera that photographs the driver. Based on the detection information input from the driver state detection unit 12041, the in-vehicle information detection unit 12040 can calculate the driver's fatigue or the driver's concentration, or can determine whether the driver is dozing off.

[0252] The microcomputer 12051 can calculate the control target value of the driving force generation device, the steering mechanism, or the braking device based on the information about the inside or outside of the vehicle obtained by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and output a control command to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of the advanced driver assistance system (ADAS), which includes collision prevention or shock absorption for the vehicle, follow-up driving based on the following distance, maintaining the vehicle speed for driving, warning of vehicle collision, warning of vehicle deviation from the lane, etc.

[0253] In addition, the microcomputer 12051 can perform collaborative control for automatic driving by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about outside or inside the vehicle obtained by the outside information detection unit 12030 or the inside information detection unit 12040, thereby enabling the vehicle to travel automatically without relying on the driver's operation, etc.

[0254] In addition, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information about the outside of the vehicle obtained by the vehicle outside information detection unit 12030. For example, the microcomputer 12051 can perform cooperative control aimed at preventing glare by controlling the headlights to change from high beam to low beam according to the position of the front vehicle or the oncoming vehicle detected by the vehicle outside information detection unit 12030.

[0255] The sound / image output unit 12052 sends an output signal of at least one of sound and image to an output device, which can visually or auditorily notify the occupants of the vehicle or the outside of the vehicle of information. Fig.21 In the embodiment of FIG. 1 , an audio speaker 12061, a display portion 12062, and a dashboard 12063 are shown as output devices. For example, the display portion 12062 may include at least one of an on-board display and a head-up display.

[0256] Fig. 22 This is a diagram describing an example of the installation position of the imaging unit 12031.

[0257] exist Fig. 22 In the figure, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104 and 12105.

[0258] The imaging units 12101, 12102, 12103, 12104 and 12105 are, for example, disposed at positions on the front nose, side mirrors, rear bumper and rear door of the vehicle 12100 and at positions on the upper portion of the windshield inside the vehicle. The imaging unit 12101 disposed at the front nose inside the vehicle and the imaging unit 12105 disposed at the upper portion of the windshield mainly obtain images in front of the vehicle 12100. The imaging units 12102 and 12103 disposed to the side mirrors mainly obtain images on the sides of the vehicle 12100. The imaging unit 12104 disposed to the rear bumper or rear door mainly obtains images of the rear of the vehicle 12100. The imaging unit 12105 disposed at the upper portion of the windshield inside the vehicle is mainly used to detect vehicles ahead, pedestrians, obstacles, signals, traffic signs, lanes, etc.

[0259] By the way, Fig. 22An embodiment of the shooting range of the imaging units 12101 to 12104 is described. The imaging range 12111 represents the imaging range of the imaging unit 12101 set to the front nose. The imaging ranges 12112 and 12113 respectively represent the imaging ranges of the imaging units 12102 and 12103 set to the side mirrors. The imaging range 12114 represents the imaging range of the imaging unit 12104 set to the rear bumper or the rear door. For example, a bird's-eye view image of the vehicle 12100 viewed from above is obtained by superimposing image data imaged by the imaging units 12101 to 12104.

[0260] At least one of the imaging units 12101 to 12104 may have a function of obtaining distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

[0261] For example, the microcomputer 12051 can determine the distance to each three-dimensional object within the imaging range 12111 to 12114 and the time change of the distance (relative speed relative to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104, thereby extracting objects that exist on the driving path of the vehicle 12100 and are traveling in the same direction as the vehicle 12100 at a prescribed speed (e.g., equal to or greater than 0 km / hour). In addition, the microcomputer 12051 can pre-set the following distance to keep ahead of the leading vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. As a result, coordinated control for automatic driving that allows the vehicle to travel automatically without relying on the driver's operation, etc., can be performed.

[0262] For example, the microcomputer 12051 can classify the three-dimensional object data related to the three-dimensional object into three-dimensional object data of a two-wheeled vehicle, a standard vehicle, a large vehicle, a pedestrian, a utility pole, and other three-dimensional objects based on the distance information obtained from the imaging units 12101 to 12104, extract the classified three-dimensional object data, and use the extracted three-dimensional object data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 as obstacles that can be visually recognized by the driver of the vehicle 12100 and obstacles that are difficult for the driver of the vehicle 12100 to visually recognize. Then, the microcomputer 12051 determines a collision risk indicating the risk of collision with each obstacle. In the case where the collision risk is equal to or higher than the set value and therefore there is a possibility of collision, the microcomputer 12051 outputs a warning to the driver via the audio speaker 12061 or the display unit 12062, and performs forced deceleration or evasive steering via the drive system control unit 12010. The microcomputer 12051 can thereby assist driving to avoid collisions.

[0263] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. The microcomputer 12051 may, for example, identify a pedestrian by determining whether a pedestrian exists in the captured images of the imaging units 12101 to 12104. This identification of a pedestrian is performed, for example, by a process of extracting feature points in the imaged images of the imaging units 12101 to 12104 as infrared cameras and by performing pattern matching processing on a series of feature points representing the outline of an object to determine whether it is a pedestrian. When the microcomputer 12051 determines that a pedestrian exists in the imaged images of the imaging units 12101 to 12104 and thus identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 so that a square outline for emphasis is displayed as superimposed on the identified pedestrian. The sound / image output unit 12052 may also control the display unit 12062 so that an icon representing a pedestrian or the like is displayed at a desired position.

[0264] That is, a description of an embodiment 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 the imaging device 12031 of the above configuration. Applying the technology according to the present disclosure to the imaging unit 12031 can realize the imaging unit 12031 with a simpler configuration.

[0265] <7. Other Implementation Methods>

[0266] The present technology is not limited to the above-described embodiments, and can be modified in various ways without departing from the gist thereof. For example, two or more of the above-described embodiments may be combined.

[0267] The light emitting device according to the first embodiment of the present disclosure includes a first reflective layer placed above the second compound semiconductor layer, thereby effectively suppressing or preventing light emitted from the active layer from leaking. Therefore, the first reflective layer can effectively reflect light, thereby improving the light extraction efficiency of the light emitting device.

[0268] Furthermore, the first electrode in the light emitting device is electrically coupled to the first reflective layer and a portion of the second compound semiconductor layer, thereby sufficiently ensuring the reflective region of the first reflective layer and further improving light extraction efficiency.

[0269] The light emitting device according to the second embodiment of the present disclosure further includes an insulator in the light emitting device according to the first embodiment. The insulator is placed between the second compound semiconductor layer and the first reflective layer, specifically, between the transparent electrode and the first reflective layer, and is light-transmissive and insulating.

[0270] Therefore, the insulator can effectively suppress or prevent composition changes in the first reflective layer caused by the transparent electrode, thereby maintaining the reflectivity of the first reflective layer and improving light extraction efficiency.

[0271] The light emitting device according to the third embodiment of the present disclosure includes a second reflective layer along the mesa-shaped side surface of at least a portion of the first compound semiconductor layer, the active layer, and the second compound semiconductor layer in the light emitting device according to the first embodiment or the second embodiment. The second reflective layer reflects light emitted from the active layer and light reflected from the first reflective layer toward the first compound semiconductor layer.

[0272] Therefore, the light emitting device can effectively extract light due to the second reflective layer, thereby further improving light extraction efficiency.

[0273] The light emitting device according to the fourth embodiment of the present disclosure further includes a second electrode on the first reflective layer on the opposite side of the second compound semiconductor layer in the light emitting device according to any one of the first to third embodiments. The second electrode is formed by sequentially stacking a barrier metal layer, an Al alloy layer, and a barrier metal layer.

[0274] This improves the electrical reliability of the second electrode in the light emitting device.

[0275] <Configuration of this technology>

[0276] The present technology has the following configuration. The following configuration of the present technology can enhance the light extraction efficiency of the light emitting device. (1)

[0278] A light emitting device, comprising:

[0279] a first compound semiconductor layer having a first conductivity type;

[0280] an active layer stacked on the first compound semiconductor layer;

[0281] a second compound semiconductor layer, stacked on the active layer on a side opposite to the first compound semiconductor layer, the second compound semiconductor layer having a second conductivity type opposite to the first conductivity type;

[0282] a first reflective layer disposed away from a surface of the second compound semiconductor layer on a side opposite to the active layer, the first reflective layer reflecting light emitted from the active layer; and

[0283] The first electrode is disposed between the second compound semiconductor layer and the first reflective layer and electrically connects a portion of the second compound semiconductor layer and a portion of the first reflective layer. (2)

[0285] The light emitting device according to (1), wherein the first reflective layer includes one or more materials selected from Al, Al alloy, Ag, and Ag alloy. (3)

[0287] The light emitting device according to (1) or (2), further comprising a transparent electrode between the second compound semiconductor layer and the first electrode, wherein

[0288] The first electrode is electrically coupled to the second compound semiconductor layer with a transparent electrode interposed between the second compound semiconductor layer and the first electrode. (4)

[0290] The light emitting device according to (3), wherein the first electrode includes Ti or a Ti alloy. (5)

[0292] The light emitting device according to (2), wherein the first electrode includes Ni, Pd or Cr. (6)

[0294] The light emitting device according to any one of (1) to (5), wherein the first electrode includes a plurality of first electrodes. (7)

[0296] The light emitting device according to (6), wherein the first electrode has an area viewed in a thickness direction of the first electrode that is smaller than an area of ​​the first reflective layer viewed in the same direction. (8)

[0298] The light emitting device according to (6) or (7), wherein the total area of ​​the first electrodes is not less than 1% and not more than 30% of the area of ​​the first reflective layer. (9)

[0300] The light emitting device according to any one of (1) to (8), wherein the first reflective layer has a reflectivity of 75% or more with respect to blue light. (10)

[0302] The light emitting device according to any one of (1) to (9), further including an insulator between the second compound semiconductor layer and the first reflective layer, the insulator being light-transmissive and insulating. (11)

[0304] The light emitting device according to (10), wherein the insulator includes AlO, SiO, or SiN. (12)

[0306] The light emitting device according to any one of (1) to (11), wherein the second compound semiconductor layer has a thickness that amplifies light extraction efficiency. (13)

[0308] The light emitting device according to any one of (1) to (11), wherein at least a portion of the first compound semiconductor layer, the active layer, and the second compound semiconductor layer have a mesa shape, and

[0309] The light emitting device further includes a second reflective layer disposed along a side surface of the mesa shape, the second reflective layer reflecting light emitted from the active layer and light reflected from the first reflective layer toward the first compound semiconductor layer. (14)

[0311] The light emitting device according to (13), wherein the second reflective layer is located at the same layer as the first reflective layer and includes the same material as the first reflective layer. (15)

[0313] The light emitting device according to (13) or (14), wherein the second reflective layer is formed integrally with the first reflective layer. (16)

[0315] The light emitting device according to (13), wherein the second reflective layer is electrically isolated from the first reflective layer. (17)

[0317] The light emitting device according to (16), wherein the second reflective layer includes a material different from a material of the first reflective layer. (18)

[0319] The light-emitting device according to any one of (1) to (17) further includes a second electrode, which is on the first reflective layer, on the side opposite to the second compound semiconductor layer, and includes a barrier metal layer, an Al alloy layer, and a stack of barrier metal layers stacked in sequence. (19)

[0321] The light emitting device according to (18), further comprising a wiring electrically coupled to the second electrode using a plug wiring inserted between the wirings. (20)

[0323] The light-emitting device according to any one of (1) to (19), wherein the first compound semiconductor layer, the active layer, and the second compound semiconductor layer constitute a light-emitting element, and

[0324] The light emitting element includes an array of a plurality of light emitting elements constituting a micro light emitting device.

[0325] This application claims the benefit of Japanese Priority Patent Application JP2022-131103 filed in the Japan Patent Office on August 19, 2022, the entire contents of which are incorporated herein by reference.

[0326] It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A light emitting device, comprising: a first compound semiconductor layer having a first conductivity type; an active layer, stacked on the first compound semiconductor layer; a second compound semiconductor layer, stacked on the active layer on a side opposite to the first compound semiconductor layer, the second compound semiconductor layer having a second conductivity type opposite to the first conductivity type; a first reflective layer arranged away from a surface of the second compound semiconductor layer on a side opposite to the active layer, the first reflective layer reflecting light emitted from the active layer; as well as A first electrode is disposed between the second compound semiconductor layer and the first reflective layer and electrically connects a portion of the second compound semiconductor layer and a portion of the first reflective layer.

2. The light emitting device according to claim 1, wherein: The first reflective layer includes one or more materials selected from Al, Al alloy, Ag and Ag alloy.

3. The light emitting device according to claim 2, further comprising: a transparent electrode between the second compound semiconductor layer and the first electrode, wherein The first electrode is electrically coupled to the second compound semiconductor layer with the transparent electrode interposed between the second compound semiconductor layer and the first electrode.

4. The light emitting device according to claim 3, wherein: The first electrode includes Ti or a Ti alloy.

5. The light emitting device according to claim 2, wherein: The first electrode includes Ni, Pd or Cr.

6. The light emitting device according to claim 1, wherein: The first electrode includes a plurality of first electrodes.

7. The light emitting device according to claim 6, wherein: The first electrode has an area viewed in a thickness direction of the first electrode that is smaller than an area of ​​the first reflective layer viewed in the same direction.

8. The light emitting device according to claim 7, wherein: The total area of ​​the first electrodes is greater than or equal to 1% and less than or equal to 30% of the area of ​​the first reflective layer.

9. The light emitting device according to claim 1, wherein: The first reflective layer has a reflectivity of more than 75% for blue light.

10. The light emitting device according to claim 1, further comprising: An insulator is between the second compound semiconductor layer and the first reflective layer, the insulator being light-transmissive and insulating.

11. The light emitting device according to claim 10, wherein: The insulator includes AlO, SiO or SiN.

12. The light emitting device according to claim 1, wherein: The second compound semiconductor layer has a thickness that amplifies light extraction efficiency.

13. The light emitting device according to claim 1, wherein: At least a portion of the first compound semiconductor layer, the active layer, and the second compound semiconductor layer have a mesa shape, and The light emitting device further includes a second reflective layer disposed along a side surface of the mesa shape, the second reflective layer reflecting light emitted from the active layer and light reflected from the first reflective layer toward the first compound semiconductor layer.

14. The light emitting device according to claim 13, wherein: The second reflective layer is located at the same layer as the first reflective layer and includes the same material as the first reflective layer.

15. The light emitting device according to claim 13, wherein: The second reflective layer is formed integrally with the first reflective layer.

16. The light emitting device according to claim 13, wherein: The second reflective layer is electrically isolated from the first reflective layer.

17. The light emitting device according to claim 16, wherein: The second reflective layer includes a material different from that of the first reflective layer.

18. The light emitting device according to claim 1, further comprising: A second electrode is formed on the first reflective layer on a side opposite to the second compound semiconductor layer, the second electrode including a barrier metal layer, an Al alloy layer, and a stack of barrier metal layers stacked in sequence.

19. The light emitting device according to claim 18, further comprising: A wiring is electrically coupled to the second electrode using a plug wiring inserted between the wirings.

20. The light emitting device according to claim 1, wherein: The first compound semiconductor layer, the active layer, and the second compound semiconductor layer constitute a light emitting element, and The light emitting element includes an array of a plurality of light emitting elements to form a micro light emitting device.

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