Patent Publication Number: US-11049902-B2

Title: Light-emitting element wafer, light emitting element, electronic apparatus, and method of producing light-emitting element wafer

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a division of U.S. patent application Ser. No. 15/919,799 filed Mar. 13, 2018, which is a continuation of U.S. patent application Ser. No. 15/240,266 filed Aug. 18, 2016, now U.S. Pat. No. 9,960,206 issued May 1, 2018, which is a continuation of U.S. patent application Ser. No. 14/294,264 filed Jun. 3, 2014, now U.S. Pat. No. 9,461,197 issued Oct. 4, 2016, the entireties of which are incorporated herein by reference to the extent permitted by law. This application claims the benefit of Japanese Priority Patent Application JP 2013-121462 filed Jun. 10, 2013, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure relates to a light-emitting element wafer including a semiconductor material, a method of producing the light-emitting element wafer, a light emitting element, and an electronic apparatus using the light emitting element. 
     A light emitting element that includes a luminescent layer having a laminated structure has been known. In recent years, such a light emitting element is produced as a light-emitting element wafer in which a plurality of light emitting elements are arranged from a viewpoint of reducing the size of the element structure and improving the productivity (see Japanese Patent Application Laid-open No. 2008-172040). Specifically, by causing crystal growth of a luminescent layer on a wafer and forming an element isolation trench on the luminescent layer with a reactive ion etching (RIE) method, a plurality of light emitting elements are formed on the wafer. After that, each light emitting element is isolated from the wafer, and is mounted on an electronic apparatus such as a display apparatus and a lighting apparatus. 
     SUMMARY 
     In the method of producing a light-emitting element wafer described in Japanese Patent Application Laid-open No. 2008-172040, the depth of the element isolation trench is significantly affected by the etching rate. Here, it is desirable to use a wafer having a larger area from a viewpoint of mass production. However, it is difficult to obtain a uniform etching rate in a wafer surface as the area of the wafer increases. Therefore, in the case where a wafer having a large area is used, it is difficult to obtain a uniform depth of the element isolation trench in the wafer surface and the height of each element on the wafer is non-uniform, which may affect an electronic apparatus after the wafer is mounted on the electronic apparatus. 
     Furthermore, in each light emitting element described in Japanese Patent Application Laid-open No. 2008-172040, the luminescent layer is exposed, and it is difficult to ensure electrical insulating properties and physical and chemical stability of the element when a wiring is formed on the luminescent layer. 
     In view of the circumstances as described above, it is desirable to provide a light-emitting element wafer that is capable of producing elements with a uniform height in large amounts and has high stability of element characteristics, a method of producing the light-emitting element wafer, a light emitting element, and an electronic apparatus using the light emitting element. 
     According to an embodiment of the present disclosure, there is provided a light-emitting element wafer including a supporting substrate, a luminescent layer, a junction layer, a first inorganic film, a second inorganic film, an isolation trench portion, and a third inorganic film. The luminescent layer is formed of a semiconductor and has a first surface and a second surface, the first surface including a first electrode, the second surface including a second electrode, the second surface being arranged between the supporting substrate and the first surface. The junction layer joins luminescent layer to the supporting substrate and is arranged between the supporting substrate and the second surface. The first inorganic film is formed on the first surface. The second inorganic film is formed between the junction layer and the second surface. The isolation trench portion isolates elements and is formed to have a depth such that the isolation trench portion extends from the first inorganic film to the supporting substrate. The third inorganic film connects the first inorganic film and the second inorganic film. 
     Because the light-emitting element wafer has a configuration in which the junction layer, the second inorganic film, the luminescent layer, and the first inorganic film are laminated on the supporting substrate, and the isolation trench portion isolates them for each element, many elements with a uniform height can be formed on the supporting substrate. Therefore, it is possible to improve the uniformity of the shape of the elements on the light-emitting element wafer while maintaining high productivity. In addition, the first, second, and third inorganic films reliably protect the luminescent layer, and it is possible to ensure electrical insulating properties of the luminescent layer. 
     The first inorganic film may have a first end portion formed in parallel with the first surface, the first end portion projecting to the isolation trench portion, and the third inorganic film may have a second end portion that takes an example from the first end portion to project to the isolation trench portion. 
     Accordingly, it is possible to increase the strength of the element. 
     Furthermore, the second inorganic film and the third inorganic film may include a first insulating layer, a metal layer, and a second insulating layer, and are formed sequentially, the first insulating layer being formed adjacent to the luminescent layer, the metal layer being formed on the first insulating layer, the second insulating layer being formed on the metal layer. 
     Accordingly, it is possible to cause light emitted from the luminescent layer to be reflected on the second and third inorganic film, and to increase the emission intensity. 
     Moreover, the luminescent layer may have a first concavo-convex portion formed on the first surface, and the first inorganic film may have a second concavo-convex portion formed taking an example from the first concavo-convex portion. 
     Accordingly, it is possible to cause light emitted from the luminescent layer to be reflected on the first and second concavo-convex portions, and to increase the emission intensity. 
     The luminescent layer may emit red light. 
     Moreover, specifically, the semiconductor may include at least any one of materials of an AsP compound semiconductor, an AlGaInP compound semiconductor, and a GaAs compound semiconductor. 
     The first inorganic film may be the first electrode including a transparent conductive material. 
     Accordingly, it is possible to output, from the entire first surface, light emitted from the luminescent layer, and to increase the output efficiency. 
     According to an embodiment of the present disclosure, there is provided a light emitting element including a luminescent layer, a first inorganic film, a second inorganic film, and a third inorganic film. 
     The luminescent layer is formed of a semiconductor and has a first surface, a second surface, and a peripheral surface, the first surface including a first electrode, the second surface including a second electrode and being opposite to the first surface, the peripheral surface connecting the first surface and the second surface. The first inorganic film is formed on the first surface. The second inorganic film is formed on the second surface. The third inorganic film is formed to cover the peripheral surface and connects the first inorganic film and the second inorganic film. 
     According to an embodiment of the present disclosure, there is provided an electronic apparatus including a substrate and at least one first semiconductor light-emitting element. On the substrate, a drive circuit is formed. The at least one first semiconductor light-emitting element is provided on the substrate and includes a luminescent layer, a first inorganic film, a second inorganic film, and a third inorganic film. The luminescent layer is formed of a semiconductor and has a first surface, a second surface, and a peripheral surface, the first surface including a first electrode connected to the drive circuit, the second surface including a second electrode, the second surface being disposed between the substrate and the first surface, the second electrode being connected to the drive circuit, the peripheral surface connecting the first surface and the second surface. The first inorganic film is formed on the first surface. The second inorganic film is formed between the luminescent layer and the second surface. The third inorganic film is formed to cover that peripheral surface and connects the first inorganic film and the second inorganic film. 
     Accordingly, the electronic apparatus can be configured to include the first light emitting element in which the luminescent layer is protected and electrical insulating properties of the luminescent layer can be ensured. Thus, it is possible to provide an electronic apparatus with a few flaws. 
     In addition, the electronic apparatus may further include a plurality of second semiconductor light-emitting elements configured to emit blue light and a plurality of third semiconductor light-emitting elements configured to emit green light, in which the at least one first semiconductor light-emitting element may include a plurality of first semiconductor light-emitting element configured to emit red light, and the plurality of first, second, and third semiconductor light-emitting elements may be arranged on the substrate. 
     Accordingly, it is possible to provide an electronic apparatus such as a display having high assembly accuracy and desired display properties by using the plurality of first semiconductor elements with high shape uniformity. 
     According to an embodiment of the present disclosure, there is provided a method of producing a light-emitting element wafer including forming a luminescent layer having a laminated structure in which a semiconductor is laminated on a first substrate. A first inorganic film is formed on a first surface of the luminescent layer, and the first substrate is removed to expose a second surface of the luminescent layer, the second surface being opposite to the first surface. The luminescent layer is etched from the second surface with the first inorganic film being an etching stop layer to form a first isolation trench that isolates the luminescent layer for each element. A second inorganic film that covers the second surface and a wall surface and a bottom surface of the first isolation trench is formed. 
     Because the first inorganic film laminated on the luminescent layer functions as an etching stop layer when the first isolation trench is formed, it is possible to increase the uniformity of the depth of the first isolation trench. Therefore, it is possible to improve the productivity and to increase the shape uniformity of each element. Moreover, because the first inorganic film is formed on the bottom surface of the first isolation trench and the second inorganic film is formed on the bottom surface, the first and second inorganic films cover the surface of the luminescent layer. Therefore, it is possible to improve the insulating properties of the luminescent layer and to protect the luminescent layer. 
     The forming of the first isolation trench may include etching the luminescent layer by a dry etching method. 
     Accordingly, it is possible to reduce the side etching as compared with the case of a wet etching method, and to perform a fine process on the first isolation trench. 
     The forming of the first isolation trench may include forming the first isolation trench so that a cross-sectional area of the luminescent layer for each element is gradually increased from the second surface to the first surface. 
     Accordingly, it is possible to easily form the second inorganic film. 
     The forming of the second inorganic film may include forming the first insulating layer on the second surface and the wall surface and the bottom surface of the first isolation trench, forming a metal layer on the first insulating layer, and forming a second insulating layer on the metal layer. 
     Accordingly, it is possible to cause light emitted from the luminescent layer to be reflected on the metal layer, and to increase the emission intensity. 
     The method of producing a light-emitting element wafer may further include forming a first concavo-convex structure on the first surface before the forming of the first inorganic film and after the forming of the luminescent layer. 
     Moreover, the forming of the first inorganic film may include taking an example from the first concavo-convex structure to form a second concavo-convex structure. 
     Accordingly, it is possible to form the first concavo-convex structure on a flat surface to have a desired shape right after the luminescent layer is formed. Therefore, it is possible to cause light emitted from the luminescent layer to be effectively reflected on the first concavo-convex structure, and to increase the emission intensity. 
     Furthermore, the method of producing a light-emitting element wafer may further include detachably joining the second substrate to the first inorganic film via a tentative a tentative junction layer before the exposure of the second surface and after the forming of the first inorganic film. 
     Accordingly, it is possible to improve the handling properties of the formed element structure. 
     Furthermore, the method of producing a light-emitting element wafer may further include forming an electrode for each device on the second surface before the forming of the first isolation trench after the exposure of the second surface, removing a part of the second inorganic film to expose the electrode after the forming of the second inorganic film, forming an external connection terminal that is electrically connected to the electrode on the second surface, and detachably joining a third substrate to the external connection terminal via the junction layer. 
     Accordingly, it is possible to easily ensure a wiring when the light emitting element is mounted on an electronic apparatus or the like. In addition, because the third substrate is joined, it is possible to improve the handling properties of the formed element structure. 
     Furthermore, the method of producing a light-emitting element wafer may further include removing the second substrate to expose the first inorganic film, and etching the first inorganic film remained on the bottom surface of the first isolation trench to form a second isolation trench that isolates the first inorganic film for each element, after the joining of the third substrate. 
     Accordingly, because the elements are isolated, it is possible to easily transfer each element to another transfer substrate, a wiring substrate, or the like. 
     Furthermore, the method of producing a light-emitting element wafer may further include preparing a transfer substrate arranged to face the first inorganic film, and isolating the external connection terminal from the third substrate by laser ablation of the junction layer to transfer each element on the transfer substrate, after the forming of the second isolation trench. 
     By the laser ablation, it is possible to easily transfer each element to a predetermined position on the transfer substrate without processes such as mechanical removal of a substrate. In addition, by using the transfer substrate, the elements can be arranged at sufficient intervals, and a wiring can be smoothly formed between the elements, for example. Therefore, it is possible to easily mount each element on the wiring substrate or the like of the electronic apparatus or the like. 
     As described above, according to the present disclosure, it is possible to provide a light-emitting element wafer that is capable of producing elements with a uniform height in large amounts and has high stability of element characteristics, a method of producing the light-emitting element wafer, a light emitting element, and an electronic apparatus using the light emitting element. 
     These and other objects, features and advantages of the present disclosure will become more apparent in light of the following detailed description of best mode embodiments thereof, as illustrated in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic plan view of a light-emitting element wafer according to a first embodiment of the present disclosure; 
         FIG. 2  is a schematic cross-sectional view of the light-emitting element wafer; 
         FIG. 3  is a schematic cross-sectional view showing the configuration of a light emitting element shown in  FIG. 1 ; 
         FIGS. 4A and 4B  are each a diagram for explaining an operation of orientation of a first inorganic film shown in  FIG. 1 ,  FIG. 4A  is a schematic cross-sectional view of a main portion of the light emitting element, and  FIG. 4B  is a diagram showing a correlation between a refractive index N and a thickness t (nm) of the first inorganic film of the light emitting element and light orientation distribution; 
         FIGS. 5A and 5B  are each a graph showing exemplary distribution of emission intensity with respect to an emission angle θ; 
         FIG. 6  is a flowchart of a method of producing the light-emitting element wafer; 
         FIGS. 7A, 7B and 7C  are each a cross-sectional view for explaining the method of producing the light-emitting element wafer; 
         FIGS. 8A and 8B  are each a cross-sectional view for explaining the method of producing the light-emitting element wafer; 
         FIGS. 9A and 9B  are each a cross-sectional view for explaining the method of producing the light-emitting element wafer; 
         FIGS. 10A and 10B  are each a cross-sectional view for explaining the method of producing the light-emitting element wafer; 
         FIGS. 11A and 11B  are each a cross-sectional view for explaining the method of producing the light-emitting element wafer; 
         FIGS. 12A and 12B  are each a cross-sectional view for explaining the method of producing the light-emitting element wafer; 
         FIGS. 13A and 13B  are each a schematic cross-sectional view for explaining a process of forming a reflection film (second inorganic film) in the method of producing the light-emitting element wafer; 
         FIGS. 14A and 14B  are each a schematic cross-sectional view for explaining the process of forming the reflection film (second inorganic film) in the method of producing the light-emitting element wafer; 
         FIG. 15  is a schematic plan view of a display apparatus (electronic apparatus) using the light emitting element; 
         FIG. 16  is a flowchart of a method of producing the display apparatus; 
         FIG. 17  is a schematic plan view for explaining the method of producing the display apparatus; 
         FIGS. 18A, 18B and 18C  are each a schematic plan view for explaining the method of producing the display apparatus; 
         FIG. 19  is a schematic cross-sectional view of a light-emitting element wafer according to a second embodiment of the present disclosure; 
         FIGS. 20A, 20B and 20C  are each a schematic cross-sectional view for explaining the method of producing the light-emitting element wafer; 
         FIGS. 21A, 21B and 21C  are each a schematic cross-sectional view for explaining the method of producing the light-emitting element wafer; 
         FIGS. 22A and 22B  are each a schematic cross-sectional view for explaining the method of producing the light-emitting element wafer; and 
         FIGS. 23A and 23B  are each a schematic cross-sectional view for explaining the method of producing the light-emitting element wafer. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. 
     First Embodiment 
       FIG. 1  is a schematic plan view of a light-emitting element wafer  100  according to a first embodiment of the present disclosure, and  FIG. 2  is a schematic cross-sectional view of the light-emitting element wafer  100 . Hereinafter, the configuration of the light-emitting element wafer  100  according to this embodiment will be described. It should be noted that in  FIGS. 1 and 2 , an X-axis and Y-axis represent directions orthogonal to each other (in-plane direction of the light-emitting element wafer  100 ), and a Z-axis is a direction orthogonal to the X-axis and the Y-axis (thickness direction of the light-emitting element wafer  100 , i.e., vertical direction). 
     (Semiconductor Light-Emitting Element Wafer) 
     The light-emitting element wafer  100  includes a supporting substrate  10 , a plurality of light emitting elements  1 , and isolation trench portions  60 . The light-emitting element wafer  100  has a configuration in which the plurality of light emitting elements  1  are arranged on the supporting substrate  10 . The light-emitting element wafer  100  according to this embodiment is used to supply the light emitting elements  1  to be mounted on an electronic apparatus such as a display apparatus and a lighting apparatus, as will be described later. 
     The supporting substrate  10  has a surface  11  on which the light emitting elements  1  are arranged, and includes, for example, a 2 to 12-inch wafer. The supporting substrate  10  includes, for example, a material having a high transmittance of a wavelength of a laser to be applied in a production process to be described later, e.g., sapphire (Al 2 O 3 ). 
     The plurality of light emitting elements  1  are arranged on the supporting substrate  10  along the X-axis direction and the Y-axis direction, and adjacent light emitting elements  1  are isolated by the isolation trench portion  60 . Specifically, the isolation trench portion  60  is formed to have a depth extending from a first inorganic film  40  of the plurality of light emitting elements  1 , which will be described later, to the surface  11  of the supporting substrate  10 , and isolates the light emitting elements  1 . It should be noted that in the following description, the light emitting elements  1  will be referred to simply also as “the elements  1 .” 
     (Light Emitting Element) 
     The light emitting element  1  includes a light emitting diode (LED) having a laminated structure of a semiconductor compound. In this embodiment, the plurality of light emitting elements  1  are arranged on the supporting substrate  10 . The size of the light emitting element  1  can be appropriately set depending on the size of the supporting substrate  10 , the configuration of the electronic apparatus on which the light emitting element  1  is mounted, or the like, and the light emitting element  1  may have a length of not less than 1 μm and not more than 300 μm along the X-axis direction, and a length of not less than 1 μm and not more than 300 μm along the Y-axis direction, and a height of not less than 1 μm and not more than 20 μm along the Z-axis direction, for example. 
       FIG. 3  is a schematic cross-sectional view showing the configuration of the light emitting element  1 . The light emitting element  1  includes a luminescent layer  20 , a junction layer  30 , the first inorganic film  40 , a second inorganic film  520 , and a third inorganic film  530 . Moreover, the second inorganic film  520  and the third inorganic film  530  are collectively referred to also as the reflection film (second inorganic film  50 ). 
     The luminescent layer  20  has a first surface  201  including a first electrode  710  and a second surface  202  that includes a second electrode (electrode)  720  and is arranged between the supporting substrate  10  and the first surface  201 , and is formed of a semiconductor. 
     The junction layer  30  is arranged between the supporting substrate  10  and the second surface  202 , and joins the luminescent layer  20  to the supporting substrate  10 . 
     The first inorganic film  40  is formed on the first surface  201 . 
     The second inorganic film  520  is formed between the junction layer  30  and the second surface  202 . 
     The third inorganic film  530  connects the first inorganic film  40  and the second inorganic film  520 . 
     Hereinafter, each component of the light emitting element  1  will be described. 
     (Luminescent Layer) 
     In this embodiment, the luminescent layer  20  has a laminated structure of a semiconductor that emits red light, and includes, for example, a GaAs semiconductor compound and an AlGaInP semiconductor compound. The luminescent layer  20  includes a first conductive-type first semiconductor layer  21 , an active layer  23  formed on the first semiconductor layer  21 , and a second conductive-type second semiconductor layer  22  formed on the active layer  23 . In this embodiment, the first conductive type and the second conductive type represent an n-type and a p-type, respectively, but are not limited thereto. 
     The luminescent layer  20  has the first surface  201 , the second surface  202  opposite to the first surface  201 , and a peripheral surface  203  that connects the first surface  201  and the second surface  202 . The first surface  201  and the second surface  202  are arranged to face each other in the Z-axis direction. The entire thickness of the luminescent layer  20  is not less than about 1 μm and not more than 20 μm. The entire shape of the luminescent layer  20  is not particularly limited. For example, the luminescent layer  20  is formed to have a truncated square pyramid shape. In this case, the luminescent layer  20  is formed so that the cross-sectional area of the luminescent layer  20  perpendicular to the Z-axis direction is gradually increased from the second surface  202  to the first surface  201  and the peripheral surface  203  has four tapered surfaces. 
     The first surface  201  has a connection area  2011  in which the first electrode  710  is formed, and a light extraction area  2012  in which a first concavo-convex portion  210  is formed. The connection area  2011  occupies the center portion of the first surface  201 , and the light extraction area  2012  is arranged to surround the connection area  2011 . It should be noted that the position and shape of the connection area  2011  are not limited, and a plurality of connection areas  2011  may be arranged in an island shape. 
     The first concavo-convex portion  210  may be appropriately configured to obtain desired optical properties of output light. For example, the first concavo-convex portion  210  may have a prism shape having a ridge line as shown in  FIG. 3 , or groove-like concave portions may be formed on a flat surface (convex portion) (see  FIGS. 7 to 12 ). 
     Moreover, “the first surface  201  is substantially perpendicular to the Z-axis direction” represents that a reference surface  201   s  of the first surface  201  is substantially perpendicular to the Z-axis direction. In addition, the reference surface  201   s  of the first surface  201  represents a virtual flat surface including top portions (top surface) of a plurality of convex portions of the first concavo-convex portion  210 . 
     In this embodiment, the second surface  202  is formed to have the area smaller than that of the first surface  201  when view from the Z-axis direction. The second surface  202  has a connection area  2021  that occupies the center portion of the second surface  202 , on which the second electrode  720  is formed, and a reflection area  2022  that surrounds the connection area  2021 . The reflection area  2022  is covered by the second inorganic film  520  of the reflection film  50 . 
     In the luminescent layer  20 , light emitted from the active layer  23  is output via the light extraction area  2012  of the first surface  201 . In this embodiment, the peripheral surface  203  is formed as a tapered surface and is covered by the third inorganic film  530  to be described later, and the light extraction area  2012  of the first surface  201  has the first concavo-convex portion  210 . Accordingly, it is possible to increase the output efficiency by reflecting the light toward the upper side of the Z-axis direction, and to control the orientation of light. 
     The first semiconductor layer  21  has a laminated structure of a first contact layer  211  and a first cladding layer  212 . The first contact layer  211  is connected to the second electrode  720 , and is formed to have almost the same area as that of the second electrode  720  when viewed from the Z-axis direction, for example. The first contact layer  211  includes a material that is capable of forming ohmic contact with the second electrode  720 , e.g., n-type GaAs. The first cladding layer  212  is formed on the first contact layer  211  to occupy the entire second surface  202  when viewed from the Z-axis direction. Specifically, an exposed surface of the first cladding layer  212  forms the reflection area  2022  of the second surface  202 . The first cladding layer  212  includes, for example n-type AlGaInP. 
     The active layer  23  has a multiquantum well structure of a well layer and a barrier layer formed of semiconductors having different compositions, for example, and is formed to be capable of emitting light of a predetermined wavelength. The active layer  23  according to this embodiment is capable of emitting red light of a light emission wavelength of about 500 to 700 nm. The active layer  23  includes about 10 to 20 well layers and about 10 to 20 barrier layers, for example. Each well layer includes GaInP and each barrier layer includes AlGaInP. The well layers and the barrier layers are laminated to each other. 
     The second semiconductor layer  22  has a laminated structure of a second cladding layer  221  and a second contact layer  222 . The second cladding layer  221  is formed on the active layer  23 , and includes, for example, p-type AlGaInP. The second contact layer  222  is formed on the second cladding layer  221 , and is connected to the first electrode  710 . The second contact layer  222  occupies the entire first surface  201  when viewed from the Z-axis direction, and the exposed surface of the second contact layer  222 , on which the first electrode  710  is not formed, forms the light extraction area  2012  of the first surface  201 . The second contact layer  222  includes a material that is capable of forming ohmic contact with the first electrode  710 , e.g., p-type GaP. 
     It should be noted that in the first and second semiconductor layers  21  and  22 , another layer may be appropriately provided between the above-mentioned layers. For example, the second semiconductor layer  22  may include a protective layer between the active layer  23  and the second cladding layer  221 . The protective layer includes undoped AlGaInP, and is capable of preventing dopants of the second cladding layer  221  or the like from diffusing to the side of the active layer  23 . Moreover, the material shown in each layer of the luminescent layer  20  is given for exemplary purposes, and can be appropriately selected in view of the configuration of the light emitting element  1 , desired light emission properties, and the like. 
     The first electrode  710  is formed in the connection area  2011  of the first surface  201 , and is connected to the second contact layer  222 . Specifically, the surface of the first electrode  710  forms the connection area  2011  of the first surface  201 . The shape of the first electrode  710  is not particularly limited, and the first electrode  710  is formed to have an elliptical shape, a circular shape, or a rectangle shape, with a short axis length of about 1 to 10 μm along the X-axis direction and a long axis length of about 1 to 10 μm along the Y-axis direction, for example. In addition, the thickness of the first electrode  710  may be 200 to 600 μm, for example. The first electrode  710  may include a metal material such as Ti, Pt, Au, Ge, Ni, and Pd, an alloy or laminated body containing them, or a transparent conductive material such as ITO. 
     The second electrode  720  is formed in the connection area  2021  of the second surface  202 , and is connected to the first contact layer  211 . Specifically, the surface of the second electrode  720  forms the connection area  2021  of the second surface  202 . The shape of the second electrode  720  is not particularly limited, and the second electrode  720  is formed to have a circular shape, for example. However, the shape of the second electrode  720  may be an elliptical shape or a rectangular shape. In addition, the thickness of the second electrode  720  may be 200 to 600 μm, for example. The second electrode  720  may include a metal material such as Ti, Pt, Au, Ge, Ni, and Pd, an alloy or laminated body containing them, or a transparent conductive material such as ITO. 
     (First Inorganic Film) 
     The first inorganic film  40  is formed to cover the light extraction area  2012  of the first surface  201 . Specifically, the first inorganic film  40  includes a connection hole  420  that is formed on the first electrode  710  (the connection area  2011 ) and faces the first electrode  710 . The thickness of the first inorganic film  40  is, for example, not less than 200 μm and not more than 600 μm, more favorably, not less than 300 μm and not more than 500 μm. 
     Moreover, the first inorganic film  40  has a second concavo-convex portion  410  that is formed taking an example from the first concavo-convex portion  210  of the first surface  201 , and a first end portion  41  that is formed around the second concavo-convex portion  410 . The first end portion  41  forms a flat surface that is formed in parallel with the first surface  201 , and projects outward of the first surface  201 . Here, “formed in parallel with the first surface  201 ” represents being formed in parallel with the reference surface  201   s  of the first surface  201 . 
     The first inorganic film  40  has permeability, and includes silicon nitride (hereinafter, referred to as SiN) having a refractive index of not less than 1.9 and not more than 2.3, silicon oxide such as SiO 2 , or a laminated body of SiN and SiO 2 , for example. Alternatively, the first inorganic film  40  may include an insulating material such as TiN and TiO 2 . Accordingly, it is possible to ensure insulating properties of the first surface  201  of the luminescent layer  20 , and to cause the first inorganic film  40  to function as a protection film of the first surface  201 . Furthermore, as will be described later, because the first inorganic film  40  has a predetermined thickness and a predetermined refractive index, it is possible to increase the emission intensity of the light emitting element  1  in the front direction. 
     (Reflection Film) 
     The reflection film  50  includes the second inorganic film  520  and the third inorganic film  530 , and is formed to cover the second surface  202  and the peripheral surface  203  of the luminescent layer  20 . The reflection film  50  reflects, to the side of the first surface  201 , light emitted from the luminescent layer  20 , which contributes to improve the output efficiency. 
     The second inorganic film  520  is formed to cover the reflection area  2022  of the second surface  202  of the luminescent layer  20 . In addition, the second inorganic film  520  includes a connection hole  540  that is formed on the second electrode  720  (connection area  2021 ) and faces the second electrode  720 . The entire thickness of the second inorganic film  520  is, for example, not less than 0.1 μm. 
     The third inorganic film  530  is formed continuously with the second inorganic film  520 , and is formed to cover the entire peripheral surface  203  of the luminescent layer  20 . Moreover, the third inorganic film  530  has a second end portion  510  that projects outward taking an example from the first end portion  41  of the first inorganic film  40 . Specifically, the second end portion  510  is formed as a flange portion of the reflection film  50  that is folded in parallel with the first surface  201 . The thickness of the area along the peripheral surface  203  of the third inorganic film  530  is, for example, not less than 0.2 μm, and the thickness of the second end portion  510  is, for example, not less than 0.2 μm and not more than 5 μm. 
     With this configuration, a height H 2  of the second end portion  510  of the reflection film  50  (third inorganic film  530 ) along the Z-axis direction from the surface  11  of the supporting substrate  10  is lower than a height H 1  of the surface of the first inorganic film  40  at the first end portion  41  (see  FIG. 2 ). 
     The reflection film  50  includes a first insulating layer  51  formed adjacent to the luminescent layer  20 , a metal layer  53  formed on the first insulating layer  51 , and a second insulating layer  52  formed on the metal layer  53 . Specifically, the reflection film  50  has a laminate structure in which the reflection film  50  is continuously formed with the second and third inorganic films  520  and  530 . 
     The first insulating layer  51  covers from the reflection area  2022  of the second surface  202  to the peripheral surface  203 , and is formed over the second end portion  510  located immediately below the first end portion  41 . On the other hand, the second insulating layer  52  is formed in an area overlapped with the first insulating layer  51  when viewed from the Z-axis direction. The first and second insulating layers  51  and  52  may include silicon oxide such as SiO 2 , SiN, TiN, TiO 2 , another insulating inorganic material, or a laminated body thereof. 
     The metal layer  53  includes an opening  531  that is larger than the connection hole  540 , and is formed from a part of the reflection area  2022  to the second end portion  510  via the peripheral surface  203 , for example. The metal layer  53  has a function to reflect, to the first surface  201 , light emitted from the luminescent layer  20 . Specifically, a material having high reflection efficiency of the light emitted from the luminescent layer  20  only has to be adopted. In this embodiment, the metal layer  53  includes a metal material such as Al, Au, Ti, Cu, Ni, and Ag, or an alloy or laminated body thereof. 
     Moreover, because the metal layer  53  is formed to the second end portion  510 , it is possible to reflect light that has entered the first end portion  41  upward in the Z-axis direction, and to output the reflected light. Accordingly, it is possible to increase the intensity of output light in the front direction. 
     The connection hole  540  is formed by the first and second insulating layers  51  and  52 . Specifically, to the peripheral surface of the connection hole  540 , the first and second insulating layers  51  and  52  are exposed, and the metal layer  53  is not exposed. Accordingly, insulating properties between the metal layer  53  and the second electrode  720  are maintained. 
     The first and second end portions  41  and  510  each have an end surface in parallel with the Z-axis direction. In this embodiment, these end surfaces are formed in the same plane. Moreover, as shown in  FIG. 3 , the first and second insulating layers  51  and  52  and the metal layer  53  may be exposed from the end surface of the second end portion  510 . Accordingly, it is possible to increase the heat radiation property of the light emitting element  1 . Alternatively, the metal layer  53  may be formed not to be exposed from the end surface of the second end portion  510 , or may be formed to cover only the peripheral surface  203 . 
     Furthermore, the light emitting element  1  according to this embodiment further includes an external connection terminal  730  connected to the second electrode  720  that is exposed from the connection hole  540 . 
     (External Connection Terminal) 
     The external connection terminal  730  is arranged between the junction layer  30  and the second inorganic film  520 . The external connection terminal  730  is formed to be connected to the second electrode  720  and to cover the second inorganic film  520  and the second electrode  720 , and has a rectangular shape with almost the same size as the second inorganic film  520  when viewed from the Z-axis direction. The thickness of the external connection terminal  730  is not particularly limited, but is not less than 0.1 μm and not more than 0.5 μm, for example. The external connection terminal  730  includes a metal material such as Al, Au, and Ti, or an alloy or laminated body containing them. 
     It should be noted that as shown in  FIG. 3 , a resin film  732  may be formed so that a concave portion  733  of the external connection terminal  730 , which is formed due to the connection hole  540 , is embedded. The resin film  732  includes adhesive resin material, for example. It should be noted that the resin film  732  may be formed not only in the concave portion  733  but also in the entire area in which the external connection terminal  730  is formed (see resin R 3  in  FIG. 12A ). 
     (Junction Layer) 
     With reference to  FIG. 2 , the junction layer  30  is arranged between the external connection terminal  730  and the supporting substrate  10 , and joins the light emitting element  1  to the supporting substrate  10 . The thickness of the junction layer  30  is, for example, not less than 0.2 μm and not more than 2 μm. The junction layer  30  includes a thermoplastic resin material having adhesiveness such as polyimide. Therefore, the junction layer  30  is ablated when being heated to evaporation by irradiation of a laser light having a predetermined wavelength, for example. Accordingly, the junction layer  30  can be easily isolated from the supporting substrate  10  by the power of the ablation. The material of the junction layer  30  is not limited to the above, and ultraviolet curable resin, an adhesive sheet, an adhesive material can be adopted, for example. 
     In each light emitting element  1  having such a configuration, the junction layer  30 , the external connection terminal  730 , the second inorganic film  520 , the luminescent layer  20 , and the first inorganic film  40  are laminated in the stated order on the supporting substrate  10 . Moreover, these layers are isolated for each element  1  by the isolation trench portions  60  as described above. Specifically, in the light-emitting element wafer  100 , the light emitting elements  1  can be formed to have a uniform height on the entire supporting substrate  10 . Specifically, variation in heights of the plurality of light emitting elements  1  from the surface  11  on the light-emitting element wafer  100  can be suppressed to 10% or less, for example. 
     Furthermore, the first, second, and third inorganic films  40 ,  520 , and  530  cover the entire surface of the luminescent layer  20  excluding the connection areas  2011  and  2021 . Accordingly, it is possible to ensure insulating properties of the luminescent layer  20  and physical and chemical stability of the luminescent layer  20 . 
     Moreover, in the metal layer  53  having a tapered surface, and the first and second concavo-convex portions  210  and  410 , and it is possible to reflect light emitted from the luminescent layer  20  and to efficiently output the light from the first surface  201 . 
     Furthermore, by adjusting the thickness and the refractive index of the first inorganic film  40 , it is possible to use interference of light having a predetermined wavelength, and to adjust the orientation of output light of the light emitting element  1 . Hereinafter, the operation of the orientation of the output light of the first inorganic film  40  will be described. 
     (Operation of Orientation of First Inorganic Film) 
       FIG. 4A  is a schematic cross-sectional view of the luminescent layer  20  of light emitting element  1 , and  FIG. 4B  is a diagram showing the correlation between the refractive index N and the thickness t (nm) of the first inorganic film  40  and the light orientation distribution. More specifically, the horizontal axis represents a value of Nt/λ when the wavelength of output light is assumed to be λ (nm), and the vertical axis represents the ratio of actual emission intensity and emission intensity when the far field pattern (FFP) has a Lambertian profile in a direction at an angle of 45 degrees to the normal line direction of the first surface  201  (direction in parallel with the Z-axis direction) (hereinafter, the ratio being referred to as Lambertian curve ratio). It should be noted that the Lambertian represents the state of the FFP of output light. Assuming that an emission angle from the normal line direction of the output surface is θ, the Lambertian represents the light distribution such that the value of the FFP of output light is constant regardless of the angle, when the FFP of output light on an output surface is divided by cos θ. For example, when the FFP of output light has a Lambertian profile, the emission intensity has a maximum value in the front direction (θ=0°), and the output intensity tends to be decreased as the absolute value of the emission angle θ is increased. 
     As shown in  FIG. 4B , values of the distribution of the Lambertian carve ratio change at a cycle of Nt/λ being about ½ due to the influence of the interference of light. Specifically, the value is concave down (maximum) when Nt/λ is about 1.5 (6/4) (hereinafter, referred to as (B)), and is concave up (minimum) when Nt/λ is about 1.25 (5/4) (hereinafter, referred to as (A)) and about 1.79 (7/4+0.05) (hereinafter, referred to as (C)). 
     Here, Figs. are each a graph showing the distribution of emission intensity with respect to the emission angle θ,  FIG. 5A  shows an example of the (B) in the graph of  FIG. 4B  in which the emission intensity is maximum, and  FIG. 5B  shows an example of the (A) and (C) in the graph of  FIG. 4B  in which the emission intensity is minimum. In  FIGS. 5A and 5B , the FFP in the case of the Lambertian is represented by a light colored line as a reference. 
     As shown in  FIG. 5A , in the case of the (B), the emission intensity is large in the range of −70&lt;θ&lt;70 as compared with the case of Lambertian, and the emission intensity in the front direction (θ=0) is relatively small. On the other hand, as shown in  FIG. 5B , in the case of the (A) and (C), the emission intensity is small as a whole as compared with the case of Lambertian, and the emission intensity in the front direction is relatively large. 
     Based on these results, in order to increase the emission intensity in the front direction, it only needs to adjust the value of Nt/λ in the first inorganic film  40  to be concave up as in the (A) and (C) in the graph of  FIG. 4B , for example. Therefore, based on the value of Nt/λ and the fluctuation cycle of Nt/λ in the (A) and (C), it only needs to adjust N (refractive index of the first inorganic film  40 ), t (thickness of the first inorganic film  40 ), and λ (wavelength of output light of the luminescent layer  20 ) so as to satisfy the following equation (1):
 
 Nt /λ=( x+ 1)/4±10.15( x= 2,4,6,8)  (1).
 
     In this embodiment, λ is about 630 (nm), for example. Moreover, in the case where SiN is used for the first inorganic film  40 , the refractive index N satisfies the equation, 2.0≤N≤2.1, for example. Therefore, by setting the thickness t of the first inorganic film  40  to 141.75 (nm), 393.75 (nm), 552.25 (nm), and 708.75 (nm) in the case where N=2.0 and x=2, 4, 6, and 8, respectively, it is possible to increase the emission intensity in the front direction. 
     As described above, by adjusting the material and the thickness of the first inorganic film  40  depending on the wavelength of light emitted from the luminescent layer  20  based on the equation (1), it is possible to increase the emission intensity of the light emitted from the luminescent layer  20  in the front direction due to the constructive interference of light having a predetermined wavelength. For example, by adopting SiN that satisfies the equation, 1.95≤N≤2.3, more favorably, 2.0≤N≤2.1, or a laminated structure of SiN and SiO2, or adjusting the thickness of the first inorganic film  40  to satisfy the equation, 200≤N≤600, more favorably, 300≤N≤500, so as to satisfy the equation (1), it is possible to maintain the productivity of the first inorganic film  40  and to improve the light orientation of the light emitting element  1 . 
     Hereinafter, a method of producing the light-emitting element wafer  100  according to this embodiment will be described. 
     (Method of Producing Light-Emitting Element Wafer) 
       FIG. 6  is a flowchart of a method of manufacturing the light-emitting element wafer  100  according to this embodiment, and  FIGS. 7 to 12  are each a schematic cross-sectional view for explain the production method. Hereinafter, a description will be given with reference to these figures. 
     A luminescent layer  20   a  is formed on a first substrate  10   a  first (ST 101 ). Here, on the first substrate  10   a , a metal organic chemical vapor deposition (MOCVD) method is used to cause crystal growth of layers of the luminescent layer  20   a . The first substrate  10   a  is a wafer including, for example, gallium arsenide (GaAs), and a crystal surface on which the luminescent layer  20   a  is formed is, for example, a C surface (0001). 
     As described above, on the first substrate  10   a , a plurality of element areas  1   a  corresponding to the elements  1  are defined along the X-axis direction and the Y-axis direction. The plurality of element areas  1   a  are typically defined by a virtual boarder line L. 
     On the first substrate  10   a , crystal growth of a stop layer  214   a , a first contact layer  211   a , and a first cladding layer  212   a  is caused in the stated order first. The first stop layer  214   a , the first contact layer  211   a , and the first cladding layer  212   a  are first-conductive type. The stop layer  214   a  functions as an etching stop layer when the first substrate  10   a  is removed, and only needs to be formed of a material that is capable of ensuring etch selectivity ratio that is larger than a predetermined value with the first substrate  10   a . Of the layers, the stop layer  214   a  is removed together with the first substrate  10   a  in a subsequent process. Therefore, the first semiconductor layer  21  of the light emitting element  1  includes the first contact layer  211   a  and the first cladding layer  212   a.    
     Next, a multiquantum well layer  23   a  is formed. In the multiquantum well layer  23   a,  10 to 20 well layers and 9 to 20 barrier layers are laminated to each other, for example. The multiquantum well layer  23   a  forms the active layer  23  of the light emitting element  1 . 
     Furthermore, on the multiquantum well layer  23   a , crystal growth of a second cladding layer  221   a  and a second contact layer that are second conductive-type is sequentially caused. It should be noted that the second contact layer is not shown in  FIGS. 7 to 12 . The second semiconductor layer  22  of the light emitting element  1  includes the second cladding layer  221   a  and the second contact layer. 
     It should be noted that the luminescent layer  20   a  is not limited the above-mentioned configuration, and can be appropriately modified as necessary. 
     Next, as shown in  FIG. 7A , on a first surface  201   a , a first concavo-convex structure  210   a  is formed (ST 102 ). The first concavo-convex structure  210   a  is formed by a photolithography technique, a reactive ion etching (RIE) method, or the like. Moreover, in this process, a connection area  2011   a  at the center of the element area  1   a  and a boundary area  610   a  between the element areas  1   a  may be covered by a mask (not shown) not to form the first concavo-convex structure  210   a . Accordingly, the connection area  2011   a  and the boundary area  610   a  can each have a flat surface. The first electrode  710   a  is formed in the connection area  2011   a  in the next process, and the first end portion  41  and the isolation trench portion  60  are formed in the boundary area  610   a  subsequently. 
     Next, as shown in  FIG. 7B , the first electrode  710   a  is formed in the connection area  2011   a  of the first surface  201   a  (ST 103 ). The first electrode  710   a  is formed by an appropriate method such as a sputtering method, a deposition method, an ion plating method, and a plating method, and is pattern-formed in a predetermined shape such as an elliptical shape. In addition, at least one first electrode  710   a  is formed for each element area  1   a.    
     Then, as shown in  FIG. 7C , a first inorganic film  40   a  is formed on the first surface  201   a  including the first electrode  710   a  (ST 104 ). The first inorganic film  40   a  includes SiN, TiO 2 , SiO 2 , SiON, NiO, AlO, or a lamination film thereof. In addition, the first inorganic film  40   a  is formed to have a uniform thickness taking an example from the first surface  201   a . Specifically, in this process, a second concavo-convex structure  410   a  is formed taking an example from the first concavo-convex structure  210   a.    
     Next, a second substrate  10   b  is detachably joined on the first inorganic film  40   a  via a temporal junction layer  31   a  (ST 105 ). In this embodiment, the temporal junction layer  31   a  has a laminated structure of a first resin film  311   a , an adhesive layer  312   a , and second resin film  313   a . It should be noted that  FIG. 8A  shows the state vertically inverted from the state shown in  FIG. 7C  so that the first substrate  10   a  is arranged on the upper side of the figure. 
     As shown in  FIG. 8A , the first resin film  311   a  is formed on the first inorganic film  40   a  by application or the like first. Next, the adhesive layer  312   a  is attached on the first resin film  311   a . The adhesive layer  312   a  includes a resin adhesive sheet or an adhesive material. Furthermore, the second resin film  313   a  is formed on the adhesive layer  312   a  by application or the like. 
     The first and second resin film  311   a  and  313   a  may include a thermosetting resin material having adhesiveness such as polyimide, for example. Accordingly, in the process of removing the second substrate  10   b  to be described later, the first and second resin film  311   a  and  313   a  are ablated when being heated to evaporation by irradiation of a laser light having a predetermined wavelength, for example. Accordingly, the adhesiveness of first and second resin film  311   a  and  313   a  can be easily lost by the power of the ablation. The thermosetting resin material is not limited to the above, and any material that is capable of absorbing a laser light having a predetermined wavelength and causing ablation can be used. 
     Then, as shown in  FIG. 8A , the second substrate  10   b  is attached on the second resin film  313   a  of the temporal junction layer  31   a . In this embodiment, the second substrate  10   b  is a disk-shaped semiconductor wafer including sapphire (Al 2 O 3 ) or the like. 
     It should be noted that the configuration of the temporal junction layer  31   a  is not limited to the above, and the temporal junction layer  31   a  may include only the first resin film  311   a  and the adhesive layer  312   a , for example. Moreover, in the above-mentioned process, a part or all of the temporal junction layer  31   a  may be formed on the second substrate  10   b  in advance, and the first inorganic film  40   a  and the second substrate  10   b  may be joined. 
     Next, as shown in  FIG. 8B , the first substrate  10   a  is removed to expose a second surface  202   a  of the luminescent layer  20   a , which is opposite to the first surface  201   a  (ST 106 ). In this process, the first substrate  10   a  is removed by a wet etching method or the like first. At this time, an etchant having a high etch selectivity ratio with the stop layer  214   a  and the first substrate  10   a  is used. Accordingly, the wet etching is suppressed at the stop layer  214   a , and thus the first substrate  10   a  can be reliably removed. Furthermore, the stop layer  214   a  is removed by a dry etching method or the like. Accordingly, the first contact layer  211   a  is exposed on the luminescent layer  20   a.    
     It should be noted that in this process, the second surface  202   a  is formed of the surface of the first contact layer  211   a . Moreover, the configuration including the layers from the first contact layer  211   a  to the second cladding layer  221   a  (second contact layer) is referred to as a luminescent layer  20   b.    
     Next, with reference to  FIG. 9A , a second electrode (electrode)  720   a  is formed on the second surface  202   a  (ST 107 ). The second electrode  720   a  is pattern-formed in a circular shape having a diameter of about 1 to 20 μm, for example. At least one second electrode  720   a  is formed for each element area  1   a.    
     Furthermore, in this embodiment, the first contact layer  211   a  is etched using the second electrode  720   a  as a mask. Accordingly, as shown in  FIG. 9A , the first contact layer  211   a  is removed excluding the area located immediately below the second electrode  720   a . The pattern-formed first contact layer is referred to as the first contact layer  211   b . Moreover, in this process and following processes, the second surface is formed of the surfaces of the second electrode  720   a  and a second cladding layer  212   a , and is referred to as the second surface  202   b.    
     Next, as shown in  FIG. 9B , the luminescent layer  20   a  is etched from the second surface  202   b  using the first inorganic film  40   a  as an etching stop layer, and a first isolation trench  61   a  that isolates the luminescent layer  20   a  for each element (element area)  1   a  is formed (ST 108 ). In this process, the luminescent layer  20   a  is etched by a dry etching method, for example. 
     A mask layer M 1  is formed for each element area  1   a  on the second surface  202   b  first. The mask layer M 1  is pattern-formed for each element area  1   a  in a shape corresponding to the second surface  202  after the formation of the element  1 . Specifically, the mask layer M 1  includes an opening M 11  formed along the boundary between the element areas  1   a . Moreover, the material of the mask layer M 1  may be any material that has a low etching rate in the etchant used in this process. For example, SiO 2 , SiN, Ti, Ni, Cr, Al or the like is employed. 
     Then, a dry etching is performed via the opening M 11  of the mask layer M 1  to form the first isolation trench  61   a  along the boundary between the element areas  1   a . At this time, an etching gas (etchant) having a high etch selectivity ratio with a semiconductor including AlGaInP, GaAs, GaP, or the like being the material of the luminescent layer  20   a  and SiN or SiO2 being the material of the first inorganic film  40   a  is used. Examples of such an etchant include SiCl 4 . Accordingly, even if the etching rate is not uniform in the plane of the first substrate  10   a , the first isolation trench  61   a  can be formed in the plane to have a uniform depth because the first inorganic film  40   a  functions as an etching stop layer. It should be noted that in the following description, the etching gas used in a dry etching is also referred to as the etchant. 
     Moreover, in this process (ST 108 ), the luminescent layer  20   a  can be formed for each element  1   a  to have a cross-sectional area that gradually is increased from the second surface  202   b  to the first surface  201   a . Specifically, the cross-sectional area of the opening of the first isolation trench  61   a  on the side of the second surface  202   b  is larger than the cross-sectional area of a bottom surface  612   a . Such a first isolation trench  61   a  can be appropriately formed under the condition of taper etching. The specific etching condition depends on the size of a wafer, the configuration of an etching apparatus, and the like. For example, the antenna power is 100 to 1000 W, the bias power is 10 to 100 W, the processing pressure is 0.25 to 1 Pa, and the substrate temperature is 100 to 200° C. It should be noted that the “cross-sectional area” represents a cross-sectional area in a direction perpendicular to the Z-axis direction. Then, after the first isolation trench  61   a  is formed, the mask layer M 1  is removed by an etching or the like. 
     In this process (ST 108 ), the first isolation trench  61   a  having a wall surface  611   a  to be a tapered surface and the bottom surface  612   a  is formed. The end surfaces of the layers of the luminescent layer  20   b  excluding the first contact layer  211   b  are exposed to the wall surface  611   a , and the first inorganic film  40   a  is exposed to the bottom surface  612   a . Moreover, the wall surface  611   a  corresponds to the peripheral surface  203  of the light emitting element  1 . 
     Next, as shown in  FIG. 10A , a reflection film (second inorganic film)  50   a  that covers the wall surface  611   a  and the bottom surface  612   a  of the first isolation trench  61   a  and the second surface  202   b  is formed (ST 109 ). As described above, the reflection film  50   a  has a laminated structure of a first insulating layer  51   a , a metal layer  53   a , and a second insulating layer  52   a , which are formed in the stated order. 
       FIGS. 13 and 14  are each a schematic cross-sectional view for explaining this process (ST 109 ). It should be noted that in  FIGS. 13 and 14 , the layers of the first and second concavo-convex structures  210   a  and  410   a  and the temporal junction layer  31   a , and the second substrate  10   b  are not shown. 
     As shown in  FIG. 13A , the first insulating layer  51   a  is formed on the wall surface  611   a  and the bottom surface  612   a  of the first isolation trench  61   a  and the second surface  202   b  (ST 109 - 1 ). In this process, a CVD method, a sputtering method, or the like can be used. Alternatively, a resin material such as SOG (applying material for forming an SiO2 coating film) can be used to form the first insulating layer  51   a  by a spin coating method or application. Moreover, these methods can be used to form a laminated structure. Specifically, in this embodiment, because the wall surface  611   a  is formed to have a tapered shape, the first insulating layer  51   a  can be easily formed using a material having a relatively low viscosity. 
     Next, the metal layer  53   a  is formed on the first insulating layer  51   a  (ST 109 - 2 ). For the pattern-formation of the metal layer  53   a  in this process, a lift-off method is adopted, for example. Specifically, as shown in  FIG. 13B , a resist R 1  is formed on the area in which the metal layer  53   a  should be prevent from being formed. As the resist R 1 , a positive resist or a negative resist may be adopted. It should be noted that by using the positive resist, the halation during exposure can be suppressed. Moreover, the area in which the resist R is formed specifically includes the area including the second electrode  720   a  and the area at the center of the bottom surface  612   a  when viewed from the Z-axis direction. These areas correspond to the opening  531  of the metal layer  53  and the isolation trench portions  60  when the element  1  is completed, respectively. 
     Specifically, a metal layer  53   b  is formed first on the entire surface of the first insulating layer  51   a  including the resist R 1  by an appropriate method such as a sputtering method, a deposition method, an ion plating method, and a plating method. For example, for the metal layer  53   b , a laminate structure of Al and Au is appropriately adopted. Accordingly, it is possible to reflect light having a wavelength of about 500 to 700 nm at a high reflectance. Moreover, by using a sputtering method, it is possible to improve the adhesiveness between the metal layer  53   b  and the first insulating layer  51   a.    
     Then, the resist R 1  to which the metal layer  53   b  is attached is removed. Accordingly, as shown in  FIG. 14A , the metal layer  53   a  including an opening  531   a  corresponding to the opening  531  and a second opening  532   a  is formed. 
     Furthermore, as shown in  FIG. 14B , the second insulating layer  52   a  is formed on the metal layer  53   a  (ST 109 - 3 ). In this process, the entire surfaces of the metal layer  53   a  and the first insulating layer  51   a  are covered by the second insulating layer  52   a . As the method of forming the second insulating layer  52   a , a CVD method, a sputtering method, or an application method can be appropriately adopted similarly to the first insulating layer  51   a.    
     Accordingly, in the entire inner surfaces of the second surface  202   b  and the first isolation trench  61   a , the reflection film  50   a  is formed. The reflection film  50   a  on the second surface  202   b  corresponds to the second inorganic film  520 , and the reflection film  50   a  on the wall surface  611   a  corresponds to the third inorganic film  530 . 
     As described above, in this embodiment, the metal layer  53   a  is formed by a lift-off method. Therefore, it is possible to suppress the influence of side etching of the resist and to form the metal layer  53   a  having a desired shape. Moreover, even if the metal layer  53   a  is formed of chemically stable metal, it is possible to easily perform a fine process. 
     As the next process, as shown in  FIG. 10B , a part of the reflection film  50   a  is removed to expose the second electrode  720   a  (ST 110 ). Accordingly, a connection hole  540   a  is formed in the first insulating layer  51   a  and the second insulating layer  52   a  of the reflection film  50   a . In this process, a resist (not shown) on which the pattern of the shape corresponding to the second electrode  720   a  is formed is formed first, and an etching method or the like via the resist is used. 
     Then, as shown in  FIG. 11A , an external connection terminal  730   a  that is electrically connected to the second electrode  720   a  is formed on the second surface  202   b  (ST 111 ). A metal film may be formed on the second surface  202   b  by an appropriate method such as a sputtering method, a deposition method, an ion plating method, and a plating method, and the metal film may be patterned into a predetermined shape by a wet etching method, a dry etching, or the like, thereby forming the external connection terminal  730   a  according to this process. Alternatively, a metal film may be formed after a resist having a predetermined pattern is formed by a lift-off method, thereby forming the external connection terminal  730   a . Accordingly, the external connection terminal  730   a  is formed on the second electrode  720   a  in the connection hole  540   a  and on the reflection film  50   a  on the second surface  202   b.    
     Moreover, accordingly, a space portion surrounded by the adjacent external connection terminals  730   a  on the first isolation trench  61   a  is formed. Hereinafter, a description will be made with the first isolation trench  61   a  and the space portion being collectively referred to as the trench portion  613   a.    
     Next, a third substrate  10   c  is detachably joined on the external connection terminal  730   a  via a junction layer  30   a  (ST 112 ). 
     As shown in  FIG. 11B , in this process, a resin R 2  is filled in the trench portion  613   a  first. Accordingly, when the third substrate  10   c  is joined, it is possible to prevent a void from being generated due to the trench portion  613   a , for example. The method of filling the resin R 2  is not particularly limited, and an applying method, a spin coating method, spraying, or a dipping method can be appropriately adopted, for example. Furthermore, the resin R 2  is etched back after the application. Thus, the resin R 2  can be formed to have almost the same height as the surface of the external connection terminal  730   a . The material of the resin R 2  is not particularly limited. 
     Next, as shown in  FIG. 12A , for example, an adhesive resin R 3  is formed on the resin R 2  and the external connection terminal  730   a . Accordingly, it is possible to improve the adhesiveness between the junction layer  30   a  and the external connection terminal  730   a . Moreover, the resin R 3  corresponds to the resin film  732  described above. The method of forming the resin R 3  is not particularly limited, and an applying method, a spin coating method, spraying, or a dipping method can be appropriately adopted, for example. It should be noted that  FIG. 12A  shows the state vertically inverted from the state shown in  FIG. 11B . 
     Then, on the external connection terminal  730   a  and the resin R 3 , the third substrate  10   c  on which the junction layer  30   a  is formed is joined. The third substrate  10   c  corresponds to the supporting substrate  10 , and is a disk-shaped semiconductor wafer including sapphire or the like. 
     An applying method, a spin coating method, spraying, a dipping method or the like is appropriately adopted to form the junction layer  30   a  on the third substrate  10   c . The junction layer  30   a  may include a thermosetting resin material having adhesiveness such as polyimide. In this case, any material that is capable of absorbing a laser light having a predetermined wavelength and causing ablation can be used similarly to the second resin film  313   a.    
     It should be noted that the method of joining the third substrate  10   c  is not limited to the above-mentioned method. For example, at least any one of the resin R 2  and the resin R 3  does not need to be formed. Alternatively, the junction layer  30   a  does not necessarily need to be formed on the third substrate  10   c , and may be formed on the external connection terminal  730   a  (the resin R 2  and the resin R 3 ). 
     Next, with reference to  FIGS. 12A and 12B , the second substrate  10   b  is removed to expose the first inorganic film  40   a  (ST 113 ). The second substrate  10   b  is irradiated with a laser light having a predetermined wavelength from above the second substrate  10   b , for example, and the second resin film  313   a  is ablated when being heated to evaporation. As a result, the second substrate  10   b  is removed by the power of the ablation. Accordingly, as shown in  FIG. 12A , the second substrate  10   b  is removed on the interface between the second substrate  10   b  and the second resin film  313   a . By using such a method of laser ablation, the second substrate  10   b  can be easily removed. 
     After that, the second resin film  313   a , the adhesive layer  312   a , and the first resin film  311   a  can be removed by a wet etching method, a dry etching method, or the like. Accordingly, the entire temporal junction layer  31   a  is removed, and thus, it is possible to expose the first inorganic film  40   a  as shown in  FIG. 12B . 
     It should be noted that after the first inorganic film  40   a  is exposed, the first inorganic film  40   a  on the first electrode  710   a  can be removed to from a connection hole  420   a . In this process, a resist (not shown) on which the pattern of the shape corresponding to the first electrode  710   a  is formed is formed first, and a dry etching method or the like via the resist is used similarly to the connection hole  540   a.    
     Subsequently, with reference to  FIG. 12B , the first inorganic film  40   a  that has left on the bottom surface  612   a  of the first isolation trench  61   a  is etched to form a second isolation trench  62   a  that isolates the first inorganic film  40   a  for each element  1   a  (ST 114 ). In this process, a dry etching method such as an RIE method or a wet etching method is used to form the second isolation trench  62   a.    
     In this process, the first inorganic film  40   a  in an area that faces the bottom surface  612   a  of the first isolation trench  61   a  is etched first. Next, an area of the second inorganic film  50   a , which is formed in the bottom surface  612   a , is etched similarly. Then, the resin R 2 , the resin R 3 , and the junction layer  30   a  formed in the area that faces the bottom surface  612   a  are also etched isotropically. Accordingly, the second isolation trench  62   a  having a depth from the first inorganic film  40   a  to the third substrate  10   c  is formed. The second isolation trench  62   a  corresponds to the isolation trench portion  60  of the light emitting elements  1 . It should be noted that the above-mentioned etching of the components may be performed under the same conditions or different conditions. 
     It should be noted that in this embodiment, the metal layer  53   a  includes the second opening  532   a  in the area thereof that faces the bottom surface  612   a , and only the first and second insulating layers  51   a  and  52   a  exist in the area. Accordingly, the area of the reflection film  50   a  can be easily etched. Moreover, the resin R 3  and the junction layer  30   a  are etched using the external connection terminal  730   a  as a mask. Therefore, it is possible to leave only the resin R 3  and the junction layer  30   a  that exist in the area facing the external connection terminal  730   a  as they are. 
     In this process, the junction layer  30  on the third substrate  10   c  (supporting substrate  10 ), the external connection terminal  730 , the luminescent layer  20  covered by the reflection film  50 , and the first inorganic film  40  are isolated for each element  1 , and thus, the light-emitting element wafer  100  is formed. 
     In the light emitting element  1  according to this embodiment, the first inorganic film  40   a  is formed on the first surface  201   a  of the luminescent layer  20   a , and the reflection film  50   a , the external connection terminal  730   a , and the junction layer  30   a  are formed on the second surface  202   b  opposite the first surface  201   a . Specifically, crystal growth of the luminescent layer  20   a  is caused with a uniform thickness in the plane, and the light emitting element  1  has a configuration in which the layers are laminated on the luminescent layer  20   a . Thus, the elements  1  in the wafer plane can be formed to have a uniform thickness. Accordingly, variation in the thicknesses of the elements  1  in the wafer plane can be suppressed to 10% or less, for example. 
     Moreover, the first concavo-convex structure  210   a  of the luminescent layer  20   a  is formed right after the crystal growth of the luminescent layer  20   a  is caused. Accordingly, it is possible to form the first concavo-convex structure  210   a  in a desires shape accurately. Therefore, it is possible to increase the output efficiency, and to control the orientation of light. 
     Furthermore, because the first inorganic film  40   a  functions as an etching stop layer in the process of forming the first isolation trench  61   a  by a dry etching method or the like, it is possible to form the first isolation trench  61   a  to have a uniform depth in the plane. Specifically, the first inorganic film  40   a  can be configured to be exposed to the bottom surface  612   a  of the first isolation trench  61   a . Accordingly, the first inorganic film  40  and the reflection film  50  can be connected and the second end portion  510  of the reflection film  50  and the first end portion  41  of the first inorganic film  40  can be laminated after the elements  1  are formed. Therefore, the elements  1  can be formed to have a uniform shape, and variation in the heights of the plurality of light emitting elements  1  on the light-emitting element wafer  100  from the surface  11  can be suppressed to 10% or less, for example. 
     Moreover, accordingly, there is no need to provide an etching stop layer for the luminescent layer  20   a  when the first isolation trench  61   a  is formed, which can contribute to the increase in the material selectivity of the luminescent layer and the simplification of the production process. 
     Furthermore, because a dry etching method is used, the area of a wafer is increased and an isolation trench can be formed in a uniform shape in the plane even if the isolation trench is formed to be narrow. 
     Moreover, in this embodiment, because the wall surface  611   a  of the first isolation trench  61   a  can be formed to be a tapered surface, the reflection film  50   a  can be easily formed. In particular, a resin material having low viscosity can be used for the first and second insulating layers  51   a  and  52   a , and it is possible to easily form the first and second insulating layers  51   a  and  52   a  using a spin coating method or the like. 
     Furthermore, because the metal layer  53   a  can be accurately formed as described above, it is possible to expose the metal layer  53  to the end surface of the second end portion  510  after the element  1  is formed. Therefore, it is possible to increase the heat radiation property of the metal layer  53   a  and to reduce the flaws of the element  1 . Moreover, because the metal layer  53  is capable of suppressing the side etching of the second end portion  510  when the second isolation trench  62   a  is formed, the second isolation trench  62   a  can be formed accurately. 
     The respective light emitting elements  1  on the light-emitting element wafer  100  formed in this way are mounted on a display apparatus (electronic apparatus)  80 , for example. 
       FIG. 15  is a schematic plan view of the display apparatus  80 . Specifically, the light emitting element  1  that emits red light and light emitting elements  2  and  3  that emit blue light and green light constitute a light emitting element unit  81 , and a light emitting element module on which a plurality of light emitting element units  81  are arranged is mounted on a substrate  810  of the display apparatus  80 . Next, a method of producing the display apparatus  80  and a configuration example of the display apparatus  80  will be described. It should be noted that in the elements  1 ,  2 , and  3  shown in  FIG. 15 , configurations such as resin that covers them, a wiring, and the like are not shown. 
     (Method of Producing Display Apparatus) 
       FIG. 16  is a flowchart of a method of producing the display apparatus  80  according to this embodiment,  FIG. 17  is a schematic plan view for explaining the production method, and  FIG. 18  are each a schematic cross-sectional view for explaining the production method. To the processes shown in  FIG. 16 , reference numerals continued from ST 114  shown in  FIG. 6  are added. In  FIG. 17 , only 12 elements  1  are shown for description. 
     With reference to  FIG. 17 , the outline of the method of producing the display apparatus  80  will be described. The respective light emitting elements  1  on the light-emitting element wafer  100  are transferred to a first transfer substrate (transfer substrate)  910  first, and are arranged at predetermined intervals larger than the width of the isolation trench portion  60 . Furthermore, the element  1  is transferred to a second transfer substrate  920  and is covered by the coating layer  922 , and a wiring and the like (not shown) are formed. After that, the element  1  is transferred to the substrate  810  of the electronic apparatus  80  as a light emitting element chip  90  covered by the coating layer  922 . 
     As shown in  FIG. 18A , the first transfer substrate  910  arranged to face the first inorganic film  40  of the respective elements  1  of the light-emitting element wafer  100  is prepared first (ST 115 ). The first transfer substrate  910  is formed to have a size such that the elements  1  can be arranged at predetermined intervals. The first transfer substrate  910  is formed of a glass substrate or a plastic substrate, for example. 
     On the transfer substrate  910 , a first temporal junction layer  911  and an adhesive layer  912  are formed, for example. The first temporal junction layer  911  is formed on the transfer substrate  910 , and may include fluorine resin, silicone resin, a water-soluble adhesive agent such as PVA, or polyimide, for example. Moreover, the adhesive layer  912  is formed on the first temporal junction layer  911 , and may include an ultraviolet (UV) curable resin having adhesiveness, thermosetting resin, thermoplastic resin, or the like. 
     Moreover, the adhesive layer  912  may have an uncured area  912   a  and a cured area  912   b . Specifically, because the light emitting element  1  to be transferred is aligned to face the uncured area  912   a , the light emitting element  1  can be reliably transferred to the adhesive layer  912  in the later transfer process. Moreover, in the case where UV curable resin is used for the adhesive layer  912 , for example, the cured area  912   b  can be formed by selectively applying ultraviolet rays only to the area corresponding to the cured area  912   b  to cure the area. Furthermore, in the uncured area  912   a , a concave portion having the shape corresponding to the light emitting element  1  may be formed. 
     Next, with reference to  FIGS. 18A and 18B , the external connection terminal  730  and the supporting substrate  10  are isolated by the laser ablation of the junction layer  30  from the side of the supporting substrate (third substrate)  10  of the light-emitting element wafer  100 , and the respective elements  1  are transferred to the first transfer substrate (transfer substrate)  910  (ST 116 ). 
     In this process, as shown in  FIG. 18A , a laser light Lb is applied from the side of the supporting substrate  10  to the junction layer  30  of the light emitting element  1  to be transferred. As the laser, an excimer laser having a predetermined light emission wavelength or a harmonic YAG laser can be used, for example. Accordingly, the junction layer  30  is heated to be cured, the adhesiveness is lost, and a part of the resin evaporates, for example. Thus, the junction layer  30  and the external connection terminal  730  are explosively removed. Specifically, the entire element  1  is output in the Z-axis direction and is attached to the adhesive layer  912 . Therefore, as shown in  FIG. 18B , the light emitting element  1  is transferred to the adhesive layer  912  that faces the light emitting element  1 . 
     Then, the uncured area  912   a  to which the light emitting element  1  is transferred is cured by the UV irradiation or the like. Accordingly, the light emitting elements  1  can be reliably joined to the adhesive layer  912 . Furthermore, a wiring layer  740  may be formed on the external connection terminal  730  as necessary. 
     Moreover, in this process, a light-emitting element wafer  200  including the first transfer substrate (supporting substrate)  910  and the plurality of light emitting elements  1  can be formed. Specifically, by performing the process on the respective desired elements  1 , the light-emitting element wafer  200  in which the plurality of light emitting elements  1  are arranged on the first transfer substrate  910  can be formed. 
     Next, with reference to  FIG. 18C , the respective light emitting elements  1  are transferred to the second transfer substrate  920 , and the first transfer substrate  910  is removed (ST 117 ). The second transfer substrate  920  typically has almost the same size as the first transfer substrate  910 , and a second temporal junction layer  921  including fluorine resin, silicone resin, a water-soluble adhesive agent such as PVA, polyimide, or the like is formed thereon. The external connection terminal  730  and the wiring layer  740  of the respective elements  1  joined to the first transfer substrate  910  are joined to the second temporal junction layer  921  first. Next, a laser light is applied from above the first transfer substrate  910  to the first temporal junction layer  911  of the first transfer substrate  910 , and thus, the first temporal junction layer  911  and the adhesive layer  912  are isolated. Accordingly, the entire adhesive layer  912  in which the elements  1  are embedded is transferred to the second temporal junction layer  921 . 
     Furthermore, as shown in  FIG. 18C , a third isolation trench  63  may be formed in the adhesive layer  912  between the elements  1  to isolate adhesive layer  912  for each element  1 . Accordingly, the coating layer  922  formed of the adhesive layer  912 , which covers the element  1 , is formed. Furthermore, a wiring layer  750  that is connected to the first electrode may be formed. Hereinafter, the light emitting element chip  90  having a configuration in which the elements  1  and the coating layer  922  covering the elements  1  are included will be described. Specifically, the light emitting element chip  90  includes the elements  1 , the coating layer  922 , and the wiring layers  740  and  750 . 
     Then, each light emitting element chip  90  is transferred to the substrate  810  of the display apparatus  80  (ST 118 ). As the transfer method, the above-mentioned laser ablation may be adopted, for example, or an adsorption holder or the like may be used to perform the transfer mechanically. The substrate  810  is formed of a wiring substrate on which a predetermined drive circuit (not shown) is formed. 
     Moreover, as shown in  FIG. 17 , the light emitting element chips  90  are arranged on the substrate  810  at predetermined pitches along the X-axis direction and the Y-axis direction. The predetermined pitch is three times or more of the length of the light emitting element chip  90  along the X-axis direction and the Y-axis direction. Accordingly, the light emitting element module  81  can be formed by arranging a light emitting element chip including the light emitting element  2  that emits blue light and a light emitting element chip including the light emitting element  3  that emits green light between the light emitting element chips  90  including the light emitting elements  1  that emit red light. Moreover, because the light emitting element chips are arranged in space, a wiring or the like can be formed using the space. 
     In this way, the display apparatus  80  shown in  FIG. 15  is formed. Specifically, the display apparatus  80  includes the substrate  810  on which a drive circuit is formed, the plurality of light emitting elements  1  that emit red light, the plurality of light emitting elements  2  that emit blue light, the plurality of light emitting elements  3  that emit green light, and the plurality of light emitting elements  1 ,  2 , and  3  are arranged on the substrate  810 . 
     It should be noted that in addition to the process, still another transfer substrate may be used to perform the transfer. Specifically, after the process of transferring to the second transfer substrate  920 , a process of transferring to a third transfer substrate and a process of transferring to a fourth transfer substrate may be performed. Accordingly, the respective elements  1  can be transferred at larger intervals, which is advantageous for the formation of a wiring layer or the production of a display apparatus with a larger area. 
     It should be noted that in this embodiment, because the metal layer  53  of the reflection film  50  is exposed to the second end portion  510 , the metal layer  53  is not exposed to the first inorganic film  40 . Specifically, even if the wiring layer  750  that is extracted from the first electrode  710  to the first inorganic film  40  is formed, two insulating layers of the first inorganic film  40  and the first insulating layer  51  are sandwiched between the metal layer  53  and the wiring layer  750 . Accordingly, it is possible to suppress short-circuiting between the metal layer  53  and the wiring layer  750 , and to reduce the flaws of the element  1 . 
     Moreover, as described above, in this embodiment, it is possible to form the second isolation trench  62   a  accurately in the step of ST 114 . Specifically, it is possible to suppress the side etching of the junction layer  30   a  etched by using the external connection terminal  730  as a mask, and to prevent the position of the center of gravity of the junction layer  30   a  and the luminescent layer  20   a  in the XY plane from being displaced. Therefore, it is possible to suppress the positional displacement due to the output of the element  1  obliquely to the Z-axis direction or the falling of the element  1  due to the rotation during the output when the laser ablation is performed for each element  1  in the step of ST 116 , for example. Therefore, it is possible to transfer the element to a desired position. 
     Second Embodiment 
       FIG. 19  is a cross-sectional view of a main portion showing the configuration of a light-emitting element wafer according to a second embodiment of the present disclosure. In  FIG. 19 , the same components as those according to the first embodiment will be denoted by the same reference symbols and a description thereof will be omitted. 
     A light emitting element  1 A of a light-emitting element wafer  100 A according to this embodiment is different from the light emitting element  1  in that a first inorganic film  40 A functions also as a first electrode  710 A. Accordingly, the entire first surface  201   a  serves as a light extraction surface, and thus, it is possible to improve the output efficiency of light emitted from the luminescent layer  20 . 
     The first inorganic film  40 A serves also as a first electrode  710 A including a transparent conductive material, and includes a transparent conductive material such as ITO. Accordingly, it is possible to ensure the conductivity while maintaining the translucency of the first inorganic film  40 A. The first inorganic film  40 A may have a first end portion  41 A formed on the peripheral portion similarly to the first embodiment, and a second concavo-convex portion (not shown) formed taking an example from the first concavo-convex portion  210 . 
     The light emitting element  1 A may further include an extraction electrode  711 A. The extraction electrode  711 A is connected to the first inorganic film  40 A serving as the first electrode  710 A, and is capable of extracting the first electrode  710 A to the side of the second surface  202 . Specifically, the extraction electrode  711 A is connected to the first electrode  710 A on the side of the first surface  201 , and is formed to above the second surface  202  (second inorganic film  520 ) via the peripheral surface  203  (third inorganic film  530 ) of the luminescent layer  20 . The material of the extraction electrode  711 A is not particularly limited, and the extraction electrode  711 A includes a metal material such as Al, Au, and Ti, or an alloy or laminated body containing them. 
     Moreover, the reflection film  50   a  may have no second end portion. Accordingly, the extraction electrode  711 A can be connected to the first inorganic film  40 A (first electrode  710 A) via the first end portion  41 A. 
     An external connection terminal  730 A is connected to the second electrode  720  via the connection hole  540 A. In this embodiment, the external connection terminal  730 A may be extended from the area located immediately below the second electrode  720  to the isolation trench portion  60  in one direction, for example. Accordingly, it is possible to prevent the external connection terminal  730 A from being brought into contact with the extraction electrode  711 A, and to prevent the problem such as short-circuiting from occurring. 
     In the light emitting element  1 A having such a configuration, the first electrode  710 A including a transparent conductive material is connected to the extraction electrode  711 A including a metal material. Accordingly, it is possible to reduce the change in the connection resistance between them, and to improve the process margin. Moreover, the connection resistance between the first electrode  710 A and the second semiconductor layer  22  can be reduced, and also the driving voltage can be reduced. 
       FIGS. 20 to 23  are each a schematic cross-sectional view for explaining a method of producing a light-emitting element wafer  1 A. In the method of producing the light-emitting element wafer  1 A according to this embodiment, the process of forming the first electrode (ST 103 ) and the process of forming the first inorganic film (ST 104 ) of the processes in the method of producing the light-emitting element wafer  1  can be performed simultaneously. Other processes will be denoted by the same reference symbols as those shown in the flowchart of  FIG. 6 , and components different from those according to the first embodiment will be mainly described. 
     First, a metal organic chemical vapor deposition (MOCVD) method is used to form the luminescent layer  20   a  on the first substrate  10   a  (ST 101 ) similarly to the first embodiment. Next, as shown in  FIG. 20A , the first concavo-convex structure  210   a  is formed on the first surface  201   a  by, for example, a dry etching method (ST 102 ). In this embodiment, because the first concavo-convex structure  210   a  can be formed on the entire first surface  201   a , a mask may be formed or a mask does not need to be formed when the first concavo-convex structure  210   a  is formed. Moreover, the method of forming the first concavo-convex structure  210   a  is not limited to a dry etching method or the like, and oxygen ions, blast processing, or the like may be used to rough the first surface  201   a.    
     Next, as shown in  FIG. 20B , a first inorganic film  40 Aa serving as a first electrode  710 Aa is formed on the first surface  201   a  (ST 103  and ST 104 ). The first inorganic film  40 Aa includes, for example, a transparent conductive material such as ITO, and is formed by a sputtering method or the like. 
     Then, by a lift-off method using a mask, a boundary area  610 Aa of the first inorganic film  40 Aa between element areas  1 Aa can be removed, and the first inorganic film  40 Aa can be pattern-formed in the shape shown in  FIG. 20B . 
     Next, as shown in  FIG. 20C , a second substrate  10 Ab is joined to the first inorganic film  40 Aa (ST 105 ). The second substrate  10 Ab may be formed of a sapphire (Al 2 O 3 ) substrate, a silicon (Si) substrate, a quartz substrate, or a glass substrate, for example. Accordingly, the surface of the second substrate  10 Ab is activated by plasma, and the second substrate  10 Ab can be directly joined to the first inorganic film  40 Aa by a method such as anodic bonding and room-temperature bonding. Moreover, the second substrate  10 Ab can be joined to the first inorganic film  40 A via a temporal junction layer such as a resin film similarly to the first embodiment. It should be noted that  FIG. 20C  shows the state vertically inverted from the state shown in  FIG. 20B  so that the first substrate  10   a  is arranged on the upper side of  FIG. 20C . 
     Next, as shown in  FIG. 21A , the first substrate  10   a  is removed to expose the second surface  202   a  of the luminescent layer  20   a , which is opposite to the first surface  201   a  (ST 106 ) similarly to the first embodiment. Next, on the second surface  202   a , the second electrode  720   a  is formed (ST 107 ). Moreover, the second electrode  720   a  is used as a mask to etch the first contact layer  211   a.    
     Next, as shown in  FIG. 21B , the luminescent layer  20   a  is etched from the second surface  202   b  using the second substrate  10 Ab as an etching stop layer, and a first isolation trench  61 Aa that isolates the luminescent layer  20   a  for each element (element area)  1 Aa is formed (ST 108 ). In this process, an etchant having a high etch selectivity ratio with the material of the second substrate  10 Ab and the luminescent layer  20   a  is used to perform a dry etching after the mask M 1  is formed similarly to the first embodiment, and thus, a first isolation trench  61 Ab can be formed to have a uniform depth in the wafer plane. Accordingly, the second substrate  10 Ab is exposed to a bottom surface  612 Aa of the first isolation trench  61 Aa. Furthermore, the mask M 1  is removed after the first isolation trench  61 Aa is formed. 
     Alternatively, similarly to the first embodiment, the first isolation trench  61 Aa may be formed using the first inorganic film  40 Aa as an etching stop layer. In this case, an etchant having a high etch selectivity ratio with the first inorganic film  40 Aa and the luminescent layer  20   a  can be used to perform a dry etching. 
     Next, as shown in  FIG. 21C , similarly to the first embodiment, a reflection film (second inorganic film)  50 Aa that covers a wall surface  611 Aa and the bottom surface  612 Aa of the first isolation trench  61 Aa and the second surface  202   b  is formed (ST 109 ). Although not shown in  FIGS. 21C to 23B , the reflection film  50 Aa has a laminate structure of a first insulating layer  51 Aa, a metal layer  53 Aa, and a second insulating layer  52 Aa, which are formed in the stated order, as described above. Then, as shown in  FIG. 21C , a part of the reflection film  50 Aa is removed to expose the second electrode  720   a  (ST 110 ). 
     Next, as shown in  FIG. 22A , on the second surface  202   b , an external connection terminal  730 Aa that is electrically connected to the second electrode  720   a  is formed (ST 111 ). In this embodiment, in this process, an extraction electrode  711 Aa that is electrically connected to the first electrode  710 Aa (first inorganic film  40 Aa) is formed. An appropriate method such as a sputtering method, a deposition method, an ion plating method, and a plating method is used to form a metal film having a predetermined pattern on the reflection film  50 Aa, similarly to the first embodiment, thereby forming the external connection terminal  730 Aa and the extraction electrode  711 Aa. 
     Next, with reference to  FIG. 22B , on the external connection terminal  730 Aa and the extraction electrode  711 Aa, a third substrate  10 Ac is detachably joined via a junction layer  30 Aa (ST 112 ). The junction layer  30 Aa may include resin having adhesiveness such as polyimide, or resin that is capable of absorbing a laser light having a predetermined wavelength, similarly to the first embodiment. Moreover, the third substrate  10 Ac may be formed of a sapphire substrate, for example. 
     Next, as shown in  FIG. 23A , the second substrate  10 Ab is removed to expose the first inorganic film  40 Aa (ST 113 ). In this process, the second substrate  10 Ab can be removed by a dry etching method, a wet etching method, laser ablation in the case of bonding using resin that is capable of absorbing a laser light having a predetermined wavelength, or the like. 
     Then, as shown in  FIG. 23B , the junction layer  30 Aa between elements  1 Aa is isolated to form a second isolation trench  62 Aa (ST 114 ). In this process, a part of the junction layer  30 Aa can be removed by a dry etching method or the like. Alternatively, a wet etching method, a laser process, or the like can be used to remove the junction layer  30 Aa. Moreover, because the first inorganic film  40 Aa includes a transparent conductive material such as ITO, the junction layer  30 Aa can be etched using the first inorganic film  40 Aa as a mask. Accordingly, there is no need to perform the process of forming a mask separately. 
     By the above-mentioned processes, the light-emitting element wafer  100 A according to this embodiment is formed. In this embodiment, the second substrate  10 Ab can be joined without a temporal junction layer. Moreover, in the process of forming the first concavo-convex structure  210   a  (ST 102 ), the process of isolating for each element  1 A (ST 115 ), or the like, a mask does not need to be formed. Therefore, it is possible to reduce the number of processes, and thus, it is advantageous from a viewpoint of the productivity and cost. 
     Although embodiments of the present disclosure have been described, the embodiments of the present disclosure are not limited to the above-mentioned embodiments and various modifications can be made without departing from the gist of the present technology. 
     For example, in the embodiments, the luminescent layer has been described to emit red light. However, the luminescent layer is not limited thereto, and may emit blue light or green light, for example. For example, in the case where the luminescent layer emits blue light, a GaN material or the like can be used as the material of the semiconductor, for example. 
     Furthermore, in the embodiments, the light emitting element has been described to be an LED. However, the light emitting element may include a semiconductor laser or the like. Moreover, the electronic apparatus is not limited to a display apparatus, and may be a lighting apparatus such as a car tail lamp, an inspection apparatus on which an LED or a semiconductor laser is mounted, a pickup apparatus that is capable of writing to or reading an optical disc, or the like. 
     Moreover, in the first embodiment, the metal layer is exposed from the end surface of the second end portion. However, the metal layer is not limited thereto, and does not need to be exposed. In this case, in the process of forming the metal layer (ST 109 - 2 ), with reference to  FIG. 13B , by forming the resist to have almost the same width (length along the width direction between the wall surfaces of the first isolation trench) as the width of the bottom surface, the second end portion does not need to be formed. 
     Moreover, although the peripheral surface has been described to have a tapered surface, the peripheral surface does not limited thereto, and may be perpendicular to the first and second surfaces, for example. 
     Furthermore, the reflection film does not have a laminated structure, and may have only one layer. In this case, the reflection film may include an insulating material having a desired reflectance with respect to output light, for example. Moreover, the reflection film may have a two-layered structure of an insulating layer and a metal layer, and the metal layer may be formed as an extraction electrode of the first electrode similarly to the extraction electrode according to the second embodiment. 
     Moreover, in the first embodiment, the second substrate  10   b  has been described to be joined via the temporal junction layer  31   a . However, the second substrate  10   b  may be joined without the temporal junction layer  31   a  similarly to the second embodiment. 
     It should be noted that the present disclosure may also take the following configurations. 
     (1) A light-emitting element wafer, including: 
     
         
         
           
             a supporting substrate; 
             a luminescent layer that is formed of a semiconductor and has a first surface and a second surface, the first surface including a first electrode, the second surface including a second electrode, the second surface being arranged between the supporting substrate and the first surface; 
             a junction layer that joins luminescent layer to the supporting substrate and is arranged between the supporting substrate and the second surface; 
             a first inorganic film formed on the first surface; 
             a second inorganic film formed between the junction layer and the second surface; 
             an isolation trench portion that isolates elements and is formed to have a depth such that the isolation trench portion extends from the first inorganic film to the supporting substrate; and 
             a third inorganic film that connects the first inorganic film and the second inorganic film.
 
(2) The light-emitting element wafer according to (1), in which
 
             the first inorganic film has a first end portion formed in parallel with the first surface, the first end portion projecting to the isolation trench portion, and 
             the third inorganic film has a second end portion that takes an example from the first end portion to project to the isolation trench portion.
 
(3) The light-emitting element wafer according to (2), in which
 
             the second inorganic film and the third inorganic film include a first insulating layer, a metal layer, and a second insulating layer, and are formed sequentially, the first insulating layer being formed adjacent to the luminescent layer, the metal layer being formed on the first insulating layer, the second insulating layer being formed on the metal layer.
 
(4) The light-emitting element wafer according to any one of (1) to (3), in which
 
             the luminescent layer has a first concavo-convex portion formed on the first surface, and 
             the first inorganic film has a second concavo-convex portion formed taking an example from the first concavo-convex portion.
 
(5) The light-emitting element wafer according to any one of (1) to (4), in which
 
             the luminescent layer emits red light.
 
(6) The light-emitting element wafer according to (5), in which
 
             the semiconductor includes at least any one of materials of an AsP compound semiconductor, an AlGaInP compound semiconductor, and a GaAs compound semiconductor.
 
(7) The light-emitting element wafer according to any one of (1) to (6), in which
 
             the first inorganic film is the first electrode including a transparent conductive material.
 
(8) A light emitting element, including:
 
             a luminescent layer that is formed of a semiconductor and has a first surface, a second surface, and a peripheral surface, the first surface including a first electrode, the second surface including a second electrode and being opposite to the first surface, the peripheral surface connecting the first surface and the second surface; 
             a first inorganic film formed on the first surface; 
             a second inorganic film formed on the second surface; and 
             a third inorganic film that is formed to cover the peripheral surface and connects the first inorganic film and the second inorganic film.
 
(9) An electronic apparatus, including:
 
             a substrate on which a drive circuit is formed; and 
             at least one first semiconductor light-emitting element that is provided on the substrate and includes 
             a luminescent layer that is formed of a semiconductor and has a first surface, a second surface, and a peripheral surface, the first surface including a first electrode connected to the drive circuit, the second surface including a second electrode, the second surface being disposed between the substrate and the first surface, the second electrode being connected to the drive circuit, the peripheral surface connecting the first surface and the second surface, 
             a first inorganic film formed on the first surface, 
             a second inorganic film formed between the luminescent layer and the second surface, 
             a third inorganic film that is formed to cover that peripheral surface and connects the first inorganic film and the second inorganic film.
 
(10) The electronic apparatus according to (9), further including:
 
             a plurality of second semiconductor light-emitting elements configured to emit blue light; and 
             a plurality of third semiconductor light-emitting elements configured to emit green light, in which 
             the at least one first semiconductor light-emitting element includes a plurality of first semiconductor light-emitting element configured to emit red light, and the plurality of first, second, and third semiconductor light-emitting elements are arranged on the substrate.
 
(11) A method of producing a light-emitting element wafer, including:
 
             forming a luminescent layer having a laminated structure in which a semiconductor is laminated on a first substrate; 
             forming a first inorganic film on a first surface of the luminescent layer; 
             removing the first substrate to expose a second surface of the luminescent layer, the second surface being opposite to the first surface; 
             etching the luminescent layer from the second surface with the first inorganic film being an etching stop layer to form a first isolation trench that isolates the luminescent layer for each element; and 
             forming a second inorganic film that covers the second surface and a wall surface and a bottom surface of the first isolation trench.
 
(12) The method of producing a light-emitting element wafer according to (11), in which
 
             the forming of the first isolation trench includes etching the luminescent layer by a dry etching method.
 
(13) The method of producing a light-emitting element wafer according to (12), in which
 
             the forming of the first isolation trench includes forming the first isolation trench so that a cross-sectional area of the luminescent layer for each element is gradually increased from the second surface to the first surface.
 
(14) The method of producing a light-emitting element wafer according to any one of (11) to (13), in which
 
             the forming of the second inorganic film includes
           forming a first insulating layer on the second surface and the wall surface and the bottom surface of the first isolation trench,   forming a metal layer on the first insulating layer, and   forming a second insulating layer on the metal layer.
 
(15) The method of producing a light-emitting element wafer according to any one of (11) to (14), further including
   
         
             forming a first concavo-convex structure on the first surface before the forming of the first inorganic film and after the forming of the luminescent layer.
 
(16) The method of producing a light-emitting element wafer according to (15), in which
 
             the forming of the first inorganic film includes taking an example from the first concavo-convex structure to form a second concavo-convex structure.
 
(17) The method of producing a light-emitting element wafer according to (11) to (16), further including
 
             detachably joining the second substrate to the first inorganic film via a tentative a tentative junction layer before the exposure of the second surface and after the forming of the first inorganic film.
 
(18) The method of producing a light-emitting element wafer according to (17), further including:
 
             forming an electrode for each device on the second surface before the forming of the first isolation trench after the exposure of the second surface; 
             removing a part of the second inorganic film to expose the electrode after the forming of the second inorganic film; 
             forming an external connection terminal that is electrically connected to the electrode on the second surface; and 
             detachably joining a third substrate to the external connection terminal via the junction layer.
 
(19) The method of producing a light-emitting element wafer according to (18), further including:
 
             removing the second substrate to expose the first inorganic film; and 
             etching the first inorganic film remained on the bottom surface of the first isolation trench to form a second isolation trench that isolates the first inorganic film for each element, after the joining of the third substrate.
 
(20) The method of producing a light-emitting element wafer according to (19), further including:
 
             preparing a transfer substrate arranged to face the first inorganic film; and 
             isolating the external connection terminal from the third substrate by laser ablation of the junction layer to transfer each element on the transfer substrate, after the forming of the second isolation trench. 
           
         
       
    
     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.