Light emitting element

Abstract

[Problem] To provide a light-emitting element with excellent light-emitting efficiency and light extraction efficiency. [Solution] A light-emitting element of the present technology comprises: a layered body; a light-emitting surface; and a reflecting body. The layered body comprises: a first semiconductor layer having a first semiconductor type; a second semiconductor layer having a second semiconductor type; and an active layer sandwiched between the first semiconductor layer and the second semiconductor layer. The layered body also includes: a first surface which is the surface of the first semiconductor layer on the side opposite the active layer; a second surface which is the surface of the second semiconductor layer on the side opposite the active layer; and a circumferential surface which connects the first surface and the second surface, and which includes an end surface of the active layer. The first semiconductor layer has formed therein a groove that is formed from the first surface toward the active layer, that has a depth such that the groove is spaced from the active layer, and that extends in a direction parallel to the first surface. The light-emitting surface is positioned on the first surface on the side opposite the active layer, and emits light generated in the active layer. The reflecting body reflects the light emitted from the end surface toward the groove.

Description

[Technical field]

[0001] The present technology relates to a light emitting device having a light emitting diode structure. [Background technology]

[0002] A light-emitting element having a light-emitting diode structure has an active layer sandwiched between an n-type semiconductor layer and a p-type semiconductor layer, and emits light by recombination of electrons and holes generated in the active layer. The light generated in the active layer is emitted from the light-emitting surface of the light-emitting element.

[0003] In order to improve the light emission efficiency and light extraction efficiency of light-emitting elements, various element structures have been studied. For example, Patent Document 1 discloses a light-emitting element in which a reflective layer is provided on the outer peripheral surface of the light-emitting element except for the light-emitting surface, and an uneven structure is provided on the light-emitting surface as a light extraction structure. In this light-emitting element, light generated in the active layer is reflected to the light-emitting surface by the reflective layer, and is emitted in a predetermined direction by the uneven structure.

[0004] Furthermore, Patent Document 2 discloses a light-emitting diode in which the thickness of the semiconductor layer is thinned at the outer edge of the light-emitting element. In this configuration, by thinning the thickness of the semiconductor layer, an effect occurs in which it becomes difficult for current to flow through the thin portion of the semiconductor layer, i.e., a current confinement effect occurs, making it possible to concentrate the light-emitting portion of the active layer in the center of the light-emitting element. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-32809 A [Patent Document 2] International Publication No. 2016 / 125344 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in recent years, with the progress in miniaturization of light-emitting devices, there has been a problem of reduced luminous efficiency and reduced light extraction efficiency due to recombination that does not contribute to light emission (non-radiative recombination) at the outer edge of the active layer.

[0007] For example, the configuration described in the cited document 1 is a structure that improves the light extraction efficiency, but it is difficult to prevent a decrease in the light emission efficiency due to miniaturization of the light emitting device. On the other hand, the configuration described in the cited document 2 can suppress non-radiative recombination at the outer edge of the active layer by the current confinement effect, but it is difficult to provide a light extraction structure due to miniaturization of the light emitting device.

[0008] In view of the above circumstances, an object of the present technology is to provide a light-emitting element excellent in luminous efficiency and light extraction efficiency. [Means for solving the problem]

[0009] In order to achieve the above object, a light-emitting element according to an embodiment of the present technology includes a laminate, a light-emitting surface, and a reflector. The laminate includes a first semiconductor layer having a first semiconductor type, a second semiconductor layer having a second semiconductor type, and an active layer sandwiched between the first semiconductor layer and the second semiconductor layer, and has a first surface which is the surface of the first semiconductor layer opposite to the active layer, a second surface which is the surface of the second semiconductor layer opposite to the active layer, and a peripheral surface which connects between the first surface and the second surface and includes an end surface of the active layer. A groove is formed in the first semiconductor layer from the first surface toward the active layer, has a depth separating it from the active layer, and extends in a direction parallel to the first surface. The light emitting surface is located on the opposite side of the first surface to the active layer, and emits light generated in the active layer. The reflector reflects the light emitted from the end face toward the groove.

[0010] According to this configuration, the groove-shaped recess provided in the first semiconductor layer exerts a current confinement effect and an optical effect, making it possible to realize a light emitting element excellent in luminous efficiency and light extraction efficiency.

[0011] The reflector may cover the second surface and the peripheral surface, and may reflect light emitted from the second surface and the peripheral surface toward the light emitting surface.

[0012] The peripheral surfaces may be angled such that the distance between the peripheral surfaces increases from the second surface towards the first surface.

[0013] The groove may have a V-shape, U-shape or polygonal shape in cross section taken along a plane perpendicular to the extension direction of the groove.

[0014] The groove wall of the groove may be a vertical surface, an inclined surface, or a curved surface with respect to the light emitting surface.

[0015] The groove walls of the grooves may be smooth or uneven.

[0016] The grooves may extend in a direction parallel or non-parallel to the periphery of the light exit surface when viewed from a direction perpendicular to the light emitting surface.

[0017] The groove may include a plurality of grooves provided between the first electrode and the peripheral surface.

[0018] The grooves may extend linearly or curvedly when viewed from a direction perpendicular to the light emitting surface.

[0019] The groove may be formed discontinuously.

[0020] The groove may have a constant groove width when viewed from a direction perpendicular to the light emitting surface, or the groove may not have a constant groove width.

[0021] The groove may be covered with a dielectric film, and the dielectric film may form a groove wall of the groove.

[0022] The trench may or may not be filled with a dielectric therein.

[0023] the light-emitting element further includes a first electrode provided on the first surface and electrically connected to the first semiconductor layer, and a second electrode provided on the second surface and electrically connected to the second semiconductor layer; The groove may be formed between the first electrode and the peripheral surface.

[0024] The groove may be formed in a ring shape surrounding the first electrode when viewed from a direction perpendicular to the light emitting surface.

[0025] The first electrode may traverse the groove.

[0026] The first electrode may be electrically connected to the first semiconductor layer within the groove.

[0027] the laminate further includes a hole-shaped recess formed in the first semiconductor layer from the first surface toward the active layer and having a depth spaced apart from the active layer; A dielectric film may be formed on the inner surface of the hole-like recess. [Brief description of the drawings]

[0028] [Figure 1] 1 is a plan view of a light-emitting device according to an embodiment of the present technology. [Diagram 2] FIG. 2 is a cross-sectional view of the light-emitting element. [Diagram 3] 3 is a plan view of a laminate included in the light-emitting element. FIG. [Figure 4] 4 is a cross-sectional view of a laminate included in the light-emitting element. FIG. [Diagram 5] FIG. 2 is an enlarged cross-sectional view of the light-emitting element. [Figure 6] 5A to 5C are schematic diagrams illustrating the operation of the light-emitting element. [Figure 7] 5A to 5C are schematic diagrams illustrating the operation of the light-emitting element. [Figure 8]5A to 5C are schematic diagrams illustrating the operation of the light-emitting element. [Figure 9] 5A to 5C are schematic diagrams illustrating the operation of the light-emitting element. [Figure 10] 13 is a graph showing the relationship between the width of a groove provided in the light emitting element and the emission intensity. [Figure 11] 5 is a schematic diagram showing a width of a groove provided in the light-emitting element. FIG. [Figure 12] 13 is a graph showing the relationship between the position of a groove provided in the light emitting element and the emission intensity. [Figure 13] 5 is a schematic diagram showing the position of a groove provided in the light-emitting element. FIG. [Figure 14] 4 is a plan view showing a planar shape of a groove provided in the light emitting element. FIG. [Figure 15] 4 is a plan view showing a planar shape of a groove provided in the light emitting element. FIG. [Figure 16] 4 is a plan view showing a planar shape of a groove provided in the light emitting element. FIG. [Figure 17] 4 is a plan view showing a planar shape of a groove provided in the light emitting element. FIG. [Figure 18] 4 is a plan view showing a planar shape of a groove provided in the light emitting element. FIG. [Figure 19] 4 is a plan view showing a planar shape of a groove provided in the light emitting element. FIG. [Figure 20] 4 is a plan view showing a planar shape of a groove provided in the light emitting element. FIG. [Figure 21] 4 is a cross-sectional view showing a cross-sectional shape of a groove provided in the light-emitting element. FIG. [Figure 22] 4 is a cross-sectional view showing a cross-sectional shape of a groove provided in the light-emitting element. FIG. [Diagram 23] 4 is a cross-sectional view showing a cross-sectional shape of a groove provided in the light-emitting element. FIG. [Figure 24] 4 is a cross-sectional view showing a cross-sectional shape of a groove provided in the light-emitting element. FIG. [Diagram 25] 4 is a cross-sectional view showing a cross-sectional shape of a groove provided in the light-emitting element. FIG. [Figure 26] 4 is a plan view showing grooves and holes provided in the light-emitting element. FIG. [Figure 27]4 is a cross-sectional view showing a groove and a hole provided in the light-emitting element. FIG. [Figure 28] 4 is a plan view showing grooves and holes provided in the light-emitting element. FIG. [Figure 29] 4 is a cross-sectional view showing a peripheral shape of the light-emitting element. FIG. [Diagram 30] 11 is a cross-sectional view of a light-emitting element according to a modified example of the present technology. [Diagram 31] 11 is a cross-sectional view of a light-emitting element according to a modified example of the present technology. [Diagram 32] 1 is a graph showing a relationship between the thickness of a constriction portion and the luminance of a light-emitting element according to an embodiment of the present technology. [Diagram 33] 4 is a graph showing the relationship between the width of a first semiconductor layer and the luminance of a light-emitting device according to an embodiment of the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] A light-emitting device according to an embodiment of the present technology will be described.

[0030] [Light-emitting element structure] Fig. 1 is a plan view of a light emitting device 100 according to this embodiment, and Fig. 2 is a cross-sectional view of the light emitting device 100. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1.

[0031] As shown in FIGS. 1 and 2, the light emitting element 100 includes a laminate 110, a dielectric film 121, a reflector 122, a first electrode 131, and a second electrode 132.

[0032] The laminate 110 is configured by laminating a first semiconductor layer 111, a second semiconductor layer 112, and an active layer 113.

[0033] The first semiconductor layer 111 is a layer made of a p-type semiconductor, and may have a structure in which a p-type contact layer and a p-type cladding are laminated. The p-type contact layer is made of, for example, p-GaP, and is laminated on the first electrode 131 side. The p-type cladding layer is made of, for example, p-AlGaInP, and is laminated on the active layer 113 side. The layer structure and materials of the first semiconductor layer 111 are not limited to those shown here, and may be any material made of a p-type semiconductor.

[0034] The second semiconductor layer 112 is a layer made of an n-type semiconductor, and may have a structure in which an n-type contact layer and an n-type clad are laminated. The n-type contact layer is made of, for example, GaAs, and is laminated on the second electrode 132 side. The n-type clad layer is made of, for example, n-AlGaInP, and is laminated on the active layer 113 side. The layer structure and material of the second semiconductor layer 112 are not limited to those shown here, and may be any material made of an n-type semiconductor.

[0035] The active layer 113 is a layer sandwiched between the first semiconductor layer 111 and the second semiconductor layer 112, and emits light by recombination of holes flowing in from the first semiconductor layer 111 and electrons flowing in from the second semiconductor layer 112. The active layer 113 may be, for example, a layer having a multiple quantum well structure in which a large number of quantum well layers made of GaInP and barrier layers made of AlGaInP are alternately stacked. The active layer 113 may be made of any material that emits light by recombination, and may have a single semiconductor layer or a single quantum well structure.

[0036] FIG. 3 is a plan view of only the laminate 110, and FIG. 4 is a cross-sectional view of only the laminate 110. FIG. 4 is a cross-sectional view taken along line BB in FIG. 3. As shown in these figures, the surface of the first semiconductor layer 111 opposite to the active layer 113 is the first surface 110a, and the surface of the second semiconductor layer 112 opposite to the active layer 113 is the second surface 110b. In addition, the surface that connects the first surface 110a and the second surface 110b and is made up of the end surfaces of the first semiconductor layer 111, the second semiconductor layer 112, and the active layer 113 is the peripheral surface 110c. In addition, in each figure of the present disclosure, the first surface 110a is a surface parallel to the X direction and the Y direction, that is, the first surface 110a is a surface parallel to the XY plane.

[0037] 4, a groove 151 is formed in the first semiconductor layer 111 from the first surface 110a toward the active layer 113. The groove 151 is formed to a depth shallower than the depth that reaches the active layer 113, that is, the groove 151 is formed to a depth that is separated from the active layer 113.

[0038] 3, the groove 151 extends in a direction parallel to the first surface 110a (XY direction). Specifically, the groove 151 may be formed in a ring shape surrounding the first electrode 131 (see FIG. 1) when viewed from a direction perpendicular to the first surface 110a (Z direction). The shape of the groove 151 is not limited to that shown here, and will be described in detail later.

[0039] The dielectric film 121 is a film made of a dielectric material such as SiN. The dielectric film 121 is formed on the first surface 110a and on the inner surface of the groove 151, and forms a groove wall 152 made of the dielectric film 121 within the groove 151 as shown in FIG.

[0040] Fig. 5 is an enlarged view of Fig. 2. Hereinafter, as shown in Fig. 5 and Fig. 1, among the groove walls 152, the groove wall on the peripheral surface 110c side is referred to as an outer wall 152a, and the groove wall on the first electrode 131 side is referred to as an inner wall 152b. The outer wall 152a and the inner wall 152b may be surfaces perpendicular to the first surface 110a, or may have an inclined surface or the like as described later. The inside of the groove 151 may be a gap, or may be filled with a sealing resin (not shown) or the like that covers the periphery of the light-emitting element 100.

[0041] Moreover, the surface of the dielectric film 121 provided on the first surface 110a is a surface from which light generated by the light emitting element 100 is emitted, and is hereinafter referred to as a light emitting surface 123. The light emitting surface 123 is a surface located on the opposite side of the first surface 110a to the active layer 113.

[0042] Furthermore, the dielectric film 121 is also formed on the second surface 110b and the peripheral surface 110c, and covers the periphery of the laminate 110. As shown in Fig. 2, the dielectric film 121 has an opening 121a on the first surface 110a and an opening 121b on the second surface 110b.

[0043] The reflector 122 reflects light incident from the laminate 110. The reflector 122 is preferably provided so as to cover the surface of the laminate 110 excluding the light emitting surface 123, i.e., the second surface 110b and the peripheral surface 110c. The reflector 122 may be provided only on the end surface of the active layer 113 exposed to the peripheral surface 110c. The reflector 122 may be embedded in the dielectric film 121, or may be provided between the surface of the laminate 110 and the dielectric film 121. The reflector 122 may be, for example, a metal film.

[0044] The first electrode 131 is provided on the dielectric film 121 formed on the first surface 110a, contacts the first semiconductor layer 111 through the opening 121a, and is electrically connected to the first semiconductor layer 111. The first electrode 131 is preferably provided in the center of the light emitting surface 123 as shown in FIG. 1. The first electrode 131 may be formed so as to cross the groove 151, or may be in contact with the first semiconductor layer 111 inside the groove 151 and electrically connected to the first semiconductor layer 111. The first electrode 131 may be made of a conductive material such as a metal.

[0045] The second electrode 132 is provided on the dielectric film 121 formed on the second surface 110b, abuts on the second semiconductor layer 112 through the opening 121b, and is electrically connected to the second semiconductor layer 112. The second electrode 131 is preferably provided in the center of the second surface 110b, that is, at a position facing the first electrode 131 across the laminate 110. The second electrode 132 may be made of a conductive material such as a metal.

[0046] The light emitting element 100 has the above-mentioned configuration. As shown in Fig. 1, the light emitting element 100 can be a square when viewed from a direction perpendicular to the light emitting surface 123 (Z direction), but is not limited thereto, and may be other shapes such as a rectangle, a circle, or a polygon with more sides than a triangle when viewed from the same direction. The size of the light emitting element 100 is not particularly limited, but typically one side of the light emitting surface 123 is about several µm to several tens of µm, and the light emitting element 100 can be a micro LED (light emitting diode).

[0047] In the above description, the first semiconductor layer 111 is a p-type semiconductor layer and the second semiconductor layer 112 is an n-type semiconductor layer, but the first semiconductor layer 111 may be an n-type semiconductor layer and the second semiconductor layer 112 may be a p-type semiconductor layer.

[0048] [Light emitting element operation] The operation of the light-emitting element 100 will be described. Figures 6 and 7 are schematic diagrams showing the operation of the light-emitting element 100. When a current is applied between the first electrode 131 and the second electrode 132, holes flow from the first semiconductor layer 111 into the active layer 113, and electrons flow from the second semiconductor layer 112 into the active layer 113. Recombination of the holes and electrons occurs in the active layer 113, causing light emission.

[0049] The light emitted in the active layer 113 is centered in the region between the first electrode 131 and the second electrode 132. In Fig. 6, the region where light mainly occurs is shown as light-emitting region E. Of the light generated in light-emitting region E, light heading toward light-emitting surface 123 (light L1 in Fig. 6) is emitted directly from light-emitting surface 123. On the other hand, light heading toward second surface 110b and peripheral surface 110c (light L2 in Fig. 6) is reflected by reflector 122 and emitted from light-emitting surface 123, or is reflected by reflector 122 again.

[0050] Furthermore, a portion of the light generated in light emitting region E (light L3 in FIG. 6) propagates through active layer 113 toward peripheral surface 110c, is reflected by reflector 122 at peripheral surface 110c, and is emitted from light emitting surface 123.

[0051] Here, part of the current flowing between the first electrode 131 and the second electrode 132 causes recombination that does not generate light, called non-radiative recombination, in the peripheral region of the active layer 113. In Fig. 7, the peripheral region of the active layer 113 is shown as peripheral region R. When non-radiative recombination occurs in peripheral region R, the current is not used for light emission, and the light emission efficiency decreases.

[0052] In contrast, in the light emitting element 100, the groove 151 is provided in the first semiconductor layer 111 as described above. By providing the groove 151, the thickness of the first semiconductor layer 111 between the groove 151 and the active layer 113 is reduced, as shown in Fig. 7. If this reduced thickness portion is defined as a narrowing portion N, the current flowing between the first electrode 131 and the second electrode 132 becomes less likely to pass through the narrowing portion N, that is, the narrowing portion N is subject to the current narrowing effect.

[0053] This suppresses non-radiative recombination in the peripheral region R of the active layer 113, and the current generates a lot of radiative recombination in the light-emitting region A, improving the light-emitting efficiency. For this reason, it is preferable to form the groove 151 in an annular shape surrounding the outer periphery of the first electrode 131 as shown in Fig. 1, since the periphery of the light-emitting region A can be surrounded by the narrowing portion N. Even if the groove 151 is not formed in an annular shape, the current narrowing effect due to the narrowing portion N can be partially obtained, improving the light-emitting efficiency.

[0054] The thickness of the narrowing portion N (thickness T in FIG. 7) may be any thickness that produces a current narrowing effect. FIG. 32 is a graph showing a schematic relationship between thickness T and luminance of the light-emitting element 100. As the thickness T is made thinner, the resistance of the narrowing portion N increases, the current flowing through the narrowing portion N decreases, and the current to the peripheral region R decreases, thereby improving the luminance. The luminance of the light-emitting element 100 increases as the thickness T decreases, and after reaching a maximum, it rapidly decreases as T approaches 0. When T=0, the active layer 113 is exposed in the groove 151, and non-radiative recombination occurs in the vicinity thereof, resulting in a decrease in luminance.

[0055] Furthermore, in the light-emitting element 100, an optical effect due to the grooves 151 also occurs. Figures 8 and 9 are schematic diagrams showing the optical effect due to the grooves 151, and are enlarged views of Figure 6. As described above, the light L3 propagated through the active layer 113 is reflected by the reflector 122 and enters the grooves 151 from the outer periphery side of the light-emitting element 100.

[0056] Here, the inside of the groove 151 is a gap or filled with a sealing resin or the like, and a refractive index difference occurs between the groove 151 and the dielectric film 121. For this reason, as shown in Fig. 8, the light L3 is refracted on the surface of the dielectric film 121 at the outer wall 152a, and is emitted towards the light emitting surface 123. Since the light L3 is incident on the light emitting surface 123 at a steeper angle than when the light L3 is not refracted, it is projected further forward from the light emitting surface 123.

[0057] 8 shows only refraction at the surface of the dielectric film 121, refraction may also occur at the interface between the first semiconductor layer 111 and the dielectric film 121. Furthermore, in addition to the light L3, the light L2 (see FIG. 6) may also be refracted by the outer wall 152a.

[0058] 9, light L3 incident on groove 151 may be refracted by outer wall 152a, reflected by inner wall 152b, and emitted toward light-emitting surface 123. Light L2 may also be refracted by outer wall 152a and reflected by inner wall 152b, similar to light L3.

[0059] [Adjusting the light emission characteristics] In the light emitting device 100, the emission intensity can be adjusted by the groove 151. Fig. 10 is a graph showing the ratio of emission intensity depending on the width of the groove 151, and Fig. 11 is a schematic diagram of the light emitting device 100 having grooves 151 with different widths.

[0060] The emission intensity indicated by "W1" in Fig. 10 is the emission intensity of the light-emitting element 100 having a groove 151 with a width W1 on the light-emitting surface 123 as shown in Fig. 11(a). Similarly, "W2" in Fig. 10 is the emission intensity of the light-emitting element 100 having a groove wall 152 with a width W2 as shown in Fig. 11(b), and "W3" in Fig. 10 is the emission intensity of the light-emitting element 100 having a groove wall 152 with a width W3 as shown in Fig. 11(c). "W0" in Fig. 10 is the emission intensity of a light-emitting element that does not have the groove 151 and has the same configuration as the light-emitting element 100 in other respects, for comparison. Note that the "width" of the groove 151 here means the distance between the outer wall 152a and the inner wall 152b.

[0061] 10, the emission intensity is improved by providing the groove 151. Furthermore, the emission intensity differs depending on the width of the groove 151, and the emission intensity improves as the width of the groove 151 increases. This is because the current confinement effect of the confinement portion N (see FIG. 7) increases as the width of the groove 151 increases.

[0062] Fig. 33 is a graph showing a schematic relationship between the width of the first semiconductor layer 111 and the luminance of the light-emitting element 100. As shown in Fig. 7, the distance between the circumferential surfaces 110c is distance K1, and the distance between the inner circumference of the groove 151 and the circumferential surface 110c is distance K2. As shown in Fig. 32, as K2 / K1 increases from the case where K2 / K1=0, the luminance increases, but as K2 / K1 increases further, the luminance decreases.

[0063] Furthermore, the light emission intensity of the light emitting element 100 can be adjusted not only by the width of the groove wall 152 but also by the position at which the groove wall 152 is formed, specifically, the area of ​​the light emitting surface 123 inside the inner wall 152b.

[0064] Furthermore, in the light-emitting element 100, the viewing angle characteristics can be adjusted by the groove wall 152. Fig. 12 is a graph showing the emission intensity distribution according to the distance between the outer wall 152a and the peripheral surface 110c, and Fig. 13 is a schematic diagram of the light-emitting element 100 having different widths of the distance between the outer wall 152a and the peripheral surface 110c.

[0065] In Fig. 12, "D1" is the emission intensity distribution of the light-emitting element 100 in which the distance between the outer wall 152a and the peripheral surface 110c on the light-emitting surface 123 is distance D1 as shown in Fig. 13(a). Also, in Fig. 12, "D2" is the emission intensity distribution of the light-emitting element 100 in which the distance between the outer wall 152a and the peripheral surface 110c on the light-emitting surface 123 is distance D2 as shown in Fig. 13(b).

[0066] As shown in FIG. 12, when the distance between the outer wall 152a and the peripheral surface 110c is large (distance D1), the emission intensity distribution becomes broader, and when the distance between the outer wall 152a and the peripheral surface 110c is small (distance D2), The emission intensity distribution becomes narrower due to factors such as the angle of incidence of the light reflected by the reflector 122 onto the outer wall 152a (see FIG. 8).

[0067] In this way, in the light emitting device 100, the light emitting characteristics such as the light emitting intensity and the viewing angle characteristics can be controlled by changing the width and the formation position of the groove wall 152.

[0068] [Effects of light-emitting elements] As described above, in the light-emitting element 100, the light generated by the active layer 113 is reflected by the reflector 122 toward the light-emitting surface 123, and the light traveling toward the second surface 110b and the peripheral surface 110c can be utilized without being wasted (see FIG. 6).

[0069] Moreover, the provision of the groove 151 produces a current confinement effect, suppresses non-radiative recombination in the peripheral region of the active layer 113, and reduces current loss (see FIG. 7). Furthermore, the groove wall 152 causes light incident from the outer periphery of the light emitting element 100 by the reflector 122 to exit toward the light emitting surface 123, thereby contributing to improving the light emission intensity in the vertical direction of the light emitting surface 123 (see FIGS. 8 and 9).

[0070] Generally, as the size of a light-emitting element becomes smaller, problems arise such as a decrease in light emission efficiency and a decrease in light extraction efficiency due to non-radiative recombination. As described above, the light-emitting element 100 can improve both the light emission efficiency and the light extraction efficiency, and can realize a reduction in the size of the light-emitting element while suppressing the decrease in the light emission efficiency and the light extraction efficiency.

[0071] In addition, it is possible to control the emission intensity and emission characteristics according to the width and the formation position of the groove 151, and these can be adjusted according to the desired characteristics. Also, the shape of the groove 151 can be controlled by a mask pattern or the like in the manufacturing process, so it is possible to accommodate miniaturization and to easily form any shape.

[0072] [Shape of the groove and groove inner wall] The shape of the groove 151 provided in the light emitting element 100 according to this embodiment is not limited to the above. Fig. 14 to Fig. 25 are schematic diagrams showing various configurations of the groove 151. Fig. 14 to Fig. 20 show the shape of the groove 151 as viewed from a direction perpendicular to the light emitting surface 123 (Z direction), and Fig. 20 to Fig. 25 show the cross-sectional shape of the groove 151 in a plane perpendicular to the extension direction of the groove 151 (a plane parallel to the Z direction).

[0073] The groove 151 may be annular, surrounding the first electrode 131 and extending parallel to the periphery of the light-emitting surface S, as shown in Fig. 1, or may be annular, surrounding the first electrode 131 and extending non-parallel to the periphery of the light-emitting surface 123, as shown in Fig. 14. The groove 151 may also be annular, centered on the first electrode 131, as shown in Fig. 15.

[0074] Furthermore, the groove 151 may have a ring-shaped portion surrounding the first electrode 131 and a branch portion extending toward the periphery of the light-emitting surface 123 as shown in Fig. 16, or may be formed in an interrupted ring shape as shown in Fig. 17. Furthermore, a plurality of grooves 151 may be provided between the first electrode 131 and the circumferential surface 110c, or may be formed in a double ring shape as shown in Fig. 18.

[0075] Moreover, the groove 151 is not limited to being annular, and may extend linearly separating the light emitting surface 123 and the first electrode 131, or may be formed linearly and double, as shown in Fig. 19. Furthermore, the groove 151 is not limited to being linear, and may extend curvedly, as shown in Fig. 20. The groove width of the groove 151 as viewed from a direction perpendicular to the light emitting surface 123 (Z direction) may be constant, as shown in Figs. 1 and 14 to 19, or may not be constant, as shown in Fig. 20.

[0076] The cross-sectional shape of groove 151 in a plane perpendicular to the extension direction (plane parallel to the Z direction) is not limited to the rectangular shape shown in Fig. 2. As shown in Fig. 21, groove 151 may have groove wall 152 having a U-shape, or may have a V-shape as shown in Fig. 22 or a polygonal shape as shown in Fig. 23.

[0077] 5, the outer wall 152a and the inner wall 152b of the groove wall 152 may be perpendicular to the light-emitting surface 123, or as shown in Fig. 23, the outer wall 152a and the inner wall 152b may be inclined in part with respect to a plane perpendicular to the light-emitting surface 123. Also, only one of the outer wall 152a and the inner wall 152b may be inclined.

[0078] Furthermore, as shown in Fig. 24, the groove wall 152 may have an outer wall 152a formed in a curved shape, an inner wall 152b formed in a curved shape, or both the outer wall 152a and the inner wall 152b formed in a curved shape. The wall surfaces of the outer wall 152a and the inner wall 152b may also be smooth as shown in Fig. 1, or may be uneven as shown in Fig. 25.

[0079] As described above, the groove 151 and the groove wall 152 can be formed in various shapes, and in addition to the various shapes described above, they can be formed in any appropriate shape depending on the size and shape of the light-emitting element 100, the desired light-emitting characteristics, etc.

[0080] [About holes] As described above, the light-emitting element 100 has the groove 151 formed in the light-emitting surface 123, but it is also possible to have a hole formed in the light-emitting surface 123 in addition to the groove 151. Fig. 26 is a plan view of the light-emitting element 100 having the hole 153, and Fig. 27 is a cross-sectional view taken along line C in Fig. 26.

[0081] 26 and 27, the hole 153 is formed in the first semiconductor layer 111 from the first surface 110a toward the active layer 113, and is composed of a hole-shaped recess 154 having a depth separating it from the active layer 113, and a dielectric film 121 provided in the hole-shaped recess 154. The hole 153 may have the same depth as the groove 151, or may have a depth shallower than that of the groove 151.

[0082] The holes 153 can also impart an optical effect to the light reflected by the reflector 122, and by increasing the number of light paths, it is possible to adjust the light emitting characteristics of the light emitting element 100. The holes 153 can be provided between the groove 151 and the periphery of the light emitting element 100 as shown in Fig. 26. Fig. 28 is a plan view showing another arrangement of the holes 153, and the holes 153 may be provided between the groove 151 and the first electrode 131 as shown in the figure.

[0083] The shape of the holes 153 on the light emitting surface 123 may be circular as shown in Figures 26 and 28, or may be another shape. The size and number of the holes 153 are not limited to those shown here.

[0084] [About the surroundings] As described above, the light emitting element 100 has a peripheral surface 110c connecting the first surface 110a and the second surface 110b, but the peripheral surface 110c may be an inclined surface. Fig. 29 is a cross-sectional view of the light emitting element 100 having an inclined peripheral surface 110c.

[0085] As shown in the figure, the peripheral surface 110c can be inclined with respect to a plane perpendicular to the light emitting surface 123 so that the distance between the peripheral surfaces 110c increases from the second surface 110b toward the first surface 110a.

[0086] By inclining the peripheral surface 110c in this manner, light incident on the peripheral surface 110c is more easily reflected by the reflector 122 toward the light-emitting surface 123, and it is possible to increase the amount of light projected forward from the light-emitting surface 123. Note that the entire peripheral surface 110c may be inclined as shown in Fig. 29, or only a part of the peripheral surface 110c may be inclined. Furthermore, the peripheral surface 110c may be a curved surface formed so that the distance between the peripheral surface 110c increases from the second surface 110b toward the first surface 110a, or may be polygonal.

[0087] [Variations] A modified example of the light emitting device 100 according to this embodiment will be described below. Figures 30 and 31 are cross-sectional views of the light emitting device 100 according to the modified example.

[0088] As described above, the light emitting element 100 has the groove wall 152 made of the dielectric film 121, but the groove 151 may be filled with a dielectric 124 as shown in Fig. 30. Even with this configuration, it is possible to generate a current confinement effect by the groove 151 and an optical effect such as refraction at the interface between the groove 151 and the dielectric 124.

[0089] 31, the groove 151 may not be filled with the dielectric 124. In this case as well, it is possible to cause the groove 151 to have a current confinement effect and to cause an optical effect such as refraction on the surface of the groove 151.

[0090] The present technology can also be configured as follows. (1) a laminate including a first semiconductor layer having a first semiconductor type, a second semiconductor layer having a second semiconductor type, and an active layer sandwiched between the first semiconductor layer and the second semiconductor layer, the laminate having a first surface which is a surface of the first semiconductor layer opposite to the active layer, a second surface which is a surface of the second semiconductor layer opposite to the active layer, and a peripheral surface which connects between the first surface and the second surface and includes an end surface of the active layer, the laminate having a groove formed in the first semiconductor layer from the first surface toward the active layer, the groove having a depth separating the active layer and extending in a direction parallel to the first surface; a light emitting surface located on the first surface opposite to the active layer and configured to emit light generated in the active layer; a reflector that reflects the light emitted from the end face toward the groove; A light emitting device comprising: (2) The light-emitting device according to (1) above, The reflector covers the second surface and the peripheral surface and reflects light emitted from the second surface and the peripheral surface toward the light emitting surface. Light emitting element. (3) The light-emitting device according to (1) or (2), The light-emitting device according to claim 2, The peripheral surfaces are inclined such that the distance between the peripheral surfaces increases from the second surface toward the first surface. Light emitting element. (4) The light-emitting device according to any one of (1) to (3), The groove has a cross-sectional shape in a plane perpendicular to the extension direction of the groove, the cross-sectional shape being V-shaped, U-shaped, or polygonal. Light emitting element. (5) The light-emitting device according to any one of (1) to (3), The groove wall of the groove is a vertical surface, an inclined surface, or a curved surface with respect to the light emitting surface. Light emitting element. (6) The light-emitting device according to any one of (1) to (3), The groove walls of the grooves are smooth or uneven. Light emitting element. (7) The light-emitting device according to any one of (1) to (6), The groove extends in a direction parallel or non-parallel to the periphery of the light exit surface when viewed from a direction perpendicular to the light emitting surface. Light emitting element. (8) The light-emitting device according to any one of (1) to (7), The groove includes a plurality of grooves provided between the first electrode and the peripheral surface. Light emitting element. (9) The light-emitting device according to any one of (1) to (8), The groove extends linearly or curvedly when viewed from a direction perpendicular to the light emitting surface. Light emitting element. (10) The light-emitting device according to any one of (1) to (9), The grooves are formed intermittently. Light emitting element. (11) The light-emitting device according to any one of (1) to (10) above, The groove has a constant groove width when viewed from a direction perpendicular to the light emitting surface, or the groove has an irregular groove width. Light emitting element. (12) The light-emitting device according to any one of (1) to (11) above, The groove is covered with a dielectric film, and the dielectric film forms a groove wall of the groove. Light emitting element. (13) The light-emitting device according to any one of (1) to (11) above, The groove may or may not be filled with a dielectric material. Light emitting element. (14) A light-emitting device according to any one of claims (1) to (13), a first electrode provided on the first surface and electrically connected to the first semiconductor layer; a second electrode provided on the second surface and electrically connected to the second semiconductor layer; Further comprising: The groove is formed between the first electrode and the peripheral surface. Light emitting element. (15) The light-emitting device according to (14) above, The groove is formed in a ring shape surrounding the first electrode when viewed in a direction perpendicular to the light emitting surface. Light emitting element. (16) The light-emitting device according to (14) above, The first electrode traverses the groove. Light emitting element. (17) The light-emitting device according to (16) above, The first electrode is electrically connected to the first semiconductor layer within the groove. Light emitting element. (18) The light-emitting device according to any one of (1) to (17), the laminate further includes a hole-shaped recess formed in the first semiconductor layer from the first surface toward the active layer and having a depth spaced apart from the active layer; A dielectric film is formed on the inner surface of the hole-shaped recess. Light emitting element. [Explanation of symbols]

[0091] 100...Light emitting element 110...Laminate 111...first semiconductor layer 112...Second semiconductor layer 113...Active layer 121...Dielectric film 122...Reflector 123…Light-emitting surface 131...1st electrode 132…Second electrode 151…Ditch 152…Ditch wall 152a…outer wall 152b…Inner wall 153…hole

Claims

1. a laminate including a first semiconductor layer having a first semiconductor type, a second semiconductor layer having a second semiconductor type, and an active layer sandwiched between the first semiconductor layer and the second semiconductor layer, the laminate having a first surface which is a surface of the first semiconductor layer opposite to the active layer, a second surface which is a surface of the second semiconductor layer opposite to the active layer, and a peripheral surface which connects between the first surface and the second surface and includes an end surface of the active layer, the laminate having a groove formed in the first semiconductor layer from the first surface toward the active layer, the groove having a depth separating the active layer and extending in a direction parallel to the first surface; a first electrode provided on the first surface and electrically connected to the first semiconductor layer; a second electrode provided on the second surface and electrically connected to the second semiconductor layer; a light emitting surface located on the opposite side of the first surface from the active layer and emitting light generated in the active layer; a reflector that reflects the light emitted from the end surface toward the groove; Equipped with The groove is formed between a light emitting region, which is a region of the active layer between the first electrode and the second electrode, and a peripheral region of the active layer, when viewed from a direction perpendicular to the light emitting surface, and the first semiconductor layer between the groove and the active layer has a depth that provides a thickness that produces a current confinement effect, and a dielectric film is formed on an inner surface. Light emitting element.

2. The light emitting device according to claim 1 , The reflector covers the second surface and the peripheral surface and reflects light emitted from the second surface and the peripheral surface toward the light emitting surface. Light emitting element.

3. The light-emitting device according to claim 2 , The peripheral surfaces are inclined such that the distance between the peripheral surfaces increases from the second surface toward the first surface. Light emitting element.

4. The light-emitting device according to claim 1 , The groove has a cross-sectional shape in a plane perpendicular to the extension direction of the groove, the cross-sectional shape being V-shaped, U-shaped, or polygonal. Light emitting element.

5. The light-emitting device according to claim 1 , The groove wall of the groove is a vertical surface, an inclined surface, or a curved surface with respect to the light emitting surface. Light emitting element.

6. The light-emitting device according to claim 1 , The groove wall of the groove has a smooth surface or an uneven surface. Light emitting element.

7. The light-emitting device according to claim 1 , The groove extends in a direction parallel or non-parallel to the periphery of the light-emitting surface when viewed from a direction perpendicular to the light-emitting surface. Light emitting element.

8. The light-emitting device according to claim 1 , The groove includes a plurality of grooves provided between the first electrode and the peripheral surface. Light emitting element.

9. The light-emitting device according to claim 1 , The groove extends linearly or curvedly when viewed from a direction perpendicular to the light emitting surface. Light emitting element.

10. The light-emitting device according to claim 1 , The grooves are formed intermittently. Light emitting element.

11. The light-emitting device according to claim 1 , The groove has a constant groove width when viewed from a direction perpendicular to the light emitting surface, or the groove has an irregular groove width. Light emitting element.

12. The light-emitting device according to claim 1 , The groove is filled with a dielectric material. Light emitting element.

13. The light emitting device according to claim 1 , The groove is formed in a ring shape surrounding the first electrode when viewed in a direction perpendicular to the light emitting surface. Light emitting element.

14. The light emitting device according to claim 1 , The first electrode traverses the groove. Light emitting element.

15. The light emitting device according to claim 14, The first electrode is electrically connected to the first semiconductor layer within the groove. Light emitting element.

16. A light-emitting device according to any one of claims 1 to 15, the stack further includes a hole-shaped recess formed in the first semiconductor layer from the first surface toward the active layer and having a depth spaced apart from the active layer; A dielectric film is formed on the inner surface of the hole-shaped recess. Light emitting element.

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