JP7525787B2 - Light-emitting device - Google Patents

Description

The present invention relates to a light-emitting device.

Patent document 1 discloses a light-emitting element in which the bonding pads are soldered onto a mounting substrate.

Special table 2017-535052 publication

Patent Document 1 leaves room for improvement in terms of light extraction efficiency. The present invention aims to provide a light-emitting device that can improve light extraction efficiency while suppressing an increase in forward voltage.

According to one aspect of the present invention, there is provided a light emitting device comprising: a semiconductor laminate including a first conductivity type semiconductor layer, a light emitting layer provided on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer provided on the light emitting layer, the semiconductor laminate having a first recess which is continuous with the second conductivity type semiconductor layer, the light emitting layer, and the first conductivity type semiconductor layer and at least a part of a bottom surface of which is the first conductivity type semiconductor layer; a first insulating film provided in a region including a central part of the bottom surface of the first recess in a planar view; a first electrode having a first contact portion provided in the first recess and in contact with the first conductivity type semiconductor layer exposed from the first insulating film at the bottom surface of the first recess, and an opening exposing the first insulating film; a second electrode provided on the second conductivity type semiconductor layer and in contact with the second conductivity type semiconductor layer; and a light reflective member provided in the opening of the first electrode and having a reflectance higher than that of the first electrode for a wavelength of light emitted from the light emitting layer.
According to another aspect of the present invention, there is provided a light emitting device comprising: a semiconductor laminate including a first conductivity type semiconductor layer, a light emitting layer provided on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer provided on the light emitting layer, the semiconductor laminate having a first recess continuous with the second conductivity type semiconductor layer, the light emitting layer, and the first conductivity type semiconductor layer, and at least a part of a bottom surface of the first conductivity type semiconductor layer being the first conductivity type semiconductor layer; a first insulating film provided in a region including a central part of the bottom surface of the first recess in a planar view; a first electrode provided in the first recess and having a first contact portion in contact with the first conductivity type semiconductor layer exposed from the first insulating film at the bottom surface of the first recess, and an opening exposing the first insulating film; a second electrode provided on the second conductivity type semiconductor layer and in contact with the second conductivity type semiconductor layer; and a light reflective member provided in the opening of the first electrode, the light reflective member being a resin containing a white pigment.

The present invention makes it possible to improve light extraction efficiency while suppressing the increase in forward voltage.

1 is a schematic plan view of a light emitting device according to an embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. 1. 1 is a schematic plan view of a semiconductor laminate in a light emitting device according to an embodiment of the present invention. 2 is a schematic enlarged cross-sectional view of a portion of a light-emitting device according to an embodiment of the present invention. FIG. 11 is a schematic enlarged cross-sectional view of a portion of a modified example of a light emitting device according to an embodiment of the present invention. FIG. 11 is a schematic enlarged cross-sectional view of a portion of a modified example of a light emitting device according to an embodiment of the present invention. 2 is a schematic enlarged cross-sectional view of a portion of the VII-VII cross section in FIG. 1. FIG. 2 is a schematic plan view of a portion of a light-emitting device according to an embodiment of the present invention. FIG. 11 is a schematic plan view showing another pattern of the first insulating film. FIG. 4 is a schematic plan view of a semiconductor laminate in a light emitting device according to another embodiment of the present invention. FIG. 11 is a schematic enlarged cross-sectional view of a part of a modified example of a light emitting device according to another embodiment of the present invention. FIG. 11 is a schematic enlarged cross-sectional view of a part of a modified example of a light emitting device according to another embodiment of the present invention. FIG. 11 is a schematic enlarged cross-sectional view of a part of a modified example of a light emitting device according to another embodiment of the present invention. FIG. 11 is a schematic enlarged cross-sectional view of a part of a modified example of a light emitting device according to another embodiment of the present invention.

The following describes the embodiments with reference to the drawings. Note that the same elements in each drawing are given the same reference numerals.

FIG. 1 is a schematic plan view of a light emitting device 1 according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line II-II in FIG.

The light emitting device 1 has a substrate 100 and a semiconductor laminate 10 provided on the substrate 100. The semiconductor laminate 10 has a first conductive type semiconductor layer 11 provided on the substrate 100, a light emitting layer 12 provided on the first conductive type semiconductor layer 11, and a second conductive type semiconductor layer 13 provided on the light emitting layer 12. The first conductive type semiconductor layer 11 is, for example, n-type. The second conductive type semiconductor layer 13 is, for example, p-type.

The substrate 100 is transparent to the light emitted by the light emitting layer 12. Moreover, the substrate 100 allows the semiconductor laminate 10 to be epitaxially grown. Examples of materials for the substrate 100 include sapphire, spinel (MgAl ₂ O ₄ ), silicon carbide (SiC), silicon, ZnS, ZnO, GaAs, diamond, lithium niobate, and neodymium gallate.

For the semiconductor laminate 10, for example, a semiconductor such as _{InxAlyGa1 -XYN (} 0≦X, 0≦Y, X+Y<1) is suitably used.

As shown in FIG. 2, the first conductive type semiconductor layer 11 has a lower surface 11a. The lower surface 11a is located at the interface between the first conductive type semiconductor layer 11 and the substrate 100. Light from the light emitting layer 12 enters the substrate 100 from the lower surface 11a, passes through the inside of the substrate 100, and is extracted to the outside.

As shown in FIG. 2, a wavelength conversion member 6 may be formed on the side of the substrate 100. The wavelength conversion member 6 includes, for example, a resin and wavelength conversion particles. The wavelength conversion particles include, for example, a phosphor such as a YAG-based phosphor, a LAG-based phosphor, a KSF phosphor, a CASN-based phosphor, a SCASN-based phosphor, a β-sialon phosphor, or a chlorosilicate phosphor. Light emitted from the light-emitting layer 12 enters the wavelength conversion member 6, and the wavelength of the light is converted. Note that the wavelength conversion member 6 does not necessarily have to be provided.

The semiconductor laminate 10 has a second conductive type semiconductor layer 13, a light emitting layer 12, and a first recess 10a that is continuous with the first conductive type semiconductor layer 11 and has at least a part of the bottom surface that is the first conductive type semiconductor layer. For example, the first conductive type semiconductor layer 11, the light emitting layer 12, and the second conductive type semiconductor layer 13 are epitaxially grown in sequence on the substrate 100, and then a part of the laminated portion of the second conductive type semiconductor layer 13 and the light emitting layer 12 is removed by etching to form the first recess 10a. The part where the second conductive type semiconductor layer 13 and the light emitting layer 12 are laminated is left in a mesa shape on the first conductive type semiconductor layer 11.

Figure 3 is a schematic plan view of the semiconductor laminate 10. Figure 3 is a plan view of the semiconductor laminate 10 as viewed from the opposite side to the lower surface 11a shown in Figure 2.

For example, a plurality of circular first recesses 10a are provided on the surface opposite the lower surface 11a of the first conductive type semiconductor layer 11. The light emitting layer 12 and the second conductive type semiconductor layer 13 are provided in a region excluding the first recesses 10a and the peripheral region 11b on the surface opposite the lower surface 11a of the first conductive type semiconductor layer 11.

In the top view shown in FIG. 3, the light-emitting layer 12 and the second conductive semiconductor layer 13 are arranged to surround the first recess 10a.

As shown in FIG. 2, a second electrode made of a first conductive member 21 and a second conductive member 22 is provided on the second conductive type semiconductor layer 13. The first conductive member 21 is in contact with the upper surface of the second conductive type semiconductor layer 13.

A fourth insulating film 44 is provided on the second conductive semiconductor layer 13 so as to cover the upper surfaces of the first conductive member 21 and the second conductive semiconductor layer 13. A second insulating film 42 is further provided so as to cover the fourth insulating film 44.

The second insulating film 42 covers the side surface of the second conductive type semiconductor layer 13, the side surface of the light emitting layer 12, and the side surface of the first conductive type semiconductor layer 11 that continues from these side surfaces. In other words, the second insulating film 42 covers the side surface of the mesa portion 15, which is the portion where the light emitting layer 12 and the second conductive type semiconductor layer 13 are stacked.

The first electrode 23 is provided on the second insulating film 42. As described above, the second insulating film 42 covers the side surfaces of each member and has a step, and the first electrode 23 is provided along the step. The first electrode 23 has a first contact portion 23a that contacts the first conductive type semiconductor layer at the bottom surface of the first recess 10a, and an opening portion 23b that exposes the first insulating film 41 described below. The first electrode 23 further has a wiring portion 23c provided on the second insulating film 42 on the mesa portion 15, and a peripheral contact portion 23d that contacts the peripheral region 11b of the first conductive type semiconductor layer 11. The first contact portion 23a, the wiring portion 23c, and the peripheral contact portion 23d are connected together.

A first external connection electrode 31 is provided on the wiring portion 23c. The first external connection electrode 31 is electrically connected to the first conductivity type semiconductor layer 11 through the first electrode 23.

A portion of the fourth insulating film 44 and the second insulating film 42 covering the first conductive member 21 is opened, and the second conductive member 22 is provided in the opening. The second conductive member 22 is in contact with the first conductive member 21. A portion of the second conductive member 22 is provided on the second insulating film 42. A second external connection electrode 32 is provided on the second conductive member 22. The second external connection electrode 32 is electrically connected to the second conductive type semiconductor layer 13 through the second conductive member 22 and the first conductive member 21.

Figure 4 is a schematic enlarged cross-sectional view of the area in which the first recess 10a is provided in the light-emitting device 1.

For example, the first insulating film 41 is provided in a region including the center of the circular first recess 10a. The first recess 10a has a region including the center and a region surrounding the periphery of the region including the center. The "region including the center" refers to a region including the center of the circle when the first recess 10a is circular, a region including the center of the inscribed circle of the regular polygon or triangle when the first recess 10a is regular polygonal or triangular, and a region including the center of the circle formed by the inner or outer periphery when the first recess 10a is annular.

The second insulating film 42 is formed to cover the entire semiconductor laminate 10, and the second insulating film 42 is patterned to leave the first insulating film 41 in the first recess 10a, for example in a circular shape. Therefore, the second insulating film 42 and the first insulating film 41 are films of the same material, and the film thickness of the second insulating film 42 and the film thickness of the first insulating film 41 are approximately the same.

Due to the process of patterning the second insulating film 42, a portion 42a of the second insulating film 42 is left in the outer peripheral region of the first recess 10a, for example in a ring shape.

The first contact portion 23a of the first electrode 23 is provided around the first insulating film 41, for example, in a ring shape surrounding the circular first insulating film 41. That is, in the region including the center of the first recess 10a, the first electrode 23 is not provided, but the first insulating film 41 is provided. Therefore, in the region including the center of the first recess 10a, the light absorption by the metal constituting the first electrode 23 can be reduced, and the total reflection component at the interface between the first insulating film 41 and the first conductive type semiconductor layer 11 can be increased. This increases the reflectance at the first recess 10a of the light propagating through the first conductive type semiconductor layer 11 toward the first recess 10a, and improves the light extraction efficiency from the lower surface 11a side.

As described later, it is considered that in the first recess 10a, the current is concentrated in the outer periphery close to the wiring portion 23c of the first electrode 23. Therefore, even if the first insulating film 41 is provided in the center of the first recess 10a and the center is made non-conductive, it does not significantly hinder the current supply to the light-emitting layer 12, and it can be said that the forward voltage is unlikely to increase. Therefore, compared to the case where the first insulating film 41 is not provided in the center of the first recess 10a and the first electrode 23 is formed in the center of the first recess 10a, there is no large increase in the forward voltage Vf, and the light intensity Po can be increased due to the increase in the total reflection area by the first insulating film 41. In other words, if the light-emitting device 1 is provided with the first insulating film 41, the light extraction efficiency can be improved while suppressing the increase in the forward voltage Vf.

As shown in FIG. 2, the first electrode 23 has an opening 23b, exposing the first insulating film 41. The first electrode 23 is formed so that the first electrode 23 covers a portion of the first insulating film 41, and the opening 23b exposes the first insulating film 41. Because the first electrode 23 covers a portion of the first insulating film 41, peeling of the first insulating film 41 can be suppressed.

The opening 23b is provided with a light reflecting member 5. The light reflecting member 5 may be a member having a reflectance greater than that of the first electrode 23 for the wavelength of light emitted from the light emitting layer 12. The reflectance of the first electrode 23 here refers to, for example, the reflectance of a member that has the smallest reflectance for light from the light emitting layer 12 among the members constituting the first electrode 23. The reflectance of the first electrode 23 here refers to, for example, the reflectance of a member that contacts the first conductive type semiconductor layer 11 among the members constituting the first electrode 23. The light reflecting member 5 may be a resin containing a white pigment such as titanium oxide, zinc oxide, or alumina. Examples of resins containing white pigments include silicone resin and epoxy resin. The light reflecting member 5 may function as a member that supports the first electrode 23, the second conductive member 22, the semiconductor laminate 10, and the substrate 100 by covering them.

By providing the light reflecting member 5 in the opening 23b, the light that enters the inside of the first insulating film 41 can be reflected by the light reflecting member 5 without being reflected at the interface between the first insulating film 41 and the first conductive type semiconductor layer 11, thereby improving the light extraction efficiency from the lower surface 11a side.

As shown in FIG. 4, the light reflecting member 5 may be provided in the opening 23b, so that the light reflecting member 5 covers a portion of the first insulating film 41. By the light reflecting member 5 covering a portion of the first insulating film 41, the light incident on the first insulating film 41 is more likely to be reflected by the light reflecting member 5 with greater certainty.

Also, as shown in FIG. 5, the outer edge of the first insulating film 41 and the end of the first electrode 23 may coincide. By having the outer edge of the first insulating film 41 and the end of the first electrode 23 coincide, the area of the light reflecting member 5 covering the first insulating film 41 can be increased compared to when the first electrode 23 covers a portion of the first insulating film 41, while the area of the first contact portion 23a in contact with the first recess 10a can be made approximately the same as when the first electrode 23 covers a portion of the first insulating film 41.

Also, as shown in FIG. 6, the first insulating film and the first electrode may not overlap. By not overlapping the first insulating film and the first electrode, the area of the first insulating film 41 covered by the light reflecting member 5 increases, so that the light incident on the first insulating film 41 is more likely to be reflected by the light reflecting member 5. Also, as shown in FIG. 6, the light reflecting member 5 may be provided between the first electrode 23 and the first insulating film 41 and contact the bottom surface of the first recess 10a. By providing the light reflecting member 5 between the first electrode 23 and the first insulating film 41 and contacting the bottom surface of the first recess 10a, the light reflecting member 5 contacts the first conductive type semiconductor layer 11 when the reflectance is greater than that of the first electrode 23, and the reflectance of light in the first recess 10a can be increased while suppressing an increase in the forward voltage Vf.

Figure 7 is a schematic enlarged cross-sectional view of a portion of the VII-VII cross section in Figure 1. As shown in Figures 1, 3, and 7, in a region overlapping the first external connection electrode 31 in a plan view, there may be a second recess 10b that is continuous with the second conductive type semiconductor layer 13, the light emitting layer 12, and the first conductive type semiconductor layer 11 and at least a portion of the bottom surface of which is the first conductive type semiconductor layer.

In the region including the center of the second recess 10b, the first electrode 23 is not provided, but the third insulating film 43 is provided. Therefore, in the region including the center of the second recess 10b, it is possible to reduce light absorption by the metal constituting the first electrode 23 and increase the total reflection component at the interface between the third insulating film 43 and the first conductive type semiconductor layer 11. This increases the reflectance at the second recess 10b of the light propagating through the first conductive type semiconductor layer 11 toward the second recess 10b, improving the light extraction efficiency from the lower surface 11a side.

As shown in FIG. 7, in the second recess 10b, the first electrode 23 covers the third insulating film 43. In other words, the first electrode 23 covers the surface of the third insulating film 43 except for the surface that contacts the bottom surface of the second recess 10b, and does not have an opening that exposes the third insulating film 43. When the first electrode 23 has a higher reflectivity for light emitted from the light-emitting layer 12 than the first external connection electrode 31, the first electrode 23 covering the third insulating film 43 makes it easier for the light that enters the third insulating film 43 to be reflected by the first electrode 23.

The third insulating film 43, like the first insulating film 41, is a film made of the same material as the second insulating film 42, and the film thickness of the second insulating film 42 and the film thickness of the third insulating film 43 are approximately the same.

Due to the etching process for patterning the first insulating film 41, the cross-sectional shape of the first insulating film 41 becomes a trapezoid as shown in FIG. 4. This trapezoid has an upper base 41a and a lower base 41b that is longer than the upper base 41a, and the lower base 41b is located at the interface with the bottom surface of the first recess 10a. The same is true for the third insulating film 43.

The first conductive member 21 can be, for example, Ag, Al, Ni, Ti, Pt, or an alloy mainly composed of these metals. The first conductive member 21 can also be a single layer of these metal materials or a laminate of multiple layers of these metal materials.

The first electrode 23 and the second conductive member 22 are obtained, for example, by patterning a film of the same metal material. For the first electrode 23 and the second conductive member 22, for example, Ag, Al, Ni, Rh, Au, Cu, Ti, Pt, Pd, Mo, Cr, W, or an alloy mainly composed of these metals can be suitably used. The first electrode 23 and the second conductive member 22 may also be a single layer of these metal materials or a laminate in which multiple layers of these metal materials are stacked.

The first electrode 23 and the second conductive member 22 include, for example, an Al film, a Ti film, a Pt film, and an Au film formed in this order from the interface side with the base.

The first external connection electrode 31 and the second external connection electrode 32 can be preferably made of metals such as Cu, Au, and Ni. The first external connection electrode 31 and the second external connection electrode 32 can be formed, for example, by electrolytic plating.

The fourth insulating film 44 is, for example, a silicon nitride film. The fourth insulating film 44 prevents migration of, for example, Ag contained in the first conductive member 21. The fourth insulating film 44 may not be formed. The first insulating film 41 includes a member having a refractive index smaller than that of the first semiconductor layer 11. The first insulating film 41 is also translucent. The second insulating film 42, the first insulating film 41, and the third insulating film 43 are, for example, silicon oxide films. Note that the first insulating film 41, the second insulating film 42, the third insulating film 43, and the fourth insulating film 44 may be a dielectric multilayer film that combines a high refractive index material layer and a low refractive index material layer. The dielectric multilayer film may be, for example, a film in which two or more pairs of titanium oxide film/silicon oxide film are stacked. In addition to the titanium oxide film and the silicon oxide film, for each layer constituting the dielectric multilayer film, for example, a niobium oxide film, an aluminum oxide film, a zirconium oxide film, an aluminum nitride film, a silicon nitride film, etc. can be used.

The first external connection electrode 31 and the second external connection electrode 32 are exposed from the light reflecting member 5 and are joined to pads formed on the wiring board on which the light emitting device 1 is mounted, for example, via a conductive material such as solder. That is, in the light emitting device 1, with the first external connection electrode 31 and the second external connection electrode 32 facing the wiring board, the lower surface 11a of the substrate 100 and the first conductive type semiconductor layer 11 faces upward from the wiring board. Note that the substrate 100 may not be present.

The light emitted from the light-emitting layer 12 is extracted to the outside through the bottom surface 11a. Most of the area on the opposite side of the bottom surface 11a is covered with a metal film (containing, for example, Ag or Al, which has good light reflectivity) that constitutes the second conductive member 22 and the first electrode 23. Therefore, light that does not travel directly from the light-emitting layer 12 to the bottom surface 11a and light reflected at the interface between the first conductive type semiconductor layer 11 and the substrate 100 can be reflected by the metal film and directed toward the bottom surface 11a.

As described above, the first electrode 23 is not provided in the region including the center of the first recess 10a, but the first insulating film 41 is provided. Therefore, in the region including the center of the first recess 10a, light absorption by the metal constituting the first electrode 23 can be reduced, and the total reflection component at the interface between the first insulating film 41 and the first conductive type semiconductor layer 11 can be increased. This increases the reflectance at the first recess 10a of the light propagating through the first conductive type semiconductor layer 11 toward the first recess 10a, and improves the light extraction efficiency from the lower surface 11a side.

Figure 8 is a schematic plan view showing the relative positions of the region of the first insulating film 41 that contacts the first recess 10a, the region of the first electrode 23 that contacts the first recess 10a, and the region of the second insulating film 42 that contacts the first recess 10a. In Figure 8, φ1 indicates the diameter of the first recess 10a. Also, φ2 indicates the diameter of the first insulating film 41 in the portion that contacts the first recess 10a.

When the diameter φ2 of the first insulating film 41 in contact with the first recess 10a is kept constant and the diameter φ1 of the first recess 10a is reduced, the forward voltage Vf increases as the diameter φ1 of the first recess 10a decreases.
In contrast, if the diameter φ1 of the first recess 10a is kept constant and the diameter φ2 of the first insulating film 41 in contact with the first recess 10a is increased within a range smaller than the diameter φ1 of the first recess 10a, no significant increase in the forward voltage Vf due to the increase in the diameter φ2 of the first insulating film 41 is observed.

From these results, it is considered that in the first recess 10a, the first contact portion 23a of the first electrode 23 has current concentrated in the outer periphery close to the wiring portion 23c, and almost no current flows in the center, and current is concentrated near the outer periphery of the first recess 10a. Therefore, even if the first insulating film 41 is provided in the center of the first recess 10a and the center is made non-conductive, it does not significantly hinder the supply of current to the light-emitting layer 12, and the forward voltage is unlikely to increase.
Therefore, the light emitting device 1 provided with the first insulating film 41 can improve the light extraction efficiency while suppressing an increase in the forward voltage Vf.

The contact area of the first contact portion 23a with the first recess 10a is preferably 40% to 70% of the area of the first recess 10a. In addition, this contact area can be 140 ^μm2 to ²⁵⁰ μm2.

The shape of the first recess 10a and the first insulating film 41 is not limited to a circular shape, but may be a polygonal shape.

As shown in FIG. 8, when a circular first insulating film 41 is provided in a circular first recess 10a, the shape of the first contact portion 23a provided around the first insulating film 41 can be a circular ring without corners. A first contact portion 23a having such a shape makes it easier to uniformize the current density distribution.

As shown in FIG. 4, the cross-sectional shape of the first insulating film 41 is trapezoidal. This ensures a large interface area between the lower surface (lower base of the trapezoid) 41b of the first insulating film 41 and the first conductive type semiconductor layer 11, while improving the coverage of the first insulating film 41 with the first electrode 23 compared to when the cross-sectional shape of the first insulating film 41 is, for example, rectangular.

Figure 9 is a schematic plan view showing another pattern of the first insulating film 41.

As shown in FIG. 9, the first insulating film 41 is formed so as to be connected to a portion 42a of the second insulating film 42. In this case, the first insulating film 41 and the second insulating film 42 are formed integrally, so peeling of the first insulating film 41 can be suppressed.

Figure 10 is a schematic plan view of the semiconductor laminate 10 in a light-emitting device of another embodiment. The first recess 10a has a circular ring shape in a plan view, and a protrusion 16 is provided inside the circular ring shape, where a part of the semiconductor laminate 10 protrudes. The protrusion 16 is a portion where the light-emitting layer 12 and the second conductive type semiconductor layer 13 are laminated. The protrusion 16 may be a portion where the first conductive type semiconductor layer 11 protrudes, without including the light-emitting layer 12 and the second conductive type semiconductor layer 13.

Figure 11 is a schematic enlarged cross-sectional view of a region in which the first recess 10a is provided in a light-emitting device of another embodiment.

As shown in FIG. 11, the first insulating film 41 covers the upper surface and side surfaces of the protrusion 16. The first insulating film 41 is provided directly on the side surfaces of the protrusion 16. A fourth insulating film 44 and a first conductive member 21 are provided between the first insulating film 41 and the upper surface of the protrusion 16. Note that the fourth insulating film 44 and the first conductive member 21 may not be provided between the first insulating film 41 and the upper surface of the protrusion 16, and the first insulating film 41 may be provided directly on the upper surface of the mesa portion 15.

A first electrode 23 is provided on the first insulating film 41. The first contact portion 23a of the first electrode 23 is in contact with the first conductive type semiconductor layer 11 exposed at the bottom surface of the first recess 10a.

As shown in FIG. 11, the opening 23b of the first electrode 23 exposes the first insulating film 41. The first electrode 23 is formed such that the first electrode 23 covers a portion of the first insulating film 41, and the opening 23b exposes the first insulating film 41. Because the first electrode 23 covers a portion of the first insulating film 41, peeling of the first insulating film 41 can be suppressed.

Also, as shown in FIG. 12, the outer edge of the first insulating film 41 may coincide with the end of the first electrode 23 in a plan view. By having the outer edge of the first insulating film 41 coincide with the end of the first electrode 23, the area over which the light reflecting member 5 covers the first insulating film 41 can be increased, while the area over which the first contact portion 23a contacts the first recess 10a can be maximized.

Also, as shown in FIG. 13, the first insulating film 41 and the first electrode 23 can be made not to overlap in a plan view. By the first insulating film 41 and the first electrode 23 not overlapping in a plan view, the area of the first insulating film 41 covered by the light reflecting member 5 increases, so that the light incident on the first insulating film 41 is more reliably reflected by the light reflecting member 5. Also, as shown in FIG. 13, the light reflecting member 5 may be provided between the first electrode 23 and the first insulating film 41 and contact the bottom surface of the first recess 10a. By providing the light reflecting member 5 between the first electrode 23 and the first insulating film 41 and contacting the bottom surface of the first recess 10a, the light reflecting member 5, which has a higher reflectance than the first electrode 23, contacts the first conductive type semiconductor layer 11, and the reflectance of light in the first recess 10a can be increased while suppressing an increase in the forward voltage Vf.

By providing the first insulating film 41 three-dimensionally so as to cover the upper and side surfaces of the protrusion 16, the area of the first insulating film 41 in the region including the center of the first recess 10a can be increased compared to the planar first insulating film 41 shown in FIG. 4. Therefore, in the region including the center of the first recess 10a, the amount of light from the light-emitting layer 12 that is totally reflected by the first insulating film 41 can be increased. Furthermore, the first electrode 23 has an opening 23b that exposes the first insulating film 41, and a light reflecting member 5 is formed in the opening 23b, thereby improving the light extraction efficiency.

As shown in FIG. 14, the protrusion 16 may be a protruding portion of the first conductive type semiconductor layer 11 without including the light emitting layer 12 and the second conductive type semiconductor layer 13. Since the height of the protrusion 16 can be made lower than that of the protrusion 16 including the light emitting layer 12 and the second conductive type semiconductor layer 13, it is easier to form the first insulating film 41 with excellent coverage.

The above describes the embodiments of the present invention with reference to specific examples. However, the present invention is not limited to these specific examples. All forms that a person skilled in the art can implement by appropriately modifying the design based on the above-described embodiments of the present invention also fall within the scope of the present invention as long as they include the gist of the present invention. In addition, a person skilled in the art can come up with various modifications and amendments within the scope of the concept of the present invention, and it is understood that these modifications and amendments also fall within the scope of the present invention.

1...light emitting device, 10...semiconductor laminate, 10a...first recess, 10b...second recess, 11...first conductive type semiconductor layer, 11a...lower surface, 12...light emitting layer, 13...second conductive type semiconductor layer, 21...first conductive member, 22...second conductive member, 23...first electrode, 23a...first contact portion, 23b...opening, 23c...wiring portion, 23d...peripheral contact portion, 31...first external connection electrode, 32...second external connection electrode, 41...first insulating film, 42...second insulating film, 43...third insulating film, 44...fourth insulating film, 5...light reflecting member, 6...wavelength conversion member, 100...substrate

Claims (11)

A semiconductor laminate including a first conductive type semiconductor layer, a light emitting layer provided on the first conductive type semiconductor layer, and a second conductive type semiconductor layer provided on the light emitting layer, the semiconductor laminate having a plurality of first recesses that are continuous with the second conductive type semiconductor layer, the light emitting layer, and the first conductive type semiconductor layer, and at least a portion of a bottom surface of the first conductive type semiconductor layer;
a first insulating film provided in a region including a central portion of the bottom surface of the first recess in a plan view;
a first electrode provided in the first recess, the first electrode having a first contact portion in contact with the first conductive type semiconductor layer exposed from the first insulating film at the bottom surface of the first recess, and an opening portion exposing the first insulating film;
a second electrode provided on the second conductive type semiconductor layer and in contact with the second conductive type semiconductor layer; and a light reflecting member provided in the opening of the first electrode and having a reflectance for a wavelength of light emitted from the light emitting layer higher than that of the first electrode. A semiconductor laminate including a first conductive type semiconductor layer, a light emitting layer provided on the first conductive type semiconductor layer, and a second conductive type semiconductor layer provided on the light emitting layer, the semiconductor laminate having a plurality of first recesses that are continuous with the second conductive type semiconductor layer, the light emitting layer, and the first conductive type semiconductor layer, and at least a portion of a bottom surface of the first conductive type semiconductor layer;
a first insulating film provided in a region including a central portion of the bottom surface of the first recess in a plan view;
a first electrode provided in the first recess, the first electrode having a first contact portion in contact with the first conductive type semiconductor layer exposed from the first insulating film at the bottom surface of the first recess, and an opening portion exposing the first insulating film;
a second electrode provided on the second conductive type semiconductor layer and in contact with the second conductive type semiconductor layer; and a light-reflecting member, which is a resin containing a white pigment and is provided in the opening of the first electrode. The light-emitting device according to claim 1 or 2, wherein the first electrode covers a portion of the first insulating film. The light-emitting device according to claim 1 or 2, wherein the first insulating film and the first electrode do not overlap in a plan view. The light-emitting device according to claim 4, wherein the light-reflecting member is provided between the first electrode and the first insulating film and contacts the bottom surface of the first recess. In a plan view, the first recess and the first insulating film have a circular shape,
6. The light emitting device according to claim 1, wherein the first contact portion is disposed so as to surround the periphery of the first insulating film in a plan view. The light-emitting device according to any one of claims 1 to 6, wherein the cross-sectional shape of the first insulating film is a trapezoid having an upper base and a lower base that is longer than the upper base, and the lower base is located at the interface with the bottom surface of the first recess. the first recess has a circular ring shape in a plan view, and has a protruding portion in which a part of the semiconductor laminate protrudes inside the circular ring shape in a plan view;
7. The light emitting device according to claim 1, wherein the first insulating film covers the protruding portion. The light-emitting device according to any one of claims 1 to 8, wherein at least a portion of the light-reflecting member is in contact with the first insulating film. A second insulating film is provided on the second electrode,
the first electrode extends onto the second insulating film;
10. The light emitting device according to claim 1, further comprising a wiring portion connected to the first electrode above the second insulating film. The semiconductor device further includes an external connection electrode provided above the wiring portion,
the semiconductor laminate further includes, in a region overlapping with the external connection electrode in a plan view, a second recess that is continuous with the second conductive type semiconductor layer, the light emitting layer, and the first conductive type semiconductor layer and has at least a portion of a bottom surface formed by the first conductive type semiconductor layer;
a third insulating film provided in a region including a central portion of the bottom surface of the second recess in a plan view;
the first electrode further includes a second contact portion in contact with the first conductive type semiconductor layer exposed from the third insulating film at the bottom surface of the second recess,
The light emitting device according to claim 10 , wherein the first electrode covers the third insulating film.

Images