TWI648873B - Light emitting diode structure - Google Patents

Abstract

A light emitting diode structure includes a substrate, a semiconductor epitaxial structure, and a reflective conductive structure layer. The semiconductor epitaxial structure is disposed on the substrate and exposes a portion of the substrate. The reflective conductive structure layer covers a portion of the semiconductor epitaxial structure and a portion of the substrate that is exposed by the semiconductor epitaxial structure.

Description

Light-emitting diode structure

This invention relates to a semiconductor structure, and more particularly to a light emitting diode structure.

Generally, when fabricating a light-emitting diode wafer, a substrate is usually provided first, and an epitaxial structure is formed on the substrate by epitaxial growth, and then an electrode is disposed on the epitaxial structure to supply electric energy. Light is emitted by the photoelectric effect. Thereafter, a plurality of criss-crossing dicing streets are formed in the epitaxial structure by a lithography technique. Wherein, each adjacent two longitudinal scribe lines and the adjacent two horizontal scribe lines together define a light-emitting diode die. After that, the polishing and cutting process of the latter stage is performed, and the light-emitting diode wafer is divided into a plurality of light-emitting diode crystal grains, thereby completing the fabrication of the light-emitting diode.

In order to increase the light-emitting efficiency of the light-emitting diode, an ohmic contact layer, a reflective layer and a barrier layer are sequentially added to the epitaxial structure, wherein the ohmic contact layer, the reflective layer and the barrier layer cover only part of the epitaxial structure. on. Although the above method can increase the light-emitting efficiency of the light-emitting diode, the light-emitting efficiency cannot meet the requirements for pursuing high light-emitting efficiency. Therefore, how to fully improve the light-emitting efficiency of the light-emitting diode is still However, it is an urgent problem to be overcome.

The invention provides a light emitting diode structure which has good light-emitting efficiency.

The light emitting diode structure of the embodiment of the present invention includes a substrate, a semiconductor epitaxial structure, a first insulating layer, a reflective layer, a second insulating layer, and at least one electrode. The semiconductor epitaxial structure is disposed on the substrate and exposes a portion of the substrate. The first insulating layer covers a portion of the semiconductor epitaxial structure and a portion of the substrate exposed by the semiconductor epitaxial structure. The reflective layer is disposed on the first insulating layer, and the second insulating layer is disposed on the reflective layer. The electrode is disposed on the second insulating layer and the electrode is electrically connected to the semiconductor epitaxial structure.

The light emitting diode structure of the embodiment of the present invention includes a substrate, a semiconductor epitaxial structure, a transparent conductive layer, a reflective layer, a first insulating layer, and at least one electrode. The semiconductor epitaxial structure is disposed on the substrate and exposes a portion of the substrate. The transparent conductive layer is disposed on the semiconductor epitaxial structure. The reflective layer is disposed on the partially transparent conductive layer and extends over a portion of the substrate exposed by the semiconductor epitaxial layer. The first insulating layer is disposed on the reflective layer. The electrode is disposed on the second insulating layer, and the electrode is electrically connected to the semiconductor epitaxial structure.

The light emitting diode structure of the embodiment of the present invention includes a substrate, a semiconductor epitaxial structure, a first insulating layer, a reflective layer, a second insulating layer, and at least a first electrode. The semiconductor epitaxial structure is disposed on the substrate. The first insulating layer covers a portion of the semiconductor epitaxial structure and a portion of the substrate. The reflective layer is disposed on the first insulating layer, and the second insulating layer is disposed Placed on the reflective layer. The first electrode is disposed on the second insulating layer, and the electrode is electrically connected to the semiconductor epitaxial structure.

The light emitting diode structure of the embodiment of the present invention includes a substrate, a semiconductor epitaxial structure, a transparent conductive layer, a reflective layer, a first insulating layer, and at least one electrode. The semiconductor epitaxial structure is disposed on the substrate. The transparent conductive layer is disposed on the semiconductor epitaxial structure. The reflective layer is on the substrate and covers at least a portion of the transparent conductive layer and at least a portion of the semiconductor epitaxial structure. The first insulating layer covers at least a portion of the reflective layer and at least a portion of the transparent conductive layer and at least a portion of the semiconductor epitaxial structure. The electrode is disposed on the second insulating layer, and the electrode is electrically connected to the semiconductor epitaxial structure.

Based on the above, since the light emitting diode structure of the present invention has a reflective conductive structure layer, and the reflective conductive structure layer covers a portion of the semiconductor epitaxial layer and a portion of the substrate exposed by the semiconductor epitaxial layer. Therefore, the reflective conductive structure layer can effectively reflect the light from the semiconductor epitaxial layer, and the portion of the substrate exposed by the semiconductor epitaxial layer also has the effect of reflection. In this way, the arrangement of the reflective conductive structure layer can effectively increase the reflective area, thereby effectively improving the light extraction efficiency of the overall light emitting diode structure.

The above described features and advantages of the invention will be apparent from the following description.

100a, 100b, 100c, 100d‧‧‧Lighting diode structure

110a, 110b‧‧‧ substrate

112a, 112b‧‧‧ upper surface

114b‧‧‧ annular inclined surface

120a‧‧‧Semiconductor epitaxial layer, semiconductor epitaxial structure

122a‧‧‧first type semiconductor layer

124a‧‧‧Lighting layer

126a‧‧‧Second type semiconductor layer

130a, 130b, 130c, 130d‧‧‧ reflective conductive structural layer

132a, 132b, 132c, 132d‧‧‧ conductive layer, transparent conductive layer

134a, 134b, 134c, 134d‧‧‧reflective layer, Bragg mirror layer

136a, 136b, 136c, 136d‧‧‧ barrier layer

140a, 140d‧‧‧Insulation, first insulation

145a, 145d‧‧‧Electrical insulation, second insulation

150a‧‧‧first electrode

160a‧‧‧second electrode

170a‧‧‧Connection layer

A‧‧‧Yuanyuan

C‧‧‧ recessed area

S1‧‧‧ first semiconductor block

S2‧‧‧second semiconductor block

1 is a cross-sectional view showing a structure of a light emitting diode according to an embodiment of the present invention; schematic diagram.

2 is a cross-sectional view showing a structure of a light emitting diode according to another embodiment of the present invention.

3 is a cross-sectional view showing a structure of a light emitting diode according to another embodiment of the present invention.

4 is a cross-sectional view showing a structure of a light emitting diode according to another embodiment of the present invention.

1 is a cross-sectional view showing a structure of a light emitting diode according to an embodiment of the present invention. Referring to FIG. 1, in the embodiment, the LED structure 100a includes a substrate 110a and a semiconductor epitaxial layer 120a (the semiconductor epitaxial layer referred to in the following paragraphs may also be referred to as a semiconductor epitaxial structure) and A reflective conductive structure layer 130a. The semiconductor epitaxial layer 120a is disposed on the substrate 110a and exposes a portion of the substrate 110a (at the imaginary circle A in FIG. 1). The reflective conductive structure layer 130a is disposed on the semiconductor epitaxial layer 120a, wherein the reflective conductive structure layer 130a covers a portion of the semiconductor epitaxial layer 120a and a portion of the substrate 110a exposed by the semiconductor epitaxial layer 120a.

More specifically, in the embodiment, the substrate 110a is, for example, a sapphire substrate, but not limited thereto, wherein the substrate 110a has an upper surface 112a. The semiconductor epitaxial layer 120a includes a first type semiconductor layer 122a, a light emitting layer 124a, and a second type semiconductor layer 126a sequentially disposed on the substrate 110a. Here, the first type The semiconductor layer 122a is, for example, an N-type semiconductor layer, and the second-type semiconductor layer 126a is, for example, a P-type semiconductor layer, but is not limited thereto. As shown in FIG. 1, the semiconductor epitaxial layer 120a does not completely cover the upper surface 112a of the substrate 110a, but exposes a portion of the upper surface 112a of the substrate 110a.

In particular, the reflective conductive structure layer 130a of the present embodiment is a transparent conductive layer 132a (the transparent conductive layer referred to in the following paragraphs may also be referred to as a conductive layer) and a reflective layer 134a (in the following paragraphs). The reflective layer referred to may also be referred to as a Bragg mirror layer) and a barrier layer 136a. The transparent conductive layer 132a can be regarded as an ohmic contact layer for the purpose of increasing current conduction and uniformly distributing current, wherein the transparent conductive layer 132a is disposed on the semiconductor epitaxial layer 120a and the cover substrate 110a is exposed by the semiconductor epitaxial layer 120a. Out of the upper surface 112a. Here, the material of the transparent conductive layer 132a is selected from the group consisting of indium tin oxide, aluminum-doped zinc oxide, indium zinc oxide, and the like. The transparent conductive layer 132a in this example is composed of indium tin oxide. The reflective layer 134a is disposed on the transparent conductive layer 132a. The reflective layer 134a can reflect the light from the semiconductor epitaxial layer 120a to the substrate 110a, and when the light-emitting diode structure 100a of the present invention is applied to, for example, a flip-chip light-emitting diode, the light-emitting efficiency can be improved. Here, the material of the reflective layer 134a is, for example, one selected from the group consisting of silver, chromium, nickel, aluminum, and the like; or the reflective layer 134a is, for example, a Bragg mirror. The reflective layer 134a in this example is composed of silver. The barrier layer 136a is disposed on the reflective layer 134a and covers the upper surface 112a of the substrate 110a exposed by the semiconductor epitaxial layer 120a. The barrier layer 136a may also have a reflective function to protect the reflective layer 134a. The structure avoids diffusion of metal in the reflective layer 134a. Here, the edge of the barrier layer 136a is aligned with the edge of the substrate 110a, and the material of the barrier layer 136a is selected, for example, from titanium tungsten alloy, titanium, tungsten, titanium nitride, tantalum, chromium, chromium copper alloy, nitrogen. In one embodiment, the barrier layer 136a is made of titanium, tungsten, and a titanium-tungsten alloy.

Furthermore, the LED structure 100a of the present embodiment further includes an insulating layer 140a (the insulating layer referred to in the following paragraphs may also be referred to as a first insulating layer), wherein the insulating layer 140a is disposed on the substrate 110a and reflectively conductive. Between the structural layers 130a and between the semiconductor epitaxial layer 120a and the reflective conductive structure layer 130a, the semiconductor epitaxial layer 120a and the reflective conductive structure layer 130a are effectively electrically insulated. As shown in FIG. 1, the insulating layer 140a of the present embodiment is directly disposed on the semiconductor epitaxial layer 120a, and is disposed along the sidewall of the semiconductor epitaxial layer 120a and is disposed on the substrate 110a exposed by the semiconductor epitaxial layer 120a. On the surface 112a. The transparent conductive layer 132a and the reflective layer 134a thereon do not completely cover the insulating layer 140a, and the barrier layer 136a extends along the sidewalls of the transparent conductive layer 132a and the reflective layer 134a to cover the insulating layer 140a. Here, the edge of the insulating layer 140a is also aligned with the edge of the barrier layer 136a and the edge of the substrate 110a.

In addition, the LED structure 100a of the present embodiment further includes a first electrode 150a, a second electrode 160a, and a connection layer 170a. The semiconductor epitaxial layer 120a has a recessed region C, and the recessed region C divides the semiconductor epitaxial layer 120a into a first semiconductor block S1 and a second semiconductor block S2. The first electrode 150a is disposed on the first semiconductor block S1, and the second electrode 160a is disposed on the second semiconductor block S2, wherein the first electrode 150a and the second electrode 160a are electrically electrically can. The connection layer 170a is disposed in the recessed region C and electrically connected to the first electrode 150a and the semiconductor epitaxial layer 120a. Here, the material of the first electrode 150a and the connection layer 170a may be the same or different, preferably different materials. The material of the first electrode 150a is selected from the group consisting of gold, tin, gold-tin alloy, and the like. The material of the connection layer 170a is selected from the group consisting of chromium, platinum, gold, aluminum, alloys of the above materials, and one of the above-mentioned groups. The difference in materials allows the first electrode 150a to have a better electrical connection with the connection layer 170a, but is not limited thereto. Here, the first electrode 150a is electrically connected to the first type semiconductor layer 122a of the semiconductor epitaxial layer 120a through the connection layer 170a, and the second electrode 160a is transparent to the second type semiconductor layer of the reflective epitaxial layer 120a and the semiconductor epitaxial layer 120a. 126a is electrically connected to provide electrical energy through the first electrode 150a and the second electrode 160a to cause the light emitting diode structure 100a to emit light.

In addition, the LED structure 100a may further include an electrically insulating layer 145a (the electrically insulating layer referred to in the following paragraph may also be referred to as a second insulating layer), wherein the electrically insulating layer 145a is disposed at least in the first Between the electrode 150a and the reflective conductive structure layer 130a and between the connection layer 170a and the reflective conductive structure layer 130a, the conductive structure layer 130a, the connection layer 170a and the first electrode 150a are electrically insulated. Here, the edge of the electrically insulating layer 145a is also aligned with the edge of the barrier layer 136a, the edge of the insulating layer 140, and the edge of the substrate 110a.

Since the light emitting diode structure 100a of the present embodiment has the reflective conductive structure layer 130a, the reflective conductive structure layer 130a covers a portion of the semiconductor epitaxial layer 120a and a portion of the substrate 110a exposed by the semiconductor epitaxial layer 120a. Therefore, the reflective conductive structure layer 130a can effectively reflect light from the semiconductor epitaxial layer 120a. The line, and the portion of the substrate 110a exposed by the semiconductor epitaxial layer 120a also has a reflective effect. In this way, when the light emitting diode structure 100a is applied to, for example, a flip chip design, the arrangement of the reflective conductive structure layer 130a can effectively increase the reflective area, thereby effectively improving the light extraction efficiency of the overall light emitting diode structure 100a.

It is to be noted that the following embodiments use the same reference numerals and parts of the above-mentioned embodiments, and the same reference numerals are used to refer to the same or similar elements, and the description of the same technical content is omitted. For the description of the omitted portions, reference may be made to the foregoing embodiments, and the following embodiments are not repeated.

2 is a cross-sectional view showing a structure of a light emitting diode according to another embodiment of the present invention. Referring to FIG. 2, the LED structure 100b of the present embodiment is similar to the LED structure 100a of FIG. 1, but the main difference is that the substrate 110b of the embodiment has an upper surface 112b and a connection. The annular inclined surface 114b of the upper surface 112b, wherein the insulating layer 140b and the barrier layer 136b extend from the upper surface 112b over the annular inclined surface 114b. As shown in FIG. 2, the transparent conductive layer 132b and the reflective layer 134b of the reflective conductive structure layer 130b do not extend over the annular inclined surface 114b.

3 is a cross-sectional view showing a structure of a light emitting diode according to another embodiment of the present invention. Referring to FIG. 3, the LED structure 100c of the present embodiment is similar to the LED structure 100b of FIG. 2, but the main difference is that the transparent conductive layer 132c of the reflective conductive structure layer 130c of this embodiment The reflective layer 134c and the barrier layer 136c extend from the upper surface 112b to cover the annular inclined surface 114b, and the edge of the transparent conductive layer 132c, the edge of the reflective layer 134c, and the barrier layer 136c The edges are all aligned to the edge of the substrate 110b. This design allows the reflective conductive layer 130c to be disposed not only on the upper surface of the substrate 110b but also on the annular inclined surface 114b to increase the reflective area.

4 is a cross-sectional view showing a structure of a light emitting diode according to another embodiment of the present invention. Referring to FIG. 4, the LED structure 100d of the present embodiment is similar to the LED structure 100b of FIG. 2, but the main difference is that the transparent conductive layer 132d of the reflective conductive structure layer 130d of the present embodiment The reflective layer 134d and the barrier layer 136d, and the insulating layer 140d and the electrically insulating layer 145d both extend from the upper surface 112b and cover the annular inclined surface 114b and converge to the same position.

In summary, since the light emitting diode structure of the present invention has a reflective conductive structure layer, the reflective conductive structure layer covers a portion of the semiconductor epitaxial layer and a portion of the substrate exposed by the semiconductor epitaxial layer. Therefore, the reflective conductive structure layer can effectively reflect the light from the semiconductor epitaxial layer, and the portion of the substrate exposed by the semiconductor epitaxial layer also has the effect of reflection. In this way, the arrangement of the reflective conductive structure layer can effectively increase the reflective area, thereby effectively improving the light extraction efficiency of the overall light emitting diode structure.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

Claims (9)

A light emitting diode structure comprising: a substrate having a top surface; a semiconductor epitaxial structure disposed on the top surface of the substrate and exposing a portion of the top surface; a first insulating layer covering the semiconductor An epitaxial structure and a portion of the top surface exposed by the substrate, and forming at least a first opening and at least a second opening respectively exposing a portion of the semiconductor epitaxial structure; a connecting layer at least partially disposed at the first The first opening of the insulating layer is electrically connected to the semiconductor epitaxial structure; a conductive layer is at least partially disposed in the second opening of the first insulating layer and electrically connected to the semiconductor epitaxial structure a Bragg mirror layer disposed on at least the conductive layer and the first insulating layer, wherein at least a portion of the top surface of the substrate is covered by the Bragg mirror layer; a second insulating layer Provided on the Bragg mirror layer; a first electrode is disposed on the first insulating layer, the second insulating layer and the Bragg mirror layer, and is electrically connected through the first opening The connection layer and the semiconductor epitaxial structure; and a second electrode disposed on the first insulating layer and the Bragg mirror layer, and electrically connecting the conductive layer and the semiconductor epitaxial structure through the second opening, wherein The light emitting diode structure has a flat side surface, and the flat side surface package The substrate, the first insulating layer and the second insulating layer are included. The light emitting diode structure of claim 1, wherein the semiconductor epitaxial structure comprises a first type semiconductor layer, a light emitting layer and a second type semiconductor layer, which are sequentially disposed on the substrate, and The material of the substrate is different from the material of the first type semiconductor layer, and one side surface of the semiconductor epitaxial structure includes the first type semiconductor layer, the light emitting layer and the second type semiconductor layer, wherein the first insulating layer is further Covering the entire side surface of the semiconductor epitaxial structure. The light emitting diode structure of claim 1 or 2, wherein the substrate further comprises an inclined surface connected to the top surface, the semiconductor epitaxial structure further exposing the inclined surface, the second The insulating layer covers a portion of the top surface and at least a portion of the inclined surface on which the substrate is exposed. The light-emitting diode structure of claim 1, further comprising a barrier layer disposed on the semiconductor epitaxial structure and electrically connected to the conductive layer. The light emitting diode structure of claim 1, wherein the flat side surface further comprises the Bragg mirror layer. The light emitting diode structure of claim 1 or 2, wherein the substrate further comprises an inclined surface connected to the top surface, the semiconductor epitaxial structure further exposing the inclined surface, the Bragg reflection The mirror layer further covers at least a portion of the inclined surface of the substrate. The light emitting diode structure of claim 1 or 2, wherein the substrate further comprises an inclined surface, the inclined surface is connected to the top surface, and the semiconductor epitaxial structure further exposes the inclined surface, the first The insulating layer covers at least part of the substrate Divided into the inclined surface. The light emitting diode structure of claim 2, wherein the Bragg mirror layer covers the entire side surface of the semiconductor epitaxial structure. The light emitting diode structure of claim 2, wherein the second insulating layer covers the entire side surface of the semiconductor epitaxial structure.