CN109713103B

CN109713103B - LED chip

Info

Publication number: CN109713103B
Application number: CN201811626985.3A
Authority: CN
Inventors: 沈铭
Original assignee: Yingrui Optoelectronic Technology Shanghai Co ltd
Current assignee: Yingrui Optoelectronic Technology Shanghai Co ltd
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2021-03-02
Anticipated expiration: 2038-12-28
Also published as: CN109713103A

Abstract

The invention discloses an LED chip, comprising: the N-GaN layer, the quantum well layer and the P-GaN layer are stacked in sequence; a reflective layer formed on the P-GaN layer; a barrier layer formed on the reflective layer, the barrier layer covering the reflective layer; the material of the material layer of the part of the barrier layer, which is in contact with the P-GaN layer, is one or more of Al, Ag, Zn and AlCu alloy. The invention replaces the material layer in the barrier layer, which is in contact with the surface of the P-GaN layer and the surface of the reflecting layer, with the metal layer with high reflectivity, so that the barrier layer can reduce light absorption, and maintain the original function of protecting the reflecting layer, thereby realizing the purposes of improving the light-emitting rate of the LED chip and further improving the brightness of the LED chip.

Description

LED chip

Technical Field

The invention relates to the field of LED chip manufacturing, in particular to an LED chip.

Background

An ohmic contact layer (usually a transparent conductive layer) for ohmic contact, a reflective layer for reflecting, and a barrier layer for covering the reflective layer and the transparent conductive layer are sequentially formed on the surface of the p-GaN layer of most of the existing GaN-based LED chips. The barrier layer is a laminated structure consisting of Ti, Pt, Au and Ti, wherein the material layer in contact with the surface of the p-GaN layer and the surface of the reflecting layer is a Ti layer, and the Ti layer has a light reflection rate of only about 40% and is a light absorption material.

The study finds that most of the light emitted by the GaN material is reflected by the reflecting layer to the other side of the LED chip, but a small part of the light is absorbed by the Ti material layer of which the blocking layer exceeds the part of the reflecting layer, so that the final brightness of the LED chip is affected.

Disclosure of Invention

The invention aims to provide an LED chip and a preparation method thereof, which can reduce the light absorption of a barrier layer as much as possible and keep the original function of a protective reflecting layer so as to improve the light-emitting rate of the LED chip and further improve the brightness of the LED chip.

In order to achieve the above purpose, the invention is realized by the following technical scheme:

an LED chip, comprising: the N-GaN layer, the quantum well layer and the P-GaN layer are stacked in sequence; a reflective layer formed on the P-GaN layer; a barrier layer formed on the reflective layer, the barrier layer covering the reflective layer; the material of the material layer of the part of the barrier layer, which is in contact with the P-GaN layer, is one or more of Al, Ag, Zn and AlCu alloy.

Furthermore, the thickness of the material layer of the part of the barrier layer, which is in contact with the P-GaN layer, ranges from 0.01 mu m to 100 mu m.

Further, the barrier layer further comprises a protective layer formed on the material layer of the portion, in contact with the P-GaN layer, of the barrier layer, and the protective layer is made of one or more of Ti, TiW, Pt, Ni, Au and Cr.

Further, the protective layer is made of one or more of Al, Ag, Zn and AlCu alloy.

Furthermore, the material of the reflecting layer is Ag, Al or Rh.

Further, the method also comprises the following steps: the groove penetrates through the barrier layer, the high-reflectivity metal layer, the reflecting layer, the P-GaN layer and the quantum well layer and exposes the N-GaN layer; the insulating layer is formed on the barrier layer and the side wall of the groove; the bonding layer faces the insulating layer and fills the groove to be electrically connected with the N-GaN layer; the passivation layer covers the P-GaN layer, the quantum well layer, the side wall of the N-GaN layer and the insulating layer; and the P electrode is formed on one side of the P-GaN layer, the quantum well layer and the N-GaN layer and is electrically connected with the P-GaN layer through the barrier layer.

Further, the method also comprises the following steps: and the rough surface is formed on the surface of the N-GaN layer, which faces away from the quantum well layer.

Further, the insulating layer has a single-layer structure formed by one of SiO2, SiN, SiON, Al2O3, and TiO2, or a stacked-layer structure formed by any combination of SiO2, SiN, SiON, Al2O3, and TiO 2.

Further, the material of the passivation layer is SiO 2.

Furthermore, the bonding layer material is Au, Sn, AuSn alloy or NiSn alloy.

The invention has the following technical effects:

the invention replaces the material layer in the barrier layer, which is in contact with the surface of the P-GaN layer and the surface of the reflecting layer, with the metal layer with high reflectivity, so that the barrier layer can reduce light absorption, and maintain the original function of protecting the reflecting layer, thereby realizing the purposes of improving the light-emitting rate of the LED chip and further improving the brightness of the LED chip. Further, the undoped layer is roughened to form a rough surface, so that the light extraction rate is improved.

Drawings

Fig. 1 is a schematic view of a partial structure of an LED chip according to an embodiment of the present invention.

Detailed Description

A LED chip of the present invention will now be described in more detail with reference to the schematic drawings, in which a preferred embodiment of the invention is shown, it being understood that one skilled in the art could modify the invention herein described while still achieving the advantageous effects of the invention. Accordingly, the following description should be construed as broadly as possible to those skilled in the art and not as limiting the invention.

In the interest of clarity, not all features of an actual implementation are described. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific details must be set forth in order to achieve the developer's specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art.

In order to make the objects and features of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It is to be noted that the drawings are in a very simplified form and employ non-precise ratios for the purpose of facilitating and distinctly facilitating the description of one embodiment of the present invention.

As shown in fig. 1, the present embodiment provides an LED chip, including: an N-GaN layer 100, a quantum well layer 101 and a P-GaN layer 102 which are stacked in sequence; a reflective layer 200 formed on the P-GaN layer 102; a barrier layer 300 formed on the reflective layer 200, the barrier layer 200 covering the reflective layer 200; the material layer of the barrier layer 300 in contact with the P-GaN layer 102 is a metal layer 31 with high reflectivity. The barrier layer 300 further includes a protection layer 32 formed on the high-reflectivity metal layer 31, the material of the protection layer 32 is one or more of Ti, TiW, Pt, Ni, Au, and Cr, or the material of the protection layer 32 may also be one or more of Al, Ag, Zn, and AlCu alloy, which is the same as the material of the high-reflectivity metal layer. The metal layer with high reflectivity is made of one or more of Al, Ag, Zn and AlCu alloy. The thickness range of the high-reflectivity metal layer is 0.01-100 mu m. The reflecting layer is made of Ag, Al or Rh.

The LED chip further includes: a groove (shown in the figure) penetrating the barrier layer, the high-reflectivity metal layer, the reflective layer, the P-GaN layer and the quantum well layer and exposing the N-GaN layer; an insulating layer (shown) formed on the barrier layer and the sidewalls of the recess; a bonding substrate (shown in the figure) and a bonding layer positioned on the bonding substrate, wherein the bonding layer faces the insulating layer and fills the groove to be electrically connected with the N-GaN layer; a passivation layer (shown in the figure) covering the P-GaN layer, the quantum well layer, the sidewall of the N-GaN layer and the insulating layer; and the P electrode is formed on one side of the P-GaN layer, the quantum well layer and the N-GaN layer and is electrically connected with the P-GaN layer through the barrier layer. And a rough surface (shown in the figure) formed on the surface of the N-GaN layer, which faces away from the quantum well layer. The insulating layer is a single-layer structure formed by one of SiO2, SiN, SiON, Al2O3 and TiO2, or a laminated structure formed by any combination of SiO2, SiN, SiON, Al2O3 and TiO 2. The passivation layer is made of SiO 2.

The bonding layer is made of Au, Sn, AuSn alloy or NiSn alloy.

In summary, the invention replaces the material layer in the barrier layer, which is in contact with the surface of the reflecting layer, with the metal layer with high reflectivity, so that the barrier layer can reduce light absorption, and maintain the original function of protecting the reflecting layer, thereby achieving the purposes of improving the light-emitting rate of the LED chip and improving the brightness of the LED chip. Furthermore, the light extraction rate can be improved by roughening the undoped layer to form a rough surface.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.

Claims

1. An LED chip, comprising: the N-GaN layer, the quantum well layer and the P-GaN layer are stacked in sequence;

a reflective layer formed on the P-GaN layer;

a barrier layer formed on the reflective layer, the barrier layer covering the reflective layer;

the material of the material layer of the part of the barrier layer, which is in contact with the P-GaN layer, is one or more of Ag, Zn and AlCu alloy so as to improve the reflectivity of the barrier layer, the barrier layer further comprises a protective layer formed on the material layer of the part of the barrier layer, which is in contact with the P-GaN layer, and the material of the protective layer is one or more of Ti, TiW, Pt, Ni, Au and Cr.

2. The LED chip of claim 1, wherein the thickness of the material layer of the portion of the barrier layer in contact with the P-GaN layer ranges from 0.01 μ ι η to 100 μ ι η.

3. The LED chip of claim 2, wherein the reflective layer is made of Ag, Al, or Rh.

4. The LED chip of claim 3, further comprising:

a groove penetrating the barrier layer, the reflective layer, the P-GaN layer, and the quantum well layer and exposing the N-GaN layer;

the insulating layer is formed on the barrier layer and the side wall of the groove;

the bonding layer faces the insulating layer and fills the groove to be electrically connected with the N-GaN layer;

the passivation layer covers the P-GaN layer, the quantum well layer, the side wall of the N-GaN layer and the insulating layer; and

and the P electrode is formed on one side of the P-GaN layer, the quantum well layer and the N-GaN layer and is electrically connected with the P-GaN layer through the barrier layer.

5. The LED chip of claim 4, further comprising:

and the rough surface is formed on the surface of the N-GaN layer, which faces away from the quantum well layer.

6. The LED chip according to claim 4, wherein the insulating layer is a single-layer structure formed of one of SiO2, SiN, SiON, Al2O3 and TiO2, or a stacked-layer structure formed of any combination of SiO2, SiN, SiON, Al2O3 and TiO 2.

7. The LED chip of claim 4, wherein the passivation layer is made of SiO 2.

8. The LED chip of claim 4, wherein the bonding layer material is Au, Sn, AuSn alloy, or NiSn alloy.