CN201667345U

CN201667345U - High-power GaN-based LED epitaxial structure suitable for laser stripping

Info

Publication number: CN201667345U
Application number: CN2010201672361U
Authority: CN
Inventors: 刘长江; 张成山; 徐现刚; 任忠祥
Original assignee: Shandong Huaguang Optoelectronics Co Ltd
Current assignee: Shandong Huaguang Optoelectronics Co Ltd
Priority date: 2010-04-23
Filing date: 2010-04-23
Publication date: 2010-12-08
Anticipated expiration: 2020-04-23

Abstract

The utility model provides a high-power GaN-based LED epitaxial structure suitable for laser stripping, comprising from bottom to top a sapphire substrate, an U-shaped GaN layer, a N-shaped GaN layer, a N-shaped A1GaN layer, a MQW layer, a P-shaped A1GaN layer, a P-shaped GaN layer and a current expansion layer. A stripping corrosion block layer dopting A1N or A1GaN is disposed between the U-shaped GaN layer and the N-shaped GaN layer. The utility model is advantageous in that firstly compared with a conventional LED epitaxial structure, a stripping corrosion block layer is extra disposed between an U-shaped GaN layer and a N-shaped GaN layer; secondly by optimizing growth temperature and growth condition, an even A1N surface or A1GaN surface is formed, and linear dislocation density can be effectively inhibited and MQW efficiency can be improved; thirdly as the decomposition temperature of the stripping corrosion block layer is over 2000 DEG, which is 1000 DEG higher than the decomposition temperature of GaN layer, thereby the damage on N-shaped GaN and LED luminescent layer at the time of laser stripping can be effectively controlled and product yield rate can be improved.

Description

A kind of high-power GaN base LED epitaxial structure of suitable laser lift-off

Technical field

The utility model relates to the epitaxial structure that is fit to utilize laser lift-off technique making GaN base LED chip, belongs to light-emitting diode (LED) technical field.

Background technology

Development along with high-power GaN series blue green light LED has progressively realized the semiconductor lighting technology.Light-emitting diode impels people to seek the method for various making great power LED devices in the expansion of applications such as decorative lighting, Landscape Lighting, backlight.

Make GaN series LED research still Sapphire Substrate the earliest at present, technology and technology are relatively ripe, and high-power GaN base LED epitaxial structure generally comprises Sapphire Substrate, UGaN layer (non-doped high temperature GaN layer), N type GaN layer, N type AlGaN layer, mqw layer (multiple quantum well layer), P type AlGaN, P type GaN layer and current extending from bottom to top successively.

But sapphire thermal conductivity and electric property have limited the development of power-type device.Sapphire thermal conductivity has only 35W/mK, and non-conductive, and the heat that the LED luminous zone produces when big current work looses and do not go out, and has improved the device working temperature, has reduced its reliability and range of application.Except that selecting new type of substrate for use, adopt laser lift-off technique (LLO) mostly for solving heat dissipation problem at present.

Laser lift-off technique (LLO) is to utilize laser energy to decompose epitaxial structure and Sapphire Substrate GaN resilient coating at the interface, thereby realize that the LED epitaxial wafer separates with Sapphire Substrate, luminous epitaxial structure is transferred on the better baseplate material of heat conduction, and these heat-conducting substrate materials mainly comprise silicon, carborundum, metal and metal alloy etc.

Laser lift-off is generally selected high-power pulse laser polarity scanning for use, and laser sees through Sapphire Substrate and absorbed by GaN, and heating makes GaN decompose.Because of laser energy density is very high, in the laser scanning process, be difficult to the accurately fusion penetration of control GaN, peel off difficulty, cause the damage of GaN laminar surface, influence light extraction efficiency.

Summary of the invention

The utility model is at utilizing the laser lift-off Sapphire Substrate to cause the problem of GaN layer damage in the existing high-power GaN series LED manufacturing process, a kind of high-power GaN base LED epitaxial structure that can prevent to cause the suitable laser lift-off of GaN layer damage when utilizing the laser lift-off Sapphire Substrate is provided.

The high-power GaN base LED epitaxial structure of suitable laser lift-off of the present utility model adopts following scheme:

The high-power GaN base LED epitaxial structure that should be fit to laser lift-off comprises Sapphire Substrate, U type GaN layer, N type GaN layer, N type AlGaN layer, mqw layer, P type AlGaN, P type GaN layer and current extending from bottom to top, be provided with one deck exfoliation corrosion barrier layer between U type GaN layer and N type GaN layer, AlN or AlGaN are adopted in this exfoliation corrosion barrier layer.

The thickness of peeling off the barrier layer is 100nm-3um.Grow for utilizing MOCVD (Organometallic Chemistry vapor phase deposition) equipment in AlN or AlGaN barrier layer, growth temperature is 1000-1100 ℃.Raw material use and are TMGa (trimethyl gallium), TMAl (trimethyl aluminium), NH3 (ammonia), and the chamber pressure scope is between 100-200Torr during growth, and temperature range is between 975-1100 degree centigrade.

The utility model has inserted one deck exfoliation corrosion barrier layer than the common LED epitaxial structure between U-GaN and N-GaN; By optimizing growth temperature and growth conditions, form smooth AlN of zero defect or AlGaN surface, can effectively suppress linear dislocation density simultaneously, improve the efficient of MQW.The decomposition temperature on this exfoliation corrosion barrier layer exceeds about decomposition temperature 1000 degree of GaN more than 2000 degree, to the damage of N type GaN and LED luminescent layer, improves the finished product rate in the time of can effectively controlling laser lift-off.

Description of drawings

Fig. 1 is the schematic diagram of the utility model LED epitaxial structure.

Among the figure: 1, Sapphire Substrate, 2, the U-GaN layer, 3, the exfoliation corrosion barrier layer, 4, the N-GaN layer, 5, the N-AlGaN layer, 6, mqw layer, 7, the P-AlGaN layer, 8, the P-GaN layer, 9, current extending.

Embodiment

The utility model LED epitaxial structure is based on growing GaN LED epitaxial structure on the Sapphire Substrate, as shown in Figure 1, epitaxial structure is respectively Sapphire Substrate 1, U-GaN layer 2, exfoliation corrosion barrier layer 3, N-GaN layer 4, N-AlGaN layer 5, mqw layer 6, P-AlGaN layer 7, P-GaN layer 8 and current extending 9 from bottom to top.

The utility model has inserted one deck exfoliation corrosion barrier layer 3 than the common LED epitaxial structure between U-GaN layer 2 and N-GaN layer 4; The material on exfoliation corrosion barrier layer 3 is AlN or AlGaN, and wherein al composition is adjustable, and peeling off barrier layer thickness is 100nm-3um, can adopt MOCVD equipment direct growth, and growth temperature is 1000-110 ℃.By optimizing growth temperature and growth conditions, form smooth AlN of zero defect or AlGaN surface, as shown in Figure 2, can effectively suppress linear dislocation density simultaneously, improve the efficient of MQW.The decomposition temperature on this exfoliation corrosion barrier layer exceeds about decomposition temperature 1000 degree of GaN more than 2000 degree, to the damage of N type GaN and LED luminescent layer, improves the finished product rate in the time of can effectively controlling laser lift-off.

The chip manufacturing process is at first made the good metallic reflection minute surface of reflection, adopts the large tracts of land bonding techniques, utilizes high temperature scolders such as golden tin, Yin Xi, slicker solder that epitaxial material is bonded on the good substrate of heat-conductivity conducting; Utilize laser lift-off technique that Sapphire Substrate is peeled off; Utilize the ICP lithographic technique will peel off barrier layer AlN then or the AlGaN layer etches away, expose N type GaN face; Adopt the method for wet etching or dry etching that N type GaN is carried out surface coarsening; Evaporation Ti, Al, Ni, Au etc. make the LED electrode from the teeth outwards.

Claims

1. the high-power GaN of suitable laser lift-off base LED epitaxial structure, comprise Sapphire Substrate, U type GaN layer, N type GaN layer, N type AlGaN layer, mqw layer, P type AlGaN, P type GaN layer and current extending from bottom to top, it is characterized in that: be provided with one deck exfoliation corrosion barrier layer between U type GaN layer and N type GaN layer, AlN or AlGaN are adopted in this exfoliation corrosion barrier layer.

2. the high-power GaN of suitable laser lift-off according to claim 1 base LED epitaxial structure, it is characterized in that: the described barrier layer thickness of peeling off is 100nm-3um.