CN102751403A

CN102751403A - Epitaxial structure of light emitting diode

Info

Publication number: CN102751403A
Application number: CN2011100993326A
Authority: CN
Inventors: 艾常涛; 靳彩霞; 董志江
Original assignee: Diyuan Photoelectric Science & Technology Co Ltd Wuhan
Current assignee: Diyuan Photoelectric Science & Technology Co Ltd Wuhan
Priority date: 2011-04-20
Filing date: 2011-04-20
Publication date: 2012-10-24

Abstract

The invention relates to an epitaxial structure of a light emitting diode. The epitaxial structure comprises a substrate, a buffer, a u-GaN (u-gallium nitride) layer, an n-GaN layer, an MQW (multiple quantum well) and a p-GaN layer. The epitaxial structure is characterized in that the epitaxial structure is provided with j n-GaN/MQW/p-GaN structures (j is greater than or equal to 2 but is smaller than or equal to 100), and in addition, the n-GaN and the p-GaN are connected through the MQW. The injection efficiency, the injection velocity and the injection depth of hollow cavities can be improved, the crystalline quality of epitaxial materials is improved, the luminescence wavelength is regulated, the luminescence efficiency of a device and the saturated work current are improved, and the work voltage of the device is reduced.

Description

A kind of epitaxial structure of light-emitting diode

Technical field

The invention belongs to the led technology field, be specifically related to a kind of special epitaxial structure of light-emitting diode.

Background technology

Although the defect concentration of GaN base LED reaches 10 ⁹Cm ^-2More than, it still has the luminous efficiency above traditional lighting, but along with after injection current increases to a certain degree, luminous efficiency can sharply descend, i.e. the Droop phenomenon.High-power LED illuminator spare will replace traditional lighting fully, certainly will need big current drives, therefore, reduces or eliminates the Droop effect and will need to be resolved hurrily.

The electronics overflow is a Droop effect main cause, and hole effective mass is big and doping content is lower and make it can not effectively be injected into SQW, thereby makes that a large amount of electronics can't be luminous with hole-recombination in SQW, and traditional epitaxial structure is as shown in Figure 1.

The epitaxial structure of tradition LED generally is followed successively by uGaN, nGaN, MQW, pGaN; The growth of MQW is because of the temperature sensitivity characteristic of In; Its growth temperature must lower be provided with a little on; I SQW and base (2≤i≤100) are arranged in MQW (MQW), but really play 1-2 the SQW that have only of luminous effect, the effect that other SQWs mainly play is the recombination probability that relaxes crystalline quality, improves charge carrier.Thereby there are several drawbacks in traditional structure: the one, and the SQW number can not be too many, because of crystalline quality is relatively poor brightness also had damage too much on the one hand, and the device synthesis decreased performance can only be made monochromatic device on the other hand.Though Chinese Academy of Sciences's semiconductor can be done the patent of white light (being complex light), this patent light efficiency also can raise after existing drawback, forward voltage because of the device thickening because of the problem of crystal mass.

Summary of the invention

The objective of the invention is to propose a kind of special epitaxial structure of light-emitting diode; Can improve the injection efficiency and the speed in hole and inject the degree of depth, improve the crystal mass of epitaxial material, regulate emission wavelength; Improve device luminous efficiency and operate in saturation electric current, reduce the operating voltage of device.

Technical scheme of the present invention is a kind of epitaxial structure of light-emitting diode; It comprises substrate, transition zone (Buffer), u type gallium nitride layer (u-GaN), n type gallium nitride layer (n-GaN), multiple quantum well layer (MQW), p type gallium nitride layer (p-GaN), it is characterized in that: contain between j n-GaN/MQW/p-GaN structure (2≤j≤100) and n-GaN and p-GaN and be connected through MQW.

A kind of epitaxial structure of light-emitting diode; It comprises substrate, transition zone (Buffer), u type gallium nitride layer (u-GaN), n type gallium nitride layer (n-GaN), multiple quantum well layer (MQW), p type gallium nitride layer (p-GaN), it is characterized in that: contain between j u-GaN/n-GaN/MQW/p-GaN structure (2≤j≤100) and n-GaN and p-GaN and be connected through MQW.

Described epitaxial structure of light-emitting diode; It is characterized in that each MQW contains i SQW and base (2≤i≤100); Its structure be SQW/quantum build/... / SQW/quantum is built; Or quantum base/SQW/... / quantum base/SQW, or quantum base/SQW/... / quantum base/SQW/quantum is built, or SQW/quantum base/SQW/... / quantum base/SQW.

Described epitaxial structure of light-emitting diode is characterized in that each MQW SQW number is identical or different.

Technique effect: this patent is easy to make.Traditional relatively epitaxial structure improves the injection efficiency and the speed in hole and injects the degree of depth, improves the crystal mass of epitaxial material, regulates emission wavelength, improves device luminous efficiency and operate in saturation electric current, reduces the operating voltage of device.

Description of drawings

Fig. 1 tradition epitaxial structure sketch map.

Fig. 2 embodiment of the invention 1 structural representation.

Fig. 3 embodiment of the invention 2 structural representations.

Embodiment

Embodiment 1:

Fig. 2 is embodiment 1 structural representation.In the MOCVD reacting furnace, substrate is toasted at 1200 ℃ earlier, remove the substrate surface foreign matter.At 550 ℃, deposition 25nm transition zone Al _yIn _xGa _1-x-yN (0≤x≤1,0≤y≤1,0≤x+y＜1) (Buffer layer) is elevated to 1100 ℃ with temperature again, carries out 1 μ m u type layer Al successively _yIn _xGa _1-x-yN (0≤x≤1,0≤y≤1,0≤x+y＜1) (u-GaN), 1 μ m n type layer Al _yIn _xGa _1-x-yN (0≤x≤1,0≤y≤1,0≤x+y＜1) preparation (n-GaN); At 750 ℃ of growth MQW, wherein the trap in each cycle is wide is 2nm, and building wide is 10nm; Under 900 ℃, the Mg doped p type layer of deposition 220nm is at 750 ℃ of growth MQW; Again temperature is elevated to 1100 ℃, the n type layer Al of growth 0.8um _yIn _xGa _1-x-yN (0≤x≤1,0≤y≤1,0≤x+y＜1) (n-GaN); At 750 ℃ of growth MQW; Wherein the trap in each cycle is wide is 2nm, and building wide is 10nm, under 900 ℃; The Mg doped p type layer of deposition 250nm, so (the n-GaN+MQW+p-GaN+MQW+ n-GaN+MQW+p-GaN) in a repeated growth j cycle.This structure can improve injection efficiency and the speed in hole and inject the degree of depth, and it is about 5% to improve the device luminous efficiency, reduces the operating voltage 0.05-0.1V of device, and the intact MQW of every growth simultaneously when high annealing growth n-GaN, can improve the crystal mass of MQW again.

Embodiment 2:

As shown in Figure 3, in the MOCVD reacting furnace, substrate is toasted at 1200 ℃ earlier, remove the substrate surface foreign matter.At 550 ℃, deposition 25nm transition zone Al _yIn _xGa _1-x-yN (0≤x≤1,0≤y≤1,0≤x+y＜1) (Buffer layer) is elevated to 1100 ℃ with temperature again, carries out 1 μ m u type layer Al successively _yIn _xGa _1-x-yN (0≤x≤1,0≤y≤1,0≤x+y＜1) (u-GaN), 1 μ m n type layer Al _yIn _xGa _1-x-yN (0≤x≤1,0≤y≤1,0≤x+y＜1) preparation (n-GaN); At 750 ℃ of growth MQW, wherein the trap in each cycle is wide is 2nm, and building wide is 10nm; Under 900 ℃, the Mg doped p type layer of deposition 220nm is at 750 ℃ of growth MQW; Again temperature is elevated to 1100 ℃, growth 0.8um u type layer Al _yIn _xGa _1-x-yN (0≤x≤1,0≤y≤1,0≤x+y＜1) (u-GaN), the n type layer Al of 0.8um _yIn _xGa _1-x-yN (0≤x≤1,0≤y≤1,0≤x+y＜1) (n-GaN); At 750 ℃ of growth MQW; Wherein the trap in each cycle is wide is 1.5nm, and building wide is 8nm, under 900 ℃; The Mg doped p type layer of deposition 250nm, so (the u-GaN+n-GaN+MQW+p-GaN+MQW+ u-GaN+n-GaN+MQW+p-GaN) in a repeated growth j cycle.This structure can improve injection efficiency and the speed in hole and inject the degree of depth, and it is about 5% to improve the device luminous efficiency, reduces the operating voltage 0.05-0.1V of device, and the intact MQW of every growth simultaneously when high annealing growth n-GaN, can improve the crystal mass of MQW again.

Claims

1. epitaxial structure of light-emitting diode; It comprises substrate, transition zone Buffer, u type gallium nitride layer u-GaN, n type gallium nitride layer n-GaN, multiple quantum well layer MQW, p type gallium nitride layer p-GaN; It is characterized in that: contain j n-GaN/MQW/p-GaN structure; 2≤j≤100, and be connected through MQW between n-GaN and p-GaN.

2. epitaxial structure of light-emitting diode according to claim 1; It is characterized in that each MQW contains i SQW and base; 2≤i≤100, its structure be SQW/quantum build/... / SQW/quantum is built, or quantum base/SQW/... / quantum base/SQW; Or quantum base/SQW/... / quantum base/SQW/quantum is built, or SQW/quantum base/SQW/... / quantum base/SQW.

3. epitaxial structure of light-emitting diode according to claim 1 and 2 is characterized in that each MQW SQW number is identical or different.

4. epitaxial structure of light-emitting diode; It comprises substrate, transition zone Buffer, u type gallium nitride layer u-GaN, n type gallium nitride layer n-GaN, multiple quantum well layer MQW, p type gallium nitride layer p-GaN; It is characterized in that: contain j u-GaN/n-GaN/MQW/p-GaN structure; 2≤j≤100, and be connected through MQW between n-GaN and p-GaN.

5. epitaxial structure of light-emitting diode according to claim 4; It is characterized in that each MQW contains i SQW and base; 2≤i≤100, its structure be SQW/quantum build/... / SQW/quantum is built, or quantum base/SQW/... / quantum base/SQW; Or quantum base/SQW/... / quantum base/SQW/quantum is built, or SQW/quantum base/SQW/... / quantum base/SQW.

6. according to claim 4 or 5 described epitaxial structure of light-emitting diode, it is characterized in that each MQW SQW number is identical or different.