CN102683523A

CN102683523A - Method for extending light emitting diodes (LED) on low-dislocation gallium nitride (GaN) nanometer columns

Info

Publication number: CN102683523A
Application number: CN2012101845311A
Authority: CN
Inventors: 吴奎; 魏同波; 闫建昌; 刘喆; 王军喜; 李晋闽
Original assignee: Institute of Semiconductors of CAS
Current assignee: Institute of Semiconductors of CAS
Priority date: 2012-06-06
Filing date: 2012-06-06
Publication date: 2012-09-19

Abstract

The invention discloses a method for extending light emitting diodes (LED) on low-dislocation gallium nitride (GaN) nanometer columns. The method comprises the following steps of: 1) corroding a GaN film on a sapphire substrate by using alkali liquor or mixed acid to form hexagonal micro pits; 2) continuously etching the hexagonal micro pits by using an inductively coupled plasma (ICP) method to form the GaN nanometer columns around the hexagonal micro pits; and 3) extending a GaN LED layer on the GaN nanometer columns by using a metal organic chemical vapor deposition (MOCVD) method to form air columns between the GaN LED layer and the sapphire substrate, and finishing preparation. By adoption of the method, the dislocation density of a GaN extension layer can be effectively reduced, and the crystal quality and uniformity of an extension material are improved.

Description

The method of extension LED on low dislocation GaN nano-pillar

Technical field

The invention belongs to the semi-conducting material preparation field, particularly a kind of in the method for hanging down extension LED on the dislocation GaN nano-pillar.

Background technology

GaN base LED has energy-saving and environmental protection, cold light source, color rendering index is high, response speed is fast, volume is little and outstanding advantage such as long working life, and its green solid light source as a new generation's illumination revolution demonstrates huge application potential.

Sapphire Substrate is that nitride carries out one of the most frequently used substrate of heteroepitaxial growth at present.Owing to have very macrolattice constant mismatch and thermal expansion coefficient difference between Sapphire Substrate and the nitride epitaxial layer; Therefore there are very big residual stress and many crystal defects in the nitride epitaxial layer; Influence the crystal mass of material, limited the further raising of device photoelectric performance.

The present invention forms the local GaN nano-pillar of low-dislocation-density through existing GaN epitaxial loayer is handled, and extension GaN material on this nano-pillar structure can effectively reduce the dislocation density of extension GaN layer, improves the crystal mass and the uniformity of epitaxial material.

Summary of the invention

For effectively reducing the dislocation density of GaN epitaxial loayer, improve the crystal mass and the uniformity of epitaxial material, the objective of the invention is to propose a kind of in the method for hanging down extension LED on the dislocation GaN nano-pillar.

It is a kind of in the method for hanging down extension LED on the dislocation GaN nano-pillar that the present invention provides, and comprises the steps:

1) with the GaN mould on alkali lye or the nitration mixture corrosion Sapphire Substrate to form the little hole of hexagonal;

2) method of employing ICP continues the little hole of etching hexagonal, forms the GaN nano-pillar on every side in the little hole of hexagonal;

3) method of employing MOCVD, extension GaN LED layer makes between GaN layer and the Sapphire Substrate and forms air column on the GaN nano-pillar, accomplishes preparation.

Wherein the thickness of GaN film is 2um.

Wherein alkali lye is KOH solution, and corrosion temperature is 80 ℃, and etching time is 1-2min, perhaps uses volume ratio to be H ₂SO ₄: H ₃PO ₄=3: 1 mixed acid liquid, the temperature of this mixed acid liquid are 260 ℃, and etching time is 4-8min.

Wherein use the method etching of ICP, make on the GaN template the little hole of hexagonal continue to be etched away, etching depth is less than the thickness of GaN mould, and its mechanism is high dislocation zone etch rate obviously greater than low dislocation zone, formation GaN nano-pillar.

Wherein the ICP etching gas is Cl ₂, build-up of luminance power 450w, etching power 75w, etch period are 150-250s, and 0.8-1.2um is continued to etch away in 20 zones, the little hole of hexagonal.

Description of drawings

For making the auditor can further understand structure of the present invention, characteristic and purpose thereof, below in conjunction with the detailed description of accompanying drawing and preferred embodiment as after, wherein:

Fig. 1 is a 2umGaN template of the present invention, and wherein 10 is Sapphire Substrate, and 11 is the GaN film;

Fig. 2 is the little hole after the 2um GaN template corrosion of the present invention, and wherein 10 is Sapphire Substrate, and 11 is the GaN film, and 20 is the little hole of GaN hexagonal;

Fig. 3 forms the hexagonal nano-pillar for the surface of the present invention's GaN template after excessive erosion and etching, and wherein 10 is Sapphire Substrate, and 11 is the GaN film, and 30 is nano-pillar;

Fig. 4 is the present invention extension GaN on the GaN template of handling, and wherein 10 is Sapphire Substrate, and 40 is the GaN of new extension, and 41 is air column;

Embodiment

See also Fig. 1-Fig. 4, it is a kind of in the method for hanging down extension LED on the dislocation GaN nano-pillar that the present invention provides, and comprises the steps:

Step 1: with the GaN mould 11 on alkali lye or the nitration mixture corrosion Sapphire Substrate 10 to form the little hole 20 of hexagonal (among Fig. 1, Fig. 2); The thickness of this GaN film 11 is 2um, and said alkali lye is KOH solution, and corrosion temperature is 80 ℃; Etching time is 1-2min, perhaps uses volume ratio to be H ₂SO ₄: H ₃PO ₄=3: 1 mixed acid liquid, the temperature of this mixed acid liquid are 260 ℃, and etching time is 4-8min, form the little hole 20 of hexagonal;

Step 2: adopt the method for ICP, continue the little hole 20 of etching hexagonal, etching gas is a Cl base gas; Build-up of luminance power 450w; Etching power 75w, etch period are 150-250s, and 0.8-1.2um is continued to etch away in 20 zones, the little hole of hexagonal; The little hole of hexagonal 20 degree of depth are increased, around the little hole 20 of hexagonal, form GaN nano-pillar 30 (among Fig. 3);

Step 3: the method that adopts MOCVD; Extension GaN LED layer 40 (among Fig. 4) on GaN nano-pillar 30; This extension GaN LED is horizontal extensions during layer 40; So the GaN LED layer 40 of extension can not fall into the gap between each GaN nano-pillar 30, make to form air column 41 between GaN layer 40 and the Sapphire Substrate 10, and then carry out other technology of extension LED.

This method can be used for photoelectric devices such as GaN base LED, LD, HEMT.Also can be used for III/V, other semiconductor device epitaxy technology of II/VI.

The above; Be merely the embodiment among the present invention, but protection scope of the present invention is not limited thereto, anyly is familiar with this technological people in the technical scope that the present invention disclosed; The conversion that can expect easily or replacement all should be encompassed in of the present invention comprising within the scope.Therefore, protection scope of the present invention should be as the criterion with the protection range of claims.

Claims

1. the method for an extension LED on low dislocation GaN nano-pillar comprises the steps:

2. according to claim 1 in the method for hanging down extension LED on the dislocation GaN nano-pillar, wherein the thickness of GaN film is 2um.

3. according to claim 1 wherein alkali lye is KOH solution in the method for hanging down extension LED on the dislocation GaN nano-pillar, and corrosion temperature is 80 ℃, and etching time is 1-2min, perhaps uses volume ratio to be H ₂SO ₄: H ₃PO ₄=3: 1 mixed acid liquid, the temperature of this mixed acid liquid are 260 ℃, and etching time is 4-8min.

4. according to claim 1 in the method for hanging down extension LED on the dislocation GaN nano-pillar; Wherein use the method etching of ICP; Make on the GaN template the little hole of hexagonal continue to be etched away; Etching depth is less than the thickness of GaN mould, and its mechanism is that high dislocation zone etch rate obviously greater than low dislocation zone, forms the GaN nano-pillar.

5. according to claim 4 in the method for hanging down extension LED on the dislocation GaN nano-pillar, wherein the ICP etching gas is Cl ₂, build-up of luminance power 450w, etching power 75w, etch period are 150-250s, and 0.8-1.2um is continued to etch away in 20 zones, the little hole of hexagonal.