CN1389904A

CN1389904A - Transverse epitaxial growth process of high-quality gallium nitride film

Info

Publication number: CN1389904A
Application number: CN 02113084
Authority: CN
Inventors: 张�荣; 修向前; 顾书林; 卢佃清; 毕朝霞; 沈波; 江若琏; 施毅; 朱顺明; 韩平; 胡立群; 郑有炓
Original assignee: Nanjing University
Current assignee: Nanjing University
Priority date: 2002-05-31
Filing date: 2002-05-31
Publication date: 2003-01-08
Anticipated expiration: 2022-05-31
Also published as: CN1174470C

Abstract

The invention relates to the method of growth of gallium nitride film in high quality by the technique of extension in the lateral direction. GaN crystal seed layer is grown by use of the MOCVD, MBE or other method. The SiO2, Si3N4W etc. films are deposited on the GaN crystal seed layer with sertain graph being etched by etching method. The direction of the parallel strip opening is along the direction of GaN [1100]. The width of the mask area is 2-20 microns. The width of the GaN window area is 0.2-20 microns. Then the MOCVD or HVPE method is accepted to grow GaN in epitaxial growth till the mask layer is overspreader by the GaN. Continuing growth obtains the gallium nitride film with low dislocation density. Since HVPE providing quick growth rare, to the HVPE thick film extension can obtain GaN film even lower dislocation density.

Description

The method of transversal epitaxial growth high-quality gallium nitride film

One, technical field

The present invention relates to the method and the technology of horizontal extension technology and bond organics gaseous phase extended (MOCVD), hydride gas-phase epitaxy thin film technique growing gallium nitride (GaN) films such as (HVPE), the method for the low dislocation density GaN film of especially growing.

Two, background technology

III-V group nitride material (claiming the GaN sill again) based on GaN and InGaN, AlGaN alloy material is the novel semiconductor material of extremely paying attention in the world in recent years, the direct band gap of its 1.9-6.2eV continuous variable, excellent physics, chemical stability, high saturated electron drift velocity, superior functions such as high disruptive field intensity and high heat conductance make it become the most preferably material of short wavelength's semiconductor photoelectronic device and high frequency, high pressure, the preparation of high temperature microelectronic component.

Because the restriction of the physical property of GaN own, the growth of GaN body monocrystalline has very big difficulty, as yet practicability not.Yet, carry out homoepitaxy with the GaN substrate and obtain III group-III nitride thin-film material and but demonstrated extremely superior performance, therefore with the low-dislocation-density substrate carry out GaN homoepitaxy be improve III nitride epitaxial layers quality than good method.Early stage people mainly adopt hydride gas-phase epitaxy (HVPE) method direct growth GaN on Sapphire Substrate, are separated again, obtain the GaN backing material.The outstanding shortcoming of this method is that dislocation density is very high in the GaN epitaxial loayer, generally reaches 10 ¹⁰Cm ^-2About.The key technology that reduces dislocation density at present is to adopt horizontal extension (Epitaxial-Lateral-Overgrown, method ELO).Dislocation density can reduce by 4～5 magnitudes.

GaN horizontal extension technology is meant that the deposit masking material is (as SiO on the GaN planar materials that has obtained ₂, Si ₃N ₄, W etc.) and carve specific graphical window, carry out the secondary epitaxy of GaN more thereon.Employing horizontal extension technology can reduce the dislocation density in the epitaxial loayer significantly, and improves epitaxial layer quality, reduces the involuntary doping electron concentration of epitaxial loayer, thereby reduces P type doping difficulty etc.

In the present invention, we adopt the horizontal extension method in conjunction with MOCVD, the HVPE film growth techniques low dislocation density GaN film of growing on Sapphire Substrate, and dislocation density is lower than 10 ⁶/ cm ²

Three, summary of the invention

The present invention seeks to: the horizontal extension method is in conjunction with MOCVD, the HVPE film growth techniques low dislocation density GaN film of growing on Sapphire Substrate.

Technical solution of the present invention:

At first use MOCVD, MBE or additive method growing GaN inculating crystal layer; On the GaN inculating crystal layer, deposit SiO ₂, Si ₃N ₄, film such as W, utilize photoetching method to etch certain figure (as strip, hexagon etc.); With MOCVD or the epitaxial growth of HVPE method, be paved with by GaN until mask layer then, continued growth obtains thick film.Zhi Bei GaN thin film dislocation density is lower like this (is lower than 10 ⁶/ cm ²), be of high quality.

Mechanism of the present invention and technical characterstic are:

In GaN horizontal extension technology, because selective epitaxy, only in the epitaxial growth of GaN window portion energy GaN ability, and SiO ₂Partly be difficult to nucleation Deng mask layer.When the GaN that goes out when extension in the GaN window region surpasses mask layer thickness, when grow with vertical direction, the generation cross growth.After acquiring a certain degree, cross growth just can be carried out the GaN epitaxial loayer of lid entirely.This growth is " accurate free " growth conditions because meet, and the direction of growth is perpendicular to the direction of climbing of former GaN dislocation, thereby very high quality is arranged, and dislocation density is lower more than direct growth.The HVPE growth rate is very fast, can reach youngster ten even hundreds of μ m/ hour.Because away from dislocation density is lower at the interface, thus on the horizontal extension film HVPE thick film extension, can obtain the lower GaN film of dislocation density.

Four, description of drawings

Fig. 1 is the GaN film sectional view of horizontal extension of the present invention and HVPE technology growth, and dislocation density is lower than 10 ⁶/ cm ²

Growth conditions: 1100 ℃, [NH ₃]: [HCl]=0.076: 0.0023.

Fig. 2 is the GaN film AFM surface topography map of horizontal extension of the present invention and HVPE technology growth.Among the figure, GaN

GaN in window region and the mask district combines.Growth conditions: 1100oC,

[NH ₃]∶[HCl]＝0.076∶0.0023。

Five, embodiment

The transversal epitaxial growth technology that the present invention adopts comprises following a few step:

1, adopts MOCVD, MBE or additive method growing GaN inculating crystal layer on Sapphire Substrate.

2, deposit SiO on the GaN inculating crystal layer ₂, Si ₃N ₄, film such as W makes mask layer, thickness is 100nm.

3, obtain certain figure with the photoetching method etch mask layer, the mask district is generally all greater than window region.Graphics shape

Mainly contain parallel long strip and orthohexagonal.For the parallel long strip, mask sector width 2-20 μ m, GaN

Window region width 0.2-20 μ m, the opening direction of parallel long strip is orientated along GaN [1 ī 00].Positive six

The opening of limit shape, [the 1 ī 00] orientation that makes GaN is perpendicular to orthohexagonal limit.

4, control V valency N atom and III valency Ga atomic ratio (33～83: 1), growth temperature (1030～1100 ℃),

The selection of window and mask regions is compared etc., under different conditions, and HVPE on above-mentioned figure GaN inculating crystal layer

Extension GaN thick film.On the figure inculating crystal layer, also can directly carry out horizontal extension and thick film life with MOCVD

Long, just the time is long more than HVPE.

5, in addition, above-mentioned steps 4 also can be carried out like this: elder generation's MOCVD growing GaN on figure GaN, when

After film covers with whole mask layer, adopt the HVPE growing technology acquisition thick film of growing fast again.

The GaN film that obtains of growth like this, dislocation density can be lower than 10 ⁶/ cm ²

Claims

1, the method for transversal epitaxial growth high-quality gallium nitride film is characterized in that with MOCVD, MBE or additive method growing GaN inculating crystal layer; On the GaN inculating crystal layer, deposit SiO ₂, Si ₃N ₄, film such as W, utilize photoetching method to etch certain figure, for the parallel long strip, mask sector width 2-20 μ m, GaN window region width 0.2-20 μ m, the opening direction of parallel long strip are orientated along GaN [1 ī 00]; For orthohexagonal opening, [1 ī 00] orientation of GaN with MOCVD or HVPE method epitaxial growth GaN, is paved with by GaN until mask layer then perpendicular to orthohexagonal limit, continued growth obtains the low-dislocation-density gallium nitride film.

2,, it is characterized in that V valency N atom and III valency Ga atomic ratio 33～83: 1 by the method for the described transversal epitaxial growth high-quality gallium nitride film of claim 1.