CN101086083B

CN101086083B - Method for preparing group III nitride substrate

Info

Publication number: CN101086083B
Application number: CN2007100235558A
Authority: CN
Inventors: 徐科; 杨辉; 王建峰; ***
Original assignee: Suzhou Institute of Nano Tech and Nano Bionics of CAS
Current assignee: SUZHOU NANOWIN SCIENCE AND TECHNOLOGY Co Ltd
Priority date: 2007-06-08
Filing date: 2007-06-08
Publication date: 2011-05-11
Anticipated expiration: 2027-06-08
Also published as: CN101086083A

Abstract

The invention discloses a method for preparing nitride substrate. It is characterized in that it comprises following steps: (1) growing nitride film on aquamarine substrate, the film thickness is between 50 nanometer and 50 micrometre; (2) irradiating with high- energy laser from back of substrate, to make incomplete separation of nitrite from aquamarine substrate, the separation area is 10- 99% of the total area; the photoelectron energy of said high- energy laser is between the bandwidth of nitrite and aquamarine substrate; (3) growing nitrite film continuously by taking halide gas epitaxial growth method until getting required thickness, and getting said nitride substrate. The invention can gurantte the film planeness, automatic complete separtion of film from aquamarine substrate at original position, and gets self- support epitaxial film with required thickness.

Description

A kind of method for preparing the III-nitride substrate

Technical field

The present invention relates to the method that a kind of method with vapor phase epitaxial growth prepares the III-nitride substrate, be used to obtain large-area III-nitride substrate, and the III group-III nitride thick film substrate of any component and self-supporting mono-crystal substrate.

Background technology

For the application of III group nitride material, the researchdevelopment through more than ten years makes a breakthrough at aspects such as blue light-emitting diode, short wavelength laser, ultraviolet detector and LED white-light illuminating light sources in succession.At present the further raising of device performance and some new devices designs and produces the restriction that has been subjected to extension film quality in substrate material and the device architecture.Reported that a lot of methods improve the quality of epitaxial film, as epitaxial lateral overgrowth, many buffer layers technology etc.Obtain the high-quality GaN substrate is the target that people pursue always.The main method of growing GaN substrate has the direct reaction preparation and the halogenide vapor phase epitaxial growth method (HVPE) of autoclave nitrogen and gallium at present.Preceding a kind of method is difficult to obtain large-size crystals, and then a kind of method is the main flow of studying at present.

Halogenide vapor phase epitaxial growth method (HVPE) is to utilize HCl gas to carry out the method for vapour phase epitaxy, and its process forms metal halide for the gas HCl source metal of flowing through, and generates required product with another kind of gas reaction then.A typical example is the HVPE system that is used for the III group-III nitride, gas HCl flow through metal (Ga, Al, In), form metal halide (GaCI, AlCl, InCl), then with group V source NH ₃Reaction generates GaN, AlN, InN.Advantages such as the advantage of HVPE equipment is that speed of response is fast, can reach 250 μ m/hr, and production cost is low are widely used in material growth field.Because the nitride epitaxial film that obtains is used as substrate usually and uses, thereby is also referred to as nitride.

Among the above-mentioned preparation method, the nitride epitaxial film grows on the Sapphire Substrate usually.Wherein the subject matter of Cun Zaiing is because the used substrate material and the lattice and the coefficient of thermal expansion mismatch of epitaxial film, will stress when epitaxial film reaches tens microns and ftracture, can not obtain the substrate wafer of large size self-supporting, particularly the problem of epitaxial film (as GaN) being peeled off from Sapphire Substrate how never is well solved.The method of the method for laser lift-off, laterally overgrown mask etc. implements and is inconvenient, and yield rate is low.

Summary of the invention

The object of the invention provides a kind of method for preparing the III-nitride substrate, to solve influences such as cracking that stress causes, distortion, obtains smooth, the nitride of thickness greatly.

For achieving the above object, the technical solution used in the present invention is: a kind of method for preparing the III-nitride substrate comprises the following steps:

(1) growth III-nitride film on Sapphire Substrate, film thickness is between 50 nanometers to 50 micron;

(2) with high energy laser from substrate back incident irradiation, III-nitride film and Sapphire Substrate are not exclusively peeled off, separating area be the total area 10% to 99% between, the photon energy of described high energy laser is between III-nitride and sapphire bandwidth;

(3) adopt halogenide vapor phase epitaxial growth method to proceed the III-nitride film growth to III-nitride after handling and Sapphire Substrate,, promptly obtain required III-nitride substrate to desired thickness.

In the technique scheme, in the described step (1), both can adopt the chemical vapor deposition method behind growth one deck III-nitride film on the Sapphire Substrate, promptly enter step (2), also can be after adopting chemical vapor deposition method growing film, then adopt halogenide vapor phase epitaxial growth method that film thickness is increased between 10 microns to 50 microns, enter step (2) again, i.e. the method for step (1) employing is a prior art.In the described step (2), the high energy laser that adopts does not absorb when penetrating Sapphire Substrate, and the energy of laser to be the III-nitride film absorb fully, decompose at the local melting of realization at the interface of substrate and film, cause not exclusively peeling off between film and Sapphire Substrate.

In the technique scheme, in the described step (2), the isolating position of irradiation constitutes mottled array, and the size of described each spot is between 0.1 millimeter to 5 millimeters; The product that obtains in the described step (3) is and the locally-attached III-nitride substrate of Sapphire Substrate.

Perhaps, in the described step (2), the isolating position of irradiation is strip and distributes, and width of fringe is between 0.1 millimeter to 5 millimeters; In the described step (3),, on the Sapphire Substrate of weak connection, separate automatically, obtain the epitaxial film of self-supporting in that III-nitride is thin when growing to desired thickness.

Wherein, described strip pattern is selected from a kind of in vertical bar line, concentric(al) circles, concentration ellipsis, spiral-line or the Polygons.

The present invention has proposed the method that a kind of in-situ accomplishes III-nitride thick film cuts separation from Sapphire Substrate, and can be used to prepare the III group-III nitride substrate of growth temperature at all components more than 600 ℃ by technique scheme.

With the gan is example, and present method forms weak the connection between GaN rete and Sapphire Substrate, by the accumulation of growth stress or in the lifting temperature course STRESS VARIATION realize separating of GaN and substrate.

At first utilize at the GaN film about growth 50 nanometers to 50 micron on sapphire (sapphire) substrate, utilize high energy laser from substrate back incident irradiation, GaN film and Sapphire Substrate are not exclusively peeled off, promptly be part and separate, separating area reaches between 10% to 99%.Concrete grammar is to select the high energy laser (for example KrF excimer laser) of photon energy between GaN and sapphire bandwidth, locality ground heating sapphire/GaN GaN at the interface, make GaN at the interface experience high temperature and exploded, realize the weak stress-strain that is connected, discharges in the GaN rete of GaN epitaxial film and Sapphire Substrate.Then GaN/ sapphire samples continued growth in HVPE of handling through laser irradiation, when GaN grows into certain thickness, because stress, the GaN epitaxial film will separate from the substrate of weak connection automatically, thereby realizes the epitaxy of GaN self-supporting film.

Because the technique scheme utilization, the present invention compared with prior art has following advantage:

1. the present invention utilizes the partial radiation of high energy laser, realize that film and the weak of substrate are connected, solved the stress problem between epitaxial film and the substrate, film appearance cracking or flexural deformation in preparation process have been avoided, the novel method of utilizing halogenide vapor phase epitaxial growth method to realize the III-nitride substrate preparation is provided, has can be used for preparing large-area III group-III nitride substrate more than 1 inch;

2. when the present invention adopts latticed or mottled discontinuous figure to realize not exclusively peeling off, can effectively discharge stress, guarantee to obtain the planeness of film;

3. when the present invention adopts the striated figure to realize not exclusively peeling off, can pass through stress accumulation, realize that when film reaches desired thickness film separates automatically with the original position of Sapphire Substrate, thereby obtain the self-supporting epitaxial film of desired thickness.

Description of drawings

Accompanying drawing 1 is the synoptic diagram of growing of GaN among the embodiment one in HVPE;

Accompanying drawing 2 is a synoptic diagram of using laser apparatus irradiation among the embodiment one;

Accompanying drawing 3 is the pattern synoptic diagram of film and the mottled disengaging of substrate among the embodiment one;

Accompanying drawing 4 is the pattern synoptic diagram that film and substrate striated break away among the embodiment three.

Wherein: 1, substrate; 2, film; 3, laser.

Embodiment

Below in conjunction with drawings and Examples the present invention is further described:

Embodiment one: to shown in the accompanying drawing 3, thickness is greater than 10 microns the growth of GaN on Sapphire Substrate referring to accompanying drawing 1.

As shown in Figure 1, at first with grow on Sapphire Substrate 1 GaN of one deck 2 micron thickness of HVPE, growth pattern also can adopt MOCVD or MBE method.Sample is taken out in cooling then, adopt high energy laser 3 from substrate back incident as Fig. 2, go out as shown in Figure 3 figure by scan mode at interface scanning, its mode is, the long laser apparatus of radiothermy is from substrate back irradiation GaN and substrate interface, the wavelength region of laser apparatus be photon energy between sapphire and thin-film material bandwidth, when the laser penetration substrate, do not absorb like this, and the energy of laser to be film 2 absorb fully, realize that at substrate and film interface local melting decomposes.In the accompanying drawing 3, the spot position is the position that local melting breaks away from, and its area accounts for 10%～99% of the total area.Because substrate and film are middle with the gallium connection in partial disengagement, will regrow through the sample of handling so then, just can solve the buckling problem of thick film GaN substrate wafer.Because stress is discharged by the part, do not needing under the complicated lateral growth process condition, more than the GaN film growth to 100 micron.Adopt opticmicroscope to amplify 50 times and observes, the GaN/sapphire direct growth of not passing through laser treatment is to 100 micron thickness, GaN film discrepitate; And adopting GaN film growth to 100 micron after the present embodiment method is handled, the GaN rete does not have crackle in the photo.

Embodiment two, thickness are greater than 10 microns the growth of AIGaN substrate on Sapphire Substrate.

At first with on Sapphire Substrate, the grow GaN of one deck 1 micron thickness of MOCVD method.Sample is taken out in cooling then, adopts high energy laser from substrate back incident as Fig. 2, goes out as shown in Figure 3 figure by scan mode at interface scanning.In HVPE sample is heated to 1100 ℃ of direct growth AlGaN then, wherein in the metal ingredient, the weight ratio of Al can be any component of from 0% to 100%.According to the component of Al and the thickness of needs growth, aforesaid method can repeatedly use.

The growth of embodiment three, GaN self-supporting homo-substrate.

At first with grow on the Sapphire Substrate GaN of one deck 2 micron thickness of HVPE, growth pattern also can or be used the MBE method in MOCVD.Sample is taken out in cooling then, adopts high energy laser from substrate back incident as Fig. 2, goes out the striated figure by scan mode at interface scanning.Shown in the accompanying drawing 4 that a kind of GaN film of can realizing is in position in the process of growth and the laser scanning figure that cuts separation of Sapphire Substrate.With more than the GaN film growth to 100 micron just under the effect of growth stress, realized separating fully of GaN film and substrate.Separate the back continuous growth, just can access GaN self-supporting homo-substrate.

Claims

1. a method for preparing the III-nitride substrate comprises the following steps:

(1) go up growth III-nitride film (2) in Sapphire Substrate (1), film thickness is between 50 nanometers to 50 micron;

(2) use high energy laser (3) from substrate back incident irradiation, III-nitride film and Sapphire Substrate are not exclusively peeled off, separating area be the total area 10% to 99% between, the photon energy of described high energy laser is between III-nitride and sapphire bandwidth;

(3) adopt halogenide vapor phase epitaxial growth method to proceed the III-nitride film growth to III-nitride after handling and Sapphire Substrate,, promptly obtain required III-nitride substrate to desired thickness;

It is characterized in that: in the described step (2), the isolating position of irradiation constitutes mottled array, and the size of described each spot is between 0.1 millimeter to 5 millimeters; The product that obtains in the described step (3) is and the locally-attached III-nitride substrate of Sapphire Substrate.