# US 10,309,037 B2 · Method for producing III-N templates and the reprocessing thereof and III-N template

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- Number: US 10,309,037 B2
- Document ID: US10309037B2
- Status: Granted
- Kind: B2
- Application number: 14/386,845
- Filed: 2013-03-21
- Published: 2015-02-19
- Granted: 2019-06-04
- Earliest claimed: 2012-03-21
- Assignees: Freiberger Compound Materials GmbH
- Applicants: Freiberger Compound Materials GmbH
- Inventors: Frank Lipski; Ferdinand Scholz; Martin Klein; Frank Habel
- Web page: https://patentgrep.com/patent/US10309037B2

## CPC

- C30B 25/16: Controlling or regulating (controlling or regulating in general G05)
- C30B 25/04: Pattern deposit, e.g. by using masks
- C30B 25/10: Heating of the reaction chamber or the substrate
- C30B 25/18: characterised by the substrate
- C30B 29/40: AIIIBV compounds {wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi}
- C30B 29/403: {AIII-nitrides}
- C30B 29/406: {Gallium nitride}
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/2921: {being crystalline insulating materials}
- H10P 14/32: {characterised by intermediate layers between substrates and deposited layers}
- H10P 14/3216: {Nitrides}
- H10P 14/3238: {being insulating materials}
- H10P 14/3416: {Nitrides}
- Y10T 428/24851: Intermediate layer is discontinuous or differential
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention relates to the production of III-N templates and also the production of III-N single crystals, III signifying at least one element of the third main group of the periodic table, selected from the group of Al, Ga and In. By adjusting specific parameters during crystal growth, III-N templates can be obtained that bestow properties on the crystal layer that has grown on the foreign substrate which enable flawless III-N single crystals to be obtained in the form of templates or even with large III-N layer thickness.

## Claims

### Claim 1

A process for preparing a template for producing a III-N crystal, the template comprising a substrate and at least one III-N crystal layer, wherein the process comprises,
a) selecting at least one group III element from the group consisting of Al, Ga and In;
b) forming a non-continuous III-N nucleation layer comprising the at least one selected group III element, on a substrate comprising sapphire, wherein the non-continuous III-N nucleation layer comprises non-coalesced III-N crystallites;
c) depositing a mask material that inhibits III-N growth as an interlayer on the III-N nucleation layer, wherein the interlayer is formed as a non-continuous layer on the III-N nucleation layer; and
d) growing a crystalline III-N material comprising the at least one selected group III element on the mask material,
wherein the curvature Ks of the growth surface of the crystalline III-N material at a first, relatively earlier time point is greater than the curvature Ke at a second, relatively later time point; and
the distance between the mask material and the substrate is at most 300 nm.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the curvature difference between the first and second time points (Ks−Ke) is at least 5 km−1.

### Claim 3 (depends on 1)

The process according to claim 1, wherein the template is further used for producing epitaxially grown III-N bulk crystal, wherein the III-N bulk crystal comprises one or more crystals selected from the group consisting of GaN, AlN, AlGaN, InN, InGaN, AlInN and AlInGaN.

### Claim 4 (depends on 1)

A process for producing III-N single crystal, wherein the process comprises:
aa) preparing a template comprising a III-N crystal layer in accordance with claim 1;
bb) selecting at least one group III element from the group consisting of Al, Ga and In; and
cc) epitaxially growing a crystalline III-N material comprising the at least one selected group III element on the template, wherein the template is not or essentially not bowed or is negatively bowed within a range of a growth temperature.

### Claim 5 (depends on 4)

The process according to claim 4, characterized in that when, for the template, the substrate comprises sapphire with a thickness (dsapphire) of approximately 430 μm (i.e. ±20 μm) and the III-N crystal layer comprises GaN with a thickness (dGaN) of approximately 7 μm (i.e. ±0.5 μm) is used or set, a curvature of the template (KT) at the growth surface of the crystalline III-N material:
(i) is in the range from 0 to −150 km−1 at the growth temperature and
(ii) is in the range of <−200 km−1 at room temperature;
wherein the curvature value KT depends on respective layer thicknesses (dsapphire/dGaN) analogous to the Stoney equation in the following range:
KT(dGaN;dsapphire)=KT(7μm,430μm)×(430 μm/dsapphire)2×(dGaN/7 μm).

### Claim 6 (depends on 4)

The process according to claim 4, further comprising separating the crystalline III-N material from the substrate.

### Claim 7 (depends on 1)

The process according to claim 1, wherein the mask material is deposited in situ during the production of the template on the region above the substrate and the growth of the crystalline III-N material is continued in a same reactor.

### Claim 8 (depends on 1)

The process according to claim 1, wherein a compressive stress is created in the crystalline III-N material.

### Claim 9 (depends on 1)

The process according to claim 1, wherein the substrate consists of sapphire.

### Claim 10 (depends on 1)

The process according to claim 1, wherein the curvature is additionally changed in at least one growth phase by lowering the growth temperature compared to that of a preceding deposition stage of III-N material of the template.

### Claim 11 (depends on 1)

The process according to claim 1, wherein the mask material is selected from the group consisting of Si3N4, TiN, Al2O3, SiO2, WSi, and WSiN.

### Claim 12 (depends on 1)

The process according to claim 1, wherein the distance between the mask material and the substrate is at most 50 nm.

### Claim 13 (depends on 1)

The method according to claim 1, wherein the III-N crystallites exhibit sizes from 1 nm to 40 nm with irregular forms and are arranged in a disorderly manner on the substrate.

### Claim 14 (depends on 1)

The method according to claim 1, wherein the mask material is deposited at a thickness of below 5 nm.

### Claim 15 (depends on 1)

The method according to claim 1, wherein the mask material is deposited at a thickness of below 1 nm.

### Claim 16 (depends on 1)

The method according to claim 1, wherein the mask material is deposited at a thickness 0.3 nm or less.

### Claim 17

A process for preparing a template for producing a III-N crystal, the template comprising a substrate and at least one III-N crystal layer, wherein the process comprises,
a) selecting at least one group III element from the group consisting of Al, Ga and In;
b) forming a III-N layer comprising the at least one selected group III element, on a substrate comprising sapphire;
c) depositing a mask material that inhibits III-N growth as an interlayer on the III-N layer, wherein the interlayer is a discontinuous layer that, as viewed along a face surface of the template, the interlayer comprises nanometer-scale islands of mask material and microscopic and/or nanometer scale gaps lacking mask material; and
d) growing a crystalline III-N material comprising the at least one selected group III element on the mask material, wherein the mask material,
wherein the curvature Ks of the growth surface of the crystalline III-N material at a first, relatively earlier time point is greater than the curvature Ke at a second, relatively later time point; and
the distance between the mask material and the substrate is at most 300 nm.