# US 9,752,255 B2 · Base material on which single-crystal diamond is grown comprised of a base substrate, bonded single-crystal MgO layer, and heteroepitaxial film, and method for manufacturing a single-crystal diamond substrate on the base material

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- Number: US 9,752,255 B2
- Document ID: US9752255B2
- Status: Granted
- Kind: B2
- Application number: 13/159,074
- Filed: 2011-06-13
- Published: 2011-12-29
- Granted: 2017-09-05
- Earliest claimed: 2010-06-28
- Assignees: Shin-Etsu Chemical Co., Ltd.
- Applicants: Hitoshi Noguchi; Shozo Shirai
- Inventors: Hitoshi Noguchi; Shozo Shirai
- Web page: https://patentgrep.com/patent/US9752255B2

## CPC

- C30B 29/04: Diamond
- C30B 25/183: {being provided with a buffer layer, e.g. a lattice matching layer}
- Y10T 428/263: Coating layer not in excess of 5 mils thick or equivalent
- Y10T 428/266: of base or substrate
- Y10T 428/30: Self-sustaining carbon mass or layer with impregnant or other layer
- 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
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A single-crystal diamond growth base material on which single-crystal diamond is grown having at least a base substrate of a material having a linear expansion coefficient smaller than that of MgO and not smaller than 0.5×10−6/K; a single-crystal MgO layer formed on a face of the base substrate where the single-crystal diamond is grown by a bonding method; and a film constituted of any one of an iridium film, a rhodium film, and a platinum film heteroepitaxially grown on the single-crystal MgO layer.

## Claims

### Claim 1

A single-crystal diamond growth base material on which single-crystal diamond is grown, comprising at least:
a base substrate consisting of a material having a linear expansion coefficient smaller than that of MgO and not smaller than 0.5×10−6/K;
a single-crystal MgO layer formed on a face of the base substrate where the single-crystal diamond is grown by bonding a single-crystal MgO substrate having a thickness of 200 to 1000 μm to the base substrate and thinning the single-crystal MgO substrate by mechanical polishing; and
a film constituted of any one of an iridium film, a rhodium film, and a platinum film heteroepitaxially grown on the single-crystal MgO layer;
wherein bonding the single-crystal MgO substrate to the base substrate is done through a bonding layer obtained by forming on a bonding interface a film of an element or compound selected from the group consisting of gold (Au), platinum (Pt), titanium (Ti), chromium (Cr), iridium (Ir), rhodium (Rh), silicon (Si), and silicon oxide (SiO2), or a laminated film formed of these films, the bonding layer having a thickness of 0.001 to 1000 μm.

### Claim 2 (depends on 1)

The single-crystal diamond growth base material according to claim 1, wherein the base substrate consists of any one of Al2O3, SiC, AlN, Si, Si3N4, diamond, and SiO2.

### Claim 3 (depends on 1)

The single-crystal diamond growth base material according to claim 1, wherein a thickness of the base substrate is 0.03 to 20.00 mm.

### Claim 4 (depends on 2)

The single-crystal diamond growth base material according to claim 2, wherein a thickness of the base substrate is 0.03 to 20.00 mm.

### Claim 5 (depends on 1)

The single-crystal diamond growth base material according to claim 1, wherein a thickness of the single-crystal MgO layer is 0.1 to 100 μm.

### Claim 6 (depends on 2)

The single-crystal diamond growth base material according to claim 2, wherein a thickness of the single-crystal MgO layer is 0.1 to 100 μm.

### Claim 7 (depends on 3)

The single-crystal diamond growth base material according to claim 3, wherein a thickness of the single-crystal MgO layer is 0.1 to 100 μm.

### Claim 8 (depends on 4)

The single-crystal diamond growth base material according to claim 4, wherein a thickness of the single-crystal MgO layer is 0.1 to 100 μm.

### Claim 9 (depends on 1)

The single-crystal diamond growth base material according to claim 1, wherein any one of the iridium film, the rhodium film, and the platinum film is heteroepitaxially grown on the single-crystal MgO layer by a sputtering method.

### Claim 10 (depends on 1)

The single-crystal diamond growth base material according to claim 1, wherein a thickness of any one of the iridium film, the rhodium film, and the platinum film is 5 Å to 100 μm.

### Claim 11 (depends on 2)

The single-crystal diamond growth base material according to claim 2, wherein a thickness of any one of the iridium film, the rhodium film, and the platinum film is 5 Å to 100 μm.

### Claim 12 (depends on 3)

The single-crystal diamond growth base material according to claim 3, wherein a thickness of any one of the iridium film, the rhodium film, and the platinum film is 5 Å to 100 μm.

### Claim 13 (depends on 4)

The single-crystal diamond growth base material according to claim 4, wherein a thickness of any one of the iridium film, the rhodium film, and the platinum film is 5 Å to 100 μm.

### Claim 14 (depends on 5)

The single-crystal diamond growth base material according to claim 5, wherein a thickness of any one of the iridium film, the rhodium film, and the platinum film is 5 Å to 100 μm.

### Claim 15 (depends on 6)

The single-crystal diamond growth base material according to claim 6, wherein a thickness of any one of the iridium film, the rhodium film, and the platinum film is 5 Å to 100 μm.

### Claim 16 (depends on 7)

The single-crystal diamond growth base material according to claim 7, wherein a thickness of any one of the iridium film, the rhodium film, and the platinum film is 5 Å to 100 μm.

### Claim 17 (depends on 8)

The single-crystal diamond growth base material according to claim 8, wherein a thickness of any one of the iridium film, the rhodium film, and the platinum film is 5 Å to 100 μm.

### Claim 18 (depends on 9)

The single-crystal diamond growth base material according to claim 9, wherein a thickness of any one of the iridium film, the rhodium film, and the platinum film is 5 Å to 100 μm.

### Claim 19 (depends on 1)

The single-crystal diamond growth base material according to claim 1, wherein a surface of any one of the iridium film, the rhodium film, and the platinum film is subjected to a bias treatment.

### Claim 20

A method for manufacturing a single-crystal diamond substrate, comprising at least:
a step of preparing a base substrate that consists of a material having a linear expansion coefficient smaller than that of MgO and not smaller than 0.5×10−6/K;
a step of bonding a single-crystal MgO substrate having a thickness of 200 to 1000 μm to the prepared base substrate through a bonding layer obtained by forming on a bonding interface a film of an element or compound selected from the group consisting of gold (Au), platinum (Pt), titanium (Ti), chromium (Cr), iridium (Ir), rhodium (Rh), silicon (Si), and silicon oxide (SiO2), or a laminated film formed of these films, the bonding layer having a thickness of 0.001 to 1000 μm, and thinning the single-crystal MgO substrate by mechanical polishing to obtain a single-crystal MgO layer;
a step of heteroepitaxially growing a film constituted of any one of an iridium film, a rhodium film, and a platinum film on the bonded single-crystal MgO layer;
a step of heteroepitaxially growing single-crystal diamond on the heteroepitaxially grown film; and
a step of separating the heteroepitaxially grown single-crystal diamond to obtain a single-crystal diamond substrate.

### Claim 21 (depends on 20)

The method for manufacturing a single-crystal diamond substrate according to claim 20, wherein a substrate consisting of any one of Al2O3, SiC, AIN, Si, Si3N4, diamond, and SiO2 is prepared as the base substrate to be prepared.

### Claim 22 (depends on 20)

The method for manufacturing a single-crystal diamond substrate according to claim 20, wherein a bias treatment is carried out with respect to a surface on which the single-crystal diamond is heteroepitaxially grown before the step of heteroepitaxially growing the single-crystal diamond.

### Claim 23 (depends on 20)

The method for manufacturing a single-crystal diamond substrate according to claim 20, wherein the single-crystal diamond is heteroepitaxially grown by a microwave CVD method or a direct-current plasma CVD method at the step of heteroepitaxially growing the single-crystal diamond.