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

Patent metadata

Field	Value
Publication number	US-9752255-B2
Application number	US-201113159074-A
Country	US
Kind code	B2
Filing date	Jun 13, 2011
Priority date	Jun 28, 2010
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

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.

First claim

What is claimed is:

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 (SiO 2 ), or a laminated film formed of these films, the bonding layer having a thickness of 0.001 to 1000 μm.

2. The single-crystal diamond growth base material according to claim 1 , wherein the base substrate consists of any one of Al 2 O 3 , SiC, AlN, Si, Si 3 N 4 , diamond, and SiO 2 .

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. 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.

10. 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.

11. 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.

12. 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.

13. 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.

14. 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.

15. 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.

16. 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.

17. 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.

18. 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.

19. 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.

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 (SiO 2 ), 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.

21. The method for manufacturing a single-crystal diamond substrate according to claim 20 , wherein a substrate consisting of any one of Al 2 O 3 , SiC, AIN, Si, Si 3 N 4 , diamond, and SiO 2 is prepared as the base substrate to be prepared.

22. 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.

23. 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.

Assignees

• Noguchi Hitoshi
• Shirai Shozo
• Shinetsu Chemical Co

Inventors

• Noguchi Hitoshi
• Shirai Shozo

Classifications

• Y10T428/263

  Coating layer not in excess of 5 mils thick or equivalent · CPC title

• Y10T428/30

  Self-sustaining carbon mass or layer with impregnant or other layer · CPC title

• C30B29/04 Primary

  Diamond · CPC title

• C30B25/183

  being provided with a buffer layer, e.g. a lattice matching layer · CPC title

• Y10T428/266

  of base or substrate · CPC title