Diamond substrate and diamond substrate manufacturing method
A diamond substrate is formed of diamond single crystals by preparing a base substrate; forming plural pillar-shaped diamonds formed of diamond single crystals on one side of the base substrate; causing a diamond single crystal to grow from a tip of each pillar-shaped diamond and coalescing the diamond single crystals growing from the tips of the pillar-shaped diamonds to form a diamond substrate layer; separating the diamond substrate layer from the base substrate; and manufacturing a diamond substrate from the diamond substrate layer, a shape in an in-plane direction of the diamond substrate is a circular shape or a circular shape having an orientation flat plane formed therein and has a diameter of two inches or more.
1. A diamond substrate manufacturing method comprising:
preparing a base substrate;
forming a plurality of pillar-shaped diamonds formed of diamond single crystals on one side of the base substrate;
causing a diamond single crystal to grow from a tip of each pillar-shaped diamond and coalescing the diamond single crystals grown from the tips of the pillar-shaped diamonds to form a diamond substrate layer;
separating the diamond substrate layer from the base substrate; and
manufacturing a diamond substrate from the diamond substrate layer,
wherein a shape in an in-plane direction of the diamond substrate is a circular shape or a circular shape having an orientation flat plane formed therein and has a diameter of two inches or more.
2. The diamond substrate manufacturing method according to claim 1 , wherein the separating of the diamond substrate layer from the base substrate is performed by generating a stress in the pillar-shaped diamonds and destroying the pillar-shaped diamonds.
3. The diamond substrate manufacturing method according to claim 2 , wherein the stress is a stress generated due to a difference in lattice constant between the base substrate and the diamond substrate layer and/or a stress generated due to a difference in thermal expansion coefficient between the base substrate and the diamond substrate layer.
4. The diamond substrate manufacturing method according to claim 1 , wherein an aspect ratio of each pillar-shaped diamond is equal to or more than five.
5. The diamond substrate manufacturing method according to claim 1 , wherein a diameter and a pitch of the pillar-shaped diamonds are set to 10 p.m or less.
6. The diamond substrate manufacturing method according to claim 1 , wherein surface roughness Ra of the one side of the base substrate is equal to or less than 10 nm.
7. The diamond substrate manufacturing method according to claim 1 , wherein a height direction of the pillar-shaped diamonds is set to a direction perpendicular to (001) plane of diamond single crystals forming the pillar-shaped diamonds.
8. The diamond substrate manufacturing method according to claim 1 , wherein each pillar-shaped diamond has a cylindrical shape, and
a diameter of a central portion of each pillar-shaped diamond in the height direction is smaller than a diameter of a tip portion thereof.
9. The diamond substrate manufacturing method according to claim 1 , wherein the diameter ranges from two inches to eight inches.