Single crystal silicon-carbide substrate and polishing solution
A process of manufacturing a single-crystal silicon-carbide substrate, includes contacting a surface of a single-crystal silicon-carbide plate with a surface of a polishing pad; and moving the surface of the single-crystal silicon-carbide plate relative to the surface of the polishing pad while supplying a polishing solution to the surface the polishing pad, to polish the surface of the single-crystal silicon-carbide plate. The polishing pad comprises a non-woven fabric or a porous resin. The polishing solution comprises an oxidizing agent which comprises a transition metal having oxidation-reduction potential of 0.5 V or more. Neither the polishing pad nor the polishing solution comprises an abrasive.
1. A process of manufacturing a single-crystal silicon-carbide substrate, the process comprising:
contacting a surface of a single-crystal silicon-carbide plate with a surface of a polishing pad; and
moving the surface of the single-crystal silicon-carbide plate relative to the surface of the polishing pad while supplying a polishing solution to the surface the polishing pad, to polish the surface of the single-crystal silicon-carbide plate,
wherein the polishing pad comprises a non-woven fabric or a porous resin,
wherein the polishing solution comprises an oxidizing agent which comprises a transition metal having oxidation-reduction potential of 0.5 V or more, and
wherein neither the polishing pad nor the polishing solution comprises an abrasive.
2. The process according to claim 1 , further comprising holding the single-crystal silicon-carbide plate with a carrier, wherein the surface of the single-crystal silicon-carbide plate is moved relative to the surface of the polishing pad by moving the carrier relative to the polishing pad.
3. The process according to claim 1 , wherein a pH of the polishing solution is 11 or less.
4. The process according to claim 1 , wherein a pH of the polishing solution is 5 or less.
5. The process according to claim 1 , wherein a pH of the polishing solution is 3 or less.
6. The process according to claim 1 , wherein the oxidizing agent comprises a permanganate ion.
7. The process according to claim 1 , wherein the oxidizing agent comprises potassium permanganate or sodium permanganate.
8. The process according to claim 6 , wherein an amount of the permanganate ion in the polishing solution is 0.05 mass % or more and 5 mass % or less.
9. The process according to claim 6 , wherein an amount of the permanganate ion in the polishing solution is 0.1 mass % or more and 4 mass % or less.
10. The process according to claim 6 , wherein an amount of the permanganate ion in the polishing solution is 0.2 mass % or more and 3.5 mass % or less.
11. The process according to claim 1 , wherein the single-crystal silicon-carbide substrate comprises a principal surface having an atomic step-and-terrace structure, the atomic step-and-terrace structure comprising atomic steps and terraces derived from a crystal structure, wherein the atomic step-and-terrace structure has a proportion of an average line roughness of a front edge portion of the atomic step to a height of the atomic step being 20% or less.
12. The process according to claim 11 , wherein the principal surface is a surface on which a crystal is to be epitaxially grown to form a silicon-carbide semiconductor layer or a gallium-nitride semiconductor layer.
13. The process according to claim 11 , wherein a width of the terrace is substantially the same in each terrace.
14. The process according to claim 11 , wherein the front edge portion of the atomic step is a straight line having the average line roughness.
15. The process according to claim 2 , wherein a pH of the polishing solution is 3 or less.
16. The process according to claim 15 , wherein the oxidizing agent comprises a permanganate ion.
17. The process according to claim 16 , wherein an amount of the permanganate ion in the polishing solution is 0.1 mass % or more and 4 mass % or less.
18. The process according to claim 16 , wherein an amount of the permanganate ion in the polishing solution is 0.2 mass % or more and 3.5 mass % or less.
19. The process according to claim 17 , wherein the single-crystal silicon-carbide substrate comprises a principal surface having an atomic step-and-terrace structure, the atomic step-and-terrace structure comprising atomic steps and terraces derived from a crystal structure, wherein the atomic step-and-terrace structure has a proportion of an average line roughness of a front edge portion of the atomic step to a height of the atomic step being 20% or less.
20. The process according to claim 18 , wherein the single-crystal silicon-carbide substrate comprises a principal surface having an atomic step-and-terrace structure, the atomic step-and-terrace structure comprising atomic steps and terraces derived from a crystal structure, wherein the atomic step-and-terrace structure has a proportion of an average line roughness of a front edge portion of the atomic step to a height of the atomic step being 20% or less.