Compound semiconductor substrate production method
View Patent ↗A method of making a compound semiconductor substrate includes providing a GaN compound semiconductor single crystal ingot, and cutting the ingot with a cutter to form a GaN single crystal substrate. The cutting is performed while controlling a temperature in a contact portion between the ingot and the cutter to be not more than 160° C. such that a cut surface of the GaN single crystal substrate has an arithmetical mean waviness (Wa) not more than 9 μm.
1. A method of making a compound semiconductor substrate, said method comprising:
providing a GaN compound semiconductor single crystal ingot; and
cutting the ingot with a cutter to form a GaN single crystal substrate,
wherein the cutting is performed while controlling a temperature in a contact portion between the ingot and the cutter to be not more than 160° C., and
wherein a cut surface of said GaN single crystal substrate has an arithmetical mean waviness (Wa) not more than 9 μm.
2. A method of making a compound semiconductor substrate, said method comprising:
providing an AlN compound semiconductor single crystal ingot; and
cutting the ingot with a cutter to form an AlN single crystal substrate,
wherein the cutting is performed while controlling a temperature in a contact portion between the ingot and the cutter to be not more than 200° C., and
wherein a cut surface of said AlN single crystal substrate has an arithmetical mean waviness (Wa) not more than 9 μm.
3. A method of making a compound semiconductor substrate, said method comprising:
providing a SiC compound semiconductor single crystal ingot; and
cutting the ingot with a cutter to form a SiC single crystal substrate,
wherein the cutting is performed while controlling a temperature in a contact portion between the ingot and the cutter to be not more than 240° C., and
wherein a cut surface of said SiC single crystal substrate has an arithmetical mean waviness (Wa) not more than 18 μm.
4. The method according to claim 1 , wherein said controlling the temperature is performed by blasting a coolant at the contact portion.
5. The method according to claim 4 , further comprising:
setting a temperature of the coolant such that the temperature in the contact portion be not more than 160° C.
6. The method according to claim 1 , wherein the temperature in the contact portion between the ingot and the cutter is not more than 140° C.
7. The method according to claim 6 , wherein the arithmetical mean waviness of the cut surface of said GaN single crystal substrate is less than 6 μm.
8. The method according to claim 1 , wherein the temperature in the contact portion between the ingot and the cutter is not less than 100° C.
9. The method according to claim 3 , wherein said controlling the temperature is performed by blasting a coolant at the contact portion.
10. The method according to claim 9 , further comprising:
setting a temperature of the coolant such that the temperature in the contact portion be not more than 160° C.
11. The method according to claim 3 , wherein the temperature in the contact portion between the ingot and the cutter is not more than 200° C.
12. The method according to claim 11 , wherein the arithmetical mean waviness of the cut surface of said SiC single crystal substrate is saturated at less than 12 μm.
13. The method according to claim 3 , wherein the temperature in the contact portion between the ingot and the cutter of not less than 150° C. results in the arithmetical mean waviness of the cut surface of said SiC single crystal substrate of less than 12 μm.