Nitride semiconductor substrate and method of making same
A method of making a nitride semiconductor substrate having the steps of providing a free-standing substrate that is of a nitride semiconductor and has one of a penetrating pit and a penetrating crack that penetrate from a top surface to a back surface of the free-standing substrate, attaching a metal to the penetrating pit or the penetrating crack, the metal being adapted to be nitrided, and nitriding the metal to form a nitride that seals the penetrating pit or the penetrating crack. A nitride semiconductor substrate has a free-standing substrate that is formed of a nitride semiconductor and has one of a penetrating pit and a penetrating crack that penetrate from a top surface to a back surface of the free-standing substrate, and a metal nitride that seals the penetrating pit or the penetrating crack. The metal nitride is formed of GaN, InN and AlN.
1. A method of making a nitride semiconductor substrate, comprising:
providing a free-standing substrate that comprises a nitride semiconductor and one of a penetrating pit and a penetrating crack that penetrate from a top surface to a back surface of the free-standing substrate;
attaching a metal to the penetrating pit or the penetrating crack, the metal being adapted to be nitrided; and
nitriding the metal to form a nitride that seals the penetrating pit or the penetrating crack.
2. The method according to claim 1 , wherein:
the metal comprises one of gallium, indium and aluminum.
3. The method according to claim 1 , wherein:
the nitriding of the metal is conducted by heating the free-standing substrate at temperature in a range of 300° C. to 1200° C. in an atmosphere comprising ammonia (NH 3 ) gas.
4. The method according to claim 2 , wherein:
the nitriding of the metal is conducted by heating the free-standing substrate at temperature in a range of 300° C. to 1200° C. in an atmosphere comprising ammonia (NH 3 ) gas.
5. The method according to claim 1 , wherein:
the nitriding of the metal is conducted in an atmosphere comprising an ammonia (NH 3 ) gas plasma or a plasma and ammonia (NH 3 ) gas.
6. The method according to claim 2 , wherein:
the nitriding of the metal is conducted in an atmosphere comprising an ammonia gas (NH 3 ) plasma or a plasma and ammonia (NH 3 ) gas.