SiC single crystals with reduced dislocation density grown by step-wise periodic perturbation technique

摘要

In a crystal growth method, a seed crystal 8 and a source material 4 are provided in spaced relation inside of a growth crucible 6. Starting conditions for the growth of a crystal 14 in the growth crucible 6 are then established therein. The starting conditions include: a suitable gas inside the growth crucible 6, a suitable pressure of the gas inside the growth crucible 6, and a suitable temperature in the growth crucible 6 that causes the source material 4 to sublimate and be transported via a temperature gradient in the growth crucible 6 to the seed crystal 8 where the sublimated source material precipitates. During growth of the crystal 14 inside the growth crucible 6, at least one of the following growth conditions are intermittently changed inside the growth crucible 6 a plurality of times: the gas in the growth crucible 6, the pressure of the gas in the growth crucible 6, and the temperature in the growth crucible 6.

主权项

1. A SiC PVT crystal growth method comprising:
(a) providing a SiC seed crystal and SiC source material in spaced relation inside of a growth crucible; (b) establishing in the growth crucible starting conditions for PVT growth of a SiC crystal therein, said starting conditions comprising: (1) a suitable gas inside the growth crucible, (2) a suitable total pressure of the gas inside the growth crucible, and (3) a suitable temperature in the growth crucible that causes the SiC source material to sublimate and be transported via a temperature gradient in the growth crucible to the SiC seed crystal where the sublimated SiC source material precipitates to form the growing SiC crystal; and (c) intermittently changing at least one of the following growth conditions inside the growth crucible a plurality of times during growth of the SiC crystal; an amount of a dopant gas comprising the gas in the growth crucible, the total pressure of the gas in the growth crucible, and the temperature in the growth crucible, wherein each instance of intermittently changing at least one of the growth conditions includes changing said at least one growth condition from its starting growth condition and then returning the changed growth condition back to its starting growth condition after a period of time that is on the order of minutes or hours.