Producing high quality bulk silicon carbide single crystal by managing thermal stresses at a seed interface

摘要

A method is disclosed for producing a high quality bulk single crystal of silicon carbide in a seeded growth system by reducing the separation between a silicon carbide seed crystal and a seed holder until the conductive heat transfer between the seed crystal and the seed holder dominates the radiative heat transfer between the seed crystal and the seed holder over substantially the entire seed crystal surface that is adjacent the seed holder.

主权项

1. A method of producing high quality silicon carbide single crystal using a seeded growth system, the method comprising:
reducing the separation between a silicon carbide seed crystal and a seed holder until the conductive heat transfer between the seed crystal and the seed holder dominates the radiative heat transfer between the seed crystal and the seed holder over substantially the entire seed crystal surface that is adjacent the seed holder; initiating growth at substantially the same diameter as the seed crystal while minimizing torsional forces on the seed crystal; thereafter growing a bulk single crystal at substantially the same diameter as the seed crystal using a seeded sublimation technique while minimizing a concentration of dopants that contribute to conductive characteristics to produce an as-grown compensated crystal; later processing the as-grown compensated crystal by heating the as-grown compensated crystal to a temperature from 2000 degrees C. to 2400 degrees C. to increase point defects; subsequently cooling the as-grown compensated crystal at a rate from 30 degrees C. to 150 degrees C. per minute to avoid annealing the point defects back into the as-grown compensated crystal; and cutting a silicon carbide single crystal wafer from the as-grown compensated crystal, the silicon carbide single crystal wafer having a resistivity greater than 10,000 ohm-cm and a micropipe density less than 200 cm−2.