Method for manufacturing SiC wafer fit for integration with power device manufacturing technology

摘要

A method for producing silicon carbide substrates fit for epitaxial growth in a standard epitaxial chamber normally used for silicon wafers processing. Strict limitations are placed on any substrate that is to be processed in a chamber normally used for silicon substrates, so as to avoid contamination of the silicon wafers. To take full advantage of standard silicon processing equipment, the SiC substrates are of diameter of at least 150 mm. For proper growth of the SiC boule, the growth crucible is made to have interior volume that is six to twelve times the final growth volume of the boule. Also, the interior volume of the crucible is made to have height to width ratio of 0.8 to 4.0. Strict limits are placed on contamination, particles, and defects in each substrate.

主权项

1. A method for manufacturing SiC crystal to a grown volume, comprising:
i. introducing a mixture comprising silicon chips into a reaction cell, the reaction cell being made of graphite and having cylindrical interior of internal volume in the range of from six to twelve times the grown volume of the SiC crystal; ii. placing a silicon carbide seed crystal inside the reaction cell adjacent to a lid of the reaction cell; iii. sealing the cylindrical reaction cell using the lid; iv. surrounding the reaction cell with graphite insulation; v. introducing the cylindrical reaction cell into a vacuum furnace; vi. evacuating the vacuum furnace; vii. filling the vacuum furnace with a gas mixture comprising inert gas to a pressure near atmospheric pressure; viii. heating the cylindrical reaction cell in the vacuum furnace to a temperature in the range from 1975° C. to 2500° C.; ix. reducing the pressure in the vacuum furnace to from 0.05 torr to less than 50 torr; x. introducing source of carbon gas into the vacuum furnace and flowing nitrogen gas configured to introduce nitrogen donor concentration larger 3E18/cm2, and up to 6E18/cm2; and, xi. allowing for sublimation of silicon and carbon species and condensation of vapors on the seed and stopping the sublimation when the grown volume of the SiC crystal reaches one twelfth to one sixth of the internal volume of the reaction cell and the SiC crystal is sufficiently large to yield ten or more substrates.