Large diameter, high quality SiC single crystals, method and apparatus

USRE46315E1 · kind E1 · reissue

Assignee

• II-VI Incorporated · US

Inventors

• Ilya Zwieback · Township of Washington, US
• Thomas E. Anderson · Normal, US
• Andrew E. Souzis · Ramsey, US
• Gary E. Ruland · Morristown, US
• Avinash Gupta · Gainesville, US
• Varatharajan Rengarajan · Flanders, US
• Ping Wu · Hackettstown, US
• Xueping Xu · Vernon, US

Key dates

• Filing date: Oct 6, 2014
• Grant date: Feb 21, 2017
• Expiry date: Oct 6, 2034

Classification

• Technology area (CPC —): General

Abstract

A method and system of forming large-diameter SiC single crystals suitable for fabricating high crystal quality SiC substrates of 100, 125, 150 and 200 mm in diameter are described. The SiC single crystals are grown by a seeded sublimation technique in the presence of a shallow radial temperature gradient. During SiC sublimation growth, a flux of SiC bearing vapors filtered from carbon particulates is substantially restricted to a central area of the surface of the seed crystal by a separation plate disposed between the seed crystal and a source of the SiC bearing vapors. The separation plate includes a first, substantially vapor-permeable part surrounded by a second, substantially non vapor-permeable part. The grown crystals have a flat or slightly convex growth interface. Large-diameter SiC wafers fabricated from the grown crystals exhibit low lattice curvature and low densities of crystal defects, such as stacking faults, inclusions, micropipes and dislocations.