Lightly doped silicon carbide wafer and use thereof in high power devices

US8097524B2 · kind B2 · utility

Assignees

• Norstel AB · SE
• Siced Electronics Development GmbH & Co. KG · DE

Inventors

• Alexandre Ellison · Säter, SE
• Björn Magnusson · Säter, SE
• Asko Vehanen · Espoo, FI
• Dietrich Stephani · Bubenreuth, DE
• Heinz Mitlehner · Uttenreuth, DE
• Peter Friedrichs · Koblenzer Straße, DE

Key dates

• Filing date: Jan 13, 2009
• Grant date: Jan 17, 2012
• Expiry date: Sep 7, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S438/931
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method for manufacturing a silicon carbide single crystal. A silicon carbide single crystal is grown. The crystal has a boron concentration less than 5×1014 cm−3, and a concentration of transition metals impurities less than 5×1014 cm−3. Intrinsic defects in the crystal are minimised. The intrinsic defects include silicon vacancies or carbon vacancies. The crystal is annealed for a desired time at a temperature above 700° C. in an atmosphere containing any of the gases hydrogen or a mixture of hydrogen and an inert gas, such that the density of intrinsic defects and any associated defects is decreased to a concentration low enough to confer to the crystal a desired carrier life time of at least 50 ns at room temperature.