Move over silicon chips, there is a new semiconductor king on the horizon. Silicon carbide’s (SiC) potential has been known since the 1950’s, but the properties that make is attractive also make it hard to work with. The material is a good semiconductor, extremely resistant to heat, and hard. So hard in fact, researchers had trouble making large enough SiC crystals without defects. Now, researchers from Toyota Central Research and Development Laboratories report in Nature (registration required) they have used a Repeated A-Face method of physical vapor transport to create large SiC crystals with virtually no defects.
Takatori grows the silicon carbide crystals in several different stages. At each stage, further growth is only allowed on the cleanest face of the crystal. Hot silicon carbide vapour condenses on the crystal’s flat face and defects are gradually eliminated as the crystals grow up to seven centimetres across. Takatori’s crystals contain less than 1% of the number of defects found in a crystal produced by conventional methods.
What advantages would SiC have over traditional silicon based semiconductors? SiC has a higher energy efficiency, can handle high frequency electrical pulses and is tolerant to extreme temperatures. Previous research has shown SiC devices can operate at temperatures as high as 650C (1,202F) without the need for cooling. Kiss that noisy heat sink/fan combo goodbye! SiC’s properties could open up uses for electronic controllers inside jet engines and provide hardened circuitry for spacecraft.
Silicon is safe for now. The researchers have only been able to make pure SiC wafers up to 3 inches in diameter and improvements in the SiC deposition technique are needed to increase wafer size and lower production costs. SiC could see its first use in specialized circuitry that needs high heat tolerance, but mainstream commercial usage could be over 6 years away. The BBC also has coverage of the discovery here.