Air Water has recently established a mass production for eight-inch silicon carbide (SiC) wafers which it has had under development for some time.

Last April the company began sending out samples to companies manufacturing high frequency devices. The wafer is called the 3C-SiC (111) on Si hetropitaxial wafer. It is configured in such a way that a SiC thin film of approximately three microns can be grown on a Si substrate. This is the first instance ever of the mass production of SiC substrates with a large diameter greater than eight inches.

Producing a gallium nitrade (GaN) film on an SiC film is comparatively easy so that Air Water will offer this wafer as a substrate wafer for use as GaN substrates anticipated for utilisation with power semiconductors employed with high frequency devices.

Along with this Air Water is aiming to produce and market substrates on which GaN mono crystalline film is grown on an SiC substrate. Regarding the size of the products, for the SiC line, the range will be between two to eight inches and for the GaN line between two to six inches. Eight inch wafers could also be handled in accordance with the development of the demand. For SiC and GaN bulk wafers, slicing a mono crystalline ingot is done to produce them.

Their crystal growth potential is limited and their process conditions are difficult, however, so that four to six inch wafers are at the level where they can be mass produced, and it had been considered that diameters larger than that were really not possible. GaN on Si too, which forms GaN film directly on a Si substrate has very high technological hurdles to overcome, and are in a situation whereby achieving this result is difficult.