Nippon Steel Corporation reports having successfully developed six-inch diameter silicon carbide (SiC) single-crystal wafers in a project partially funded through NEDO. SiC wafers help reduce power loses in many high power electronics applications.
The company says that the 6-inch waffer is expected to increase the efficiency of SiC device production and to decrease the cost of device manufacture compared to 3- or 4-inch wafers. The company has to further refine the method to eventually manufacture the wafers. Nippon Steel says that the wafers will further extend applications to automobiles (EV/HEV, etc.), rapid-transit railways, and other broader areas.
SiC single crystal is usually manufactured through the sublimation- recrystallization method in which the equipment is heated to over 2500 degrees C. The growth of SiC single crystal is achieved by having vapor sublimated from SiC material in powder form recrystallize on top of seed crystals. Nippon Steel points out, that as the crystal diameters increased, the crystals tended to become more suceptable to cracking from crystal defects and thermal stress.
The company says that it used numerical simulation technology to develop the mechanism and process operating conditions suitable for producing the 6-inch wafer. Then the company successfully restrained crystal defects and crystal cracks in the growth to produce Japan