Impact of precise temperature control for 4H-SiC epitaxy on large diameter wafers

Abstract

Homo-epitaxial 4H-SiC films were grown using high speed wafer rotation vertical CVD method, and the correlation between repeatability of the film properties and wafer temperature which is directly monitored by pyrometers was investigated. When the single zone control of the wafer temperature was performed, a large fluctuation of the thickness and doping concentration was observed in iteration of the epitaxial growth. This fluctuation of the thickness and doping concentration corresponded to that of the temperature distribution on wafers, although no significant fluctuation of apparent power introduced to the heaters was observed. On the other hand, when the double zone control of the wafer temperature was performed, the fluctuation of the thickness, doping concentration and temperature distribution was considerably decreased. The large fluctuation of the temperature distribution by the single zone control seems to be due to the variation of the crystalline quality of the 4H-SiC wafers.