Progress in the industrial production of SiC substrates for semiconductor devices

The production of large diameter, high quality SiC substrates is essential to realize the full potential of this important semiconductor material. The current status of SiC bulk sublimation growth for the production of these substrates is reviewed from an industrial point of view. Specific efforts towards larger diameter high quality substrates have led to the production of 50 and 75 mm diameter 4H and 6H wafers and the demonstration of high quality 100-mm wafers. We present thermal conductivity data for material of different doping levels, relevant for device applications. In SiC, micropipes are the most harmful defects for SiC device production. By continuous optimization of the growth process we were able to steadily decrease the micropipe density over the past several years, down to densities as low as 1.1 cm−2 for an entire 50-mm wafer, indicating that micropipes may be totally eliminated in the next few years. In order to achieve this goal for SiC substrates of increasing diameter, a thorough understanding of the growth process is essential. We will summarize results of modeling the growth process and its experimental verification. The effect of micropipe densities and their characteristic lateral distribution in SiC wafers on achievable device yields will be discussed, using large area Schottky diodes as an example.