HCl assisted growth of thick 4H-SiC epilayers for bipolar devices

The addition of hydrogen chloride (HCl) to our conventional CVD process allows for high growth rates up to 50 μm/h while maintaining the step-flow growth mode. Such epilayers exhibit quite low total concentrations of point defects less than 2 x 1013 cm-3. But, the HCl addition shows an ambivalent influence on the concentration of the lifetime killer defect Z1/2. For low growth rates, the Z1/2 concentration slightly decreases with increasing HCl addition. For higher growth rates, the Z1/2 concentration increases with increasing HCl addition.