Growth and characterization of 4H–SiC in vertical hot-wall chemical vapor deposition

Abstract

Vertical hot-wall chemical vapor deposition of SiC at high growth rates has been investigated. 4H–SiC epilayers, with a quality even superior to conventional epilayers, were grown at 25– 60 μm/h , 5–10 times higher than the conventional speed. The correlation of the growth mechanism to Si cluster decomposition is described. Excellent surface morphology of the epilayer grown at 25– 60 μm/h was attained by control of H 2 etching during the heating process, in which C 3H 8 was introduced at 1200°C and SiH 4 at 1300°C. The lowest net donor concentration was 5×10 12 cm −3 . In the low-temperature photoluminescence spectrum, free exciton peaks were remarkably dominant, and no impurity-related peaks were observed. Through DLTS measurements, the EH 6/7 center located at the midgap of E c −1.65 eV was detected. This trap could be suppressed under a C-rich condition as in the case of the Z 1/2 center.