Growth and electrical characterization of 4H-SiC epilayers

Homoepitaxial growth of 4H-SiC and characterization of deep levels obtained mainly in the authors' group have been reviewed. The growth rate has been increased to 24 mu m/h with keeping very good surface morphology and low trap concentration on 8 degrees off-axis 4H-SiC(0001) by hot-wall chemical vapor deposition at 1650 degrees C. The increased growth rate has resulted in the enhanced conversion of basal-plane dislocations into threading edge dislocations in epilayers. The Z(1/2) and EH6/7 concentrations can be decreased to about 1x10(12) cm(-3) by increasing the C/Si ratio during CVD. Extensive investigation on as-grown and electron-irradiated epilayers indicates that both the Z(1/2) and EH6/7 centers may be attributed to the same origin related to carbon displacement, probably a carbon vacancy. Deep levels observed in as-grown and irradiated p-type 4H-SiC are also presented.