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 om/h with keeping very good surface morphology and low trap concentration on 8o off-axis 4H-SiC(0001) by hot-wall chemical vapor deposition at 1650oC. The increased growth rate has resulted in the enhanced conversion of basal-plane dislocations into threading edge dislocations in epilayers. The Z1/2 and EH6/7 concentrations can be decreased to about 1·1012 cm-3 by increasing the C/Si ratio during CVD. Extensive investigation on as-grown and electron-irradiated epilayers indicates that both the Z1/2 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.