Optical-Capacitance-Transient Spectroscopy Study for Deep Levels in 4H-SiC Epilayer Grown by Cold Wall Chemical Vapor Deposition

摘要

Optical cross sections for deep levels in 4H-SiC grown by cold wall chemical vapor deposition (CVD) were investigated by optical-capacitance-transient spectroscopy (O-CTS). By fitting the measured data with the theoretically calculated curve, we obtained optical excitation energy of 1.50 eV for the Z_(1/2) center. We also obtained its thermal activation energy of 0.61 eV. From these energy values and previously reported the capture barrier and the negative-U property, we drew the configuration coordinate diagram of the Z_(1/2) center, and then the Frank-Condon shift of 0.96-0.97 eV was estimated. In addition, the EH_(6/7) center was also characterized by O-CTS measurements.