DLTS study on point defects in silicon induced by accelerated particles

FZ silicon wafers for power device materials are irradiated by neutron and proton for obtaining homogeneous distribution of resistivity and increase in switching, respectively. However, those processes introduce damages to silicon crystal by bombarding particles. The effect of irradiation damage on FZ silicon crystal properties has been studied by electrical measurement such as Deep Level Transient Spectroscopy (DLTS). There were several typical point defects induced by the accelerated particle irradiations. Their energy levels were in the wide range of the silicon band gap, and some were sufficiently deep enough to affect the carrier lifetime. Their concentrations were also significantly enough to be considered in power device fabrication processes. Hence there must be a delicate heat treatment technology to control the prerequisite defects and their concentrations