Measurements on a hole trap in neutron-irradiated silicon

High resistivity n-type Si has been neutron irradiated and characterized by Deep Level Transient Spectroscopy (DLTS). In addition to common irradiation induced traps we have observed a hole trap with activation energy around 0.475 eV. For characterizing the trap we have observed the DLTS signal versus filling pulse bias combined with simulations of carrier concentrations. According to these measurements, the capture cross section is very small for holes as well as for electrons; of the order of 10−18–10−20 cm2. The hole capture cross section is temperature dependent in the temperature range covered.