Studies of defects in neutron-irradiated p-type silicon by admittance measurements of n+-p diodes

Defects introduced in p-type silicon by neutron irradiation were studied by measuring the admittance of n+-p diodes. It was shown that the energy levels and capture cross sections estimated from the temperature dependence of the admittance had some uncertainty due to the temperature dependence of the concentration of free carriers in the bulk and the high-frequency-junction capacitance. So, we presented the method of determination of the energy levels, capture cross sections, and concentrations of defects from the frequency dependence of the admittance. This method consists of the measurements of G/ω and C as a function of frequency. From this method, assuming that capture cross sections are independent of temperature, the energy levels of Ev+0.16 and Ev+0.36 eV were obtained. For these defects, the calculated values of the hole capture cross section were 2.4×10−14 and 3.7×10−14 cm2, respectively. Comparing with other published data, the energy level of Ev+0.36 eV was found to be correlated with the divacancy.