On the interface trap density and series resistance of tin oxide film prepared on n-type Si (1 1 1) substrate: Frequency dependent effects before and after 60Co γ-ray irradiation

Abstract

We report the first investigation of the frequency dependent effects of gamma irradiation on interface state density and series resistance determined from capacitance–voltage (C–V) and conductance–voltage (G–V) characteristics in SnO2/n-Si structures prepared by spray deposition method. The samples were irradiated using a 60Co γ-ray source at 500kGy at room temperature. The C–V and G–V measurements of the samples were performed in the voltage range −6V to 2V and at 10kHz, 100kHz, 500kHz and 1MHz at room temperature before and after 500kGy irradiation. The measurement capacitance and conductance are corrected for series resistance. It has been seen that the value of the series resistance Rs of sample decreases from 204Ω to 55.4Ω with increasing the frequency before irradiation while it decreases from 248Ω to 60Ω with increasing frequency at 500kGy irradiation. It has been found that and Dit values of MOS structure increases up to 100kHz and then decreases up to 1MHz while the Rs increases with increasing irradiation dose for our sample. The interface state density Dit ranges from 1.83×1013cm−2eV−1 for before irradiation to 1.54×1013cm−2eV−1 for 500kGy irradiation dose at 500kHz and decreases with increasing frequency.