60Co γ-ray irradiation effects on the interface traps density of tin oxide films of different thicknesses on n-type Si (1 1 1) substrates

We report the first investigation of the gamma irradiation effects on interface state density and series resistance determined from capacitance–voltage (C–V) and conductance–voltage (G–V) characteristics in Au/SnO2/n-Si (MOS) structures prepared at various SnO2 layer thicknesses by spray deposition technique. It was fabricated three samples depending on deposition time. The samples were irradiated using a 60Co γ-ray source irradiation with the total dose range was 0–500 kGy at room temperature. The C–V and G–V measurements of the samples were performed at high frequency (500 kHz) at room temperature before and after irradiation. The measurement capacitance and conductance are corrected for series resistance. The thicknesses of SnO2 films obtained from the measurement of the oxide capacitance in the accumulation region for MOS Schottky diodes were 19, 52, 191 Å, for D1, D2 and D3 samples, respectively. It has been seen that the value of the series resistance Rs of samples D1 (50 Ω), D2 (66 Ω) and D3 (157 Ω) increases with increasing the oxide layer thickness and increases from 50 Ω to 62.7 Ω with increasing irradiation dose. The single frequency method of Hill-Coleman was used to determine the interface state density (Dit).