A comprehensive study on the interface states in the ECR-PECVD SiO2/p-Si MOS structures analyzed by different method

The electrical properties of SiO₂/p-Si films deposited by ECR-PECVD s were studied at different frequencies (100-1 MHz) and gate voltages (−6–3 V). Results showed a frequency dispersion of C-V_g and G/ω-V_g. With increasing frequency, the capacitance and conductance are strongly decreased. An apparent peak in the depletion regime of the G/ω-Vg plots can be attributed to the existence of density N_ss at Si/SiO₂. The (N_ss)value vary from 1.5 × 10¹² to 0.5 × 10¹¹ eV⁻¹ cm⁻², it has been determined by High-Low frequency capacitance technic. The N_ss- V_g curve presents a peak at about −3 V, suggesting the presence N_ss between the (Si)/SiO₂ interface. Hill and Coleman method shows that the N_ss decreases with increasing frequency which explains the high value of capacitance at low frequency. The N_ss and their relaxation time τ by the conductance method ranged from 1.8 × 10¹³ to 1.37 × 10¹¹ eV⁻¹ cm⁻² and 5.17 10⁻⁷ to 8 × 10⁻⁶ s, in the range (0.189-E_v) and (0.57- E_v) eV, respectively. The N_ss was responsible for the non-ideal behavior of C-V_g and G-V_g leading to the breakdown of such device. Comparing the three method results show that parallel conductance is very precise and accurate.