Effects of temperature, bias and frequency on the dielectric properties and electrical conductivity of Ni/SiO2/p-Si/Al MIS Schottky diodes

Abstract

In this paper, we have studied the effects of temperature, bias and frequency on the dielectric properties of Ni/SiO2/p-Si/Al MIS diode. For that, we have carried out the capacitance and conductance measurements of the diode in wide temperature range from 95 K to 300 K and with varied bias from 1 V to 3 V at frequency range of 10 kHZ to 1 MHZ. The experimentally obtained I–V characteristics of the diode reveals excellent rectification behaviour in the measured temperature range. The dielectric study shows that the values of dielectric constant (ε′), dielectric loss (ε′′), loss tangent (tanδ), ac conductivity (σac) and electric modulus (M′) are sensitive to the temperature, bias voltage and frequency. The values of ε′ increases with increase in the temperature, applied bias and shows dispersion in the low frequency region and found to be independent in the higher frequency region. The loss tangent (tanδ) vs ln(ω) plot shows peak at higher frequencies which indicates the evidence for hopping of charge carriers. The ac conductivity (σac) was analysed by using power law and found to increase with temperature, applied bias and becomes less dependent on frequency at higher voltages. The Arrhenius plot of σac reveals two different slopes in the measured temperature range which indicates the presence of two distinct trap states. Also, the activation energy found to change significantly with the frequency at higher temperatures. In addition, the variation of electric modulus (M′) with temperature and frequency are found to be consistent with above obtained results.