The investigetion of frequency and temperature dependence of electrical and dielectric properties of Au/SiO2/n-GaAs (MOS) structures

The frequency, temperature and oxide thickness dependence of electrical characteristics such as series resistance (Rs), interface states (Nss) and ac electrical conductivity ( ? ac) and dielectric properties such as dielectric constant ( ? '), dielectric loss ( ? "), dielectric loss tangent (tan ? ), real and imaginary part of electric modulus ( ? ' and ? ") of the Au/SiO2/n-GaAs (MOS) structures have been investigated in the temperature range of 80-350 K at various frequencies by using experimental capacitance-voltage (C-V) and conductance-voltage (G/w-V) measurements. Experimental results show that both the values of C and G/w were quite sensitive to frequency, temperature and oxide layer thickness at relatively high temperatures and low frequencies due to a continuous density distribution of Nss and their relaxation time ( ? ), and thermal restructuring and reordering of the interface. The values Rs and Nss of the Au/SiO2/n-GaAs (MOS) structure were obtained from Nicollian and Hill-Coleman methods, respectively, and their values decrease with increasing frequency. While the series resistance decreases with increasing temperature, it increases linearly with increasing oxide layer thickness. The dielectric constant, dielectric loss, loss tangent and the electric modulus were found a strong function of frequency, temperature and oxide layer thickness. While the values of the ?', ?'' and tan? decrease with increasing frequencies, the electric modulus (real and imaginary part) increase with increasing frequency. Also, while the dielectric constant and dielectric loss increase with increasing temperature, electric modulus (real and imaginary part) decrease with increasing temperature. While the ?' decreases with increasing oxide layer thickness tan ?? and imaginary electric modulus increase with increasing oxide layer thickness.