The investigation of temperature dependence of electrical parametres ofAu/SiO2/n-Si (MİS) structures

In this study, the temperature and voltage dependence of interface states (Nss) and resistance profile of Au/SiO2/n-Si structure with 79 ? insulator layer thickness were obtained from the forward and reverse bias capacitance-voltage (C-V) and conductance-voltage (G/ ? -V) measurements in the temperature range of 80-400 K at 1 MHz. The main electrical parameters, such as doping concentration (ND), Fermi energy level (EF), depletion layer width (WD), density of interface states (Nss) and barrier height (?CV), of these structures were also determined from the reverse bias C-2 vs V plots in the same range. The values of ?CV at the absolute temperature (T=0 K) and the temperature coefficient (?) of barrier height were found as 1.152 eV and -2.4x10-4 eV/K, respectively. These values are in a close agreement with the bandgap value of Si at 0 K (Eg = 1.17 eV) and its temperature coefficient value (-4.73x10-4 eV/K). C-V plots for all temperature levels show an anomalous peak in the accumulation region because of the effect of series resistance (Rs). Similarly, G/ ? -V plots also show a peak in the depletion region in the temperature range of 160-320 K. The effect of series resistance (Rs) on the capacitance (C) and conductance (G) is found noticeable especially at high temperatures. Therefore, the measured C and G values were corrected in order to minimize the effect of Rs using Nicollian and Brews method. In addition, the temperature dependent ac conductivity ( ? ac) data obtained between 200 and 400 K showed a linear behavior and was fitted to the Arrhenius plot. The values of activation energy (Ea) obtained from the slope ln ? -q/kT plots are 21.7, 18.5, 15.0 and 11.5 meV for the values of applied biases 3.5, 4.0, 4.5 and 5.0 V, respectively.