ALD TiO2 thin film as dielectric for Al/p-Si Schottky diode

Electrical analysis of Al/p-Si Schottky diode with titanium dioxide (TiO2) thin film was performed at room temperature. The forward and reverse bias current-voltage (I-V) characteristics of diode were studied. Using thermionic emission (TE) theory, the main electrical parameters of the Al/TiO2/p-Si Schottky diode such as ideality factor (n), zero bias barrier height (Phi(Bo)) and series resistance (R-s) were estimated from forward bias I-V plots. At the same time, values of n, Phi(Bo) and R-s were obtained from Cheung's method. It was shown that electrical parameters obtained from TE theory and Cheung's method exhibit close agreement with each other. The reverse-bias leakage current mechanism of Al/TiO2/p-Si Schottky barrier diodes was investigated. The I-V curves in the reverse direction are taken and interpreted via both Schottky and Poole-Frenkel effects. Schottky effect was found to be dominant in the reverse direction. In addition, the capacitance-voltage (C-V) and conductance-voltage (G/w-V) characteristics of diode were investigated at different frequencies (50-500 kHz). The frequency dependence of interface states density was obtained from the Hill-Coleman method and the voltage dependence of interface states density was obtained from the high-low frequency capacitance method.