In order to good interpret the experimentally observed non-ideal Al/SnO2/p-Si (MIS) Schottky diode Parameters such as the barrier height Phi(B), series resistance R-s and density of interface states N-ss, a calculation method has been reported by taking into account interfacial oxide layer and ideality factor n in the current transport mechanism. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of MIS diodes are studied over a wide temperature range of 80-350 K. The effects of R-s, interfacial layer and N-ss on I-V and C-V characteristics are investigated. The values of n were strongly temperature dependent and decreased with increasing temperature. The energy distribution of N-ss was determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. The mean N-ss estimated from I-V and C-V measurements decreased with increasing temperature. The R-s estimated from Cheung's functions was strongly temperature dependent and decreased with increasing temperature. The I-V characteristics confirmed that the distribution of N-ss R-s and interfacial layer are important parameters that influence the electrical characteristics of MIS devices. (C) 2003 Published by Elsevier Ltd.