The authors have developed a new equivalent circuit model to analyze the charging dynamics of the interface states in Schottky barrier diodes at reverse bias condition. Trap density and the capture/ emission times are extracted by incorporating the measured ac admittance of erbium silicide Schottky diode with the newly developed equivalent circuit model. The extracted trap density is 1.5 X 10(12) cm(-1) eV(-1) and the capture and emission transition times are 19 and 5.9 us, respectively. Trap density decreases to 6.1 X 10(9) cm(-2) eV(-1) after N-2 annealing. (c) 2007 American Vacuum Society.