We compared the passivation methods for GaAs surface using (NH4)(2)S+Se and P2S5/(NH4)(2)S + Se. The characteristics of the Schottky contacts fabricated on GaAs, passivated using these methods, were studied through current-voltage and capacitance-voltage measurements. The long term variations in these characteristics show that the method using (NH4)(2)S+Se provides stable Schottky barrier while the contacts fabricated using P2S5/ (NH4)(2)S + Se present ohmic behavior. (C) 2004 American Vacuum Society.