Surface passivation at low processing temperature becomes an important topic for crystalline and multicrystalline silicon solar cells, In this work, silicon oxide (250degreesC) and silicon nitride (300degreesC) have been developed by Photo-CVD and PECVD technique respectively. Effects of deposition parameters on the optoelectronic and structural properties of the films have been investigated. Interface-trap density (D-it) and fixed charge density (Qf) have been estimated by high frequency (1 MHz) capacitance-voltage measurement on Metal-Insulator-Silicon structure (CV-MIS). The effect of silicon oxide and silicon nitride on the performance of c-Si solar cells have been studied. (C) 2002 Elsevier Science B.V. All rights reserved.