Low temperature (250 ° C) silicon oxide (α-SiOx:H) films have been developed for surface passivation as well as antireflection coating in silicon solar cell. Films have been fabricated by ion damage free photochemical vapor decomposition technique using SiH4, N2O, and H-2 gas mixture. In this paper we have reported the effect of N2O to SiH4 ratio (R) on optoelectronic and structural properties of the films. The bonding configurations of Si and H were investigated in detail by IR absorption measurement. The Si-H stretching mode supports the presence of H-(Si3-nOn)(n =0-3) structural unit, which is also present in the Si-O stretching mode. Developed silicon oxide films also have been studied on the c-Si solar cell. A substantial enhancement (11.2%) in efficiency has been achieved. © 2005 American Vacuum Society.