Si-containing silicon oxide (SSO) films and Ge-containing silicon oxide (GSO) films were deposited on p-type Si substrates using the RF magnetron sputtering technique with a Si-SiO2 and a Ge-SiO2 composite target, respectively. These films were annealed in a N2 ambient at temperatures from 300 to 1100℃. Using high resolution transmission electron microscopy,nanometer Si particles and nanometer Ge particles were observed in the SSO and GSO films,respectively,after annealing at 900 or 1100℃. All the PL spectra from the two types of films annealed at various temperatures have similar shapes with peak positions around 580nm (～2.1eV). It is indicated that light emission originates from luminescence centers in Si oxide films. The experimental results have been explained reasonably.