A method of forming a silicon oxide layer over a substrate disposed in a high density plasma substrate processing chamber. The silicon oxide layer is formed by flowing a process gas including a silicon-containing source, an oxygen-containing source, an inert gas and a hydrogen-containing source into the substrate processing chamber and forming a high density plasma (i.e., a plasma having an ion density of at least 1null1011 ions/cm3) from the process gas to deposit said silicon oxide layer over said substrate. In one embodiment, the hydrogen-containing source in the process gas is selected from the group of H2, H2O, NH3, CH4 and C2H6.