Non-heating atomic layer deposition of SiO2 is developed using tris(dimethylamino)silane (TDMAS) and plasma-excited water vapor. The plasma-excited water is effective in oxidizing the TDMAS-adsorbed SiO2 surface while leaving OH sites on the growing surface at room temperature for further TDMAS adsorption. The growth rate is measured to be 0.075 nm/cycle at room temperature. SiO2 stacking directly on a Ge (100) wafer at room temperature is demonstrated, where an atomically flat interface is confirmed by transmission electron microscope observation. (C) 2012 Elsevier B.V. All rights reserved.