Thermal stability of RuO2 thin films formed by modified atomic layer deposition on SiO2 substrate was investigated. Rapid thermal annealing was conducted for 2 min under NH3 and N-2 ambient. It was demonstrated that NH3 gas can completely reduce RuO2 to pure Ru at a relatively low annealing temperature of 500 degrees C, while partial reduction of RuO2 into Ru at the outmost surface was observed after N-2 annealing. Agglomeration of the NH3 annealed film was not observed due to high quality of the as-deposited film that was dense and had low level of impurities such as hydrogen and carbon. (C) 2012 Elsevier B.V. All rights reserved.