The temperature coefficient of resistance (TCR) for an as-deposited RuO2.2thin film resistor changes from −131.6 to 1007.95 ppm/°C after the annealing at 600 °C for 30 min. Typically, a near zero TCR about 0±0.12 ppm/°C can be obtained after annealing at 300 °C for 30 min in an Ar ambient. The changes of TCR from negative to positive is attributed to the grain growth ofRuOxfilms from fine grain (30–40Å)to a larger one (500–800Å)during the annealing process. Rutherford backscattering spectroscopy andin situx-ray photoemission spectroscopy show that the ratio of O/Ru in the RuOxfilm decreases from 2.2 to 2.0, due to the out diffusion of oxygen during the annealing process, which is independent of the changes in TCR. ©1997 American Institute of Physics.