Achievement of zero temperature coefficient of resistance with RuOx thin film resistors

The temperature coefficient of resistance (TCR) for an as-deposited RuO2.2 thin film resistor changes from -131.6 to 1007.95 ppm/degrees C after the annealing at 600 degrees C for 30 min. Typically, a near zero TCR about 0 +/- 0.12 ppm/degrees C can be obtained after annealing at 300 degrees C for 30 min in an Ar ambient. The changes of TCR from negative to positive is attributed to the grain growth of RuO, films from fine grain (30-40 Angstrom) to a larger one (500-800 Angstrom) during the annealing process. Rutherford backscattering spectroscopy and in situ x-ray photoemission spectroscopy show that the ratio of O/Ru in the RuOx film 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. (C) 1997 American Institute of Physics.