Effect of O2 flow ratio on the microstructure and stress of room temperature reactively sputtered RuOx thin films

Abstract

RuO x thin films were deposited at room temperature by reactive radio frequency magnetron-sputtering using Ar∕O2 discharges of varying O2 flow ratio (fO2) over the range 10%–50% and were characterized using x-ray diffraction, x-ray reflectivity, x-ray photoelectron spectroscopy, resistivity, and stress-temperature measurements. With the increase of fO2, the film texture changed from (110) to (101). Films deposited with fO2>25% were determined stoichiometric. The residual stresses in as-deposited films were all compressive and increased with addition of O2, except for the film sputtered at fO2=20% which was in biaxial tension. The film deposited at fO2=30% had a low resistivity value of 68μΩcm and near zero stress (<50MPa tensile) after a thermal cycle in air up to 500 °C which is promising for use in microdevices.