Stresses in sputtered RUOx thin films

RuOx thin films have been deposited by reactive sputtering in an O-2/Ar atm osphere. The films were characterized for their stress and resistivity as a function of deposition temperature (room temperature, 300 degrees C) and t he O-2 content (25-100%) in the sputtering gas. Additionally, the stresses in these films were determined as a function of annealing temperature (up t o 600 degrees C) using an in-situ curvature measurement technique. The as-d eposited films were found to be under a state of compressive stress for all deposition conditions. The compressive stresses sharply increased with inc reasing deposition temperature from a value of around 200 MPa at 200 degree s C to 1400 MPa at 300 degrees C. This dramatic increase has been attribute d to differences in microstructure at these deposition temperatures. The mi crostructural differences also led to the widely differing stress-temperatu re behavior during annealing of these films. For films deposited at tempera tures lower than 200 degrees C, the annealing process resulted in a decreas e in the compressive stress and resistivity of the films. However, films de posited at a temperature of 300 degrees C did not show any changes in the c ompressive stress or resistivity after annealing. The results of this study can be used to deposit RuOx thin films with low resistivity and minimal st resses. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.