Abstract
The variation of stress with respect to temperature in ZnO films, prepared by r.f. magnetron sputtering on Si and GaAs substrates, has been studied by using a bending beam technique. The thermal expansion coefficients and biaxial moduli of the films have been determined from the stress-temperature curves upon cooling. For most of the films, the obtained biaxial modulus ranges from 250 to 360 GPa at temperatures from 25 to 400 °C, whilst the thermal expansion coefficient increases from 5 × 10 -6 to 8 × 10 -6 °C -1 . X-ray diffraction results reveal that the films deposited at a higher total gas pressure, i.e. 5.3 Pa, or a lower substrate temperature, i.e. 250 °C, have further crystallized upon annealing. The crystallization has caused the films to exhibit an irreversible stress behaviour upon thermal cycling. © 1995.