Internal stress and structure of evaporated chromium and MgF2 films and their dependence on substrate temperature

Abstract The internal stress in chromium and MgF2 films was measured by the cantilever beam method. The substrate temperature, which was kept constant during the film deposition, could be varied up to 500°C. At room temperature both materials exhibit only tensile stress over the whole thickness range. At higher temperature for both materials compressive as well as tensile stresses are found as the film thickness increases. Similar stress versus thickness curves have previously been obtained for the low melting point metals silver, copper and gold deposited at room temperature. The model for the origin of the internal stress proposed to interpret the stress curves of the metals of the copper group is again applicable. Thus the changes in the stress curves obtained at different substrate temperatures can again be correlated with changes in the growth mode and thus the structure of the respective films. The structure determined on the basis of the stress model agrees with the film structure visible in the electron microscope.