Comparative study of the effect of thermal annealing on the hydrogen stability and the stress in a-C:H films deposited by electron cyclotron resonance glow discharge and direct current multipolar plasma methods

The effects of thermal annealing on the hydrogen stability and stress in two types of a-C:H films were measured. The films were prepared in a dual electron cyclotron resonance radiofrequency glow discharge or in a direct current multipolar plasma system from pure methane, at substrate bias voltages of -30 and -600 V for each type of film. Infrared absorption, elastic recoil detection analysis and internal stress measurements are used to measure some properties of the films in the as-deposited state and after annealing at increasing temperature up to 700 degrees C. The results indicate that the two types of samples have completely different magnitudes of stresses in their as-deposited state, and that they have also different H thermal stabilities. The stresses are also affected differently by annealing. Annealing reduces the magnitude of the stresses in all cases. For annealing temperature >400 degrees C, and for the -600 V substrate bias, the stress relaxation occurs through atomic rearrangement in the direct current plasma deposited films, while it induces a loss of adhesion in the glow discharge samples. (C) 2000 Elsevier Science B.V. All rights reserved.