Stress and Structural Relaxation in Metallo-Organic Chemical Vapor Deposited SiO₂ Films

Stress relaxation of amorphous silica films deposited by low pressure thermal decomposition of diacetoxy di-t-butoxy silane (DADBS) was studied. Significant reduction in film stress along with structural changes were observed at temperatures as low as 600°C. The activation energy for stress relaxation was found to be 75.8 kJ/mol. The low value of activation energy is attributed to the effect of water which was present in the form of silanol groups. The changes in film stress are attributed in a semi-quantitative manner to the changes in Si-O-Si angle distributions in the film.