Formation of stress reduced silicon oxide films by Ar/H2 sputtering method

The compressive internal stresses of sputtered silicon oxide films are remarkably reduced by use of an Ar/H2 gas mixture instead of the conventional Ar/O2 one. The film deposition rates are also found to be larger than those using an Ar/O2 gas mixture. The effect is thought to be caused mainly by structural relaxation of Si-O-Si network via partial Si-H terminations. The oxygen deficiency in films leads to optical absorption loss at short wavelengths (<700 nm). However, these films are still suitable as mechanically stable layers of optical devices operating above 700 nm.