Evolution of residual stress in plasma-enhanced chemical-vapor-deposited silicon dioxide film exposed to room air

Considerable increase in compressive stress was observed in silicon dioxide films upon prolonged exposure to atmospheric moisture. The compressive stress change upon exposure to atmosphere consisted of a reversible change and an irreversible change. The irreversible component was found to be due to structural changes in the Si–O–Si network. The reversible change in stress is due to water molecules absorbed on walls of the pores.