Internal stress of sputtered amorphous carbon nitride thin films

Analysis of amorphous carbon nitride thin films (a-CNx) deposited by RF magnetron sputtering on (100) silicon wafers under different target self-bias (Vb) is reported. The a-CNx films composition and microstructure have been determined combining many characterisation techniques, which revealed their porous character and their post deposition contamination by oxygen and water vapour. The residual stresses in the films were determined by measuring the curvature of the Si substrate before and after film deposition. Their low values and their evolution versus Vb are attributed to a competition between tensile stress originating from growth and compressive stress from the interaction between gaseous inclusions.