ION BOMBARDMENT-INDUCED MECHANICAL-STRESS IN PLASMA-ENHANCED DEPOSITED SILICON-NITRIDE AND SILICON OXYNITRIDE FILMS

We have studied the influence of different deposition conditions on the mechanical stress of silicon nitride and silicon oxynitride layers formed by plasma-enhanced deposition onto silicon substrates. It appears that the mechanical stress of the as-deposited silicon (oxy)nitride layer is a combined effect of the extent of ion bombardment and the deposition temperature on the hydrogen desorption rate. Deposited films show a tensile stress character when the hydrogen desorption rate is thermally controlled, whereas in the case of an ion-bombardment-controlled hydrogen desorption rate the deposited films have a compressive stress.