Some Properties of Vapor Deposited Silicon Nitride Films Obtained by the Reaction of SiBr4 and NH 3

Silicon nitride films, easily etchable in buffered HF (75 Aa/min) and usable as gallium diffusion masks, are deposited at 800°C by the and reaction (ratio ) in a forming gas atmosphere. The chemical composition of the films, deposited between 500° and 800°C, as measured by chemical and electron microprobe analysis, is nearer to than to . The 800°C films are impervious to moisture. The room temperature stress in the films deposited on silicon is very high and cannot be lowered by decreasing the temperature of deposition or the ratio. The intrinsic stress of the films is highly tensile and is much higher than that in vapor deposited films: germanium wafers tend to warp with formation of slip lines. Films of composition containing—NH groups are obtained at 800°C when the ratio of .