Semiconductor device comprising dual silicon nitride layers with varying nitrogen ratio

摘要

Disclosed is a semiconductor device comprising a semiconductor substrate, a gate electrode, a first insulating film formed between the semiconductor substrate and the gate electrode, and a second insulating film formed along a top surface or a side surface of the gate electrode and including a lower silicon nitride film containing nitrogen, silicon and hydrogen and an upper silicon nitride film formed on the lower silicon nitride film and containing nitrogen, silicon and hydrogen, and wherein a composition ratio N/Si of nitrogen (N) to silicon (Si) in the lower silicon nitride film is higher than that in the upper silicon nitride film.