Properties of ''stoichiometric'' silicon oxynitride films

The properties of amorphous SiOxNy films prepared by rf glow discharge of a SiH4-O-2-NH3 mixture at 300 degrees C are investigated as functions of the O content, x, and the N content, y. A relationship of 2x + 2.8y = 4 was found between x and y. This result suggests that the densities of homobonds, such as Si-Si, O-O and N-N, and of Si-H and O-H bonds are sufficiently lower than those of Si-O and Si-N bonds. The absence of splitting of stretching absorption bands arising from Si-O and Si-N bonds suggests that the film is a homogeneous alloy. The properties of the dangling bonds and their origins are discussed.