Electronegativity effects on the frequency of the N-H stretching mode in plasma deposited a-Si:N:H alloys

Abstract

Thin films of hydrogenated silicon nitride alloys, a-Si:N:H, have been produced by rf glow-discharge in a SiH 4 -N 2 mixture. The samples have been characterized by infrared absorption spectroscopy. The nitrogen concentration in the films has been estimated from the integrated absorption of the Si-N asymmetric stretching band at ∼850 cm −1 . The optical band gap was deduced from optical transmission measurements. In this paper, the analysis is focused on the Si-H and N-H stretching bands in the infrared spectra. In a series of samples exhibiting these two features, the Si-H stretching band varies in the range 2105–2230 cm −1 , while the N-H stretching band lies in the range 3315–3360 cm −1 . The peak frequencies of these bands increase with the nitrogen concentration in the films (0.38 E g