Optical and electrical properties of LPCVD silicon oxynitride films on silicon

The optical and electrical properties of SiOxNy films prepared by low-pressure (5.3 mbar) chemical vapour deposition (LPCVD) at 860 degreesC were studied by means of spectroscopic ellipsometry and analysis of 1 MHz capacitance-voltage characteristics. Correlation of the refractive index and dielectric permittivity of LPCVD films and their composition with the increase of nitrous oxide content in the deposition ambient is established. The density of the effective dielectric charges and interface traps reduces with nitridation of the films. The observed low densities of the interface traps are attributed to the nitrogen incorporation at the SiOxNy/Si interface which leads to suppression of interface trap generation. (C) 2001 Elsevier Science Ltd. All rights reserved.