LPCVD-silicon oxynitride films: Interface properties

The interface properties of silicon oxynitride films prepared by low-pressure chemical vapor deposition at a temperature of 860 ° C have been investigated analyzing the capacitance-voltage and ac conductance-voltage characteristics of the metal-SiO_xN_y-silicon capacitors. Consistent results for the interface trap density have been obtained from single frequency ac conductance technique, approximation C-V method and from the interface density spectrum. The post-deposition annealing results in an improvement of the interface charge properties. The contribution of the interface traps to the estimation of the fixed oxide charge has been discussed which is important for the threshold voltage control in MOS devices.