Capacitance-Voltage Characterization of LPCVD-Silicon Oxynitride Films

LPCVD-silicon oxynitride films with different compositions were deposited on n-Si(111) substrates by reacting dichlorosilane (SiH2Cl2) with nitrous oxide (N2O) and ammonia (NH3) at a temperature of 860 oC varying the gas flow rate ratio of N2O and NH3. The electrical properties of the SiOxNy films were studied by analysis of the 1 MHz capacitance–voltage characteristics of the metal–SiOxNy–silicon capacitors. It has been found that with increasing amount of N2O in the deposition ambient the concentration of the dielectric charges in the SiOxNy/Si structures goes through a minimum, while the interface trap density gradually decreases. The nature of the defects is discussed.