Capacitance-voltage characterization of LPCVD-silicon oxynitride films

LPCVD-silicon oxynitride films with different compositions were deposited o n n-Si(I I I) substrates by reacting dichlorosilane (SiH2Cl2) with nitrous oxide (N2O) and ammonia (NH3) at a temperature of 860 degreesC 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 characteri stics of the metal-SiOxNy-silicon capacitors. It has been found that with i ncreasing amount of N2O in the deposition ambient the concentration of the dielectric charges in the SiOxNy/Si structures goes through a minimum, whil e the interface trap density gradually decreases. The nature of the defects is discussed.