Correlations between electrical properties and process parameters of silicon nitride films prepared by low temperature (100°C) catalytic CVD

Silicon nitride films were deposited at 100°C by using the catalytic chemical vapor deposition technique. The source gas mixing ratio, R_N = [NH₃] / [SiH₄], was varied from 10 to 30, and the hydrogen dilution ratio, R_H = [H₂] / [SiH₄], was varied from 20 to 100. The breakdown field strength reached a maximum value at R_N = 20 and RH = 20, whereas the resistivity decreased in the same sample. The relative permittivity had a positive correlation with the breakdown field strength. The capacitance-voltage threshold curve showed an asymmetric hysteresis loop, which became more squared as RH increased. The width of the hysteresis window showed a negative correlation with the slope of the transition region, implying that the combined effect of RN and RH overides the interface defects while creating charge storage sites in the bulk region.