Instability evolution within a-SiNx film assessed through MIS structure under bias and temperature stresses

The effects of positive and negative bias stresses on plasma enhanced chemical vapor deposited (PECVD) hydrogenated amorphous silicon nitride/crystal silicon (a-SiNx/c-Si) structures were investigated as a function of both time and temperature. It was shown that the bias stress induces forward (positive) or backward (negative) shift of the capacitance–voltage (C–V) characteristic along the voltage axis according to the polarity of this applied stress voltage. The injection of charge carriers from the semiconductor substrate and their eventual dispersive hopping process, limiting the redistribution of charges throughout the insulator, seem consistent with the time evolution of both dc current and flat band voltage of the metal insulator semiconductor structure.