In this work, we investigated the gradual resistance switching phenomenon of our fabricated silicon nitride-based bipolar RRAM. By positive (set) and negative (reset) pulses applied between top electrode (TE) and bottom electrode (BE), the resistance state of the RRAM cell was delicately controlled. We checked the effect of pulse width, rise and fall time and pulse amplitude on the change of the resistance state. In conclusion, it is demonstrated that change of resistance state is determined by applied pulse area above a certain threshold voltage. The memory cell and gradual resistance change characteristics would be used to implement accurate and reliable synaptic devices in low power neuromorphic system. (C) 2017 Elsevier Ltd. All rights reserved.