Device and Circuit Interaction Analysis of Stochastic Behaviors in Cross-Point RRAM Arrays

摘要

Stochastic behaviors of resistive random access memory (RRAM) play animportant role in the design of cross-point memory arrays. A Monte Carlocompact model of oxide RRAM is developed and calibrated with experiments onvarious device stack configurations. With Monte Carlo SPICE simulations, weshow that an increase in array size and interconnect wire resistance willstatistically deteriorate write functionality. Write failure probability (WFP)has an exponential dependency on device uniformity and supply voltage (VDD),and the array bias scheme is a key knob. Lowering array VDD leads to highereffective energy consumption (EEC) due to the increase in WFP when thevariation statistics are included in the analysis. Random-access simulationsindicate that data sparsity statistically benefits write functionality andenergy consumption. Finally, we show that a pseudo-sub-array topology withuniformly distributed pre-forming cells in the pristine high resistance stateis able to reduce both WFP and EEC, enabling higher net capacity for memorycircuits due to improved variation tolerance.