Logic Circuit and Memory Design for In-Memory Computing Applications using Bipolar RRAMs

Abstract

Beyond-CMOS/beyond-von-Neumann circuits are intensively explored to extend post Moore scaling and overcome the bottleneck for high-performance energy-efficient integrated circuits. In this work, we propose functionally complete nonvolatile logic gates based on reversely connected bipolar RRAM pairs. This design has a highly regular and symmetric circuit structure, while the operations are flexible yet clean (without the need of a third resistive state). Example circuits (XNOR, full-adder) using 3T2R chains without extra routing/control gates or resistor are shown with simulation results. Easily integrated as 3D crossbar stack arrays, the proposed memory architecture not only serves as regular crossbar memory arrays but also performs in-memory-computing within the same layer and between the stacked layers. Multiple computation modes for flexible operations are discussed. Bias schemes for selected/half-selected/unselected cells are explained and verified with simulation results.