Read Challenges in Crossbar Memories With Nanoscale Bidirectional Diodes and ReRAM Devices

Abstract

This paper presents a simulation based study of the impact of nanoscale bidirectional diode reverse saturation current, junction capacitance, and crossbar coupling capacitances on the read operation of nanoscale ReRAM devices in 1Diode 1ReRAM crossbar memory architectures. Our results show that the maximum achievable crossbar memory density is a strong function of the diode reverse saturation current, which governs the sneak current in steady-state read mode. For read operations with ultrafast read voltage pulses, additional sneak paths due to diode junction capacitances and line-to-line coupling capacitances in crossbar arrays come into the picture. This causes transient spike in the read current, which can adversely affect the read energy and permissible read time. The overshoot in read current worsens as the size of crossbar arrays increases. The simulation studies presented here provides an in-depth understanding of these issues and its implications on resistive crossbar arrays.