Relevance of hidden transients in the steady state memristor measurements

Abstract

Highly non-linear selector (S) devices integrated with emerging memristor (R) devices are vital to mitigate sneak path leakage currents in crossbar arrays. For a functional 1S1R bit cell, the selector specifications (on-voltage and currents) should be compatible with the memristor devices (switching voltages and currents). The memristor’s DC switching characteristics are typically considered for selector specifications. In this work, we show that the transient device response of the memristor is necessary for accurately pairing the appropriate selector device. The relevance of hidden transient information has been demonstrated with a detailed analysis of the RESET switching currents in Pr 1-x Ca x MnO 3 (PCMO) based resistive random-access memory (RRAM). First, we demonstrate the well-known initial fast and peak current transient of a memristor, which cannot be resolved in steady-state DC timescales. Second, we captured the current for short to long timescales, demonstrating the actual current levels the device experiences before the switching event. Third, we show the dependence of current peaks on the device’s initial state with a significant deviation (~3.5x) in peak and steady-state currents. Finally, we empirically show how the success of the RESET process in the memristor is affected by the current limit imposed by a selector.