1-D simulation of a novel nonvolatile resistive random access memory device

The operation of a novel, nonvolatile memory device based on a conductive ferroelectric/semiconductor thin film multilayer stack is simulated numerically. The simulation involves the self-consistent steady-state solution of the transport equation for electrons assuming a drift-diffusion transport mechanism and the Poisson equation. Special emphasis is put on the screening of the spontaneous polarization by conduction electrons as a function of the applied voltage. Depending on the orientation of the polarization in the ferroelectric layer, a high and a low resistive state are found, giving rise to a hysteretic I-V characteristic. The switching ratio, ranging from > 50% to several orders of magnitude, is calculated as a function of the dopant content. The suggested model provides one possible physical explanation of the I-V hysteresis observed for single-layer ferroelectric devices, if interfacial layers are taken into consideration. The approach will allow one to develop guidelines to improve the performance of these devices.