Switching Voltage and Time Statistics of Filamentary Conductive Paths in HfO₂-Based ReRAM Devices

Switching voltage and time statistics of HfO₂-based one transistor-one resistor structures are investigated with the aim of clarifying the underlying physical mechanism that governs the formation and rupture of filamentary paths in the insulating layer. From the oxide reliability viewpoint, constant and ramped voltage stress experiments provide strong support to the so-called E-model, which is shown to be in line with current theories relating the reversibility of the conduction states in resistive random access memory devices to ionic drift and ultimately to Kramers' escape rate theory. It is shown how the switching statistics can be used to estimate the width and formation energy of the insulating gap along the filament as well as its temperature.