OFF State Conduction in Filamentary RRAM

In spite of extensive research, the physics of electric transport in the OFF (high resistance) state of resistive random access memory remains poorly understood. Here, we propose a theory that explains the observed activation nature of that transport, its exponential non-ohmicity, variations between nominally identical structures, and failure trends. Our theory proceeds from the finding that the diffusion transport mechanisms must be ruled out as leading to nonphysically high temperatures (T ~ 4000 - 5000 K) well above melting. The Schottky emission remains acceptable due to its underlying ballistic transport by ~1 eV electrons spreading the Joule heat over much larger distances without melting. Taking into account, the random fields of charged defects the Schottky emission enables one to describe the device variability and failures.