Dielectric breakdown - recovery in logic and resistive switching in memory : bridging the gap between the two phenomena

Abstract

Dielectric breakdown is a well documented phenomenon studied for logic transistors using SiO2/SiON and HfO2 as the oxide material with thickness ranging from 1-5 nm. Recovery of dielectric breakdown has also been reported recently and its implications on the prolonged time dependent dielectric breakdown (TDDB) lifetime are very significant. Similarly, in the non-volatile memory arena, orders of magnitude change in conductance of the oxide has been observed for different voltage levels, voltage polarities and current densities, which is commonly referred to as “resistive switching”. Interestingly, although the gate stacks used for logic and memory applications are very similar in the materials used and dimensions as well, the mechanisms postulated to explain the breakdown-recovery mechanism in logic and switching mechanism in memory are very different. Often, the mechanism underlying switching tends to be very speculative without any convincing physical and electrical evidence that confirms the underlying kinetics of the reversible conductance state transition process. The issue stems from the fact that researchers in logic and memory operate in two distinct domains and seldom interact with each other and as a result, the link between the devices used for these two applications is not clearly recognized by most scientists. In this study, we will bridge the gap between these two phenomena and take advantage of our understanding of dielectric breakdown and recovery to convincingly explain the fundamental physics governing the switching process.