Destructive dielectric breakdown of 2D muscovite mica

Abstract

This study investigates the destructive breakdown (DBD) phenomenon in the van der Waals gate dielectric 2D muscovite mica (4–12 nm thick), focusing on its electrical reliability as a gate dielectric material. Capacitor test structures were electrically stressed, and the resulting impact on the physical structure was analyzed using atomic force microscopy. The volume of material removed in a DBD event is found, and the energy required (Ereq) to vaporize the volume was calculated. It is found that Ereq is proportional to the average electrical energy dissipated in the capacitor during breakdown (BD), indicating a direct correlation between damage caused during DBD and the current flow at BD location. In contrast to other thin film dielectrics, the 2D mica is highly susceptible to DBD even at very low current density (<1 A/cm2) and the abrupt, destructive BD more resembles that of thick film dielectric breakdown. An explanation for these finding is proposed in which intercalated K+ ions agglomerate around defects generated by the electrical stressing such that the defect density increases substantially in the local vicinity of BD locations, which leads to increased current and associated Joule heating after the BD event.