Endurance Study of Silicon-Doped Hafnium Oxide (HSO) and Zirconium-Doped Hafnium Oxide (HZO)-Based FeFET Memory

We report a detailed characterization of the fluorite-structure-based Si:HfO2 (HSO) and Zr:HfO2 (HZO) ferroelectric (FE) materials integrated into a metal-FE-insulator-semiconductor (MFIS) FE field-effect transistors (FeFETs) gate-stack with the silicon oxynitride (SiON) interface layer. The pressing issue in the emerging FeFET concept is the limited endurance range (104-105) of program/erase cycles and is attributed to the gate-stack degradation. In a gate-first scheme, the effect of dopant type on the endurance performance of the fluorite structure-based FeFETs is investigated. The zirconium (Zr)-doped FeFETs show faster memory window (MW) degradation when compared with silicon (Si)-doped hafnium dioxide (HfO2) FeFETs. The physical mechanism responsible for endurance degradation is identified and attributed to the higher number of traps in the HZO-based FeFETs compared with the HSO ones.