The charge storage characteristics of ZrO2 nanocrystallite-based charge trap nonvolatile memory

Abstract

ZrO2 nanocrystallite-based charge trap flash memory capacitors incorporating a (ZrO2)0.6(SiO2)0.4 pseudobinary high-k oxide film as the charge trapping layer were prepared and investigated. The precipitation reaction in the charge trapping layer, forming ZrO2 nanocrystallites during rapid thermal annealing, was investigated by transmission electron microscopy and X-ray diffraction. It was observed that a ZrO2 nanocrystallite-based memory capacitor after post-annealing at 850 °C for 60 s exhibits a maximum memory window of about 6.8 V, good endurance and a low charge loss of ∼25% over a period of 10 years (determined by extrapolating the charge loss curve measured experimentally), even at 85 °C. Such 850 °C-annealed memory capacitors appear to be candidates for future nonvolatile flash memory device applications.