A high-k Y2O3 charge trapping layer for nonvolatile memory application

Abstract

In this letter, a silicon-oxide-high-$k$ -oxide-silicon memory structure using a high-$k$ ${\mathrm{Y}}_2{\mathrm{O}}_3$ film as the charge trapping layer is reported for nonvolatile memory application. From x-ray photoelectron spectroscopic analysis, we found that the ${\mathrm{Y}}_2{\mathrm{O}}_3$ layer formed after annealing at $700°\mathrm{C}$ for $30\mathrm{s}$ . When using channel hot electron injection for charging and band-to-band hot hole for discharging, the high-$k$ ${\mathrm{Y}}_2{\mathrm{O}}_3$ memories exhibited large threshold voltage shifting (memory window of $2.3\mathrm{V}$ ), excellent data retention (charge loss of 8% at room temperature), and good endurance characteristics (program/erase cycles up to ${10}^5$ ) because of the higher probability for trapping the charge carrier due to the formation of a well-crystallized ${\mathrm{Y}}_2{\mathrm{O}}_3$ structure.