Oxygen plasma rapid thermal annealing to improve the electrical properties of Pt–SrBi[sub 2]Nb[sub 2]O[sub 9]–SiO[sub 2]–Si gate structure

Abstract

A rapid thermal annealing (RTA) method in oxygen plasma improves the ferroelectric properties of SrBi2Nb2O9 (SBN) film at relatively lower temperature than the conventional furnace annealing in oxygen ambient. The oxygen plasma RTA raises the oxygen content from 44 to 48 at. %, which may improve the oxygen deficiency in the SBN films. The thickness of SiO2 becomes thinner due to the shorter RTA time. As a result, a typical effective memory window of the Pt–SBN–SiO2–Si gate structure is increased from 0.17 to 0.49 V at 3 V of the applied gate bias and the remnant polarization is also increased from 18.03 to 22.6 C/cm2 at ±6 V. The flat band voltage shift of the oxygen plasma RTA samples is quite stable and smaller than that of the furnace annealed ones because charge trapping is relatively smaller at the interface between Si and the oxygen plasma annealed SBN film.