Improvement of ferroelectric properties of Pt-SrBi2Nb2O9-SiO2-Si gate structure through oxygen plasma rapid thermal annealing

Abstract

A rapid thermal annealing (RTA) method in oxygen plasma improves the ferroelectric properties of SrBi2Nb2O9 (SBN) film at relatively lower temperature compared with the conventional furnace annealing in an oxygen ambient. The oxygen plasma RTA is assumed to improve the oxygen deficiency in the SBN films by increasing the oxygen content from 44 to 48 at%. The thickness of SiO2 becomes less in substantially less time, thereby improving the memory window of the Pt-SBN-SiO2-Si gate structure. The typical effective memory window is increased from 0.17 to 0.49 V at 3 V of the applied gate bias and the double remnant polarization (2P(r)) is also increased from 18.03 to 22.6 muC/cm(2). The flat-band voltage shift in the case of oxygen plasma RTA is quite stable and smaller than that in the case of furnace annealing because charge trapping is relatively less at the interface between Si and the oxygen plasma RTA-annealed SBN film. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.