Effects of O-2 annealing after etching SrBi2Ta2O9 thin film in Cl-2/CF4/Ar plasma

Abstract

The etching and 0, annealing properties of SrBi2Ta2O9 (SBT) thin films were investigated. The etch rates of SBT thin films increased with 20% additive Cl-2 into CF4/Ar plasma, which indicated that SBT thin films could be removed by chemically enhanced ion etching mechanism. The increased etch rate of SBT was due to lower boiling points of SrCl2 and BiCl3, than those of SrF2, and BiF3. The etch profile of etched SBT thin films at 20% Cl-2 in Cl-2/CF4/Ar plasma was over 80 degrees and the top corner of SBT was clean. The SBT thin films during etching process were influenced on the electrical properties of ferroelectricity by the plasma induced damages. A decreased total bismuth-oxide concentration was influenced on the electrical properties of SBT thin films. Therefore, the changes of stoichiometry on the etched surface of the SBT thin films were measured by X-ray photoelectron spectroscopy (XPS). After annealing at 700 degreesC in oxygen ambient, the decreased remnant polarization was recovered in the Pt/SBT/Pt capacitors. (C) 2002 Elsevier Science B.V. All rights reserved.