Effect of etch gas on dry etching of ferroelectric Bi3.25La0.75Ti3O12 thin films

The etch study of ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films has been performed using C2Fe6, Cl2 and HBr gases in an inductively coupled plasma (ICP). The etch rate and etch selectivity of BLT films were investigated as a function of gas concentration for each gas. The etch rates in the range of 700-900 Å/min were obtained for C2F6 gas while the etch rates by Cl2 and HBr gases were in the range of 700-1100 Å/min under the etch conditions used in this study. The etch profiles of BLT films by each gas were observed using field emission scanning electron microscopy (FESEM). Cl2 gas was more effective in obtaining a fast etch rate and clean etch profile than C2F6 and HBr gases. The surface chemistry of BLT films etched in a Cl2 plasma was analyzed by X-ray photoelectron spectroscopy (XPS).