Dry etching of SrBi2Ta2O9 thin films in Cl-2/NF3/O-2/Ar inductively coupled plasmas

Abstract

A parametric study of high density plasma etching of SrBi2Ta2O9 (SBT) thin films was carried out in a planar type inductively coupled plasma (ICP) etcher with different chemistries of Cl-2/Ar, Cl-2/NF3/Ar, and Cl-2/NF3/O-2 /Ar. The etch rate was a strong function of gas concentration, ICP source power, and rf chuck power. Both Cl-2/NF3/Ar and Cl-2/NF3/O-2/Ar plasmas showed maximum etch rates of similar to 1600 Angstrom /min at 5 mTorr, 700 W ICP power, and 150 W rf chuck power. The addition of NF3 and O-2 into the Cb /Ar mixture played an important role in not only enhancing the etch rate, but also smoothing the etched surface by reducing the kinetic energy of ions. Electrical properties of the SBT films were quite dependent of plasma chemistries: Cl-2/NF3 /O-2/Ar showed the least damage in the films and resulted in overall the best polarization-electric field hysteresis loop compared to other chemistries. (C) 2001 American Vacuum Society.