Dry etching of BaSrTiO3 and LaNiO3 thin films in inductively coupled plasmas

High density plasma etching of (Ba, Sr)TiO3 (BST) and LaNiO3 (LNO) thin films was performed in two different plasma chemistries, Cl-2/Ar and CH4/H-2/Ar. While the latter chemistry produced extremely low etch rates (less than or equal to 100 Angstrom min(-1)) under all con ditions, the Cl-2/Ar produced smooth anisotropic pattern transfer. The etching was still strongly ion-assisted, but maximum removal rates of similar to 900 Angstrom min(-1) for both materials were achieved with selectivities of similar to 16 for BST and similar to 7 for LNO over Si. A single layer of thick (similar to 7 mu m) photoresist is an effective mask under these conditions. (C) 1999 The Electrochemical Society. S0013-4651(99)01-086-1. All rights reserved.