Etching mechanism of YMnO3 thin films in Cl-2/Ar gas chemistries

Ferroelectric YMnO3 thin films are excellent dielectric materials for high integrated ferroelectric random access memory with a metal - ferroelectric- silicon field effect transistor structure. In this study, YMnO3 thin films were etched with Cl-2/Ar gas chemistries in inductively coupled plasma. The maximum etch rate of YMnO3 thin films is 285 Angstrom /min under Cl-2/(Cl- 2+Ar) of 1.0, 600 W/-200 V and 15 mTorr. The selectivities of YMnO3 over Ce O2 and Y2O3 are 2.85 and 1.72, respectively. The results of x-ray photoelec tron spectroscopy (XPS) reflect that Y is removed dominantly by chemical re action between Y and Cl, while Mn is removed more effectively by Ar ion bom bardment than chemical reaction. The results of the secondary ion mass spec trometer were equal to these of XPS. The etch profile of the etched YMnO3 f ilm is approximately 65 degrees and free of residues at the sidewall. (C) 2 001 American Vacuum Society.