Reactive ion etching of PbZr1−x TixO3 and RuO2 films by environmentally safe gases

Abstract

A new process for the reactive ion etching (RIE) of both PbZr1−x TixO3 (PZT) thin films and RuO2 electrodes is presented, employing etching gases with low ozone depletion potential (ODP) and global warming potential (GWP). The etching process has been investigated as a function of etching time, discharge power density, chamber pressure, and additive gas. Etch rates were in the range of 250–650 Å/min and 100–400 Å/min for PZT and RuO2, respectively. A large etch selectivity between PZT and RuO2 was optimized. Etched surfaces exhibited smooth morphologies. Furthermore, the ferroelectric properties of PZT were not altered significantly by the etching process. A surface residue containing Cl and F was found after etching, but this organic substance was totally removed by an after-etch bake. In addition, the etched profile of the PZT films was studied through SEM.