Yttria-stabilized zirconia (YSZ) has a good potential as a gate dielectric in various metal-oxide-semiconductor field effect transistor (MOSFET) devices for displays and a precise and anisotropic plasma etching is required for the integration of the YSZ gate structure. High density plasma etching of YSZ thin film was performed in halogen-based inductively coupled plasmas (ICPs) and the effect of process variables such as plasma composition, ICP source power and rf chuck power on the YSZ etch characteristics was examined. Higher YSZ etch rates were obtained in chlorine-based (10BCl3/5Ar and 10Cl2/5Ar) ICP discharges because of the higher volatilities of metal chloride etch products. Maximum etch rates of 1042.5 Å/min and 796 Å/min were obtained in 10BCl3/5Ar and 10CF4/5Ar ICP discharges, respectively. 10CF4/5Ar discharges were found to provide a very smooth surface morphology while a significant surface roughening has occurred after etching at high rf chuck power conditions in 10BCl3/5Ar discharges. The YSZ surfaces etched in 10BCl3/5Ar and 10CF4/5Ar maintained the stoichiometry and highly anisotropic features were transferred into YSZ by 10CF4/5Ar ICP etching.

Keywords: YSZ thin film, High density plasma etching, Halogen-based inductively coupled plasmas, Etch rate, Etch selectivity, Anisotropy.