Etching mechanism of ferroelectric film etched by helicon plasma method

The etching behavior and properties of SBT (SrBi₂Ta ₂O₉) thin films were investigated by varying the etching parameter such as gas mixing ratio in helicon plasma. We could observe that the etch rates of SBT thin films were varied with etch parameters. The decrease of Bi atoms is dominant in physical etching, while the decrease of Ta atoms is dominant in chemical reaction with Cl₂ radicals. The crystalline phases and surface reaction of the etched SBT thin films were investigated with X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Physical reaction was a major factor which made the plasma induced damage of SBT film, while the chemical reaction was a minor factor. The result of secondary ion mass spectrometer (SIMS) analysis was compared with that of XPS analysis and the results showed almost the same trends.