Selective etching of HfO₂ by using inductively-coupled Ar/C ₄F₈ plasmas and the removal of etch residue on si by using an O₂ plasma treatment

HfO₂ thin films were etched using an Ar/C₄F ₈ inductively-coupled plasma (ICP) for high etch selectivity of HfO₂/Si and the fluorocarbon remaining on the silicon surface after the HfO₂ etching was removed by using an oxygen ICP and its effect was investigated. The etching of HfO₂ using Ar/C₄F ₈ magnetically-enhanced ICP (MEICP) improved the etch selectivity of HfO₂/Si by more than three times, possibly due to the differences in the thicknesses of the fluorocarbon polymer layers formed on the surfaces of HfO₂ and Si. In addition, the oxygen ICP treatment after the HfO ₂ thin film etching by using Ar/C₄F₈ ICP removed the polymer layer on the silicon surface effectively, so for the HfO₂-nMOSFET (n-type metal-oxied-semiconductor-field-effect- transistors) devices, an improvement in drain current of more than 60 % could be observed after the O₂ ICP treatment.