Impact of Kr gas mixing in oxygen plasma etching of ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer films

Oxygen plasma etching characteristics of ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer films are investigated. It was found in MFM (M: metal; F: ferroelectric) capacitors that plasma damage effects to the ferroelectric properties were insignificant when Au metal masks were used. On the contrary, C-V (capacitance versus voltage) characteristics were significantly degraded in plasma-etched MFIS (I: insulator; S: semiconductor) diodes. The origin of this phenomenon is speculated to be degradation of the Si O2 Si interface by energetic oxygen ions and then mixing of Kr gas to the oxygen plasma is attempted to decrease the plasma damage.