Cl2/CF4 플라즈마에 Ar, O2 첨가에 따른 PZT 박막의 식각 손상 개선 효과

Abstract

In this study, the reduce of plasma etching damage in PZT thin film with additive gas and re-annealing after etching have been investigated. The PZT thin films were etched as a function of Cl2/CF4 with addition of Ar and O2 with inductively coupled plasma. The etch rates of PZT thin films were 1450 Å/min at 30% additive Ar and 1100 Å/min at 10% additive O2 into Cl2/CF4 gas mixing ratio of 8/2. In order to reduce plasma damage of PZT thin films after etching, the etched PZT thin films were re-annealed at various temperatures at O2 atmosphere. From the hysteresis curves, the ferroelectric properties are improved by O2 re-annealing process. The improvement of ferroelectric behavior at annealed PZT films is consistent with the increase of the (100) and (200) PZT peaks revealed by x-ray diffraction (XRD). From x-ray photoelectron spectroscopy (XPS) analysis, the intensity of Pb-O, Zr-O and Ti-O peak are increased and the chemical residue peak is reduced by O2 re-annealing. The ferroelectric behavior consistent with the dielectric nature of TixOy is recovered by O2 recombination during rapid thermal annealing process.