Electrical properties of Bi4-xEuxTi3O12 (BET) thin films after etching in inductively coupled CF4/Ar plasma

The etch properties of Bi4-xEuxTi3O12 (BET) thin films were evaluated with inductively coupled CF4/Ar plasma. We obtained the maximum etch rate of 78 nm/min at the gas mixing ratio of CF4 (10%)/Ar (90%). This result may suggest that sputtering by Ar ions is more effective than chemical etching by fluorine atoms for B4-xEuxTi3O12 (BET) etching. In X-ray photoelectron spectroscopy analysis, non-volatile etch byproducts (EuF2: 1380 degreesC, EuF3: 1276 degreesC) were observed. After the etching, the electrical properties of BET capacitors were characterized in terms of hysteresis curves, leakage current and switching polarization. After etching in CF4/Ar plasma, the remanent polarization decreased and the leakage current increased. The etched capacitors in the Ar/CF4 plasma retained 58% of their original polarization at 10(5) cycles. After the annealing at 600 degreesC in an O-2 atmosphere for 10 min, the ferroelectric properties were significantly recovered. The degradation of electrical properties after the etching was considered due to the physical effect of ion bombardment and chemical residue contamination. (C) 2003 Elsevier B.V. All rights reserved.