유도결합 CF4/Ar 플라즈마에 의한 Bi4-xLaxTi3O12 박막의 식각 표면 반응

Abstract

Etching species in CF4/Ar plasma and the behavior of etching rate of Bi4-xLaxTi3O12 (BLT) films were investigated in inductively coupled plasma (ICP) reactor in terms of etch parameters. The etching rate as functions of CF4 contents showed the maximum 803 /min at 20% CF4 addition in CF4/Ar plasma. The increase of rf power and dc bias voltage caused to an increase of etch rate. The variation of relative volume densities for F and Ar atoms were measured with the optical emission spectroscopy (OES). The chemical states of BLT were investigated with using X-ray photoelectron spectroscopy (XPS). XPS narrow scan analysis shows that La-fluorides remained on the etched surface. The presence of maximum etch rate at CF4(20%)/Ar(80%) may be explained by the concurrence of two etching mechanisms such as physical sputtering and chemical reaction. The roles of Ar ion bombardment include destruction of metal (Bi, La, Ti)-O bonds as well as assistant for chemical reaction of metals with fluorine atoms.