유도결합 C1₂/CF₄/Ar 플라즈마를 이용한 CeO₂ 박막 식각후 표면반응

Surface Reactions after the Etching of CeO₂ Thin films using Inductively Coupled C1₂/CF₄/Ar Plasmas

본 연구에서는 ICP 식각장비에서 700 W의 RF전력과 -200 vo1t의 dc 바이어스 전압 및 15 mTorr의 반응로 압력에서 Ar/CF₂ 혼합가스에 C1₂가스를 첨가하면서 CeO₂ 박막을 식각하였다 최대식각 속도는 10%의 C1₂ 가스를 첨가하였을 시에 250 Å/min이었고, 이 조건에서 SBT에 대한 식각 선택비는 0.4이었다. XPS를 이용하여 식각된 CeO₂ 박막의 표면반응을 검토하였다. Ce 피크는 대부분 CeO₂또는 Ce₂O₃형태로 Ce-O 결합상태임을 관찰할 수 있었다. 대부분의 Cl 피크는 CeClx 또는 Ce_x/O_yCl_z 형태로 Ce 원자와 결합하고 있었다

In this study, CeO₂ thin films were etched with an addition of Cl₂ gas to Ar/CF₄ gas mixing in an inductively coupled plasma (ICP) etcher by the etching parameter such as RF power of 700 W, chamber pressure of 15 mTorr and dc bias voltage of -200 volts. The etch rate of CeO₂ films was 250 Å/min with an addition of 10% Cl₂ gas to Ar/CF₄ gas mixture and the selectivity to SBT film was 0.4 at that condition. The surface reactions of the etched CeO₂ thin films were investigated by X-ray photoelectron spectroscopy (XPS). It was analyzed that Ce peaks were mainly observed in Ce-O bonds formed CeO₂ or Ce₂O₃ compounds. Cl peaks were detected by the peaks of Cl 2p_{3/2} and Cl 2p_{1/2}. Almost all of Cl atoms were combined with Ce atoms like CeCl_x or Ce_x/O_yCl_z compounds.