Cl-based 플라즈마에 의한 YMnO3 박막의 식각 damage에 관한 연구

Abstract

Ferroelectric YMnO3 thin films were etched with Ar/Cl2 and CF4/Cl2 inductivly coupled plasma (ICP). The maximum etch rate of YMnO3 thin film was 300 Å/min at a Ar/Cl2 gas mixing ratio of 2/8, a RF power of 800 W, a dc bias of 200 V, a chamber pressure of 15 mTorr, and a substrate temperature of 30 ºC. From the X-ray photoelectron spectroscopy (XPS) analysis, yttrium etched by chemical reactions with Cl radicals assisted by Ar ion bombardments in Ar/Cl2 plasma. In CF4/Cl2 plasma, yttrium are remained on the etched surface of YMnO3 and formed of nonvolatile YFx compounds Manganese etched effectively by chemical reactions with Cl and F radicals. From the X-ray diffraction (XRD) analysis, the (0004) diffraction peak intensity of the YMnO3 thin film etched in Ar/Cl2 plasma shows lower value than that in CF4/Cl2 plasma. It indicates that the crystallinty of YMnO3 thin film is more easily damaged by the Ar ion bombardment than the changes of stoichiometry due to nonvolatile etch by-products.