Reactive ion etching of sol–gel-derived BST thin film

Perovskite (Ba,Sr)TiO3 (BST) thin film is promising dielectric and ferroelectric material for future generation integrated DRAMs, MEMS, and other devices. The etching properties of BST films were widely concerned. The etching characteristics of sol–gel-derived BST films were investigated in a reactive ion etching (RIE) setup using CHF3/Ar plasma. The morphology and etching rate were measured by atomic force microscopy (AFM). The surface states of each element in BST films were examined by X-ray photoelectron spectroscopy (XPS). The etching mechanism of BST thin film in RIE was the cooperation of ion bombardment, ions assist chemical reaction and reaction etching effects. The highest etching rate of BST films was 5.1 nm/min.