Dry Etching of BST using Inductively Coupled Plasma

Abstract

BST thin films were etched with inductively coupled CF4/(Cl2+Ar) plasmas. The etch characteristics of BST thin films as a function of CF4/(Cl2+Ar) gas mixtures were analyzed using optical emission spectroscopy (OES) and Langmuir probe. The BST films in CF4/Cl2/Ar plasma is mainly etched by the formation of metal chlorides which depends on the emission intensity of the atomic Cl and the bombarding ion energy. The maximum etch rate of the BST thin films was 53.6 nm/min because small addition of CF4 to the Cl2/Ar mixture increased chemical and physical effect. A more fast etch rate of BST films can be obtained by increasing the DC bias and the RF power, and lowering the working pressure.