AVS 50th International Symposium
    Applied Surface Science Wednesday Sessions
       Session AS-WeP

Paper AS-WeP4
Plasma Etching of (Ba,Sr)TiO@sub 3@ Thin Films for DRAM Applications

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: G.H. Kim, Chung-Ang University, Korea
Authors: G.H. Kim, Chung-Ang University, Korea
C.I. Kim, Chung-Ang University, Korea
D.P. Kim, Chung-Ang University, Korea
K.T. Kim, Chung-Ang University, Korea
Correspondent: Click to Email
(Ba,Sr)TiO@sub 3@ (BST) thin film attracts a great interest as a new dielectric material in capacitors for the next generation ultralarge scale integrated dynamic random access memories, such as giga bit DRAM in the wide range of research institutes to semiconductor industries because of its large dielectric constant, low leakage current, low dielectric loss, lack of fatigue, and low Curie temperature. A lot of papers have been presented on BST film characteristics using growth methods, however, its patterning have been studied less. In order to realize the higher integration, it is important to minimize the dimension of storage capacitors, simplify the memory cell structure and maintain sufficient accumulated electric charge within a smaller capacitor. Although BST thin films are excellent capacitor dielectric materials for DRAMs, several problems such as fine pattern transfer and no plasma induced-damage etc. In order to solve these problems, the etch behavior of BST with Ar/Cl@sub 2@/CF@sub 4@ gas mixtures is investigated with inductively coupled plasma (ICP). In this study, ICP etching system was used for BST etching. The etching characteristics of BST thin films were investigated in terms of etch rates and selectivity as a function of Cl@sub 2@/Ar and additive CF@sub 4@ into Cl@sub 2@/Ar, rf power, dc bias voltage and chamber pressure. The Cl@sub 2@/Ar and additive CF@sub 4@ into Cl@sub 2@/Ar plasmas were characterized by optical emission spectroscopy and Langmuir probe analysis. The chemical states on the etched surface were investigated with x-ray photoelectron spectroscopy. Scanning electron microscopy was used to investigate the etching profile.