AVS 50th International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuP

Paper PS-TuP8
Effect of O@sub 2@/Cl@sub 2@ Gas Mixing Ratio on Dry Etching Characteristics and Electrical Properties of Bi@sub 4-x@La@sub x@Ti@sub 3@O@sub 12@ Films

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Poster Session
Presenter: D.P. Kim, Chung-Ang University, Korea
Authors: D.P. Kim, Chung-Ang University, Korea
C.I. Kim, Chung-Ang University, Korea
K.T. Kim, Chung-Ang University, Korea
A.M. Efremov, Ivanovo State University of Chemistry and Technology, Russia
Correspondent: Click to Email
Recently, Bi@sub 4-x@La@sub x@Ti@sub 3@O@sub 12@ (BLT) has been considered a predominant candidates for ferroelectric random access memory because of its high resistance to polarization fatigue due to Bi@sub 2@O@sub 2@ layers, which reduce space charges and the unpinning of domain walls. There are a lot of reports on deposition BLT thin films, but there is no report on the etching characteristics and electrical properties of BLT in Cl@sub 2@/O@sub 2@ plasma. The BLT of 200 nm was spun-coated on a Pt/Ti/SiO@sub 2@/Si substrate by MOD. Pt thin films, which used as top electrode, were deposited on BLT. BLT thin films were etched in Cl@sub 2@/O@sub 2@ using ICP because it is easy to control energy of infringing ions to the substrate. When Cl@sub 2@-based gas mixtures were used with Ar and O@sub 2@, the etch products remaining on the substrate could be observed after etching because of their very low vapor pressure. The etch rates and selectivity of BLT thin films were investigated as a function of gas mixing ratio, rf power, dc-bias voltage, and pressure. With adding 20 % O@sub 2@ in Cl@sub 2@ plasma, increasing rf power and dc bias voltage and lowering pressure, the etch rate of BLT increased. To understand the effects of etching parameters on the etch rates of BLT thin films, the atoms of Cl and O investigated using optical emission spectroscopy and Langmuir probe. The surface of the etched BLT was investigated with x-ray photoelectron spectroscopy. To estimate electrical properties of BLT after etching process, the etched species were characterized with measuring leakage current using semiconductor parameter analyzer [HP4145B] and P-E loops of Pt/BLT/Pt capacitor using precision work station. In Cl@sub 2@/O@sub 2@ plasma, we obtained higher low remnant polarization value and lower leakage current density compared with Cl@sub 2@/Ar plasma. @FootnoteText@ Acknowledgement: This work was supported by grant No. R01-2001-00268 from the Korea Science & Engineering Foundation.