AVS 49th International Symposium
    Dielectrics Thursday Sessions
       Session DI+EL-ThA

Paper DI+EL-ThA2
Electrical Properties of the Bi@sub 4-x@La@sub x@Ti@sub 3@O@sub 12@ Films Etched in Cl@sub 2@/Ar Inductively

Thursday, November 7, 2002, 2:20 pm, Room C-107

Session: Processing and Properties of Dielectric Materials
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
For last decade, Bi-layered perovskites materials including SrBi@sub 2@Ti@sub 2@O@sub 9@ and Bi@sub 4-x@La@sub x@Ti@sub 3@O@sub 12@ (BLT) show high resistance to polarization fatigue due to Bi@sub 2@O@sub 2@ layers, which reduce space charges and the unpinning of domain walls. The BLT of 200 nm was spun-coated on the Pt/Ti/SiO@sub 2@/Si substrate by MOD. Pt thin films, which used as not only the top electrode but also as physical mask, were deposited on the BLT films. However, there is no report on the electrical characteristics of BLT thin films after etching process. BLT thins films were etched in Cl@sub 2@/Ar using ICP due to easy control bias power. The etch rates and selectivity of BLT thin films were investigated as a function of gas mixing ratio, rf power and dc-bias voltage. With adding 20 % Cl@sub 2@ in Ar 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 the ions of Ar were investigated in Cl@sub 2@/Ar plasma 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. According to our experiment, the etch rate of BLT highly depends on removing etch-product (LaCl@sub 2@: Tm = 2700 °C) effectively. After etching process, we obtained low remnant polarization value and high leakage current density compared with virgin sample. The degraded electrical properties of BLT were recovered after annealing at 800 °C for 1 hour. @FootnoteText@ Acknowledgement This work was supported by grant No. R01-2001-00268 from the Korea Science & Engineering Foundation.