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

Paper PS-TuP5
Modeling of Etching Mechanism of PZT in Cl@sub 2@ Plasma with the Addition of Ar, O@sub 2@

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

Session: Poster Session
Presenter: S.M. Koo, Chung-Ang University, Korea
Authors: S.M. Koo, 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
Ferroelectric Lead Zirconate Titanate (Pb(Zr,Ti)O@sub 3@) thin films have been widely known as capacitor materials in nonvolatile ferroelecric random access memory (FRAM). the desirable properties such as high permittivity, high remnant polarization, fast switching speed, high Curie point and resistivity. Now, 32Mbit FRAM has been developed and some companies attempt to use FRAM as mobile phone memory. But the larger FRAM capacity, the smaller feature size. Therefore, in order to accomplish the integration of such devices, the etching process of PZT thin films with high etch rate, vertical etch profile, low by-product must be developed. PZT thin films were prepared on Pt/Ti/SiO@sub 2@/Si substrates by sol-gel processes. Pt top electrodes were deposited on PZT thin films by using rf magnetron sputtering. SiO@sub 2@ was deposited on Pt top electrodes. SiO@sub 2@ layer was etched in CF@sub 4@/Ar inductively coupled plasma with PR mask. We continued etching Pt/PZT/Pt layer without removing PR and SiO@sub 2@ patterns. PZT thin films were etched with two steps. First, it was etched with Cl@sub 2@/Ar inductively coupled plasma, then instead of Ar, it added O@sub 2@ to Cl@sub 2@ plasma. We observed the effect of etching profile in PZT thin films during etching in Cl@sub 2@/Ar, Cl@sub 2@/O@sub 2@ plasma. The ferroelectric and electrical properties were measured with a precision workstation. We obtained stable value of remanent polarization and good fatigue resistance for PZT with SiO@sub 2@ mask as compared with Pt dot, which was used as physical mask during etching process. The structural damages to the near surface of PZT are evaluated by x-ray diffraction (XRD). The chemical deformation of etched surface was surveyed x-ray photoelectron spectroscopy (XPS).