AVS 52nd International Symposium
    Thin Films Tuesday Sessions
       Session TF-TuM

Paper TF-TuM6
Coating Nanoparticles by Atomic Layer Deposition in a Rotary Fluidized Bed Reactor: Al@sub 2@O@sub 3@ ALD on ZrO@sub 2@

Tuesday, November 1, 2005, 10:00 am, Room 306

Session: Atomic Layer Deposition - Oxides
Presenter: J.A. McCormick, University of Colorado at Boulder
Authors: J.A. McCormick, University of Colorado at Boulder
A.W. Weimer, University of Colorado at Boulder
S.M. George, University of Colorado at Boulder
Correspondent: Click to Email
Ultrathin and conformal Al@sub 2@O@sub 3@ films have been grown by atomic layer deposition (ALD) on ZrO@sub 2@ particles with diameters of 60 nm and 400 nm using sequential exposures of trimethylaluminum and H@sub 2@O. This Al@sub 2@O@sub 3@ ALD on gram-scale quantities of high surface area ZrO@sub 2@ nanoparticles was performed in a novel rotary fluidized bed reactor. The rotary fluidized bed reactor consisted of a stainless steel porous metal cylinder that rotated inside a vacuum system. The nanoparticles were contained inside the porous metal cylinder and the gaseous reactants and products could easily diffuse through the porous walls without particle loss. A magnetically coupled rotary motion feedthrough rotated the porous metal cylinder and provided a fluidization-like mixing between the particles and the reactants. The Al@sub 2@O@sub 3@ ALD films were deposited on the ZrO@sub 2@ nanoparticles at 180°C with a growth rate of 1.8 Å/cycle. The composition of the Al@sub 2@O@sub 3@ ALD coating was verified using Auger electron spectroscopy, x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Transmission electron microscopy and BET surface area analysis were utilized to determine the conformality of the Al@sub 2@O@sub 3@ ALD coating and to check for particle coalescence. The Al@sub 2@O@sub 3@ ALD film uniformly coats the primary ZrO@sub 2@ particles and there was no evidence for any particle coalescence.