AVS 53rd International Symposium
    Thin Film Monday Sessions
       Session TF-MoA

Invited Paper TF-MoA3
Atomic Layer Deposition of In@sub 2@O@sub 3@ Using Cyclopentadienyl Indium: A New Synthetic Route to Transparent Conducting Oxide Films

Monday, November 13, 2006, 2:40 pm, Room 2022

Session: ALD and Applications II
Presenter: J.W. Elam, Argonne National Laboratory
Authors: J.W. Elam, Argonne National Laboratory
A.B.F. Martinson, Northwestern University
M.J. Pellin, Argonne National Laboratory
J.T. Hupp, Northwestern University
Correspondent: Click to Email
Indium Oxide (In@sub 2@O@sub 3@) forms the basis for an important class of transparent conducting oxides (TCO) that see wide use in optoelectronic devices, flat-panel displays and photovoltaics. Here we present a new method for depositing In@sub 2@O@sub 3@ thin films by atomic layer deposition (ALD) using alternating exposures to cyclopendadienyl indium and ozone. Using a precursor vaporization temperature of 40°C and deposition temperatures of 200-450°C, we measure growth rates of 1.3-2.0 Å/cycle. A significant advantage of this synthesis route over previous techniques is the ability to conformally coat porous materials such as anodic aluminum oxide membranes. The deposited films are nanocrystalline, cubic phase In@sub 2@O@sub 3@ and are highly transparent and conducting. In situ quadrupole mass spectrometry and quartz crystal microbalance measurements reveal a mechanism in which approximately 1 in 6 of the initial Cp ligands remain on the surface following each InCp exposure, and the remaining Cp ligand is burned off during the subsequent O@sub 3@ exposure to form CO@sub 2@. Using this method, we demonstrate for the first time the conformal coating of very high aspect ratio porous membranes with ALD In@sub 2@O@sub 3@. This technique will enable the functionalization of porous materials with In-based TCO films for the fabrication of novel photovoltaic devices.