AVS 47th International Symposium
    Thin Films Monday Sessions
       Session TF-MoM

Paper TF-MoM7
Electrical Characterization of Ultrathin Al@sub 2@O@sub 3@ Films Grown by Atomic Layer Deposition in a Viscous Flow Reactor

Monday, October 2, 2000, 10:20 am, Room 203

Session: Atomic Layer Chemical Vapor Deposition I
Presenter: M.D. Groner, University of Colorado
Authors: M.D. Groner, University of Colorado
J.W. Elam, University of Colorado
S.M. George, University of Colorado
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Al@sub 2@O@sub 3@ is an important insulator and is a candidate to replace SiO@sub 2@ as a gate dielectric in MOSFETS. Al@sub 2@O@sub 3@ films were deposited by atomic layer deposition (ALD) using alternating exposures of trimethylaluminum and H@sub 2@O on a variety of substrates. The films were grown in a custom viscous flow reactor employing a novel gas pulse switching method. The film growth was monitored in situ by a quartz microbalance and ex situ using ellipsometry. The electrical properties of the A l@sub 2@O@sub 3@ films were evaluated by performing I-V and C-V measurements with a mercury microprobe. The highest quality ALD Al@sub 2@O@sub 3@ films were obtained using ultraclean Si(100) substrates or molybdenum substrates. The ALD Al@sub 2@O@sub 3@ films exhibited extremely low leakage current levels. The electrical properties of the ALD Al@sub 2@O@sub 3@ films deposited on molybdenum were examined versus Al@sub 2@O@sub 3@ thickness from 30 Å to 2400 Å. The C-V measurements revealed that the dielectric constant was k=7.8 for Al@sub 2@O@sub 3@ films @>=@ 1200 Å. The dielectric constant decreased below 100 Å to k=4.0 at 25 Å. The I-V measurements showed that the Fowler-Nordheim (FN) tunneling onset voltage decreased with Al@sub 2@O@sub 3@ film thickness. The onset of FN tunneling occurred at >10 V for 600 Å films and at ~3.5 V for 60 Å Al@sub 2@O@sub 3@ films.