AVS 51st International Symposium
    Nanometer-scale Science and Technology Tuesday Sessions
       Session NS-TuP

Paper NS-TuP18
Modeling, Fabrication and Characterization of Vertically Aligned Carbon Nanofiber (VACNF) Based Triode Field Emission Devices for Use in Massively Parallel Digital E-Beam Array Lithography (DEAL)

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: X. Yang, University of Tennessee at Knoxville
Authors: X. Yang, University of Tennessee at Knoxville
W.L. Gardner, Oak Ridge National Laboratory
L.R. Baylor, Oak Ridge National Laboratory
H. Cui, Oak Ridge National Laboratory
D.K. Hensley, Oak Ridge National Laboratory
R.J. Kasica, Oak Ridge National Laboratory
D.K. Thomas, Oak Ridge National Laboratory
M.A. Guillorn, Cornell Nanofabrication Facility
M.L. Simpson, Oak Ridge National Laboratory
Correspondent: Click to Email
Field emission triodes have been fabricated for application in massively parallel Digital E-beam Array Lithography (DEAL) at Oak Ridge National Laboratory (ORNL)@footnote 1@. Vertically Aligned Carbon Nanofibers (VACNFs) were individually grown as the field emission cathode elements. Three electrodes are fabricated: the cathode, the extraction electrode and the focus electrode, separated from each other by 1µm SiO@sub 2@. We have demonstrated Fowler-Nordheim emission characteristics and electron beam focusing. The variation of beam diameter with focus aperture potential observed both optically and lithographically agrees well with electron beam simulations. Further modeling indicates that these devices will benefit from thicker (500 nm vs. 100 nm) electrodes in three ways: (1) improved focus effectiveness; (2) decreased optimal-beam size; and (3) increased depth of focus. The capability to realize thicker electrodes using a low-pressure chemical vapor deposition (LPCVD) tool is being implemented based on these results. Effects on beam shape and size due to electrode or field emitter offsets from coaxial geometry were also investigated with a 3D structure simulation. It was shown that a converged electron beam shape of 50nm or less in diameter is still obtained in the presence of small geometrical offsets. Preliminary 3x3 arrays of these devices have been fabricated and are being tested. While the extraction and focus electrodes are individually addressed the cathode is presently common to all devices. Individually addressed cathode designs, important for implementing DEAL with dose control circuits integrated into the device, are being investigated. Details of device modeling, fabrication, and characterization as well as device development to minimize offsets and realize individual cathode addressing will be presented. @FootnoteText@ @footnote 1@ ORNL is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract No. DE-AC05-00OR22725.