Synthesis of β-Mo(2)C thin films.
Thin films of stoichiometric β-Mo(2)C were fabricated using a two-step synthesis process. Dense molybdenum oxide films were first deposited by plasma-enhanced chemical vapor deposition using mixtures of MoF(6), H(2), and O(2). The dependence of operating parameters with respect to deposition rate and quality is reviewed. Oxide films 100-500 nm in thickness were then converted into molybdenum carbide using temperature-programmed reaction using mixtures of H(2) and CH(4). X-ray diffraction confirmed that molybdenum oxide is completely transformed into the β-Mo(2)C phase when heated to 700 °C in mixtures of 20% CH(4) in H(2). The films remained well-adhered to the underlying silicon substrate after carburization. X-ray photoelectron spectroscopy detected no impurities in the films, and Mo was found to exist in a single oxidation state. Microscopy revealed that the as-deposited oxide films were featureless, whereas the carbide films display a complex nanostructure.
Department of Chemical Engineering, Colorado School of Mines, Golden, Colorado 80401, USA. cwolden@mines.edu
Colin A
CA
Wolden
Anna
A
Pickerell
Trupti
T
Gawai
Sterling
S
Parks
Jesse
J
Hensley
J Douglas
JD
Way