AVS 49th International Symposium
    Surface Engineering Tuesday Sessions
       Session SE+TF-TuA

Paper SE+TF-TuA3
A Combinatorial Sputtering Approach to Properties Modification in Polaron Conducting Films

Tuesday, November 5, 2002, 2:40 pm, Room C-111B

Session: Systems Design of Functional Coatings
Presenter: R.R. Owings, University of Florida
Authors: R.R. Owings, University of Florida
P.H. Holloway, University of Florida
C.F. Windisch, Jr., Pacific Northwest National Laboratory
G.J. Exarhos, Pacific Northwest National Laboratory
Correspondent: Click to Email
The influence of sputtering parameters and cation composition on measured resistivity and optical transparency of mixed transition metal spinel oxides (AB@sub 2@O@sub 4@) has been systematically studied. A two-cathode system was used to deposit films having continuously variable compositions onto glass, silicon, and sapphire substrates (25 mm in length) as a function of process gas composition and pressure, target to substrate distance, substrate temperature, sputtering power, and sputtering time. The intent was to correlate transparency and conductivity with composition, phase purity, grain size, film thickness, and cation oxidation state. Both mixed metal oxide and metal alloy targets (nickel, cobalt, rhodium, palladium) were used for sputter deposition with variable gas mixtures of argon and oxygen. Post deposition annealing of sputtered films was found to lower film resistivity but had little effect on optical transparency. Film resistivity returned to its original value upon standing in air for two weeks. However, partial substitution of lithium for cobalt was found to not only improve the conductivity and increase transparency but also to significantly reduce property variations when subjected to post deposition annealing in air. Results suggest that the presence of lithium stabilizes higher oxidation states of the resident transition metal cations leading to lattice compression and diminished oxygen transport.