AVS 53rd International Symposium
    Electronic Materials and Processing Tuesday Sessions
       Session EM-TuA

Paper EM-TuA1
Processing of High-k Oxide Thin Films for High Energy Density Capacitors

Tuesday, November 14, 2006, 2:00 pm, Room 2003

Session: Materials for Power Electronics
Presenter: G. Sethi, The Pennsylvania State University
Authors: G. Sethi, The Pennsylvania State University
M.T. Lanagan, The Pennsylvania State University
M.W. Horn, The Pennsylvania State University
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Oxide thin films with a focus on zirconia on silicon and glass substrates were prepared with the aim of optimizing the thin film processing parameters to produce 0% crystallanity (amorphous) films. Reduction in the crystallanity will improve dielectric breakdown strength, dielectric losses and the energy density. Reactive magnetron sputtering with a metallic target (76mm) is used for producing smooth, stoichiometric and dense films with high deposition rate. It is hypothesized that crystallanity (quantified from XRD) of a film can be reduced either by high bombardment to inhibit the crystallization or by low bombardment to limit ion mobility and the crystallization. High bombardment was achieved by using a pulsed-dc deposition process at low pressure (<1.3Pa) and high power (400W). The crystallanity reduces from 70% to 40% with the high bombardment, in the 'poisoned' sputtering mode. With the transition into 'elemental' sputtering mode, the deposition rate increases (20Å/s) crystallanity reduces (22%) and films become smooth. However EDS and SEM analysis revealed that the films are highly oxygen deficient (4 wt.% O@sub 2@) and defect-full with high compressive stresses. Increasing the film oxygen content during sputtering to near-stoichiometry does not reduce crystallanity and lowers the deposition rate (1.6 Å/s). Low bombardment was achieved by using RF sputtering at high pressures (13.3Pa) and low power (<200W). As imagined, the crystallanity in the film reduces with bombardment to 5%, but the deposition rate is substantially lowered (0.3 Å/s) with maximum 100nm thickness. The films are stoichiometric and near-stress free (-200MPa). The substrate temperature rise to as low as 70°C during the sputtering is responsible for this small crystallization. The temperature rise and hence crystallanity will be reduced by using liquid Nitrogen cooled substrate. Finally, the correlation between crystal structure and dielectric properties will be presented.