AVS 53rd International Symposium
    Thin Film Monday Sessions
       Session TF-MoA

Paper TF-MoA7
Atomic Layer Deposition of Electrocatalytic Platinum for Solid Oxide Fuel Cells

Monday, November 13, 2006, 4:00 pm, Room 2022

Session: ALD and Applications II
Presenter: X. Jiang, Stanford University
Authors: X. Jiang, Stanford University
S.F. Bent, Stanford University
Correspondent: Click to Email
Atomic layer deposition (ALD) has been actively explored for a number of applications. It is currently being investigated as an enabling technology to fabricate thin film solid oxide fuel cells (SOFCs). ALD can potentially be used to grow several fuel cell components, including electrolyte, catalyst, and electrode materials, at ultrathin, nanometer-scale thickness. Here we explore the use of ALD for the deposition of the Pt electrocatalyst for an SOFC. We have successfully carried out the Pt ALD process using (methylcyclopentadienyl)trimethylplatinum (MeCpPtMe@sub3@) and O@sub2@ as precursors and N@sub2@ as a carrier and purging gas. Ex situ analysis has been carried out on the as-deposited Pt films using a variety of analytical techniques, including atomic force microscopy (AFM),scanning electron microscopy (SEM), X-ray reflectometry (XRR), X-ray photoelectron spectroscopy (XPS), and four-point probe method. The analysis on native oxide-coated silicon wafers shows that the as-deposited platinum film is of excellent uniformity, with no measurable impurities and low electrical resistivity. We have also shown that Pt films of high quality can be deposited by ALD on RF-sputtered yttria stabilized zirconia (YSZ), a good candidate for the SOFC electrolyte. Deposition on YSZ is found to occur with a shorter incubation period than that on SiO@sub2@. The expected operating temperature of the SOFC ranges from 300°C to 1000°C. Post-ALD annealing studies of the morphology and resistivity of the Pt film as a function of temperature and film thickness show that for temperatures up to at least 550°C, resistivity remains relatively constant. However, film roughness, which is desirable for catalytic activity, increases with temperature. In addition, we have carried out area selective ALD of Pt on YSZ using microcontact printing for fabrication of the electrode and current collector for the SOFC. Results of these studies will be presented.