Studies on Thermal Atomic Layer Deposition of Silver Thin Films

The growth of Ag thin films by thermal atomic layer deposition (ALD) was studied. A commercial Ag compound, Ag­(fod) (PEt3), was applied with a reducing agent, dimethyl amineborane (BH3(NHMe2)). A growth rate of 0.3 Å/cycle was measured for Ag at a deposition temperature of 110 °C. The purity of the particulate, polycrystalline Ag thin films was studied with time-of-flight elastic recoil detection analysis (TOF-ERDA) and X-ray photoelectron spectroscopy (XPS). TOF-ERDA showed only small amounts of impurities in the film deposited at 110 °C, the main impurities being oxygen (1.6 at. %), hydrogen (0.8 at. %) and carbon (0.7 at. %). In addition to the conventional ALD process, the idea of activation of the amineborate inside the ALD reactor was tested. A catalytic Ru surface was utilized to convert BH3(NHMe2) into possibly even more reducing species inside the reactor without contaminating the catalysts with a growing film.