Atomic layer deposition of ruthenium films on strontium titanate.

Atomic layer deposition of ruthenium on SrTiO3 layers was investigated using (C2H5C5H4). (NC4H4)Ru and air as precursors. For comparison, the growth was studied also on ZrO2 films and SiO2/Si surfaces. Deposition temperature was 325 degrees C. Using rather short but intense air pulses, smooth and uniform Ru films were deposited on SrTiO3. The films were crystallized at early stages of the growth. The nucleation density and rate on SrTiO3 were notably lower compared to that on ZrO2 and SiO2, but the physical qualities including the film conductivity were considerably enhanced after reaching Ru film thickness around 10 nm.