Initial growth behavior of a lead oxide thin film on ir substrates by atomic layer deposition

Lead oxide thin films were deposited on Ir IrO2 SiO2 Si substrates by atomic layer deposition at 200°C using lead bis(3-N,N-dimethyl-2-methyl-2- propanoxide) and H2 O as the Pb precursor and oxidant, respectively. The growth rate was 0.036 nmcycle up to a thickness of ∼1 nm but decreased to 0.011 nmcycle with further increases in thickness. Atomic force microscopy showed that the surface morphology changed slightly with film growth, but this variation cannot explain the large change in growth rate. X-ray photoelectron spectroscopy showed a distinct difference in the chemical composition [O(Pb+Ir) ratio] between the two thickness regions, which might be responsible for the large discrepancy in growth rate.