Characterization of platinum/titanium interlayers by AFM

Abstract

The surface microstructures of two samples of Pt/Ti interlayers, deposited onto SiO2/Si substrates by rf-magnetron sputtering, were characterized by atomic force microscopy (AFM) and X-ray diffraction (XRD). The first sample of Pt/Ti interlayer was grown at a pressure 4.6m Torr and a substrate bias current 2A. AFM studies of this interlayer show loosely packed, spherical polycrystalline Pt grains with average size 50nm. Microcracks and porosity were also present on this interlayer. The XRD studies of this sample indicated low level of preferred (111) orientations. The Pb(Zr, Ti)O3 (PZT) films grown on this interlayer also had a low level of preferred (111) orientation. The second sample of Pt/Ti interlayer was grown under pressure 2.0mTorr and using a bias current 1A. The sample exhibits strong (111) peak in XRD. Phase-contrast imaging in the tapping mode AFM revealed elongated crystallites of highly textured Pt grains. The grains are of size 6nm to 20nm in height and 100nm across and their elongation appear to follow the direction of the bias current applied to the sample. The PZT films grown on this interlayer showed a preferred (111) texture.