Growth Mechanism and Effect of Deposition Rate on Crystal Orientation in PbTiO3 Thin Film by Metallorganic Chemical Vapor Deposition.

Abstract

Lead titanate thin films were prepared on cleaved MgO (100) substrate by cold wall horizontal metallorganic chemical vapor deposition (MOCVD). Crystal structure of films was examined by X-ray 2θ/ω scan and X-ray pole-figure measurements. The growth mechanism of PbTiO3 thin film at the initial growth stage was characterized using an atomic force microscope (AFM). AFM results show that the growth mechanism of PbTiO3 thin film on MgO (100) substrate is in accordance with layer-by-layer plus islands of Stranski-Krastanov mode. Islands formed after two lattice layer with 0.8nm PbTiO3 film deposition on a MgO (100) substrate. The crystal orientation and surface roughness are dependent on deposition rate. (001) and (100) oriented grain were found at higher deposition rate (>2.5nm/min). On the other hand, (212) and (221) oriented triangular-shaped grain growth was observed at relatively lower deposition rate (<2.5nm/min), which lead to an increase of surface roughness.