Atomic layer deposition of PbTiO3 and its component oxide films

Abstract

Atomic layer deposition of ferroelectric PbTiO₃ (PTO) thin films and its component oxide films were attempted using the Pb(DMAMP)₂ and Ti(Oi-Pr)₄ or Ti(Ot-Bu)₄, as the Pb-and Ti-precursors, respectively, and H₂O as oxidant at a wafer temperature of 200 on Ir/IrO₂/SiO₂/Si substrate. The stoichiometric PTO thin films were grown by a proper control of the cycle ratio of the PbO and TiO₂ cycles. The increase of the PTO film growth rate due to the cayalytic effect was observed compared to its component oxide films for both processes using Ti(Oi-Pr)₄ or Ti(Ot-Bu)₄. The as-deposited PTO film was amorphous so that two different post-deposition annealing method, i.e. slow and fast furnace annealing at 600 , were used to crystallize PTO film. The higher growth rate of PTO film grown using Ti(Oi-Pr)₄ due to the higher growth rate of TiO₂ film compared to the case using Ti(Ot-Bu)₄ resulted in less dense PTO film with the higher density of micro-pores inside as well as surface of film after the fast furnace annealing. Slow furnace annealing improved the surface morphology of PTO film and reduced the micro-pore density. Post-deposition annealing transformed amorphous film to polycrystalline film of perovskite sturcure with an a-axis preferred crystallographic orientation.