Effects of Crystallization Annealing Sequence for SrBi₂Ta₂O₉ (SBT) Film on Pt/SBT Interface Morphology and Electrical Properties of Ferroelectric Capacitor

Abstract

SrBi 2 Ta 2 O 9 (SBT) film was crystallized to form fine grains and a smooth surface by rapid thermal annealing (RTA), but form large grains and a rough surface by main furnace annealing. The sequence of furnace annealing was changed to improve the morphology of the Pt/SBT interface and the leakage property of a Pt/SBT/Pt capacitor. For the conventional sequence of furnace annealing before top electrode deposition, the capacitor showed a good switching polarization (P * -P ∧ ) of 17 µC/cm 2 but a high short fail rate of 56% due to the rough Pt/SBT interface. However, using the new sequence of furnace annealing after top electrode deposition on RTA-treated SBT film, a very smooth Pt/SBT interface and a resultant low short fail rate of 7% was obtained, but the value of P * -P ∧ was decreased to 14 µC/cm 2 due to a restrained grain growth of the SBT film under Pt top electrode.