Effects of crystallization annealing sequence for SrBi2Ta2O9 (SBT) film on Pt/SBT interface morphology and electrical properties of ferroelectric capacitor

SrBi2Ta2O9 (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/SET 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 muC/cm(2) but a high short fail rate of 56% due to the rough Pt/SET interface. However, using the new sequence of furnace annealing after top electrode deposition on RTA-treated SET 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 muC/cm(2) due to a restrained grain growth of the SET film under Pt top electrode.