Micropatterning of SrBi_2Ta_2O_9 Ferroelectric Thin Films Using a Selective Deposition Technique Combined with Patterned Self-Assembled Monolayers and Liquid-Source Misted Chemical Deposition

摘要

We demonstrated a novel patterning method using a selective deposition technique of ferroelectric thin films without etching. Self-assembled monolayers (SAMs) of 1H,1H,2H,2H-perfluorodecyltriethoxysilane [CF_3(CF_2)_7CH_2CH_2Si(OC_2H_5)_3; FAS] were patterned on Pt/SiO_2/Si substrates. The patterned SAMs on these surfaces defined the selective area on which the liquid-source misted chemical deposition (LSMCD) of SrBi_2Ta_2O_9 (SBT) was performed. Pt top electrodes were then sputter-deposited on the patterned SBT films by the liftoff method. The remanent polarization (P_r) of the obtained SET films was 7.5 μC/cm~2 with good squareness of the hysteresis loops for 50 μm x 50 μm square capacitors. By this method, we succeeded in fabricating uniform lines of ferroelectric thin films of 0.5 μm width. These results show that a selective deposition technique is promising for realizing high-density ferroelectric random access memories (FeRAMs).