Ferroelectric Properties of Lead-Free (Bi,La)4Ti3O12 Thin Film Deposited on MTP Cell Structure for High Density FeRAM Device
Ferroelectric properties of Pb-free (Bi,La)4Ti3O12 (BLT) films were optimized on a newly developed MTP cell structure. BLT films were coated on Pt/IrOx/Ir bottom electrode using sol-gel solutions. The composition of the optimized BLT film was about Bi3.25La0.75Ti3.0O12, which was analyzed by ICP-MS method. The switchable polarization obtained in a 100nm-thick BLT film was about 20 uC/cm2 at the 3 V applied voltage, and the optimized BLT film showed little fatigue loss about 10% up to 1×1011 cycles. The imprint properties of the BLT film were also characterized at 25 °C and 90 °C operating temperature after 125 °C data storage. Regardless of operating temperature, switchable polarization of BLT had a sufficiently large margin for device operation up to 10 years.
Hyung Sun Kim, Sang-Yeop Park, Bo Young Hur and Soo Wohn Lee
K.W. Cho et al., "Ferroelectric Properties of Lead-Free (Bi,La)4Ti3O12 Thin Film Deposited on MTP Cell Structure for High Density FeRAM Device", Materials Science Forum, Vols. 486-487, pp. 285-288, 2005