Fabrication and Characterization of Gate-Connected 1T2C-Type Ferroelectric Memory with Paired Bi 4 - x La x Ti 3 O 12 Capacitors.

A gate-connected 1T2C-type ferroelectric memory, in which the bottom electrodes of paired ferroelectric capacitors are connected to the gate electrode of an underlying FET (field effect transistor) on the field oxide region, was fabricated using a Bi 4 - x La x Ti 3 O 12 (BLT) film and its electrical properties were characterized. The I D -V G (drain current-gate voltage) characteristics of a FET combined with a single ferroelectric capacitor showed that the paired capacitors had almost the same ferroelectric property. It was found in the readout operation that there existed an optimum voltage to maximize the drain current on/off ratio between datum '1' and datum '0,' and that the maximum ratio was as large as 6 × 10 4 . It was also found that the drain current level remained constant, even if the readout operation was repeatedly conducted. It was concluded from these results that the 1T2C-type memory was successfully fabricated using the proposed process and operated properly. [ABSTRACT FROM AUTHOR]