An Endurance-Free Ferroelectric Random Access Memory As A Non-Volatile Ram

We demonstrate endurance characteristics of a 1T1C, 64 Mb FRAM in a real-time operational situation. To explore endurance properties in address access time t(AA) of 100 ns, we establish a measurement set-up that covers asymmetric pulse-chain corresponding to D1- and D0-READ/RESTORE/WRITE over a frequency range from 1.0 to 7.7 MHz. What has been achieved is that endurance cycles approximate 5.9 x 10(24) of cycle times in an operational condition of V-DD = 2.0 V and 85 degrees C in the developed 64 Mb FRAM. Donor concentration due to build-up of oxygen vacancy in a ferroelectric film has also been evaluated to 2.3 x 10(20) cm(-3) from I-V-t measurements.