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-chains 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 × 10
²⁴
of cycle times in an operational condition of V
DD
= 2.0 V and 85 °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 × 10
²⁰
cm
⁻³
from I-V-t measurements.