Electrical properties of highly reliable 32Â Mb FRAM with advanced capacitor technology

Highly reliable 32 Mb FRAM was successfully developed by double annealing technique and CVD deposition technique. The highly (1 1 1) oriented ferroelectric films were fabricated by the optimized annealing method, which generates large remnant polarization. In addition to the double annealing process for sol-gel derived ferroelectric films, advanced capacitor technology of CVD process was developed for achieving strong retention properties. The CVD technique provides strong interface between electrode and ferroelectric films, giving rise to minimal integration degradation and large sensing margin. After baking test at 150 °C for 100 h, a wide sensing window of 350 mV was achieved to guarantee strong retention properties for high density FRAM products.