High endurance scaled PLZT thin films for FRAM applications

Lower operating voltage is one of the main requirements of future generation FRAM. In order to achieve this requirement, PLZT thin film capacitors must be scaled down with respect to thickness. This paper presents the ferroelectric performance of scaled PLZT thin films. The thickness of RF magnetron sputtered PLZT thin films was scaled down to 1000Angstrom. Integrated array capacitors (measured after local interconnect formation) using the scaled 1000Angstrom PLZT thin films showed good switching performance, excellent endurance (fatigue free Up to 10 12 fatigue cycles) and good data retention. An approach to accelerate the fatigue process using high electric field is introduced in order to shorten the endurance testing time at extended fatigue cycles such as above 1011 cycles. The thickness scaled PLZT thin films, showing dramatically improved ferroelectric performance, can be applied to the manufacturing of low voltage FRAM products.