Impact of Electric Field Pulse Duration on Ferroelectric Hafnium Zirconium Oxide Thin Film Capacitor Endurance
Megan K. Lenox, Samantha T. Jaszewski, Shelby S. Fields, Nikhil Shukla, Jon F. Ihlefeld
Abstract
While ferroelectric HfO 2 shows promise for use in memory technologies, limited endurance is one factor that challenges its widespread application. Herein, endurance is investigated through field cycling W/Hf 0.5 Zr 0.5 O 2 /W capacitors above the coercive field while manipulating the time under field using bipolar pulses of varying pulse duration or duty cycle. Both remanent polarization and leakage current increase with increasing pulse duration. Additionally, an order of magnitude decrease in the pulse duration from 20 to 2 μs results in an increase in endurance lifetime of nearly two orders of magnitude from 3 × 10 6 to 2 × 10 8 cycles. These behaviors are attributed to increasing time under field allowing for charged oxygen vacancy migration, initially unpinning domains, or driving phase transformations before segregating to grain boundaries and electrode interfaces. This oxygen vacancy migration causes increasing polarization before creating conducting percolation paths that result in degradation and premature device failure. This process is suppressed for 2 μs pulse duration field cycling where minimal wake‐up and lower leakage before device failure are observed, suggesting that very short pulses can be used to significantly increase device endurance. These results provide insight into the impact of pulse duration on device performance and highlight consideration of use of conditions when endurance testing.