Impact of mechanical strain on wakeup of HfO2 ferroelectric memory

Abstract

This work investigates the impact of mechanical strain on wake-up behavior of planar HfO2 ferroelectric capacitor-based memory. External in-plane strain was applied using a four-point bending tool and strain impact on remanent polarization and coercive voltage of the ferroelectric was monitored. It was established that compressive strain is beneficial for 2P(r) improvement, while tensile strain leads to its degradation, with a sensitivity of -8.4 +/- 0.5 % per 0.1% of strain. Strain-induced polarization rotation is considered to be the most likely mechanism affecting 2P(r). At the same time, no strain impact on V-c was observed in the investigated strain range. The results seen here can be utilized to undertake stress engineering of ferroelectric memory in order to improve its performance.