Improved Ferroelectric Switching in Sputtered HfZrOx Device Enabled by High Pressure Annealing

Abstract

HfZrOx (HZO) materials exhibiting ferroelectricity in ultra-thin layers can be deposited in various ways. Specifically, in sputtered HZO layers, only weak ferroelectric switching with gradual transition and small remnant polarization (P-r) is demonstrated using conventional rapid thermal annealing at high temperatures of at least 750 degrees C. Here we show that rapidly transited ferroelectric switching with a larger 2 Pr of 24 mu C/cm(2) is achieved by introducing a high pressure annealing (HPA) at even lower temperature of 550 degrees C. Our findings reveal that the HPA enhances the crystallinity of grains in the HZO, thereby enlarging the Pr and strengthening breakdown conditions. Through short pulse techniques, how interface and bulk region in the HZO are involved in the switching depending on the HPA is also investigated.