Enhanced Endurance and Imprint Properties in Hf_0.5Zr_0.5O_2−δ Ferroelectric Capacitors by Tailoring the Oxygen Vacancy

Abstract

HfO2-based ferroelectric thin films are promising in both memory and logic devices owing to their compatibility with complementary metal-oxide-semiconductor platforms and excellent thickness scalability. However, the fatigue and imprint effect are the main concerns, hindering the device’s applications. In this work, we comprehensively investigate the impact of oxygen vacancies on the reliability of Hf0.5Zr0.5O2−δ (HZO) ferroelectric capacitors. The oxygen vacancy concentration was tailored by varying the exposure time of the H2O precursor and oxygen plasma during atomic layer deposition. By decreasing the oxygen vacancy concentration to 1.9%, the endurance is enhanced owing to the suppression of defect migration under field cycling. In addition, a milder imprint with coercive field shift of below 0.6 MV/cm under 120 °C is obtained, benefiting from the alleviation of the built-in field at the ferroelectric/metal interfaces. The fabricated HZO capacitors with considerable remnant polarization show superior reliability compared with the reported ones.