Non-volatile, small-signal capacitance in ferroelectric capacitors

Abstract

Tunable, non-volatile, small-signal capacitance is observed and characterized in a TiN/ferroelectric Hf0.5Zr0.5O2 (HZO)/TiN stack. The non-volatility of the small-signal capacitance originates from the non-uniform distribution of oxygen vacancies near/at the bottom electrode, resulting in polarity-dependent responses of the domain-wall vibration. Our hypothesis also agrees with the observed frequency dispersion, which could be explained with the Maxwell Wagner effect. Furthermore, we have shown more than 104 endurance and 10-year retention at 85 °C for this non-volatile capacitance. With tunable capacitance at a fixed bias, HZO capacitors can potentially be applied to reconfigurable analog or mixed-signal circuits.