Enhanced dielectric nonlinearity with controlled domain nucleation in ferroelectric thin films

The dielectric capacitance is always maximum at around a coercive voltage in ferroelectric thin films. When the voltage stressing time is shortened, the maximum capacitance increases quickly in a rate far larger than at other voltages. With this observation, we carried out a delta pulse technique to shorten this voltage stressing time into the order of domain nucleation time so that the voltage tunability can surpass 74%. This high dielectric nonlinearity arises from the longitudinal nucleating domain oscillation confined within the film thickness with matched voltage and time under driving forces of an external stimulating electric field and internal imprint field. Otherwise, the domain oscillation becomes irreversible in accompany with a quick dielectric reduction as the nuclei grow up throughout the whole film thickness. From current-limited switching model of the domains, we can intrigue such a longitudinal domain oscillation at any frequencies with high voltage tunability through the careful control of the circuit RC time constant.