Ferroelectric memory devices and methods of using ferroelectric capacitors

A ferroelectric memory device comprising:

• a ferroelectric memory capacitor having a hysteresis characteristic defining a relationship between applied voltage and polarization condition, said memory capacitor being adapted to store selectively, based on said hysteresis characteristic, either a first memory content corresponding to a first polarization condition or a second memory content corresponding to a second polarization condition when applied voltage is zero;
• a first load capacitor which is electrically connected in series with said memory capacitor;
• a ferroelectric reference capacitor;
• and
• a second load capacitor which is electrically connected in series with said reference capacitor, said first and second load capacitors being each a ferroelectric capacitor having substantially same characteristics as said memory capacitor;
• wherein the ratio of area between said reference capacitor and said second load capacitor is such that Vref is nearly equal to the average of V1 and V2 or slightly closer to V1 from said average, where Vref is the partial voltage which appears across said reference capacitor if a specified voltage is applied to said reference capacitor and said second load capacitor connected to each other in series, where V1 is the partial voltage which appears across said memory capacitor if said specified voltage is applied to said memory capacitor and said first load capacitor connected to each other in series when said memory capacitor is in said first polarization condition, and where V2 is the partial voltage which appears across said memory capacitor if said specified voltage is applied to said memory capacitor and said first load capacitor connected to each other in series when said memory capacitor is in said second polarization condition.