Operation of Ferroelectric Gate Field-Effect Transistor Memory with Intermediate Electrode using Polycrystalline Capacitor and Metal–Oxide–Semiconductor Field-Effect Transistor

Abstract

We have investigated the basic operation of a ferroelectric gate field-effect transistor (F-FET) memory with an intermediate electrode for data writing, using a discrete circuit which consists of a polycrystalline ferroelectric capacitor connected serially to the gate of a commercial n-channel metal–oxide–semiconductor (MOSFET). By sputtering, a ferroelectric capacitor Cf was formed as a (RuO2 top electrode)/poly-Pb(Zr0.52Ti0.48)O3(PZT)/(Pt/RuO2 bottom electrode) structure on a SiO2/Si substrate. The readout characteristics showed nondestructive operation. It was also shown that the output voltage for the positive and the negative polarization memory states corresponded very well with the intermediate electrode voltages on the gate of the MOSFET. Furthermore, the ratio of the ferroelectric capacitor to the input capacitor of the MOSFET was found to be an important factor influencing the cycle number of nondestructive reading and the difference in output voltage between the positive and negative polarization states.