Abstract
Memory retention characteristics of metal–ferroelectric–metal–insulator–semiconductor (MFMIS) field effect transistors (FETs) were investigated in detail using a simple structure, referred to as quasi-MFMIS, in which one electrode of the metal–ferroelectric–metal (MFM) capacitor is connected to a gate electrode of a conventional metal–oxide–semiconductors (MOS) FET using an external interconnection cable. It was found that the memory window of the MFMIS FET was quickly lost (after about 1000 s) and from a comparison with simulations, this was attributed mainly to a decrease in ferroelectric polarization due to a depolarization field inevitably remaining in the ferroelectric film during memory retention.