MFMIS STRUCTURE FOR NONVOLATILE FERROELECTRIC MEMORY USING PZT THIN-FILM

The metal/ferroelectric material/metal/oxide insulating material/Si su bstrates (MFMIS) structure was realized by using Pb(Zr0.4Ti0.6)O-3 (PZ T) thin film. PZT (330 nm thick) thin him was sandwiched between the u pper electrode of Ti/Pt-Rh (about 380 nm thick and 123 microns in diam eter) and the lower electrode of Pt-Rh/Ti (about 380 nm thick and 378 microns in diameter). The MFM structures mentioned above were prepared on metal oxide semiconductor (MOS structures). Pt-Rh and Ti lower ele ctrodes were directly deposited on a poly-Si MOS electrode with sputte ring, and PZT layer was prepared using the sol-gel method. In order to maximize induced charge density in the MOS gate, diameters of the upp er and the lower electrodes were adjusted, and the MFM area-to-MOS are a ratio was optimized. By using the area ratio of 0.11 a memory window of 2.4 V was obtained.