Characterization of Pb(Zr,Ti)O3/ZrTiO4 double layer on Si substrates for NDRO MFISFET devices

A Pt/PZT/ZT/Si structure for metal/ferroelectric/insulator/semiconductor field-effect transistors (MFISFET) was fabricated and the electrical properties of the MFIS structure were investigated. Pb diffusion depth from the PZT (250 nm) film into the ZT film was about 25 nm during annealing at 600°C for 30 minutes, so the thicker ZT film was necessary to prevent Pb diffusion into the Si substrate. The memory window widths of the C-V curves for the MFIS structure increased from 1.2 to 2.5 V with decreasing ZT thin film thickness. The remanent polarization value of the MFIS structure was about 0.1 μC/cm², which was sufficient charge density required to induce an inversion layer at the Si surface