Abstract
The electrical characteristics of metal-ferroelectric-insulator-silicon (MFIS) structures are studied. The ferroelectric layer is lead-zirconate-titanate (PZT). The insulators layer is either TiO2 or Ta2O5. This structure is studied for the potential application of flash memory devices. The PZT layer is deposited using RF magnetron sputtering. The TiO2 layer is deposited by RF magnetron sputtering and the Ta2O5 layer is deposited by chemical vapor deposition. The purpose of insulator layer is to minimize the out-diffusion of silicon atoms during heat treatment processes. The I-V measurements show the leakage current densities are about 10-7A/cm2 even at 15V. The value shows that the insulating property of PZT/TiO2 is very good. And we successfully analyze the leakage current before and after poling by using band diagram. High frequency C-V measurements show a flat band voltage shift of 5 V under a ±15 V writing pulse, which is considered to be due to the ferroelectric nature of the PZT film.