Fabrication and Characterization of MFIS-FET Using Au/BLT/LZO/Si Structures

We fabricated the n-channel metal-ferroelectric-insulator-semiconductor field-effect transistor (MFIS-FET) using an Au/(Bi,La)4Ti3O12/LaZrOx/Si(100) gate structure. We observed that the LaZrOx thin film had the equivalent oxide thickness value of around 8.7 nm. The 420-nm-thick (Bi,La)4Ti3O12 film on a LaZrOx/Si structure, showed a good ferroelectric property and had the width of the memory window of 1.2 V for a bias voltage sweeping of 7 V. The drain current-gate voltage (ID-VG) of an Au/(Bi,La)4Ti3O12/ LaZrOx/Si(100) MFIS-FET showed threshold voltage shift (memory window width) owing to the ferroelectric (Bi,La)4Ti3O12 film. The drain current-drain voltage (ID-VD) characteristic curves exhibit typical n-channel field-effect transistor current-voltage characteristic. However, relatively large leakage current observed in the ID-VG and the ID-VD characteristic curves, might be caused by the high density of pores in the BLT film.