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

Abstract

We fabricated the n-channel metal-ferroelectric-insulator-semiconductor field-effect transistor (MFIS-FET) using an Au/(Bi,La) ₄ Ti ₃ O ₁₂ /LaZrO _x /Si(100) gate structure. We observed that the LaZrO _x thin film had the equivalent oxide thickness value of around 8.7 nm. The 420-nm-thick (Bi,La) ₄ Ti ₃ O ₁₂ film on a LaZrO _x /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 (I _D -V _G ) of an Au/(Bi,La) ₄ Ti ₃ O _12/ LaZrO _x /Si(100) MFIS-FET showed threshold voltage shift (memory window width) owing to the ferroelectric (Bi,La) ₄ Ti ₃ O ₁₂ film. The drain current-drain voltage (I _D -V _D ) characteristic curves exhibit typical n-channel field-effect transistor current-voltage characteristic. However, relatively large leakage current observed in the I _D –V _G and the I _D –V _D characteristic curves, might be caused by the high density of pores in the BLT film.

Keywords:

• Ferroelectric memory
• metal-ferroelectric-insulator-silicon
• (Bi,La)₄ Ti₃O₁₂
• LaZrO _x

Acknowledgment

This work was supported by the Seoul R&BD Program from Seoul City.