Ferroelectric-gate thin-film transistors with Bi3.15Nd0.85Ti3O12 gate insulators on LaNiO3-buffered Si substrates

Abstract

Ferroelectric-gate thin-film transistors (FGTs) with a stacked oxide structure of ZnO/Bi_3.15Nd_0.85Ti₃O₁₂ (BNT)/LaNiO₃ (LNO) on Si substrates have been prepared and characterized. The FGT devices show good electrical properties, such as a large “on” current of 2.5 × 10⁻⁴ A and low threshold voltage of 1.1 V. These are mainly attributed to the coupling enhancement of the gate electric field to the channel layer due to a-axis preferential orientation of BNT ferroelectric-gate insulator thin films obtained by using the LNO buffer layer and the relatively good interface properties. The results suggest that ZnO/BNT/LNO/Si structures are well suited for thin-film transistors for future nonvolatile memory applications.