Electrical properties of Bi3.25La0.75Ti3O12/LaAlO3/Si structures for ferroelectric field effect transistor applications

Abstract

Ferroelectric Bi3.25La0.75Ti3O12 (BLT) films and LaAlO3 (LAO) insulator layers for metal/ferroelectric/insulator/semiconductor structure were first fabricated by chemical solution deposition and pulsed laser deposition. LAO films as a buffer layer show an amorphous structure, a relatively high dielectric constant and good electrical properties. Pt/BLT/LAO/n-Si annealed at 650°C exhibit better hysteretic capacitance–voltage characteristics, with a memory window of 1.3 V and extremely low leakage current density. Furthermore, the memory window does not alter with the sweeping rates of the bias voltage. This implies that the Si surface potential has been controlled by the poling charges of BLT. The introduction of a LAO buffer layer prevents the interfacial diffusion between the BLT and Si substrate effectively. Therefore, BLT/LAO/Si is an attractive candidate for ferroelectric field effect transistor applications.