Study of ferroelectric-thin-film thickness effects on metal-ferroelectric- SiO 2-Si transistors

Abstract

This article examines the thickness effects of ferroelectric films on gate tunneling suppression and charge control in metal-ferroelectric-insulator- semiconductor field-effect transistors (MFISFETs). The formalism used is based on a blocking-layer model for the ferroelectric film and a self-consistent solution of the Poisson and Schrödinger equation. We show that with a polar ferroelectric the threshold voltage of the FET can be altered by controlling the ferroelectric film thickness. We also study the thickness dependence of the capacitance-voltage curve and the surface charge density and the effects of ferroelectric hysteresis. The tunneling probability and leakage current calculation in a MFISFET device are provided in this article. Ferroelectrics-based transistors show higher sheet charges and lower tunneling currents than oxide-based devices. © 2002 American Institute of Physics.