Conduction mechanisms in MOS gate dielectric films

This paper reviews the conduction mechanisms in the gate dielectric films of MOSFETs for VLSI and ULSI technologies. They include Fowler-Nordheim tunneling, internal Schottky (or Pool-Frenkel) effect, two-step (or trap-assisted) tunneling, shallow-trap-assisted tunneling, and band-to-band tunneling. The current transport in the gate dielectric films is manly controlled by film material composition, film processing conditions, film thickness, trap energy level and trap density in the films. In general, for a given gate dielectric film, the current transport behaviors are normally governed by one or two conduction mechanisms. (C) 2004 Elsevier Ltd. All rights reserved.