Review of Transport Mechanism in Thin Oxides of MOS Devices

Abstract

The apparent robust nature of thin SiO2 coupled with the industries acquired knowledge of oxide process control, has extended its use for the past several decades in CMOS technology. Recent efforts in gate dielectric scaling have focused on extending the use of SiO2 through thinning or introducing nitrogen into the dielectric. It has recently been demonstrated that transistors with gate oxides as thin as 13–15 Å continue to operate satisfactorily. However, under certain specific temperature and/or electric field conditions, several physical processes allow carriers such as electrons, holes, or ions to move in the oxide, thus leading to a considerable gate current, especially for the thin oxide. The objective of this chapter is to review the different carrier transport mechanisms in thin oxides and how each one contributes to the gate current.