Analysis of Off-State Leakage Current Characteristics and Mechanisms of Nanoscale MOSFETs with a High- k Gate Dielectric

Abstract

The off-state leakage current characteristics of nanoscale channel metal-oxide-semiconductor field-effect transistors with a high-𝑘 gate dielectric are thoroughly investigated. The off-state leakage current can be divided into three components: the gate leakage current, the source leakage current, and the substrate leakage current. The influences of the fringing-induced barrier lowering effect and the drain-induced barrier lowering effect on each component are investigated separately. For nanoscale devices with high-𝑘 gates, the source leakage current becomes the major component of the off-state leakage current.

A threshold voltage model of short-channel fully-depleted recessed-source/drain (Re-S/D) SOI MOSFETs with high- k dielectric

“…[16] However, the use of a thicker high-k dielectric material in place of SiO 2 causes considerable fringing-field lines, which in turn modulate the source-channel barrier height, resulting in the change of subthreshold characteristics. [17][18][19][20][21][22][23][24] The effect of fringingfield lines on the subthreshold characteristics of SOI MOS-FET is modeled in terms of a fringing capacitance C bot . [20] The fringing capacitance is attributed to the electric field interaction between the bottom of gate electrode and source/drain region through the side-wall spacer, as shown in Fig.…”