Suppression of ambipolar conduction and investigation of RF performance characteristics of gate‐drain underlap SiGe Schottky barrier field effect transistor

Abstract

In this work, a hetero structure gate-drain underlap (UL) Schottky barrier (SB) Field Effect Transistor (FET) is explored to achieve high device performance compared with high-k and low-k hetero structure SB FET (HSBFET). The effects of gate drain UL junction on the performances of UL-HSBFETs have been studied in terms of electrical characteristics including on-current (I on), subthreshold swing, I on /I off ratio, ambipolar conduction, and I off current. The low on-state current of silicon-based SB FETs can be enhanced by introducing the low bandgap silicon germanium material. Gate-drain UL and silicon germanium channel with low barrier height provides less tunnelling width which enhances the carrier injection at on-state compared with low-k and high-k HSBFET. Further, the proposed UL-HSBFET suppresses the ambipolar conduction due to holes. In contrast to conventional high-k and low-k HSBFET that suffers from severe ambipolar conduction, the UL-HSBFET device reduces the conduction at drain-channel junction with increasing the UL length to 5, 10, 15, and 20 nm. This provides better radio frequency performances with improved carrier capability of the proposed device. Therefore, UL-HSBFET device can be one of the best possible competitor for high-frequency application. The performance comparison of all the devices is carried out using Technology Computer-Aided Design (TCAD) simulator.

Analysis of non-uniform hetero-gate-dielectric dual-material control gate TFET for suppressing ambipolar nature and improving radio-frequency performance*

“…The I amb can be reduced by using the dual-material control-gate (DMCG) TFETs, [20] charge plasma-based TFETs with gate engineering, [21,22] gate material workfunction engineering, [23] lightly doped drain, [24] and gate-drain underlap structure. [25,26] Moreover, a hetero-gatedielectric (HGD) TFET with a high gate-oxide dielectric near the source side and a low gate-oxide dielectric near the drain side can enhance I on and obtain promising radio frequency performance. [27][28][29] The downscaling of gate-oxide layer thickness is an important method to enhance the steep switching characteristics of TFETs.…”

Performance Analysis of Double Gate Dielectric Modulation in Schottky FET as Biomolecule Sensor

“…2 shows the energy band diagram of the charge plasma based dielectric variation schottky barrier -FET. The energy band shows the on-state condition taking V gs = 0.8 V and V ds = 0.8 V. The thinning of schottky barrier linked with the electron plasma charges of great density being formed by the Hafnium oxide near-source region [21,22].…”

“…This grades in a rise in the chance of dopant variations which might differ the sensitivity of the SB -FET from the expected outcomes. Additionally, destructive reducing the dimensions in these SB-FET has caused bigger S/D contact resistance [17]. Later, for imminent reducing the dimensions of SB-FET-sensors in the nano rule.…”

Extended-source broken gate tunnel FET for improving direct current and analog/radio-frequency performance*

“…For the purpose of suppressing ambipolar behavior, many technologies have been used, such as low doping levels in the drain region, [5] underlap and overlap of gate-drain. [6][7][8] Furthermore, in or-der to enhance I on , many novel architectures of TFETs such as T-shape, [9,10] nanowire, [11,12] L-shape, [2,13] U-shape, [14] nanotube, [15,16] are proposed. Moreover, the materials with small energy bandgap, [17][18][19] high-k gate dielectrics, [20] high doping levels in the source region as well as abruptness at the source-channel tunnel junction are need to design.…”