Influence of Gate Material and Process on Junctionless FET Subthreshold Performance

Abstract

The recent progress of dimension scaling of electronic device into nano scale has motivated the invention of alternative materials and structures. One new device that shows great potential to prolong the scaling is junctionless FET (JLFET). In contrast to conventional MOSFETs, JLFET does not require steep junction for source and drain. The device processing directly influence the performance, therefore it is crucial to understand the role of gate processing in JLFET. This paper investigates the influence of gate material and process on subthreshold performance of junctionless FET, by comparing four sets of gate properties and process techniques. The result shows that in terms of subthreshold slope, JLFET approaches near ideal value of 60 mV/decade, which is superior than the SOI FET for similar doping rate. On the other hand, the threshold value shows different tendencies between those types of device.

Analysis of Subthreshold Swing of Symmetric Junctionless Double Gate MOSFET Using Gaussian Doping Profile

“…The junctionless MOSFETs are the most advanced transistors that can be used in digital circuits and systems as well as analog devices [1][2][3]. Unlike the junction-based double gates operating in inversion-mode, the junctionless MOSFETs operate in accumulation-mode.…”

“…The junction-based double gate MOSFET mainly uses an undoped or low doping channel. However, the number of carriers in the channel results in a strange number of carriers of approximately 10 15 /cm 3 ×10 -6 cm×10 -6 cm×10 -6 cm = 10 -3 if the volume of the channel decreases to 10 nm×10 nm×10 nm at a constant doping concentration of about 10 15 /cm 3 . In particular, it is difficult to form a pn junction between a source/drain doped at a high concentration and a channel doped at a low concentration as the channel length is shortened [12][13].…”

TCAD Simulations and Small Signal Modeling of DMG AlGaN/GaN HFET

“…GaN based devices are also very useful for high frequency high temperature microwave applications such as radar systems [3], [4]. In the recent past, studies have been done on asymmetric MOSFETs [5], junctionless FETs [6] and dual material gate AlGaAs/GaAs HEMTs structures that uses two metals of different work functions [7]. Since analytical models help us to understand internal solid state device physics thus expected to be consistent with physical behavior of device.…”