Quantum Threshold Voltage Modeling of Short Channel Quad Gate Silicon Nanowire Transistor

An improved physics-based compact model for a symmetrically biased gate-all-around (GAA) silicon nanowire transistor is proposed. Short channel effects and quantum mechanical effects caused by the ultrathin silicon devices are considered in modelling the threshold voltage. Device geometrics play a very important role in multigate devices, and hence their impact on the threshold voltage is also analyzed by varying the height and width of silicon channel. The inversion charge and electrical potential distribution along the channel are expressed in their closed forms. The proposed model shows excellent accuracy with TCAD simulations of the device in the weak inversion regime.

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A Quasi 2-D Electrostatic Potential and Threshold Voltage Model for Junctionless Triple Material Cylindrical Surrounding Gate Si Nanowire Transistor

Journal of Nanoelectronics and Optoelectronics ◽

10.1166/jno.2021.2951 ◽

2021 ◽

Vol 16 (2) ◽

pp. 318-323

Author(s):

S. Manikandan ◽

P. Suveetha Dhanaselvam ◽

M. Karthigai Pandian

Keyword(s):

Field Distribution ◽

Bias Voltage ◽

Electrostatic Potential ◽

Threshold Voltage ◽

Silicon Nanowire ◽

Electrical Characteristics ◽

Nanowire Transistor ◽

Surrounding Gate ◽

Drain Bias ◽

The Impact

A mathematical model used for determining the threshold voltage characteristics and electrostatic potential of a Junctionless Triple Material Cylindrical Surrounding Gate Silicon Nanowire Transistor (JLTMCSGSiNWT) is proposed in this research work and is obtained by resolving the poison equation. Three materials with dissimilar metal functions are used in the construction of the device gate structure. Device parameters used to determine the electrical characteristics are also included in the model. Behavior of the device is investigated through its vertical electrical field distribution along the device channel. Higher drain bias conditions leading to DIBL are reduced in the proposed structure by minimal variation of voltages owing to three different gate materials that maintain a steady field distribution along the channel. This model explicitly shows the impact of various criteria like drain bias voltage, gate bias voltage, thickness of the silicon layer, thickness of the oxide layer, and length of the channel on electrostatic potential and the deterioration of threshold voltage. The proposed analytical model is validated with TCAD simulations and it could be further extended to study the advanced electrical characteristics of the JL Triple Material CSG Silicon Nanowire Transistor.

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Analysis of an Anomalous Transistor Exhibiting Dual-Vt Characteristics and Its Cause in a 90nm Node CMOS Technology

ISTFA 2012: Conference Proceedings from the 38th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2012p0106 ◽

2012 ◽

Author(s):

Yuk L. Tsang ◽

Xiang D. Wang ◽

Reyhan Ricklefs ◽

Jason Goertz

Keyword(s):

Threshold Voltage ◽

Electrical Characterization ◽

Cmos Technology ◽

Short Channel ◽

Visual Defect ◽

Subthreshold Region ◽

Short Channel Effect ◽

Channel Effect ◽

Transistor Model

Abstract In this paper, we report a transistor model that has successfully led to the identification of a non visual defect. This model was based on detailed electrical characterization of a MOS NFET exhibiting a threshold voltage (Vt) of just about 40mv lower than normal. This small Vt delta was based on standard graphical extrapolation method in the usual linear Id-Vg plots. We observed, using a semilog plot, two slopes in the Id-Vg curves with Vt delta magnified significantly in the subthreshold region. The two slopes were attributed to two transistors in parallel with different Vts. We further found that one of the parallel transistors had short channel effect due to a punch-through mechanism. It was proposed and ultimately confirmed the cause was due to a dopant defect using scanning capacitance microscopy (SCM) technique.

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An Analytical Modeling and Performance Analysis of Graded Work Function Gate Recessed Channel SOI-MOSFET

Nanoscience &Nanotechnology-Asia ◽

10.2174/2210681208666180820151121 ◽

2019 ◽

Vol 9 (4) ◽

pp. 504-511

Author(s):

Sikha Mishra ◽

Urmila Bhanja ◽

Guru Prasad Mishra

Keyword(s):

Analytical Model ◽

Surface Potential ◽

Threshold Voltage ◽

Silicon On Insulator ◽

Junction Depth ◽

Short Channel ◽

Soi Mosfet ◽

Minimum Surface ◽

Recessed Channel ◽

The Impact

Introduction: A new analytical model is designed for Workfunction Modulated Rectangular Recessed Channel-Silicon On Insulator (WMRRC-SOI) MOSFET that considers the concept of groove gate and implements an idea of workfunction engineering. Methods: The impact of Negative Junction Depth (NJD) and oxide thickness (tox) are analyzed on device performances such as Sub-threshold Slope (SS), Drain Induced Barrier Lowering (DIBL) and threshold voltage. Results: The results of the proposed work are evaluated with the Rectangular Recessed Channel-Silicon On Insulator (RRC-SOI) MOSFET keeping the metal workfunction constant throughout the gate region. Furthermore, an analytical model is developed using 2D Poisson’s equation and threshold voltage is estimated in terms of minimum surface potential. Conclusion: In this work, the impact of Negative Junction Depth (NJD) on minimum surface potential and the drain current are also evaluated. It is observed from the analysis that the analog switching performance of WMRRC-SOI MOSFET surpasses RRC-SOI MOSFET in terms of better driving capability, high Ion/Ioff ratio, minimized Short Channel Effects (SCEs) and hot carrier immunity. Results are simulated using 2D Sentaurus TCAD simulator for validation of the proposed structure.

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