[book chapters] Equation-Based Compact Modeling

 

Debnath, P., Sarkar, B., & Chanda, M. (Eds.). (2023).

Differential Equation Based Solutions 

for Emerging Real-Time Problems

(1st ed.). CRC Press 

DOI 10.1201/9781003227847

Chapter: Differential Equation-Based Compact 2-D Modeling of Asymmetric Gate Oxide Heterojunction Tunnel FET; By: Sudipta Ghosh, Arghyadeep Sarkar

Abstract: Tunnel Field Effect Transistor (TFET) has emerged as an effective alternative device to replace MOSFET for a few decades. The major drawbacks of MOSFET devices are the short-channel effects, due to which the leakage current increases with a decrease in device dimension. So, scaling down TFET is more efficacious than that of MOSFETs. Sub-threshold swing (SS) is another advantageous characteristic of TFET devices for high-speed digital applications. In TFETs the SS could be well below 60 mV/decade, which is the thermal limit for MOSFET devices and therefore makes it more suitable than MOSFET for faster switching applications. It is observed from the literature studies that the performances of the TFET devices have been explored thoroughly by using 2-D TCAD simulation but an analytical model is always essential to understand the physical behavior of the device and the physics behind this; which facilitates further, the analysis of the device performances at circuit level as and when implemented.

Chapter: Differential Equation-Based Analytical Modeling of the Characteristics Parameters of the Junctionless MOSFET-Based Label-Free Biosensors; by: Manash Chanda, Papiya Debnath, Avtar Singh

Abstract: Recently Field Effect transistor (FET)-based biosensing applications have gained significant attention due to the demand for quick and accurate diagnosis of different enzymes, proteins, DNA, viruses, etc; cost-effective fabrication process; portability and better sensitivity and selectivity compared to the existing biosensors. FET is basically a three-terminal device with source, drain, and gate terminals. Basically, the gate terminal controls the current flow between the source and drain terminals. In FETs, first, a nanogap is created in the oxide layer or in the gate by etching adequate materials. When the biomolecules are trapped inside the nanocavity then the surface potentials change and also the threshold voltage varies. As a result, the output current also changes. Finally, by measuring the changes in the threshold voltage or the device current, one can easily detect the biomolecules easily.

[paper] Compact Model of JLNGAA MOSFET in Verilog-A

Billel Smaani^1,2, Shiromani Balmukund Rahi³ and Samir Labiod⁴

Analytical Compact Model of Nanowire Junctionless Gate-All-Around MOSFET

Implemented in Verilog-A for Circuit Simulation. 

Silicon (2022)

DOI: 10.1007/s12633-022-01847-9

   

1 Centre Universitaire Abdelhafid Boussouf, Mila, Algeria

2 Electronique Department, Constantine I University, Algeria

3 Department of Electrical Engineering, IIT Kanpur, India

4 Department of Physics, Skikda University, Algeria

Abstract: In the present research article, we have proposed an analytical compact model for Nanowire Junctionless Gate-All-Around (JLNGAA) MOSFET validated in all transistor’s operation regimes. The developed model having an analytical compact form of the current expressions, based on surface potential (ΦS), obtained from approximated solutions of Poisson’s equation. The proposed model has implemented in standard Verilog-A language using SMASH circuit simulator in order to be used in various commercial circuit simulators. The proposed model has also validated using ATLAS-TCAD simulation for various physical parameters such as the channel doping concentration (Nd) and the channel radius (R) of JLNGAA MOSFET. Finally, based on the developed Verilog-A JLNGAA MOSFET model, we have tested it in four types of low voltage circuits, CMOS inverter, CMOS NOR-Gate, an amplifier and a Colpitts oscillator.

Fig: Transient simulation of the implemented Colpitts oscillator using SMASH, where Vout is the output voltage. R = 4 nm, tox = 2 nm, L = 1 μm and Nd = 1E19/cm^3

Acknowledgments: Dr. S. B. Rahi (Indian Institute of Technology, Kanpur, India) for their useful suggestions

[paper] Junctionless pH Sensing BioFET

Nawaz Shafi, Aasif Mohamad Bhat, Jaydeep, Singh Parmar, Chitrakant Sahu, C. Periasamy

Effect of geometry and temperature variations on sensitivity and linearity 

of junctionless pH sensing FET: An experimental study

Superlattices and Microstructures, p. 107186, Mar. 2022,

doi: 10.1016/j.spmi.2022.107186

   
* Malaviya National Institute of Technology Jaipur, India

Abstract: Here-in this work, boron doped poly-silicon based dimensional variants of thin film planar junctionless field effect transistors are fabricated through CMOS compatible process for pH detection. The dimensional variants are classified into two sets as set-1 (channel length, L = 100 μm) and set-2 (channel length, L = 120 μm) with widths of 3 μm, 5 μm, 10 μm, and 20 μm. Sensitivity of the fabricated devices is analyzed using phosphate buffer saline solutions of pH 3.1, 5.2, 7, 9 and 11.2 and is computed in terms of relative shift in threshold voltage (VTh) and maximum drain current (IDS). The reference VTh and IDS are taken at neutral pH 7. Here we have experimentally analyzed the effect on pH sensitivity by varying the device widths and temperatures from 30 °C to 50 °C. It is observed that varying the device width from 3 μm to 20 μm, VTh sensitivity reduces from 19.08% to 9.17% and from 16.03% to 8.5% for set-1 and set-2 devices respectively. Increasing temperature from 30 °C to 50 °C causes reduction of VTh sensitivity from 18.68% to 13.52% for device with W/L = 3μm/100 μm and 16.78%–10.99% for device with W/L = 3μm/120 μm. The reduction in width causes average VTh sensitivity to roll-off by 0.49%/μm and 0.26%/μm for L = 100 μm and L = 120 μm respectively. Also the increase in operating temperature from 30 °C to 50 °C leads VTh sensitivity to roll-off by 0.17%/°C and 0.2%/°C for W/L = 3μm/100 μm and W/L = 3μm/120 μm respectively.

Fig: Junctionless pH sensing BioFET

Acknowledgment: This work was supported by Center of Nano Science and Engineering, Indian Institute of Science, Bangalore under Indian Nanoelectronic Users Program. Authors express gratitude to Materials Research Center MNIT-Jaipur for characterization support.

[paper] Analytical Compact Model Of Cylindrical Junctionless Nanowire FETs

Adelcio M. de Souza, Daniel R. Celino, Regiane Ragi, Murilo A. Romero

Fully analytical compact model for the Q–V and C–V characteristics 

of cylindrical junctionless nanowire FETs

Microelectronics Journal (2021): 105324

DOI: 10.1016/j.mejo.2021.105324

   

University of Sao Paulo (EESC/USP), Sao Carlos (BR)

Abstract: This paper develops a new compact model for the Q–V and C–V characteristics of cylindrical junctionless nanowire FETs in which the nanowire radius is large enough, in such a way that quantum confinement effects can be neglected. Our model is fully analytical and valid for all bias regimes, i.e., subthreshold, partial depletion, and accumulation. The obtained Q-V and C–V characteristics, as well as their derivatives, are continuous across the full range of bias voltages. The model is fully physics-based, with no fitting parameters, and it is very intuitive, since it relies on the understanding of the device as a gated resistor. Model validation is performed against previous results in the literature, demonstrating very good agreement.

Fig.  Validation of our C–V model (solid lines) in comparison to numerical results, highlighting the effect of parasitic capacitance. The free-carrier capacitance component from new model is shown in dashed lines. Simulation parameters: tox = 4.5nm, Nd = 1.6E18 cm−3, L = 200nm, VFB = 1.09V and Vds = 0.05V.

Acknowledgments: The authors would like to thank the Brazilian funding agencies CAPES, CNPq, and Fapesp for their financial support: Conselho Nacional de Desenvolvimento Científico e Tecnologico. Grant Number: 303708/2017-4; Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior; Fundaçao de Amparo a Pesquisa do Estado de Sao Paulo. Grant Number: 18/13537-6.

[paper] Charge-based Modeling of FETs

Jean-Michel Sallese 

Charge-based modeling of field effect transistors, Make it easy

Joint International EUROSOI and EuroSOI-ULIS Workshop (Sept.2020)

DOI: 10.1109/EuroSOI-ULIS53016.2021.956068

 
EDLab, EPFL,  Lausanne  (CH)
 

Abstract: In this presentation, we revisit some charge voltage dependencies for different architectures of field effect transistor, emphasizing on compactness and simplicity while maintaining a close link with physics, which makes these models predictive and accurate for general purposes of compact modeling.

Fig: The gm/I invariant versus the inversion coefficient IC. 

The operation modes of the MOSFET are clearly defined. 

Acknowledgements: I (JMS) would like to thank F. Jazaeri, C. Lallement, W. Grabinski, B. Iniguez and M. Bucher for their constructive interactions. 

TED Call for Papers on Compact Modeling of Emerging Devices

Compact Models (CMs) for circuit simulation have been at the heart of CAD tools for circuit design for almost five decades. As the mainstream CMOS technology is scaled into the nanometer regime, development of a truly physical and predictive CM for circuit simulation that covers geometry, bias, temperature, DC, AC, RF, and noise characteristics becomes a major challenge. The last call for a special issue on “advanced compact models and 45-nm modeling challenges” was in 2005. Seven years have passed, new technology nodes have been implemented, compact models have evolved and new compact models as well as compact models for new devices are being developed. Therefore, there is a need for another special issue dedicated to the advancement and challenges in core field-effect transistor (FET) models for 32-nm technologies and beyond as well as emerging technologies. For the core FET models, the associated noise/mismatch and reliability/variability models as well as proximity effects have become an essential part of the modeling effort. High-frequency, high-voltage, high-power, high-temperature devices have been extensively investigated, and their CMs are being reported in the literature. Device/circuit interaction and layout-dependent proximity effects are also hot topics today that are essential in nanometer chip designs. It is timely to report advances in these CMs in the 32-nm/22-nm technology era.

Concurrently, nonclassical MOSFETs as well as their CMs, such as multigate FinFETs and nanowire FETs, partially/fully-depleted ultrathin body (UTB) SOT, and thin-film transistors (TFTs), have emerged over the past decades. With the announcement of FinFETs being used in 22-nm and sub-22nm technology nodes, the need for such core models for fabless designers becomes an urgent reality. In these nonclassical devices, transistors are essentially short-channel, narrow-width, and thin-body. Tt is also an interesting topic to discuss and debate on the two different formalisms “top-down” drift-diffusion formulation adding ballistic effects versus “bottom-up” quasi-ballistic formulation adding scattering effects for modeling the real devices that are somewhere in between. Heterogeneous integration of various devices into the CMOS platform also becomes an important trend.

In addition, it is also timely to report advances in CMs of emerging devices beyond traditional silicon CMOS, such as different materials (III-V/Ge channel, organic) and different source/drain injection mechanisms (Schottky-barrier, tunneling, and junctionless FETs). These emerging device options for future VLSI building blocks have been studied extensively, while good physical CMs are still lacking. The special issue in these topics will stimulate research and development to promote modeling efforts such that theory would lead and guide technology realization and selection for future generations.

The special issue for the TRANSACTIONS ON ELECTRON DEVICES on compact modeling of emerging devices is devoted to the review and report of advancements in CMs for 32-nm technologies and beyond, including bulk and nonclassical CMOS and their associated noise/mismatch and reliability/variability models, as well as various emerging devices as future generation device options. It is timely as the industry is in the transition from traditional planar bulk-CMOS towards vertical FinFET technologies, and exploration of heterogeneous integration with various materials and structural choices.

Please submit manuscripts by using the following URL: http://mc.manuscriptcentral.com/ted

MAKE SURE TO MENTION THE SPECIAL ISSUE IN THE COVER LETTER

Paper submission Deadline: June 30, 2013

Scheduled Publication Date: February 2014

Guest Editors:

Xing Zhou, Nanyang Technological University, 

Jamal Deen, McMaster University, 

Benjamin Iniguez, Universitat Rovira i Virgili, 

Christian Enz, Swiss Federal Institute of Technology, 

Rafael Rios, Intel Corp.

If you have any questions about submitting a manuscript, please contact:

Jo Ann Marsh 

IEEE EDS Publications Office

445 Hoes Lane Piscataway JN 08854

Phone: +1 732 562 6855

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Digital Object Identifier 10.1109/TED.2013.2253418

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