Modeling and Simulation of Negative Capacitance Transistors
Yogesh S. ChauhanProfessor
Fellow IEEE and Editor of IEEE Trans. Electron DevicesNanolab, Department of Electrical Engineering
IIT Kanpur, IndiaEmail: [email protected]
Homepage ā http://home.iitk.ac.in/~chauhan/
My Group and Nanolab
08/11/2021 Yogesh Chauhan, IIT Kanpur 2
Current members ā 38ā¢ Postdoc ā 3ā¢ Ph.D. ā 27 ā¢ 12 PhD graduated
Device Characterization Lab- Pulsed IV/RF - ENA (100k-8.5GHz), PNA-X 43.5GHz- Keysight B1500, B1505- Load Pull, NFA
2021 2020 2019 2018 2017
Books 1
Journal 17 16 14 20 19
Conference 5 11 15 19 11
Alumni (PhD) of Nanolab
08/11/2021 Yogesh Chauhan, IIT Kanpur 3
S. No. Year Name Current Status
12. 2021* Dinesh R. Postdoc at UC Berkeley
11 2021* Chetan Dabhi Postdoc at UC Berkeley
10. 2020 Girish Pahwa Postdoc at UC Berkeley
9. 2020 Shantanu Agnihotri Asst. Prof. at Bennett University
8. 2020 Chetan Gupta Micron Hyderabad
7. 2018 Priyank Rastogi Intel Bangalore
6. 2018 Prateek Jain Postdoc at IIT Bombay
5. 2018 Avirup Dasgupta Asst. Prof. at IIT Roorkee
4. 2017 Sheikh Aamir Ahsan Asst. Prof. at NIT Srinagar
3. 2017 Chandan Yadav Asst. Prof. at NIT Calicut
2. 2017 Harshit Agarwal Asst. Prof. at IIT Jodhpur
1. 2017 Pragya Kushwaha SAC, ISRO
Nanolab@IITK: From Theory to Applications
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Theory
MaterialsAtomistic Sim.SemiconductorsTransport
Applications
FabricationCharacterizationSPICE ModelsCircuit Design
Joint Development & Collaboration
08/11/2021 Yogesh Chauhan, IIT Kanpur 5
What is a Compact Model?
Yogesh Chauhan, IIT Kanpur 608/11/2021
Compact MOSFET Model
Yogesh Chauhan, IIT Kanpur 7
Jds = f1(Vds,Vgs)
Cgs=f3(Vgd, Vgs)Cgd=f2(Vgd, Vgs)
Gate
Drain Source
CompactModel
TCADModel
08/11/2021
Compact Modeling or SPICE Modeling
ā¢ Excellent Convergenceā¢ Simulation Time ā ~Āµsecā¢ Accuracy requirements
ā ~ 1% RMS error after fittingā¢ Example: BSIM-BULK,
BSIM-CMG, BSIM-IMG
Medium of information exchange
Good model should be Accurate: Trustworthy simulations. Simple: Parameter extraction iseasy.
Balance between accuracy andsimplicity depends on end application
Yogesh Chauhan, IIT Kanpur 808/11/2021
Industry Standard Compact Models
ā¢ Standardization Body ā Compact Model Coalition
ā¢ CMC Members ā EDA Vendors, Foundries, IDMs, Fabless, Research Institutions/Consortia
Yogesh Chauhan, IIT Kanpur 908/11/2021
http://www.si2.org/cmc/
Challenges in Compact Modeling
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Materials(Si, Ge, III-V)
Physics(Quantum Mechanics, Transport)
Maths/ Computer Sc.(Compiler, Function speed,
implementation, algorithms, smoothing, integration, PDE)
Electronics(Circuit considerations āDigital/Analog/RF/noise)
SPICE Model
Some Snapshots from recent work
Yogesh Chauhan, IIT Kanpur 1108/11/2021
BSIM Family of Compact Device Models
Yogesh Chauhan, IIT Kanpur 12BSIM: Berkeley Short-channel IGFET Model
1990 20102000 20051995
BSIM1,2 BSIM3
BSIM4
BSIMSOI
BSIM-CMGBSIM-IMG
BSIM5 BSIM-BULK
Conventional MOSFET
Silicon on Insulator MOSFET
Multi-Gate MOSFETs
08/11/2021
BSIM-HV: High Voltage MOSFET Model
08/11/2021 Yogesh Chauhan, IIT Kanpur 13H. Agarwal, C. Gupta, R. Goel, P. Kushwaha, Y.-K. Lin, M.-Y. Kao, J.-P Duarte, H.-L. Chang, Y. S. Chauhan, S. Salahuddin, and C. Hu, "BSIM-HV: High Voltage MOSFET Model Including Quasi-Saturation and Self-Heating Effect", IEEE Transactions on Electron Devices, Vol. 66, Issue 10, pp. 4258-4263, Oct. 2019.
Intrinsic TxRdr,DRdr,S
š¼š¼šššš,š š š š š š ,š·š· = šš ā ššššššš¼š¼šššššš āšššššššš ā ššššššš¼š¼šššš
šššššš,š·š· =ššššš š š š šš
1 ā šæšæš»š»š»š»š¼š¼ššš š
š¼š¼šššš,š š š š š š ,š·š·
ššš·š·šššššššš1
ššš·š·šššššššš
Experimental 35V LDMOS
Modeling of TMD transistorā¢ 2D density of state ā¢ FermiāDirac statisticsā¢ Trapping effects
Yogesh Chauhan, IIT Kanpur 14
C. Yadav et. al. āCompact Modeling of Transition Metal Dichalcogenide based Thin body Transistors andCircuit Validationā, IEEE TED, March 2017.
08/11/2021
Modeling of III-V Channel DG-FETsā¢ Conduction band nonparabolicityā¢ 2-D density of states ā¢ Quantum capacitance in low DOS materialsā¢ Contribution of multiple subbands
Yogesh Chauhan, IIT Kanpur 15
C. Yadav et. al., Compact Modeling of Charge, Capacitance, and Drain Current in III-V Channel Double Gate FETs, IEEE TNANO, 2017.
08/11/2021
Modeling of Quasi-ballistic Nanowire FETs
Yogesh Chauhan, IIT Kanpur 1608/11/2021A. Dasgupta et al., "An Improved Model for Quasi-Ballistic Transport in MOSFETs", IEEE TED, Jul. 2017.
A. Dasgupta et al., "Unified Compact Model for Nanowire Transistors including Quantum Effects and Quasi-ballistic Transport", IEEE TED, Apr. 2017.
IMT PhaseFET Including Hysteresis and Multidomain Switching
08/11/2021 Yogesh Chauhan, IIT Kanpur 17
A. Dasgupta, A. Verma, and Y. S. Chauhan, "Analysis and Compact Modeling of Insulator-Metal-Transition Material based PhaseFET Including Hysteresis and Multi-domain Switching", IEEE TED, Jan. 2019.
FinFET Modeling for IC Simulation and Design: Using the BSIM-CMG Standard
Authors ChaptersYogesh Singh Chauhan, IITKDarsen D Lu, IBMNavid Payvadosi, IntelJuan Pablo Duarte, UCBSriramkumar Vanugopalan, SamsungSourabh Khandelwal, UCBAi Niknejad, UCBChenming Hu, UCB
1. FinFET- from Device Concept to Standard Compact Model2. Analog/RF behavior of FinFET3. Core Model for FinFETs4. Channel Current and Real Device Effects5. Leakage Currents6. Charge, Capacitance and Non-Quasi-Static Effect7. Parasitic Resistances and Capacitances8. Noise9. Junction Diode Current and Capacitance10. Benchmark tests for Compact Models11. BSIM-CMG Model Parameter Extraction12. Temperature Effects
08/11/2021 Yogesh Chauhan, IIT Kanpur 18
Authors ChaptersYogesh Singh Chauhan, IITKDarsen D Lu, IBMNavid Payvadosi, IntelJuan Pablo Duarte, UCBSriramkumar Vanugopalan, SamsungSourabh Khandelwal, UCBAi Niknejad, UCBChenming Hu, UCB
1. Fully Depleted Silicon on Oxide Transistor and Compact Model 2. Core Model for Independent Multigate MOSFETs 3. Channel Current Model With Real Device Effects in BSIM-IMG 4. Leakage Current and Thermal Effects 5. Model for Terminal Charges and Capacitances in BSIM-IMG6. Parameter Extraction With BSIM-IMG Compact Model 7. Testing BSIM-IMG Model Quality 8. High-Frequency and Noise Models in BSIM-IMG
Industry Standard FDSOI Compact Model BSIM-IMG for IC Design
08/11/2021 Yogesh Chauhan, IIT Kanpur 19
News (March 2018)
ā¢ Our ASM-GaN-HEMT Model is worldās first industry standard SPICE Model for GaN HEMTs
ā¢ Download ā http://iitk.ac.in/asm/
08/11/2021 Yogesh Chauhan, IIT Kanpur 20http://www.si2.org/2018/03/14/gallium-nitride-models/
http://www.si2.org/cmc/
Outlineā¢ Motivationā¢ Understanding Negative Capacitanceā¢ Experimental realization of Negative
Capacitanceā¢ NCFETs: Modeling and Analysisā¢ MFIS vs MFMIS configurations
ā Long Channelā Short Channel
ā¢ Performance of NCFET based Circuitsā¢ Conclusion
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Power challenge
22
Scaling both the VDD and VT maintains same performance (ION) by keeping the overdrive (VDD - VT) constant.
š¼š¼šššš = ššššš š š š šššš ššš·š·š·š· ā ššššš»š» 2
š¼š¼šššššš ā 10āš»š»šššššššš
A.M. Ionescu, H. Riel, āTunnel field-effect transistors asenergy-efficient electronic switchesā, Nature 479, 329 (2011)
2L DD leakage DD SCP C V f I V PĪ±= + +
A. M. Ionescu, Kathy Boucart, āTunnel FET or Ferroelectric FET to achieve a sub-60mV/decade switchā, IEDM 2009.
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Subthreshold Swing
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šš =šššššŗšŗ
šš log10 š¼š¼š·š·=šššššŗšŗšššššš
šššššššš log10 š¼š¼š·š·
= 1 +š š ššš š ššššš š
. 60mV/decade
ā¢ Amount of gate voltage required to change the current by 1-decade.
( )ds
GS
IddVSlog
=
As šš + šŖšŖšŗšŗšŖšŖšššššš
ā„ šš, šŗšŗ ā„ šššššššš/š š š š š š š š š š š š
Cins
Capacitance Definitionā¢ In general, insulator can be a non-linear dielectric whose
capacitance density (per unit volume) can be defined as
ā¢ 1: š š ššššš š = šš2šŗšŗšššš2
ā1= inverse curvature of free energy density
ā¢ 2: š š ššššš š = šššššššš
= slope of the polarization vs electric field curve
Two types of non-linear dielectrics:
ā¢ Paraelectric : No polarization when electric field is removed.ā¢ Ferroelectric : Two possible states of polarization when electric field is
removed.
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šš = Polarization in dielectric, šŗšŗ = Free energy density, šøšø = Externally applied electric field
Capacitance DefinitionCharge-Voltage Relation
šŗšŗ = Free energy density
If C < 0 As Vā, Qā
More DefinitionsCapacitance of a general dielectric:
Inverse curvature of free energy density
šŗšŗ
ššRef. - A.I. Khan, āNegative Capacitance for Ultra-low Power Computingā. PhD thesis, University of California at Berkeley, 2015.
Linear capacitor: Parabolic,
2508/11/2021 Yogesh Chauhan, IIT Kanpur
Negative Capacitance Transistorā¢ What if insulator has a Negative Capacitance!
š š ššššš š < 0 and š¶š¶ššš¶š¶šššššš
< 0, then 1 + š¶š¶ššš¶š¶šššššš
< 1 šš < 60mV/decade
ā¢ For a capacitorā Energy šŗšŗ = šš2
2š¶š¶ Capacitance š š = ļæ½
1šš2šŗšŗšššš2
= 1/š š š¶š¶š¶š¶š¶š¶š¶š¶š¶š¶š¶š¶š¶š¶š¶š¶
08/11/2021 Yogesh Chauhan, IIT Kanpur 26Energy landscape of ferroelectric materials.Ref. ā S. Salahuddin et. al., Nano Letters, 2008. šš = šššøšø + šš ā šš
G
Para- and Ferro-electric Materials
27
ā¢Paraelectric : No polarization when electric field is removed.
ā¢Ferroelectric : Two possible states of polarization when electric field is removed āSpontaneous/Remnant Polarization.
Paraelectric Ferroelectric
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FerroelectricityRequirements:ā¢ Spontaneous electric polarization: Non-Centrosymmetricity (for crystalline materials)ā¢ Reversible polarization state by the application of electric field
e.g. Lead titanate PbTiO3, HZO
[1] K. M. Rabe, C. H. Ahn, and J.-M. Triscone, Eds., Physics of Ferroelectrics: A Modern Perspective, vol. 105. Berlin, Germany: Springer, 2007.[2] A.I. Khan, āNegative Capacitance for Ultra-low Power Computingā. PhD thesis, University of California at Berkeley, 2015. 28
E = 0
Non-Centrosymmetric:- FerroelectricCentrosymmetric:- Paraelectric
P=0 at E=0
Pā 0 at E=0
08/11/2021 Yogesh Chauhan, IIT Kanpur
Paraelectric to Ferroelectric Phase TransitionParaelectric phase
Ferroelectric phase
TC = Curie TemperatureCubic Tetragonal
e.g. Pb[ZrxTi1-x]O3 Lead Zirconium Titanate (PZT)
[1] K. M. Rabe, C. H. Ahn, and J.-M. Triscone, Eds., Physics of Ferroelectrics: A Modern Perspective, vol. 105. Berlin, Germany: Springer, 2007.2908/11/2021 Yogesh Chauhan, IIT Kanpur
Landau-Khalatnikov Theory of Non-Linear Dielectrics
ā¢ Free energy of a non-linear dielectric is given asšŗšŗ = Ī±šš2 + š½š½šš4 + š¾š¾šš6 ā šøšøšš
ā¢ In general, š¼š¼ and š½š½ can be +ve or āve but š¾š¾ is always +vefor stability reasons.
ā¢ Dynamics of G is given by šæšæ ššššššš š
= āšššŗšŗšššš
ā¢ In the steady state, ššššššš š
= 0 šøšø = 2Ī±šš + 4š½š½šš3 + 6š¾š¾šš5
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For Ī± > 0 and at šøšø = 0, there exit only one real root
šš = 0A Paraelectric Material
šš = 0, Ā± šššš where šššš = š½š½2ā3š¼š¼š¼š¼āš½š½3š¼š¼
For Ī± < 0 and at šøšø = 0, there exit three real roots
A Ferroelectric Material has a non-zero P at zero E.
Ī“ = Polarization damping factor
Assumptions
Free energy of a non-linear dielectricšŗšŗ = Ī±šš2 + š½š½šš4 + š¾š¾šš6 ā šøšøšš
ā¢ Polarization and Electric field are uniaxial. (perpendicular to electrodes)
ā¢ Polarization and Electric field magnitudes are uniform throughout the ferroelectric.
ā¢ Piezo-electricity is ignored.
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L-K explanation of Phase Transition
ā¢ Ī± > 0 i.e. for T > T0; at šøšø = 0, there exists only one real root, šš = 0
ā¢ i.e. No polarization whenelectric field is removed
ā¢ Ī± < 0 i.e. for T < T0; at šøšø = 0, there exist three real roots
ā¢ Two possible states of polarization when electric field is removed.
For E = 0,
ā¢ Note, P = 0 has a maximum.
ā¢ Not possible in an isolated ferroelectric.
and
[1] K. M. Rabe, C. H. Ahn, and J.-M. Triscone, Eds., Physics of Ferroelectrics: A Modern Perspective, vol. 105. Berlin, Germany: Springer, 2007.32
Paraelectric Material Ferroelectric Material
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Positive and Negative Capacitances
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ParaelectricA Positive Capacitor
FerroelectricA Conditionally Negative Capacitor
Only one solution at šøšø = 0
Three possible solutions at šøšø = 0
šš = 0 is not possible in aisolated Ferroelectric due
to maxima of energy or a negative capacitance
š š ššššš š =šš2šŗšŗšššš2
ā1
=šššššššøšø
< 0
Application of Electric Field
Paraelectric[A Positive Capacitor]
Isolated Ferroelectric[A Conditionally Negative Capacitor]
[1] K. M. Rabe, C. H. Ahn, and J.-M. Triscone, Eds., Physics of Ferroelectrics: A Modern Perspective, vol. 105. Berlin, Germany: Springer, 2007.[2] A.I. Khan, āNegative Capacitance for Ultra-low Power Computingā. PhD thesis, University of California at Berkeley, 2015. 3408/11/2021 Yogesh Chauhan, IIT Kanpur
How to stabilize a Negative Capacitance?Add a positive dielectric capacitance in series such that total free energy of system has a minima in the negative capacitance regime of ferroelectric.
Total energy of the FE + DE system
Assuming V is small
For a stable system
35
š š š š ššš š =š š šš . |š š šš|
|š š šš| ā š š šš> 0
|š š šš| > š š šš
For a stable system
š š š š ššš š > š š šš
(minimum)
Ferroelectric
Dielectric
metal
metal
Ef, Pf
Ed, Pd
V
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Negative Capacitance in Ferroelectric
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Negative slope region can be stabilized if
š š š š ššš š š š š”š” =1
ā|š š šššš|+
1š š šš
ā1
> 0
or,|š š šššš| > š š šš
š š ššššš š = š š šššš
S. Salahuddin and S. Datta, āUse of negative capacitance to provide voltage amplification for low power nanoscale devices,ā Nano Letters, vol. 8, no. 2, pp. 405ā410, 2008.
Pr
-Pr
Ec-Ec
How to stabilize a Negative Capacitance?
ā¢ Add a positive dielectric capacitance in series such that total free energy of system has a minima in the negative capacitance regime of ferroelectric.
ā¢ 1š¶š¶š”š”š”š”š”š”
= 1š¶š¶š¹š¹š¹š¹
+ 1š¶š¶š·š·š¹š¹
> 0
ā¢ š š š·š·šš < |š š šššš| and š š šššš< 0
ā¢ š š š š ššš š = š¶š¶š·š·š¹š¹.|š¶š¶š¹š¹š¹š¹||š¶š¶š¹š¹š¹š¹|āš¶š¶š·š·š¹š¹
> 0
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A. I. Khan et al., APL, vol. 99, no. 11, p. 113501, 2011
Ferroelectric-Dielectric Systems
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A. I. Khan et al., APL, vol. 99, no. 11, p. 113501, 2011. D. J. Appleby et al., Nano Letters, vol. 14, no.7, pp. 3864ā3868, 2014.
Total Capacitance of Ferroelectric-dielectric hetro-structure becomesgreater than the dielectric capacitance.
š š š š ššš š =š š š·š·šš . |š š šššš|
|š š šššš| ā š š š·š·šš> 0
Ferroelectric-Resistor System
A. I. Khan et al., āNegative capacitance in a ferroelectric capacitor,āNature Mater., vol. 14, no. 2, pp. 182ā186, 2015.
ā¢ NC is observed only for a small duration (~ššš š )during polarization switching.
ā¢ Difficult to stabilize.
PZT ferroelectric (PbZr0.2Ti0.8O3)
3908/11/2021 Yogesh Chauhan, IIT Kanpur
First ever demonstration of S-curve
40
Hoffmann et al. IEDM, Dec 2018
Hoffmann et al. Nature Lett., Jan 201908/11/2021 Yogesh Chauhan, IIT Kanpur
Measuring S-Curve
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Ref. ā Thomas Mikolajick et al., āUnveiling the double-well energy landscape in a ferroelectric layerā, Nature, Jan. 2019.
Negative Capacitance FETs
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PbZr0.52Ti0.48O3 FE with HfO2 buffer interlayer
P(VDF0.75-TrFE0.25) Organic Polymer FE
HfZrO FECMOS compatible FE
K.-S. Li et al., in IEEE IEDM, 2015.S. Dasgupta et al., IEEE JESCDC, 2015.
J. Jo et al., Nano Letters, 2015
NCFET Structures
MetalFerroelectricMetalInsulator Semiconductor
MFMIS Structure
NC-FinFET(FE: Hf0.42Zr0.58O2)
Lg = 30 nm[Li et al. IEDM ā15]
[Rusu et al. IEDM ā10]46 mV/decade
MetalFerroelectricInsulator Semiconductor
MFIS Structure
52 mV/decadetfe = 1.5 nm
[Lee et al., IEDM ā16]
13 mV/decadeLg = 10 Āµm
[Dasgupta et al., IEEE JESCDC, ā15]
4308/11/2021 Yogesh Chauhan, IIT Kanpur
MFMIS NCFET Modeling
ā¢ Ferroelectric and baseline MOSFET can be considered as two separate circuit entities connected by a wire Simplified modeling
ā¢ Metal internal gate equipotential surface with a spatially constant Vint.
MFMIS Structures
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Device Structure
ā¢ Metal internal gate provides an equipotential surfacewith a spatially constant Vint.
ā¢ Simplifies modeling as ferroelectric and baselineMOSFET can be considered as two separate circuitentities connected by a wire.
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Metal-ferroelectric-Metal-Insulator-Semiconductor (MFMIS)
Experimental Calibration of L-K Model
08/11/2021 Yogesh Chauhan, IIT Kanpur 46
šæšæššššššš¶š¶
= āšššŗšŗšššš
Dynamics of G is given by
In the steady state, ššššššš š
= 0
šøšø =ššššššš¶š¶šššš
= 2Ī±šš + 4š½š½šš3 + 6š¾š¾šš5
Gibbās Energy, šŗšŗ = Ī±šš2 + š½š½šš4 + š¾š¾šš6 ā šøšøšš
Ī± = ā1.23 Ć 109 m/Fš½š½ = 3.28 Ć 1010 m/Fš¾š¾ = 0 (2nd order phase transition)
Calibration of L-K with P-Vfe curve for Y-HfO2 with 3.6 mol% content of YO1.5[3]
[3] J. MĀØuller et al., JAP, vol. 110, no. 11, pp. 114113, 2011.
[1] Devonshire et al., The London, Edinburgh, and DublinPhilosophical Magazine and Journal of Science, vol. 40, no. 309, pp.1040ā1063, 1949.
[2] Landau, L. D. & Khalatnikov, I. M. On the anomalous absorptionof sound near a second order phase transition point. Dokl. Akad.Nauk 96, 469472 (1954).
šš = šš ā šššøšø ā šš (Gate Charge)
Calibration of Baseline FinFET
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Calibration of baseline FinFET with 22 nm node FinFET.
BSIM-CMG model is used to model baseline FinFET.
Gate length (L) = 30nm, Fin height (Hfin) = 34nmFin thickness (Tfin) = 8nm
C. Auth et al., in VLSIT, 2012, pp. 131ā132.
Complete Modeling Flowchart
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Landau-Khalatnikov Model of ferroelectricVerilog-A Code
BSIM-CMG Model of FinFETVerilog-A Code
ššššššš š = šššŗšŗ ā šššššš
šššŗšŗ
šššŗšŗ
š¼š¼š·š·
šøšø =ššššššš¶š¶šššš
= 2Ī±šš + 4š½š½šš3 + 6š¾š¾šš5
šš = šš ā šššøšø ā šš (Gate Charge)
Capacitances and Voltage Amplification
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š š šššš =šššššššššššš
=1
š¶š¶šššš 2š¼š¼ + 12š½š½šš2 + 30š¾š¾šš4
šššššš = š¶š¶šššš 2Ī±šš + 4š½š½šš3 + 6š¾š¾šš5
Internal Voltage Gain,
š“š“š»š» =ššššššššš š šššššŗšŗ
=|š š šššš|
š š šššš ā š š ššššš š
1š š ššššš š
=1š š šššš
+1
š š šš + š š š·š·ššš š šššš + š š šššššššššššš
Capacitance matching between |Cfe| and Cint increases the gain.
šøšø =ššššššš¶š¶šššš
= 2Ī±šš + 4š½š½šš3 + 6š¾š¾šš5
Capacitance Matching
ā¢ Capacitance matching increases with tfe which increases the gain.ā¢ Hysteresis appears for |Cfe| < Cint which is region of instability.
ā¢ Increase in VD reduces the capacitance matchingā Reduces gain.ā Reduces width of hysteresis window.
08/11/2021 Yogesh Chauhan, IIT Kanpur 50
ID-VG Characteristics ā SS regionā¢ As tfe increases
ā Capacitance matching is better
ā CS and Cins are better matched
šš = 1 ā š¶š¶šš|š¶š¶šššššš|
. 60mV/dec
ā¢ As tfeā SSā
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ID-VG Characteristics ā ON regionā¢ As tfe increases
ā Capacitance matching is better
š“š“š»š» =ššššššššš š šššššŗšŗ
=|š š šššš|
š š šššš ā š š ššššš š
ā¢ As gain increases, IONincreases.
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Note the significant improvement in ION compared to SS.
ID-VG Experimental Demonstration
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SSmin=55mv/decSSmin=58mv/dec
K. S. Li et al., in IEEE IEDM , 2015M. H. Lee et al., in IEEE JEDS, July 2015.
J. Zhou et al., in IEEE IEDM, 2016. D. Kwon et al., in IEEE EDL, 2018 Jing Li et al., in IEEE EDL, 2018
ID-VD Characteristics
ā¢ NCFET is biased in negative capacitance region.ā QG or P is positive Vfe is negative.
ā¢ VDSā QG or Pā |Vfe| ā Vint=VG+|Vfe| āAV ā Current reduces
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G. Pahwa, ā¦, Y. S. Chauhan, āAnalysis and Compact Modeling of Negative Capacitance Transistor with High ON-Current and Negative Output Differential Resistanceā, IEEE TED, Dec. 2016.
FE material is different.
Experimental Demonstration
55
1.5 nm HZOCompatible with sub-10nm
technology nodeM. H. Lee et al, IEDM, pp. 12.1.1ā12.1.4., 2016
J. Zhou et al., IEDM, 2016, pp. 12.2.1-12.2.4. Krivokapic et al., IEDM, 2017, pp. 15.1.1ā15.1.4.
14nm node NCFinFETby Global Foundries
M. Si et al., Nature Nanotechnol., vol. 13 , pp. 24ā28, 2018.
SSmin=58mv/decK. S. Li et al., in IEEE IEDM , 2015 K. S. Li et al., in IEEE IEDM , 2018
08/11/2021 Yogesh Chauhan, IIT Kanpur
Negative DIBL
ā¢ VD reduces QG which, in turn reduces ššššššš š = šššŗšŗ ā ššššššin the negative capacitance region.ā Negative DIBL increases with tfe due to increased Vfe drop.
ā¢ Vth increases with VD instead of decreasing.ā Higher ION still lower IOFF!
08/11/2021 Yogesh Chauhan, IIT Kanpur 56
Negative DIBL/DIBR Effect
57
āVD increases
ā¢ Vth increases with VD instead of decreasing. Higher ION still lower IOFF!
ā¢ Negative DIBL increases with tfe due to increased Vfe drop.
Xu et al., ACS Nano, 2018
G. Pahwa et al., IEEE Eur. Solid-State Device Res. Conf. (ESSDERC), Sep. 2016, pp. 41ā46.
M. Si et al., Nature Nanotechnol., vol. 13 , pp. 24ā28, 2018.
08/11/2021 Yogesh Chauhan, IIT Kanpur
ID-VG Characteristics ā High VDS
ā¢ Hysteresis appears for |Cfe| < Cint which is the region of instability.
ā¢ As tfe increases ā SS reduces, ION increases.ā IOFF reduces for high VD.
ā¢ Width of hysteresis at larger thicknesses can be controlled with VD.
08/11/2021 Yogesh Chauhan, IIT Kanpur 58
Negative Output Differential Resistance
59
G. Pahwa et al.,ā IEEE TED, Dec. 2016
J. Zhou et al., IEDM 2016J. Zhou et al., IEEE, JEDS, 2018
Mengwei Si et al., Nature Nanotechnology, 2018
08/11/2021 Yogesh Chauhan, IIT Kanpur
Optimum NC-FinFET
08/11/2021 Yogesh Chauhan, IIT Kanpur 60
Same ION as 22 nm node FinFET.
Steeper SS of 58.2 mV/decade.
VDD reduction by 0.4 V.
IOFF reduction by 83 %.
G. Pahwa, T. Dutta, A. Agarwal, and Y. S. Chauhan, "Designing Energy Efficient and Hysteresis Free Negative Capacitance FinFET with Negative DIBL and 3.5X ION using Compact Modeling Approach", IEEE European Solid-State Device Research Conference (ESSDERC), Lausanne, Switzerland, Sept. 2016. (Invited)
Ferroelectric Parameters Variation
08/11/2021 Yogesh Chauhan, IIT Kanpur 61
If š¾š¾ = 0,
Ī± = ā3 3šøšøšššššš
š½š½ =3 3šøšøšššššš3
šššš = Remnant Polarizationšøšøšš = Coercive Field
D. Ricinschi et al., JPCM, vol. 10, no. 2, p. 477, 1998.
š š šššš =1
š¶š¶šššš 2š¼š¼ + 12š½š½šš2
Low Pr and high Ecā¢ reduce |Cfe| which leads to
improved capacitance matching and hence, a high gain.
ā¢ Low SSā¢ increase ION but reduce IOFF due to a
more negative DIBL ā high ION/IOFF.
Intrinsic Delay
ā¢ NC-FinFET driving NC-FinFETā¢ For high VDD, high ION advantage is
limited by large amount of Īšššŗšŗ to be driven.
ā¢ Outperforms FinFET at low VDD.
ā¢ Minimum at ššš·š·š·š· ā 0.28 V corresponds to a sharp transition in QG.
ā¢ NC-FinFET driving FinFET load provides full advantage of NC-FinFET.
08/11/2021 Yogesh Chauhan, IIT Kanpur 62
Delay, Ļ = Īšššŗšŗšššššš
Īšššŗšŗ = šššŗšŗ šššŗšŗ = ššš·š· = ššš·š·š·š· ā šššŗšŗ šššŗšŗ = 0,ššš·š· = ššš·š·š·š·
Power and Energy Delay Products
ā¢ NC-FinFET driving NC-FinFET shows advantage only for low VDD.
ā¢ NC-FinFET driving FinFET load is the optimum choice.08/11/2021 Yogesh Chauhan, IIT Kanpur 63
šššššš = Īšššŗšŗ .ššš·š·š·š· šøšøšššš =Īšššŗšŗ 2ššš·š·š·š·š¼š¼šššš
Modeling of MFIS NCFET
08/11/2021 Yogesh Chauhan, IIT Kanpur 6464
ā¢ P and Vint vary spatially in longitudinal direction
ā¢ Better stability w.r.t. Leaky ferroelectric and domain formation
Issues with Existing Models[1,2]:Implicit equations ā tedious iterative numerical solutions
Contrast with MFIMS structure:
[1] H.-P. Chen, V. C. Lee, A. Ohoka, J. Xiang, and Y. Taur, āModeling and design of ferroelectric MOSFETs,ā IEEE Trans. Electron Devices, vol. 58, no. 8, pp. 2401ā2405, Aug. 2011.[2] D. JimĆ©nez, E. Miranda, and A. Godoy, āAnalytic model for the surface potential and drain current in negative capacitance field-effect transistors,ā IEEE Trans. Electron Devices, vol. 57, no. 10, pp. 2405ā2409, Oct. 2010.
Explicit Modeling of Charge
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Voltage Balance:
Implicit equation in Goal: Explicit Model with good initial guesses
for each region of NCFET operation
Both the QG and its derivatives match well with implicit model
G. Pahwa, T. Dutta, A. Agarwal and Y. S. Chauhan, "Compact Model for Ferroelectric Negative Capacitance Transistor With MFIS Structure," in IEEE Transactions on Electron Devices, March 2017.
Drain Current Model Validation
08/11/2021 Yogesh Chauhan, IIT Kanpur 6666
Against Full Implicit Calculations
Against Experimental Data
[1] M. H. Lee et al., in IEDM Tech. Dig., Dec. 2016, pp. 12.1.1ā12.1.4. [2] M. H. Lee et al., in IEDM Tech. Dig., Dec. 2015, pp. 22.5.1ā22.5.4.
G. Pahwa, T. Dutta, A. Agarwal and Y. S. Chauhan, "Compact Model for Ferroelectric Negative Capacitance Transistor With MFIS Structure," IEEE Transactions on Electron Devices, March 2017.
MFIS Vs MFMIS
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ā¢ MFIS excels MFMIS for low Pr ferroelectrics only.ā¢ A smooth hysteresis behavior in MFIS compared to MFMIS.ā¢ MFIS is more prone to hysteresis ā exhibits hysteresis at lower thicknesses
compared to MFMIS.
G. Pahwa, T. Dutta, A. Agarwal, and Y. S. Chauhan, "Physical Insights on Negative Capacitance Transistors in Non-Hysteresis and Hysteresis Regimes: MFMIS vs MFIS Structures", IEEE Transactions on Electron Devices, Vol. 65, Issue 3, pp. 867-873, March 2018.
Compact Modeling of MFIS GAA-NCFET
08/11/2021 Yogesh Chauhan, IIT Kanpur 68
Voltage Balance:
Radial Dependence in Ferroelectric Parameter:
Mobile Charge Density:
Implicit Equation in Ī²:
Goal: Explicit Model for Ī² with good initial guess valid in all region of NCFET operation which will be used for further calculation of drain current and terminal charges.
(Ignored in others work)
Drain Current Model Validation
08/11/2021 Yogesh Chauhan, IIT Kanpur 6969
Against Full Implicit Calculations
A. D. Gaidhane, G. Pahwa, A. Verma, and Y. S. Chauhan, "Compact Modeling of Drain Current, Charges and Capacitances in Long Channel Gate-All-Around Negative Capacitance MFIS Transistor", IEEE Transactions on Electron Devices, Vol. 65, Issue 5, pp. 2024-2032, May 2018.
ā¢ In contrast to bulk-NCFETsā¢ Multi-gate NCFETs with an undoped body exhibit same IOFF and Vth due
to absence of bulk charges.ā¢ GAA-NCFET characteristics show different bias dependence due to the
absence of bulk charge.
Terminal Charges in GAA-NCFET
08/11/2021 Yogesh Chauhan, IIT Kanpur 7070
ā¢ Peak in the gate capacitance is observed where the best capacitance matchingoccurs between the internal FET and the ferroelectric layer.
ā¢ For high VDS, the QG for GAA-NCFET is saturates to (4/5)th of the maximumvalue (at Vds = 0) in contrast to conventional devices for which it saturates to(2/3)rd of the maximum value.
MFMIS Vs MFIS
08/11/2021 Yogesh Chauhan, IIT Kanpur 71
G. Pahwa, T. Dutta, A. Agarwal, and Y. S. Chauhan, "Physical Insights on Negative Capacitance Transistors in Non-Hysteresis and Hysteresis Regimes: MFMIS vs MFIS Structures", IEEE Transactions on Electron Devices, Vol. 65, Issue 3, Mar. 2018.
Comparing ID-VG and ID-VDCharacteristics (long channel)
08/11/2021 Yogesh Chauhan, IIT Kanpur 72
ā¢ MFIS excels MFMIS for low Pr ferroelectrics only, in long channel NCFETs.
Understanding different trends with Pr
08/11/2021 Yogesh Chauhan, IIT Kanpur 73
ā¢ Total current in ON regime ā drift current = inversion charge * horizontal electric field
ā¢ For high Pr, charge is higher for MFIS, but electric field in channel is low due to a decreasing Vint profile from source to drain, which results in lower current than MFMIS.
ā¢ For low Pr, charge is lower for MFIS, but electric field in channel is high due to a increasing Vint profile from source to drain, which results in higher current than MFMIS.
G. Pahwa, T. Dutta, A. Agarwal, and Y. S. Chauhan, "Physical Insights on Negative Capacitance Transistors in Non-Hysteresis and Hysteresis Regimes: MFMIS vs MFIS Structures", IEEE Transactions on Electron Devices, Vol. 65, Issue 3, Mar. 2018.
Hysteresis Behavior
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ā¢ Continuous switching of dipoles from source to drain results in a smooth hysteresis behavior in MFIS compared to MFMIS where dipoles behave in unison.
ā¢ Source end dipole switches, first, owing to its least hysteresis threshold.ā¢ Non-zero drain bias disturbs capacitance matching in MFMIS resulting in a
delayed onset of hysteresis.ā¢ MFIS is more prone to hysteresis ā exhibits hysteresis at lower thicknesses
compared to MFMIS.G. Pahwa, T. Dutta, A. Agarwal, and Y. S. Chauhan, "Physical Insights on Negative Capacitance Transistors in Non-Hysteresis and Hysteresis Regimes: MFMIS vs MFIS Structures", IEEE Transactions on Electron Devices, Vol. 65, Issue 3, Mar. 2018.
MFMIS vs MFIS: Short Channel Effects
08/11/2021 Yogesh Chauhan, IIT Kanpur 75
OFF Regime (low VD)
08/11/2021 Yogesh Chauhan, IIT Kanpur 76
NCFETs exhibit reverse trends in Vtand SS with scaling except for very small lengths.
G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short Channel Effects in Negative Capacitance MFIS and MFMIS Transistors: Subthreshold Behavior", IEEE Transactions on Electron Devices, Vol. 65, Issue 11, pp. 5130-5136, Nov. 2018.
2D Numerical Simulation Results in COMSOL
Pr=0.1213 ĀµC/cm2 EC=1MV/cm tfe=8nm
Reverse Vt Shift with Scaling
08/11/2021 Yogesh Chauhan, IIT Kanpur 77
ā¢ Coupling of inner fringing electric field to the ferroelectric increases with scaling, which increases the voltage drop across ferroelectric and hence, the conduction barrier height.
ā¢ In MFIS, fringing effect remains localized to channel edges only Halo Like barriers.ā¢ In MFMIS, internal metal extends this effect to the entire channel larger Vt than MFIS.G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short Channel Effects in Negative Capacitance MFIS and MFMIS Transistors: Subthreshold Behavior", IEEE Transactions on Electron Devices, Vol. 65, Issue 11, pp. 5130-5136, Nov. 2018.
Reverse SS trends with Scaling
08/11/2021 Yogesh Chauhan, IIT Kanpur 78
= Body Factor= Ferroelectric gain
š š ā, š¶š¶ššššš”š”|š¶š¶šššš|
ā,š“š“šššš ā,šš ā,š“š“šššššš ā, šššš ā (except for very small lengths where
m dominates).
Negative Fringing Charge
G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short Channel Effects in Negative Capacitance MFIS and MFMIS Transistors: Subthreshold Behavior", IEEE TED, Nov. 2018.
Impact of Spacer Permittivity
79
Increasing the spacer permittivity enhances the outer fringing electric field,which leads to a rise in Vt and reduction in SS and DIBL.
G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short-Channel Effects in Negative Capacitance MFIS and MFMIS Transistors: Subthreshold Behavior", in IEEE Transactions on Electron Devices, vol. 65, no. 11, pp. 5130ā5136, Nov. 2018.
08/11/2021 Yogesh Chauhan, IIT Kanpur
OFF Regime (high VDS): Negative DIBL
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ā¢ Negative DIBL effect increases with Scaling.ā¢ More pronounced in MFMIS than MFIS.
G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short Channel Effects in Negative Capacitance MFIS and MFMIS Transistors: Subthreshold Behavior", IEEE Transactions on Electron Devices, Vol. 65, Issue 11, pp. 5130-5136, Nov. 2018.
Impact of S/D doping
81
ā¢ NCFETs exhibit trends opposite to baseline FET with respect to the increase in ND.
ā¢ Strength of fringing field originated from ionized S/D dopant ions increases with ND.
G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short-Channel Effects in Negative Capacitance MFIS and MFMIS Transistors: Subthreshold Behavior", in IEEE Transactions on Electron Devices, vol. 65, no. 11, pp. 5130ā5136, Nov. 2018.
08/11/2021 Yogesh Chauhan, IIT Kanpur
ON Regime: Potential and field distribution
82
ā¢ The internal floating metal gate maintains a uniform electrical field distribution throughout the ferroelectric and a uniform potential (Vint) at ferroelectric-oxide interface.
ā¢ In the MFIS, however, electric field distribution and Vint at the interface are non-uniform.
G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short Channel Effects in Negative Capacitance MFIS and MFMIS Transistors: Above-Threshold Behavior", IEEE Transactions on Electron Devices, Vol. 66, Issue 3, pp. 1591ā1598, Mar. 2019.
08/11/2021 Yogesh Chauhan, IIT Kanpur
ON Regime: Electrical Characteristics
83
ā¢ Drain side charge pinches-off earlier in MFIS than MFMIS due to strong localized drain to channel coupling lower VDSat of MFIS results in lower IDS.
ā¢ However, internal metal in MFMIS helps VDS impact to easily reach source side QIS ā Larger NDR effect in MFMIS than MFIS.
ā¢ In long channel, MFMIS excels MFIS, however, for short channels vice-versa is true due to substantial NDR effect in former for iso-VFB case only.
Pr=0.1213 ĀµC/cm2
G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short Channel Effects in Negative Capacitance MFIS and MFMIS Transistors: Above-Threshold Behavior", IEEE Transactions on Electron Devices, Vol. 66, Issue 3, pp. 1591ā1598, Mar. 2019.
08/11/2021 Yogesh Chauhan, IIT Kanpur
ON Regime: Impact of Spacers
84
Without Spacers: Inner Fringing OnlyWith Spacers: Inner + Outer Fringing
ā¢ Cint increases with scaling in NCFETs with spacers due to outer fringing capacitancesāincreases gain.
ā¢ For W/O spacers, Vint decreases due to absence of outer fringing, uncompensated drain side inner fringing, and increased drain to channel coupling.
G. Pahwa et al., IEEE Transactions on Electron Devices, 2019.
08/11/2021 Yogesh Chauhan, IIT Kanpur
Impact of Quantum Mechanical Effects
85
ā¢ The QME results in an increase in the effective oxide thickness of the internalFET which eventually diminishes the benefits achievable from NC effect forthe particular value of ferroelectric thickness.
A. D. Gaidhane, G. Pahwa, A. Verma, and Y. S. Chauhan, "Compact Modeling of Drain Current, Charges and Capacitances in Long Channel Gate-All-Around Negative Capacitance MFIS Transistor", IEEE Transactions on Electron Devices, Vol. 65, Issue 5, pp. 2024-2032, May 2018.G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short Channel Effects in Negative Capacitance MFIS and MFMIS Transistors: Above-Threshold Behavior", IEEE Transactions on Electron Devices, Vol. 66, Issue 3, pp. 1591ā1598, Mar. 2019.08/11/2021 Yogesh Chauhan, IIT Kanpur
Impact of Ferroelectric Thickness
86
ā¢ NC influence decreases with tfe which also starts to homogenise the internal gate potential.
ā¢ Thus, relative difference between MFIS and MFMIS diminishes as tfe is decreased.
A. D. Gaidhane, G. Pahwa, A. Verma, and Y. S. Chauhan, "Compact Modeling of Drain Current, Charges and Capacitances in Long Channel Gate-All-Around Negative Capacitance MFIS Transistor", IEEE Transactions on Electron Devices, Vol. 65, Issue 5, pp. 2024-2032, May 2018.
08/11/2021 Yogesh Chauhan, IIT Kanpur
Does polarization damping really limit operating frequency of NC-FinFET based circuits?
08/11/2021 Yogesh Chauhan, IIT Kanpur 87
ā¢ Ring Oscillators with NC-FinFET can operate at frequencies similar to FinFETbut at a lower active power[1].
ā¢ Another theoretical study predicted intrinsic delay due to polarization damping in NCFET to be very small (270 fs)[2].
Recent Demonstration by Global Foundries on 14nm NC-FinFET
[1] Krivokapic, Z. et al., IEDM 2017
[2] Chatterjee, K., Rosner, A. J. & Salahuddin, IEEE Electron Device Letters 38, 1328ā1330 (2017).
NC-FinFET based inverters
08/11/2021 Yogesh Chauhan, IIT Kanpur 88
ā¢ Although the transistor characteristics show no Hysteresis, the VTCs of NC-FinFET inverters can still exhibit it due to the NDR region in the output characteristics.
T. Dutta, G. Pahwa, A. R. Trivedi, S. Sinha, A. Agarwal, and Y. S. Chauhan, "Performance Evaluation of 7 nm Node Negative Capacitance FinFET based SRAM", IEEE Electron Device Letters, Vol. 38, Issue 8, pp. 1161-1164, Aug. 2017.
NC-FinFET based SRAM
08/11/2021 Yogesh Chauhan, IIT Kanpur 89
ā¢ Read time: reduced due to the increased drive currentā¢ Write time: slower due to the gate capacitance
enhancement ā¢ Pavg: NC-SRAM performs better with lower standby
leakage only at small tfe, taking advantage of the lower subthreshold currents
T. Dutta, G. Pahwa, A. R. Trivedi, S. Sinha, A. Agarwal, and Y. S. Chauhan, "Performance Evaluation of 7 nm Node Negative Capacitance FinFET based SRAM", IEEE Electron Device Letters, Vol. 38, Issue 8, pp. 1161-1164, Aug. 2017.
08/11/2021 Yogesh Chauhan, IIT Kanpur 90H. Amrouch, G. Pahwa, A. D. Gaidhane, J. Henkel, and Y. S. Chauhan, "Negative Capacitance Transistor to Address the Fundamental Limitations in Technology Scaling: Processor Performance", IEEE Access, Vol. 6, Issue 1, pp. 52754-52765, Oct. 2018.
Effects of NCFET on standard cells: 7nm FinFET standard cell library
ā¢ Increasing tfe ā larger Av in transistors (i.e., steeper slope and higher ON current) Delay of cells become smaller.
08/11/2021 Yogesh Chauhan, IIT Kanpur 91
Effects of NCFET on standard cells: 7nm FinFET standard cell library
ā¢ Quantifying the relative delay decrease/improvement of cells within the 7nm FinFET standard cell library due to NCFET at VDD = 0.7V.
08/11/2021 Yogesh Chauhan, IIT Kanpur 92
Effects of NCFET on standard cells: 7nm FinFET standard cell library
ā¢ Increase in tfe leads to an increase in the total cellsā capacitance which further increases internal power of the cells.
ā¢ Same baseline performance (i.e., frequency) can be achieved at a lower voltage, which leads to quadratic saving in dynamic power and exponential saving in stand-by power, thus, compensating the side effect of NCFET with respect to power.
Effects of NCFET on future processor design
08/11/2021 Yogesh Chauhan, IIT Kanpur 93
(a) What is the frequency increase due to NCFET under the same voltage constraint?
(b) What is the frequency increase under the same (i.e., baseline) power density constraint?
(c) What is the minimum operating voltage along with the achieved power reduction under the same (i.e., baseline) performance (i.e., frequency) constraint?
H. Amrouch, G. Pahwa, A. D. Gaidhane, J. Henkel, and Y. S. Chauhan, "Negative Capacitance Transistor to Address the Fundamental Limitations in Technology Scaling: Processor Performance", IEEE Access, Vol. 6, Issue 1, pp. 52754-52765, Oct. 2018.
NC-FinFET based Processor Performance
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ā¢ NCFET with ferroelectric thickness more than 1nm leads to a noticeable temperature reduction, due to the decrease in the on-chip power density.
NC-FinFET based Processor Performance
08/11/2021 Yogesh Chauhan, IIT Kanpur 95
ā¢ Under very small power budgets harvested from body heat, NCFET technology enables the processor to operate at around 42-127% higher frequency compared to the conventional FinFET technology.
Energy harvesting and IOT
NC-FinFET RF Performance
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ā¢ Baseline Technology: 10 nm node RF FinFETā¢ RF Parameters extraction using BSIM-CMG modelā¢ BSIM CMG coupled with L-K for NC-FinFET analysis
R. Singh, K. Aditya, S. S. Parihar, Y. S. Chauhan, R. Vega, T. B. Hook, and A. Dixit, "Evaluation of 10nm Bulk FinFET RF Performance - Conventional vs. NC-FinFET", IEEE Electron Device Letters, Aug. 2018.
NC-FinFET RF Performance
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ā¢ Current gain (ā ļ潚šššš¶š¶šššš) is almost independent of š¶š¶šššš as both the šššš and š š šššš
increase with š¶š¶šššš almost at a constant rate.ā¢ Cut-off frequency (šššš) remains identical for both the Baseline and NC-
FinFET.ā¢ Temperature rise and Power consumption due to self-heating increase with š¶š¶šššš
as š¼š¼šš increases. Reduce šššššš to achieve energy efficient performance.
08/11/2021 Yogesh Chauhan, IIT Kanpur 98
NC-FinFET RF Performance
ā¢ ššššš š and self heating (āšŗšŗššš»š»šš ā ššššš š šš ā ššššš š šššš ) both increase with š¶š¶šššš due to increased capacitance matching between š š šššš and š š ššššš š .
where
ā¢ Voltage gain (š“š“š»š» = āšššš ššššš š = āš š šššš š š šŗšŗš·š·šš) decreases with š¶š¶šššš due to decrease in š š šššš .
ā¢ Maximum oscillation frequency (ššššš š šš) also reduces with š¶š¶šššš which can be compensated by reducing šššššš.
Impact of Process Variations
08/11/2021 Yogesh Chauhan, IIT Kanpur 99
ā¢ Variability in ION, IOFF, and Vt due to combined impact of variability in Lg, Tfin, Hfin, EOT, tfe, Ec, and Pr
ā¢ ION: Improvement is non-monotonic with tfeā¢ IOFF: Decreases monotonically with tfeā¢ Vt: Decreases monotonically with tfe
T. Dutta, G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Impact of Process Variations on Negative Capacitance FinFET Devices and Circuits", IEEE Electron Device Letters, Vol. 39, Issue 1, pp. 147-150, Jan. 2018.
Process Variation in Ring Oscillator
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ā¢ The overall average delay variability in NC-FinFET based RO is lesser compared to the reference RO.
ā¢ The improvement is non-monotonic with nominal FE thickness scaling. 11-stage Ring-Oscillator: Variation
in Ļ due to combined variation
T. Dutta, G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Impact of Process Variations on Negative Capacitance FinFET Devices and Circuits", IEEE Electron Device Letters, Vol. 39, Issue 1, pp. 147-150, Jan. 2018.
Variability Analysis in a 3-D Multigranular Ferroelectric Capacitor
ā¢ A simulation-based study of the variability of Pr in a multigranular FE capacitorā¢ PoissonāVoronoitessellation (PVT) algorithm is used for the nucleation of grains in the FE
region, which corresponds to the physical growth mechanism. ā¢ The PVT algorithm implemented in MATLAB is coupled with TCAD simulations, to trace
the FE hysteresis loop. ā¢ The impact of both, area and thickness scaling on the variability of Pr, is considered.
08/11/2021 Yogesh Chauhan, IIT Kanpur 101N. Pandey, K. Qureshi and Y. S. Chauhan, "Variability Analysis in a 3-D Multi-Granular Ferroelectric Capacitor", IEEE TED, Aug. 2021.
08/11/2021 Yogesh Chauhan, IIT Kanpur 102
08/11/2021 Yogesh Chauhan, IIT Kanpur 103
Fig. 11. (a) Impact of dielectric content on the variability of PāE hysteresis loops. As DE content increases the memory window of an FE capacitor decreases.
ā¢ Main Findingsā Amount of variability in Pr increases as FE
thickness decreases. ā FE with the smaller surface area exhibits a higher
variability in Pr compared to a larger surface area FE capacitor.
ā The dielectric grains cause a very large amount of variability in the FE hysteresis loop.
ā An increase in the dielectric grains also leads to a loss in the retentivity of the hysteresis loop.
08/11/2021 Yogesh Chauhan, IIT Kanpur 104
Multi-domain switching dynamics in NCFET using SPICE model
08/11/2021 Yogesh Chauhan, IIT Kanpur 105
Fig. 2. (a) SPICE circuit model for single domain of NC-FinFET. (b) SPICE circuit model for multi-domain NC-FinFET.
A. D. Gaidhane, A. Verma and Y. S. Chauhan, "Study of Multi-Domain Switching Dynamics in Negative Capacitance FET using SPICE Model", Microelectronics Journal, 2021.
ā¢ Unlike the mono-domain case, switching of the individual domains in multi-domain scenario happens at different interval of gate bias since the switching depends on their individual domain parameters (šøšøš š (šš) and šššš(šš)).
ā¢ Amplification effect due to NC effect is lower in case of multi-domain compared to the mono-domain NC-FinFET. ā¢ Lower drain current for the multi-domain NC-FinFET compared to mono-domain NC-FinFET. ā¢ The kink in the drain current for š¶š¶fe = 6 nm One of the domains does not satisfy the stability criteria i.e. |š š fe(šš)|>š š int(šš).
08/11/2021 Yogesh Chauhan, IIT Kanpur 106
NC-DEMOS FET for High-VoltageSwitching and Analog Applications
08/11/2021 Yogesh Chauhan, IIT Kanpur 107G. Pahwa, A. Gaidhane, A. Agarwal, and Y. S. Chauhan, "Assessing Negative-Capacitance Drain-Extended Technology for High-Voltage Switching and Analog Applications", IEEE Transactions on Electron Devices, Vol. 68, Issue 2, Feb. 2021.
08/11/2021 Yogesh Chauhan, IIT Kanpur 108
Modeling of NC-FDSOI FET
08/11/2021 Yogesh Chauhan, IIT Kanpur 109C. K. Dabhi, S. S. Parihar, A. Dasgupta, and Y. S. Chauhan, "Compact Modeling of Negative-Capacitance FDSOI FETs for Circuit Simulations", IEEE Transactions on Electron Devices, Vol. 67, Issue 7, July 2020.
Expt. Validation and Circuit Performance
08/11/2021 Yogesh Chauhan, IIT Kanpur 110
Open Questions
ā¢ Is NC a static or transient phenomenon?ā¢ Physical explanation of NC effectā¢ Second order effects
ā Impact of grain boundaries and their sizesā Impact of multi-domain effectsā Impact of trapsā Impact of FE thicknessā Reliability
ā¢ Impact of NDR/NDIBL on circuits08/11/2021 Yogesh Chauhan, IIT Kanpur 111
Conclusion
ā¢ Maintaining ION/IOFF is the biggest challenge in new technology nodes
ā¢ Negative capacitance FET is one of the best choiceā Need to find sweet material (HfZrO2?)ā Integration in conventional CMOS process
remains a challenge (lot of progress)ā¢ Compact (SPICE) Models are ready for circuit
evaluation
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Relevant Publications from our groupā¢ A. D. Gaidhane, A. Verma and Y. S. Chauhan, "Study of Multi-Domain Switching Dynamics in Negative Capacitance FET using
SPICE Model", Microelectronics Journal, 2021.ā¢ O. Prakash, A. Gupta, G. Pahwa, Y. S. Chauhan, and H. Amrouch, "On the Critical Role of Ferroelectric Thickness for Negative
Capacitance Device-Circuit Interaction", IEEE Journal of the Electron Devices Society, 2021.ā¢ S. Salamin, G. Zervakis, Y. S. Chauhan, J. Henkel, and H. Amrouch, "PROTON: Post-synthesis ferROelectric Thickness
OptimizatioN for NCFET Circuits", IEEE Transactions on Circuits and Systems I, 2021.ā¢ D. Rajasekharan, A. Gaidhane, A. R. Trivedi, and Y. S. Chauhan, "Ferroelectric FET-based Implementation of FitzHugh-Nagumo
Neuron Model", IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2021.ā¢ N. Pandey, K. Qureshi and Y. S. Chauhan, "Variability Analysis in a 3-D Multi-Granular Ferroelectric Capacitor", IEEE
Transactions on Electron Devices, Vol. 68, Issue 8, Aug. 2021.ā¢ S. Salamin, G. Zervakis, F. Klemme, H. Kattan, Y. S. Chauhan, J. Henkel, and H. Amrouch, "Impact of NCFET Technology on
Eliminating the Cooling Cost and Boosting the Efficiency of Google TPU", IEEE Transactions on Computers, 2021.ā¢ O. Prakash, G. Pahwa, C. K. Dabhi, Y. S. Chauhan, and H. Amrouch, "Impact of Self-Heating on Negative-Capacitance FinFET:
Device-Circuit Interaction", IEEE Transactions on Electron Devices, Vol. 68, Issue 4, April 2021.ā¢ G. Paim, G. Zervakis, G. Pahwa, Y. S. Chauhan, E. A. C. Costa, S. Bampi, J. Henkel, and H. Amrouch, "On the Resiliency of
NCFET Circuits against Voltage Over-Scaling", IEEE Transactions on Circuits and Systems I, Vol. 68, Issue 4, April 2021.ā¢ G. Zervakis, I. Anagnostopoulos, S. Salamain, Y. S. Chauhan, J. Henkel, and H. Amrouch, "Impact of NCFET on Neural Network
Accelerators", IEEE Access, Vol. 9, pp. 43748 - 43758, 2021.ā¢ G. Pahwa, A. Gaidhane, A. Agarwal, and Y. S. Chauhan, "Assessing Negative Capacitance Drain Extended Technology for High
Voltage Switching and Analog Applications", IEEE Transactions on Electron Devices, 2021.ā¢ O. Prakash, C. Dabhi, Y. Chauhan, and H. Amrouch, "Transistor Self-Heating: The Rising Challenge for Semiconductor Testing",
IEEE VLSI Test Symposium (VTSā21), April 2021.ā¢ V. M. V. Santen, S. Thomann, Y. Chauhan, J. Henkel, and H. Amrouch, "Reliability-Driven Voltage Optimization for NCFET-
based SRAM Memory Banks", IEEE VLSI Test Symposium (VTSā21), April 2021.
08/11/2021 Yogesh Chauhan, IIT Kanpur 113
Relevant Publications from our group
114
ā¢ O. Prakash, A. Gupta, G. Pahwa, Y. S. Chauhan, and H. Amrouch, "On the Critical Role of Ferroelectric Thickness for NegativeCapacitance Transistor Optimization", IEEE Electron Devices Technology and Manufacturing Conference (EDTM), Chengdu,China, Mar. 2021.
ā¢ J. Knechtel, S. Patnaik, M. Nabeel, M. Ashraf, Y. S. Chauhan, J. Henkel, O. Sinanoglu, and H. Amrouch, "Power Side-ChannelAttacks in Negative Capacitance Transistor (NCFET)", IEEE Micro, Vol. 40, Issue 6, Nov.-Dec. 2020.
ā¢ O. Prakash, G. Pahwa, Y. S. Chauhan and H. Amrouch, "Impact of Interface Traps on Negative Capacitance Transistor: Deviceand Circuit Reliability", IEEE Journal of Electron Devices Society, Vol. 8, Nov. 2020.
ā¢ K. Nandan, C. Yadav, P. Rastogi, A. T.-Lopez, A. M.-Sanchez, E. G. Marin, F. G. Ruiz, S. Bhowmick, and Y. S. Chauhan,"Compact Modeling of Multi-layered MoS2 FETs including Negative Capacitance Effect", IEEE Journal of Electron DevicesSociety, Vol. 8, Nov. 2020.
ā¢ A. D. Gaidhane, G. Pahwa, A. Dasgupta, A. Verma, and Y. S. Chauhan, "Compact Modeling of Surface Potential, Drain Currentand Terminal Charges in Negative Capacitance Nanosheet FET including Quasi-Ballistic Transport", IEEE Journal of ElectronDevices Society, Vol. 8, Nov. 2020.
ā¢ N. Pandey and Y. S. Chauhan, "Analytical Modeling of Short Channel Effects in MFIS Negative Capacitance FET includingQuantum Confinement Effects", IEEE Transactions on Electron Devices, Vol. 67, Issue 11, Nov. 2020.
ā¢ D. Rajasekharan, P. Kushwaha, and Y. S. Chauhan, "Associative Processing using Negative Capacitance FDSOI Transistor forPattern Recognition", Microelectronics Journal, Vol. 104, art. no. 104877, Oct. 2020.
ā¢ H. Amrouch, G. Pahwa, A. D. Gaidhane, C. K. Dabhi, F. Klemme, O. Prakash and Y. S. Chauhan, "Impact of Variability onProcessor Performance in Negative Capacitance FinFET Technology", IEEE Transactions on Circuits and Systems I, Vol. 67,Issue 9, Sep. 2020.
ā¢ C. K. Dabhi, S. S. Parihar, A. Dasgupta, and Y. S. Chauhan, "Compact Modeling of Negative-Capacitance FDSOI FETs forCircuit Simulations", IEEE Transactions on Electron Devices, Vol. 67, Issue 7, July 2020.
ā¢ F. Bellando, C. K. Dabhi, A. Saeidi, C. Gastaldi, Y. S. Chauhan, and A. M. Ionescu, "Subthermionic Negative Capacitance IonSensitive Field-Effect Transistor", Applied Physics Letters, Vol. 116, Issue 17, April 2020.
ā¢ A. D. Gaidhane, G. Pahwa, A. Verma, and Y. S. Chauhan, "Gate Induced Drain Leakage in Negative Capacitance FinFETs", IEEETransactions on Electron Devices, Vol. 67, Issue 3, March 2020.
ā¢ F. Klemme, Y. Chauhan, J. Henkel, and H. Amrouch, "Cell Library Characterization using Machine Learning for DesignTechnology Co-Optimization", IEEE International Conference on Computer-Aided Design (ICCAD), Paris, France, Nov. 2020.
ā¢ G. Bajpai, A. Gupta, O. Prakash, G. Pahwa, J. Henkel, Y. S. Chauhan, and H. Amrouch, "Impact of Radiation on NegativeCapacitance FinFET", IEEE International Reliability Physics Symposium (IRPS), Grapevine-Texas, USA, Mar.-Apr. 2020.08/11/2021 Yogesh Chauhan, IIT Kanpur
Relevant Publications from our group
115
ā¢ A. D. Gaidhane, G. Pahwa, A. Dasgupta, A. Verma, and Y. S. Chauhan, "Compact Modeling of Negative Capacitance Nanosheet FETincluding Quasi-Ballistic Transport", IEEE Electron Devices Technology and Manufacturing Conference (EDTM), Penang, Malaysia, Mar.2020.
ā¢ O. Prakash, A. Gupta, G. Pahwa, J. Henkel, Y. S. Chauhan and H. Amrouch, "Impact of Interface Traps Induced Degradation on NegativeCapacitance FinFET", IEEE Electron Devices Technology and Manufacturing Conference (EDTM), Penang, Malaysia, Mar. 2020.
ā¢ H. Amrouch, V. M. Van Santen, G. Pahwa, Y. S. Chauhan, J. Henkel, "NCFET to Rescue Technology Scaling: Opportunities andChallenges", IEEE Asia and South Pacific Design Automation Conference (ASP-DAC), Beijing, China, Jan. 2020.
ā¢ H. Amrouch, S. Salamin, G. Pahwa, A. D. Gaidhane, J. Henkel, and Y. S. Chauhan, "Unveiling the Impact of IR-drop on Performance Gainin NCFET-based Processors", IEEE Transactions on Electron Devices, Vol. 66, Issue 7, pp. 3215-3223, July 2019.
ā¢ G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Numerical Investigation of Short Channel Effects in Negative Capacitance MFIS and MFMISTransistors: Above-Threshold Behavior", IEEE Transactions on Electron Devices, Vol. 66, Issue 3, pp. 1591ā1598, Mar. 2019.
ā¢ G. Pahwa, A. Agarwal and Y. S. Chauhan, "Evaluating Negative Capacitance Technology for RF MOS Varactors", IEEE SOIā3DāSubthreshold Microelectronics Technology Unified Conference (S3S), San Francisco, USA, Oct. 2019.
ā¢ K. Sharma, A. D. Gaidhane and Y. S. Chauhan, "Performance Enhancement of 4T-IFGC DRAM in 7nm NC-FinFET Technology Node",IEEE SOIā3DāSubthreshold Microelectronics Technology Unified Conference (S3S), San Francisco, USA, Oct. 2019.
ā¢ H. Amrouch, G. Pahwa, J. Henkel and Y. S. Chauhan, "NCFET-Aware Voltage Scaling", IEEE International Symposium on Low PowerElectronics and Design (ISLPED), Lausanne, Switzerland, July 2019.
ā¢ M. Rapp, H. Amrouch, S. Salamin, G. Pahwa, J. Henkel and Y. S. Chauhan, "Performance, Power and Cooling Trade-Offs with NCFET-based Many-Cores", IEEE Design Automation Conference (DAC), Las Vegas, USA, June 2019.
ā¢ A. D. Gaidhane, G. Pahwa, A. Verma, and Y. S. Chauhan, "Modeling of Inner Fringing Charges and Short Channel Effects in NegativeCapacitance MFIS Transistor", IEEE Electron Devices Technology and Manufacturing Conference (EDTM), Singapore, Mar. 2019.
ā¢ G. Pahwa, A. Agarwal and Y. S. Chauhan, "Numerical Investigation of Short-Channel Effects in Negative Capacitance MFIS and MFMISTransistors: Above Threshold Behavior," in IEEE Transactions on Electron Devices, 2019.
ā¢ A.D. Gaidhane, G. Pahwa and Y.S. Chauhan, "Modeling of Inner Fringing Charges and Short Channel Effects in Negative CapacitanceMFIS Transistor", accepted in Electron Devices Technology and Manufacturing (EDTM), 2019.
ā¢ G. Pahwa, A. Agarwal and Y. S. Chauhan, "Numerical Investigation of Short-Channel Effects in Negative Capacitance MFIS and MFMISTransistors: Subthreshold Behavior," in IEEE Transactions on Electron Devices, Nov. 2018.
ā¢ Karishma Qureshi, G. Pahwa and Y.S. Chauhan, "Impact of Linear Intergranular Variation in Remnant Polarization on Negative CapacitanceField Effect Transistor", ICEE, 2018.
08/11/2021 Yogesh Chauhan, IIT Kanpur
Relevant Publications from Our group
116
ā¢ A.D. Gaidhane, G. Pahwa and Y.S. Chauhan, "Compact Modeling of Drain Current in Double Gate Negative Capacitance MFISTransistor", ICEE, 2018.
ā¢ H. Amrouch, G. Pahwa, A. D. Gaidhane, J. Henkel and Y. S. Chauhan, "Negative Capacitance Transistor to Address theFundamental Limitations in Technology Scaling: Processor Performance," IEEE Access, Sep. 2018.
ā¢ A.D. Gaidhane, G. Pahwa, A. Verma, Y. S. Chauhan, "Compact Modeling of Drain Current, Charges, and Capacitances in Long-Channel Gate-All-Around Negative Capacitance MFIS Transistor," IEEE Transactions on Electron Devices, May 2018.
ā¢ G. Pahwa, T. Dutta, A. Agarwal, and Y. S. Chauhan, āPhysical Insights on Negative Capacitance Transistors in Non-Hysteresis andHysteresis Regimes: MFMIS vs MFIS Structures", IEEE Transactions on Electron Devices, Mar. 2018.
ā¢ T. Dutta, G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Impact of Process Variations on Negative Capacitance FinFET Devices andCircuits", IEEE Electron Device Letters, Jan. 2018.
ā¢ T. Dutta, G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Performance Evaluation of 7 nm Node Negative Capacitance FinFET basedSRAM", IEEE Electron Device Letters, Aug. 2017.
ā¢ G. Pahwa, T. Dutta, A. Agarwal, and Y. S. Chauhan,"Compact Model for Ferroelectric Negative Capacitance Transistor with MFISStructure", IEEE Transactions on Electron Devices, Mar. 2017.
ā¢ G. Pahwa, T. Dutta, A. Agarwal, S. Khandelwal, S. Salahuddin, C. Hu, and Y. S. Chauhan, "Analysis and Compact Modeling ofNegative Capacitance Transistor with High ON-Current and Negative Output Differential Resistance - Part I, Model description",IEEE Transactions on Electron Devices, Dec. 2016.
ā¢ G. Pahwa, T. Dutta, A. Agarwal, S. Khandelwal, S. Salahuddin, C. Hu, and Y. S. Chauhan, "Analysis and Compact Modeling ofNegative Capacitance Transistor with High ON-Current and Negative Output Differential Resistance - Part II, Model validation",IEEE Transactions on Electron Devices, Dec. 2016.
ā¢ G. Pahwa, T. Dutta, A. Agarwal, and Y. S. Chauhan, "Energy-Delay Tradeoffs in Negative Capacitance FinFET based CMOSCircuits", IEEE ICEE, Dec. 2016. (Best Paper Award)
ā¢ G. Pahwa, T. Dutta, A. Agarwal, and Y. S. Chauhan, "Designing Energy Efficient and Hysteresis Free Negative CapacitanceFinFET with Negative DIBL and 3.5X ION using Compact Modeling Approach", IEEE ESSDERC, Switzerland, Sept. 2016.(Invited)
ā¢ G. Pahwa, A. Agarwal, and Y. S. Chauhan, "Compact Modeling of Negative Capacitance Transistor with Experimental Validation",IWPSD, Dec. 2015.
08/11/2021 Yogesh Chauhan, IIT Kanpur
Thank You
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