UTEP College of Engineering - 2D MATERIALS ROSPECTS FOR...
Transcript of UTEP College of Engineering - 2D MATERIALS ROSPECTS FOR...
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04222015-104222015-1
2D MATERIALS: PROSPECTS FOR ELECTRONICS
1Luigi Colombo, 2Sanjay K. Banerjee, & 3Alan Seabaugh1Texas Instruments, Dallas, TX, 2UT Austin, Austin, TX, 3Notre Dame University, Notre Dame, IN
US - EU Workshop on 2D Layered Materials and DevicesApril 22-24, 2015
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ACKNOWLEDGMENTSUT Dallas:
Robert Wallace; KJ Cho; Moon Kim ; Chris Hinkle; JiyoungKim groups
UT Austin:Emanuel Tutuc ; Sanjay K Banerjee groups
Ulsan Korea(now):Rodney Ruoff
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A FEW US PROGRAMS ON NANOELECTRONICS
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Univ. Nebraska-LincolnUniv. Wisconsin-Madison Univ. OaklandSUNY Buffalo UC-Irvine Univ. Delaware
SUNY-AlbanyPurdue U. Virginia Columbia U NYUCornell GIT Brown
UT-AustinUT-Dallas NCSU Texas A&MUCSD Harvard
MIT Notre Dame (2) Columbia / FloridaMinnesota Cornell / PrincetonUC-Santa Barbara UC-Riverside / GeorgiaUC-Riverside / UC-I / UC-SD / Rochester / SUNY-BuffaloDrexel University / U. Illinois-UC / U. PennsylvaniaVirginia Commonwealth / UC-R / Michigan / U. Virginia U. Pittsburgh / U. Wisconsin-Madison / Northwestern
University of Minnesota
Carnegie MellonColorado StateJohns HopkinsMITOhio StatePenn StatePurdue
U. WisconsinU. AlabamaU. ArizonaUC/BerkeleyUC/RiversideUC/Santa BarbaraUT/AustinU. IowaU. Michigan
U. NebraskaUCLA
CALTECHColumbiaCornellMITNC StatePurdueRiceStanford
UC/BerkeleyUC/IrvineUC/RiversideUC/Santa BarbaraU of PAWVAYale
Notre DameCarnegie MellonGA TechPenn StatePurdueUC/BerkeleyUC/San DiegoUC/Santa Barbara
UT/AustinUT/Dallas
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NRI MISSION STATEMENT – 2006 TIMEFRAME• NRI MISSION: Demonstrate novel computing devices capable of
replacing the CMOS FET as a logic switch in the 2020 timeframe. • These devices should show significant advantage over ultimate FETs in
power, performance, density, and/or cost to enable the semiconductor industry to extend the historical cost and performance trends for information technology. – To meet these goals, NRI pursues five research vectors:
• NEW DEVICE: Device with alternative state vector• NEW WAYS TO CONNECT DEVICES: Non-charge data transfer• NEW METHODS FOR COMPUTATION: Non-equilibrium systems • NEW METHODS TO MANAGE HEAT: Nanoscale phonon engineering• NEW METHODS OF FABRICATION: Directed self-assembly devices
– Finally, it is desirable that these technologies be capable of integrating with CMOS, to allow exploitation of their potentially complementary functionality in heterogeneous systems and to enable a smooth transition to a new scaling path.
J. Welser, IBM/SRC
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COMPUTATIONAL VARIABLES
• Charge: CMOS, TFET
• Electric Dipole: FeFET
• Magnetic Dipole: NML, SWD, and ASL
• Orbital State: BiSFET
• Strain: PiezoFET
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FIRST PRINCIPLES PREDICTIONS OF 2D CRYSTAL BANDALIGNMENTS
preferred band alignments for TFETs
Two transport optionsin‐plane
interlayer
EC
EV
Gong et al. Appl. Phys. Lett. 103, 053513 (2013)
1.3 eV
1 eV
SnSe2
WSe2
Calculated by density functional theory
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LIST OF DEVICES UNDER CONSIDERATION
7D. Nikonov and I Young, JxCDC-0004-Dec-2014
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SWITCHING ENERGY VS. DELAY OF A 32-BITADDER
Nikonov and Young, IEEE Expl. Sol. St. Comp. Dev. Circ., Dec 2014.
Benchmarking emerging devices vs. CMOS
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ARE TFET THE SOLUTION?
Fiori et al, Nature Nanotech, V9, Oct 2014
Transfer characteristics (IDS versus VGS)
Need a SS
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BottomBilayer
TopBilayer
BN
10 µm
Straight edges assumed to be principal crystal axes Layer transfer done while keeping track of orientation
DOUBLE BILAYER ITFET: FABRICATION ANDROTATIONAL ALIGNMENT
Fallahazad B et. al., Nano Letters 15,428-433 (2015)
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-0.4 -0.2 0.0 0.2 0.4-3
-2
-1
0
1
2
3
I int (
mA
/cm
2 )
0 V
- 20 V
20 V
- 40 V
I int (
nA)
VTL (V)
VBG = 40 V
-30
-20
-10
0
10
20
30
0 50 100 150 2000.0
0.2
0.4
0.6
0.8
I int (
mA
/cm
2 )
0 V10 V
20 V
30 VI in
t (nA
)
VTL (mV)
VBG = 40 V
0
2
4
6
86 monolayers
thick BNNDR!
5 monolayerthick BN
NDR!
DOUBLE BILAYER ITFET: INTERLAYER I-V CHARACTERISTICS AT RT
Vertical tunneling field-effect transistor using a stacked double bilayer graphene (BLG) and hexagonal boron nitride heterostructure
B. Fallahazad et al, Nano Letters 15, 428 (2105)S. Kang et al. IEEE ELECTRON DEVICE LETTERS, VOL. 36, NO. 4, APRIL 2015
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2D-2D TUNNELING IN HETEROJUNCTION TFETS
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VGate-MoS2 = 3V
-3.5 V -3.3 V -3.0 V
VGate-WSe2 =
0.0 0.3 0.6 0.9 1.20.0
0.5
1.0
1.5
2.0
I D (n
A)
VD (V)-0.5 0.0 0.5 1.0
10-14
10-12
10-10
10-8
10-6
10-4
I D (A
)
VD (V)
VGate-WSe2 = -3 V
VGate-WSe2 = -2.5 V
VGate-WSe2 = -2 V
Forward biasReverse bias
BTBT
Diffusion current
T. Roy, M. Tosun et al., ACS Nano, 2015
Gate controlled band‐to‐band tunneling and NDR!
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• "If you cannot measure, your knowledge is meager and unsatisfactory." Lord Kelvin
and …….
• “there cannot be devices without materials”andmining is NOT an option as a source of compounds/ML for the SC industry …..
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GRAPHENE SINGLE CRYSTALS:FROM MICRONS TO CENTIMETER
1 m
2013-15Single Crystal Graphene and BLG2005
Monolayer graphite
Novoselov et al., PNAS 2005Hao et al., Science 2013Hao et al , submitted for pub
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MOBILITY OF GRAPHENE AND MOS2 ANDPREPARATION METHODS
Fiori et al, Nature Nanotech, V9, Oct 2014
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HEXAGONAL BORON NITRIDE
Large single crystal controlled thin films needed
http://arxiv.org/ftp/arxiv/papers/1405/1405.7179.pdfA. Ismach et al., ms in preparationS. Sonde et at., ms in preparation
CVD h-BN/metals
100 m
5 nm
SiO2 h-BN
Ni
h-BNSiO2 /Si
Top
Unit cell = (2.5 ± 0.4) ÅRMS roughness = (0.35 ± 0.10) Å
Bulk h-BN
200 m
h-BN/SiO2
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TMDS
http://www.hqgraphene.com/PeriodicTableElements/Mo.phpYongji Gong, Nature Mat., V. 13, 2014R. Yue et al., ACS Nano, V9(1), 474-480 (2015)
Bulk Crystal of MoS2 TMD Heterostructuresby CVD
MoS2 HfSe2
TMD HeterostructuresBy MBE
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DIFFERENTIAL CONDUCTANCE AT ROOMTEMPERATURE ON NATURAL MOS2
Electrical properties variations across MoS2 can be correlated with localvariations in stoichiometry as well as metallic and structural defects.
R. Addou et al., ACS Appl. Mater. Interfaces, 2015, 7 (22), pp 11921–11929
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2D MATERIALS GROWTH SIMULATIONS• 2H structure (L), 1T structure (R)
• In 2H structure, the second triangle is upside-down, in 1T they are pointing at the same direction.
• Inhomogeneous adsorption energy: -0.65 eV
• Homogeneous adsorption energy: -2.56 eV
• Each bond: 2 eV• Deposition rate: 0.1 ML/s• 1E13 vibrations per second
KT Cho, UT Dallas
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1949 1958 .……………………………………………..2014
2015 ????.................................................................................???????????
J. Pelloux-Prayer et al IEDM 2014Fallahazad et al, Nano Letters, 2015
2D M
ater
ials
S
ilico
n
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FROM A FEW MM TO 300-450 MM IN DIA
AND MANY KM/MONTH IN TOTAL LENGTH
1949-50G. Teal, IEEE TED,
ED-23 (7) 1976http://www.crystal-material.com/Single-Crystal-Materials/Silicon-Si-single-crystal.html
Today
Ge Si
http://pcplus.techradar.com/2009/05/21/how-silicon-chips-are-made/
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SUMMARY• New devices will need rotationally aligned layers and will drive the need
(similar to lattice matching for cubic system):– To grow single crystals– Selective single crystal growth … heteroepitaxy
• Defect control (“bulk” and surface) – Chalcogenide materials are especially sensitive to the creation/formation of
point defects (vacancies) – bulk and surface
• Need to determine fundamental properties of materials and a deeper understanding of the materials growth processes– Metrology– Standards
• How about scaled 2D-materials-based devices … submicron???