Istituto per la Microelettronica e Microsistemi
IMM
The network on graphene at IMM
OUTLINE
• The IMM graphene research network
• The agreement with Industry
• Competences and acquired know how at IMM Agrate (MDM)
• Competences and acquired know how at IMM CT
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 1/15
The graphene research network at IMM
IMM
Graphene like materials (silicene, germanene, …)
Memories and logics
Milano
Advanced characterisation
& sensors
See V. Morandi, R. Rizzoli
Bologna
Roma
Lecce
Napoli
Catania
materials fundamentals
&
devices (Rf, power, …)
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 2/15
The graphene research network at IMM
IMM
Graphene like materials (silicene, germanene, …)
Memories and logics
Milano
Advanced characterisation
& sensors
See V. Morandi, R. Rizzoli
Bologna
Roma
Lecce
Napoli
Catania
materials fundamentals
&
devices (Rf, power, …)
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 3/15
The graphene research network at IMM
IMM
Graphene like materials (silicene, germanene, …)
Memories and logics
Milano
Advanced characterisation
& sensors
See V. Morandi, R. Rizzoli
Bologna
Roma
Lecce
Napoli
Catania
materials fundamentals
&
devices (Rf, power, …)
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 2/15
The graphene research network at IMM
IMM
Graphene like materials (silicene, germanene, …)
Memories and logics
Milano
Bologna
Roma
Lecce
Advanced characterisation
& sensors
See V. Morandi, R. Rizzoli
The industrial cluster
Napoli
Catania
3Sun
materials fundamentals
&
devices (Rf, power, …)
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 2/15
The graphene research network at IMM
IMM
Graphene like materials (silicene, germanene, …)
Memories and logics
Milano
Bologna
Roma
Lecce
Advanced characterisation
& sensors
See V. Morandi, R. Rizzoli
The industrial cluster
Napoli
Catania
3SunJ.D.A.
materials fundamentals
&
devices (Rf, power, …)
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
J.D.A.
J.D.P.
Slide 2/15
IMM-Agrate expertise on ReRAM memory devices
Challenge: Resistive Random Access Memory
(ReRAM) in graphene.
IMM
CNR- IMM- Agrate
EMMA Project-FP6 (1/9/2006-30/11/2009): Emerging
Materials for Mass-storage Architectures (contact: Marco
Fanciulli and Sabina Spiga)
MORE Project 2010-2012 (CARIPLO): Advanced MetalOxide heterostructure for nanoscle ReRAM (contact:
Sabina Spiga)
single layer graphene as electrode on Nb-doped STO
substrate for Pt/NiO/graphene nano-ReRAM
graphene
Top electrode
A
resistive material
Bottom electrode
ReRAM: a large class of emerging non-volatile memory
concepts is based on a 2-terminal resistor as a memory
element that can be programmed in a high and low
conductive state
Memristor concept introduced by HP
J. Y. Son et al., ACS Nano 4, 2010, 2655-2658
Graphene Oxide Thin Films (as switching element)
for Flexible Nonvolatile Memory applications
H.Y. Jeong at al., Nanoletters 2010, 10, 4381–4386
Large interest from worldwide industries on ReRAM
for post high-density FLASH and for Flexible
Nonvolatile Memory Applications
IMM-Agrate expertise up to now: NiO, Nb2O5, TiO2 based
metal/oxide/metal thin film- and nanowireheterostructures
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 3/15
Challenge: Graphene-like materials
IMM
CNR- IMM- Agrate
Graphene like semiconductors (silicene, germanene)
 valuable option for active material in Post-CMOS
ditital logic devices and circuits
Option 1: silicene on metals, (in analogy
with graphene)
Option 2: encapsulation silicene with
2D hexagonal dielectric lattices
MBE of Si on Ag(110), Ag(111) substrates
Ref.
Aufray et al, Appl. Phys. Lett. 97, 223109 (2010);
Aufray et al, ibidem 96, 183102 (2010)
graphite-like AlN 2D top lattice
functionalized silicene
graphite-like AlN 2D bottom lattice
• Molecular beam epitaxy apparatus for growth,
functionalization amd in situ characterization of
graphene like materials
• in situ SPM and spectroscopic diagnostic tools
@ CNR-IMM
(Lab. MDM)
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
• dielectric capping for prototypical MOS-like
devices
Slide 4/15
GRAPHENE at IMM-CT: highlights
IMM
More than 30 papers since 2005 by two groups (theory & Exp.)
growth methods
Synthesis methods
Mechanical exfoliation of highly
oriented pyrolityc graphite (HOPG)
Chemical exfoliation of highly
oriented pyrolityc graphite (HOPG)
Epitaxial graphene on SiC by
controlled graphitisation of the surface
at high temperatures (1500 –2000 °C)
in inert gas ambient
High material quality:
Low defects density,
High mobility
Can be placed on different substrates:
SiO2 , SiC, high-k dielectrics
High production yield
Can be placed on different substrates:
SiO2 , SiC, high-k dielectrics
Large area (wafer scale) sheets
on semiconductor substrate
Small sheets;
Low production yield
Small sheets;
Defects
Substrate cost
S. Sonde, F. Giannazzo, V. Raineri, and E. Rimini, J. Vac. Sci. Technol. B 27, 868 (2009).
S. Sonde, F. Giannazzo, V. Raineri, and E. Rimini, Phys. Status Solidi B, 1–4 (2010)
S. Sonde, F. Giannazzo, V. Raineri, R. Yakimova, J.-R. Huntzinger, A. Tiberj, and J. Camassel, Phys. Rev. B 80, 241406(R) (2009).
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 5/15
GRAPHENE at IMM-CT: highlights
IMM
More than 30 papers since 2005 by two groups (theory & Exp.)
growth methods
Synthesis methods
Mechanical exfoliation of highly
oriented pyrolityc graphite (HOPG)
Chemical exfoliation of highly
oriented pyrolityc graphite (HOPG)
Epitaxial graphene on SiC by
controlled graphitisation of the surface
at high temperatures (1500 –2000 °C)
in inert gas ambient
High material quality:
Low defects density,
High mobility
Can be placed on different substrates:
SiO2 , SiC, high-k dielectrics
High production yield
Can be placed on different substrates:
SiO2 , SiC, high-k dielectrics
Small sheets;
Low production yield
Small sheets;
Defects
BEYOND
STATE OF THE ART
Large area (wafer scale) sheets
on semiconductor substrate
Substrate cost
First EG on 4H-SiC off axis
Patended substrates
S. Sonde, F. Giannazzo, V. Raineri, and E. Rimini, J. Vac. Sci. Technol. B 27, 868 (2009).
S. Sonde, F. Giannazzo, V. Raineri, and E. Rimini, Phys. Status Solidi B, 1–4 (2010)
S. Sonde, F. Giannazzo, V. Raineri, R. Yakimova, J.-R. Huntzinger, A. Tiberj, and J. Camassel, Phys. Rev. B 80, 241406(R) (2009).
High mobility
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 5/15
GRAPHENE at IMM-CT: Highlights
IMM Transfer to substrates: methods and
functionalization
Silanization of SiO2
Phosphonization of SiO2
Few-layers graphene on
metal
Transfer by
nanoimprinting
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 6/15
GRAPHENE at IMM-CT: Highlights
IMM Transfer to substrates: methods and
functionalization
Silanization of SiO2
Phosphonization of SiO2
Few-layers graphene on
metal
Transfer by
nanoimprinting
CHALLENGES
• From nanoscale properties to large area EG on 4H-SiC (150 mm)
• Functionalisation (to control the G carrier concentration,
to control the G layer transfer to other substrates)
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 6/15
GRAPHENE at IMM-CT: Highlights
Quantum capacitance and local
transport
10
IMM
0
Graphene
-1
10
Graphene
n-SiC
n+
C (a.u.)
SCM Electronic
Module
Qscr Aeff
Qdepl
-2
-3
10
-4
10
Qdepl
SiC
SiO 2
10
0.0
0.5
1.0
1.5
2.0
V g (V)
25
2
A eff (×10 nm )
20
5
0.5
1.0
11
Aeff
ΔVdepl
SiO
leff
1.5
-2
n (×10 cm )
300
200
SiC
+ Vg
F. Giannazzo, S. Sonde, V. Raineri, E. Rimini, Nano Lett. 9, 23 (2009).
F. Giannazzo, S. Sonde, V. Raineri, and E. Rimini, Appl. Phys. Lett. 95, 263109 (2009).
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
l eff (nm)
C’depl
10
0
0.0
ΔVgr
C’q
15
4
Under the influence
of electric field, 2DEG+ Vg
manifests itself as a
Gnd
capacitor, Quantum
capacitor.
100
0
0
10
20
30
n (× 10 m ) Slide
6
-1
40
7/15
IMM
GRAPHENE at IMM-CT: Highlights
The role of interfaces on mobility
DG-SiC
10
6
10
5
10
4
2
23000 cm2V-1s-1
 cm /Vs
EG-SiC
Epitaxial graphene
10
6
10
5
4
10 Nci_EG=2.5x1011cm-2
10
10
Giannazzo F, Roccaforte F, Raineri V, Liotta SF, Europhys. Lett., 74, 686 (2006)
10
S. Sonde, F. Giannazzo, C. Vecchio, V. Raineri, E. Rimini, App. Phys. Lett., 97,
132101 (2010)
Also selected for publication on Virtual Journal of Nanoscale Science &
Technology.
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
6
SPP
ci
equi
exp
DG-SiO 2
5
4
0.5
1.0
11
1.5
2
nVg-n0 (×10 cm /VS)
Slide 8/15
GRAPHENE at IMM-CT: Highlights
IMM
From thin to fat FET
Atomic force microscopy
Optical microscopy
1 m
60 nm
nm
m
Gate
HSQ
Source
Pt
Pt
Drain
Pt
EG
Lg=10m
4H-SiC (0001) n-
4H-SiC (0001) n+
F. Giannazzo, C. Vecchio, V. Raineri, E. Rimini, submitted
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 9/15
GRAPHENE at IMM-CT: Highlights
IMM
fat FET characteristics
Output characteristics
-6
6.0x10
VD = 0.8 V
VD = 0.6 V
VD = 0.4 V
VD = 0.2 V
VD = 0 V
-6
4.0x10
-6
6.0x10
-4
3.0x10
-4
VG = 14 V
VG = 12 V
VG = 10 V
VG = 8 V
VG = 6 V
VG = 4 V
VG = 2 V
VG = 0 V
STEP = 1V
0.0
0
5
VD(V)
10
Transfer characteristics
Hole conduction
ID(A)
8.0x10
-5
0.0
6.0x10
-5
-6
4.0x10
-5
-6
2.0x10
0.0
2.0x10
gm(S)
-4
ID(A)
Ambipolar transport
Transconductance
9.0x10
0V < VD< 10V
0V < VG< 14V
-2.0x10
Electron conduction
Dirac point
VD = 0 V
VD = 0.2 V
VD = 0.4 V
VD = 0.6 V
VD = 0.8 V
-5
-4.0x10
-2
0
2
4 6
VG(V)
8
10 12 14
-5
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
0
5
VG(V)
10
Slide 10/15
GRAPHENE at IMM-CT: challenges
100
3000
first processing
end of processing
80
2000
60
1000
0
0
10
20
Vgs (V)
30
Mapping distribution
Frequency (%)
2
-1 -1
eff (cm V s )
IMM
40
20
0
0
20
40
60
l (nm)
80
100
6000
8000
100
80
60
40
20
0
0
2000 4000
 (cm2V-1s-1)
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 11/15
GRAPHENE at IMM-CT: challenges
100
3000
first processing
end of processing
80
2000
60
1000
0
0
10
20
Vgs (V)
30
Mapping distribution
Frequency (%)
2
-1 -1
eff (cm V s )
IMM
40
20
0
0
20
40
60
l (nm)
80
100
6000
8000
100
80
60
40
20
0
New devices architectures
(a)
Source Gate
Insulator
Vg
2000 4000
 (cm2V-1s-1)
Vg>Vth
(b)
Vg
0
FLG
Insulator
MIS inversion
layer
n+-type
p-type
SiC
Buried gate
Id
FLG
Vg
n-type
CMIS
n+-type
Drain
Vd
CHALLENGES
• Physical model nano- macro properties
• New devices architectures
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
CMIS
Rsource
CFLG
Rch,MIS
(c)
Rc,FLG-SiC
RFLG
Rdrift
Vd
Slide 11/15
GRAPHENE at IMM-CT: ELECTRON STRUCTURE AND
COHERENT TRANSPORT IN CONFINED GRAPHENE
IMM
Methodology
Electronic Structure
Quantum transport
Ab initio
Semiempirical
Transport
Density
functional
theory, LDA
and GGA
exchangecorrelation
functionals,
GAUSSIAN
and SIESTA
codes
Tight-Binding (TB): single
π-orbital Hamiltonian,
further parameterizations
based on DFT
Non-equilibrium Green’s
functions methods coupled
to Landauer-Büttiker
approach
Extended Hückel Theory
(EHT): real-orbital basis,
parameters from DFT
calculations or
experimental data
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Electrostatics
3D Poisson solver,
computational box with
Neumann/Dirichlet
boundary conditions
Slide 12/15
GRAPHENE at IMM: Highlights
IMM the simulation approach to transport properties
Previous activity overview
Computation apparatus: self-consistent transport calculations
Atomistic modeling of disorder in graphene based systems: from the single
defect/impurity to a finite density of scattering centers
GNR-metal junction
At CNR-IMM Catania
Epitaxial GNR on SiC(0001): role of interface states
• In house programming codes for
Focus on defective and functionalized epitaxial GNR
electronic structure and quantum
Complete device simulation
A. La Magna et al, PRB 80, 195413 (2009)
I. Deretzis and A. La Magna, Appl. Phys. Lett. 95, 063211 (2009)
I. Deretzis et al., J. Phys. Cond. Mat. 22, 095504 (2010)
I. Dertzis et al., Phys. Rev. B 81, 085427 (2010)
I. Deretzis et al., Phys. Rev. B 82, 161413(R) (2010)
I. D. and A. La Magna, accepted Appl. Phys. Lett.
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
transport based on atomistic semiempirical Hamiltonians (Extended
Hückel and Tight-Binding), NEGFPoisson scheme
• Full-device simulation for 103 – 107
atoms (in the case of GNRs)
• Atomistic treatment of local
alterations in the atomic structure,
disorder, etc.
• Multiscale approach (electronic
Hamiltonians calibrated or evaluated
by first-principles calculations)
Slide 13/15
Challenges
IMM
IMM - Agrate
• Memories and logics in graphene
• Graphene-like materials
IMM - CT
• From nanoscale properties to large area (150 mm wafers)
• Physical model considering nano-properties for macro-effects
• New devices architectures
• Functionalisation (to control the G carrier concentration,
to control the G layer transfer to other substrates)
• Computational transport properties: multi scale approach
IMM - Bo
• see coming presentations for details
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
Slide 14/15
IMM
Catania:
Bologna:
Antonino La Magna*
Vittorio Morandi*
Giuseppe Angilella**
Luca Ortolani***
Ioannis Deretzis***
Rita Rizzoli*
Giulio Paolo Veronese*
Raffaella Lo Nigro*
Alberto Roncaglia*
Filippo Giannazzo*
Vito Raineri*
Emanuele Rimini**
Thank you for your attention
Sushant Sonde***
Carmelo Vecchio ****
Agrate:
Marco Fanciulli**
Alessandro Molle*
Sabina Spiga*
Atom_based Nanotechnology workshop, 19th January 2011, Arcetri (FI), Italy
* Ricercatori CNR di ruolo
** Associati
*** Post-doc
**** Dottorandi
Slide 15/15