Graphene for Electronic Applications · Samsung Confidential Seongjun Park Device Lab. Device & System Research Center Samsung Advanced Institute of Technology (SAIT) Graphene for

Samsung Confidential

Seongjun Park

Device Lab. Device & System Research Center

Samsung Advanced Institute of Technology (SAIT)

Graphene for Electronic Applications


1 /40

Graphene : Carbon allotrope with hexagonal arrangemnt in one-atomic-thick sheet.

KS Novoselov, et al., Science, 306 666 (2004)

Isolated multi-layer Graphene from Graphite using scotch tape

Isolation of Graphene

Graphene

– Andre Geim and Konstantin Novoselov (Manchester University) (2004)

– Nobel Prize in Physics (2010)

“Groundbreaking experiments regarding the two dimensional materials graphene”


2 /40

Properties of Graphene

Mobility (cm2/V∙s)

Graphene Silicon

GaAs

200,000 1400 8500

Graphene

C Fiber

Steel

130

4 1

Graphene Silicon

Diamond

5300

149 2320

Ultimate Strength (GPa)

Graphene

Activated C

Silica

2630

500

800

Surface Area (m2/g)

Graphene 97.7 Transparency (%)

Graphite

Cu Platinum

35.0

1.68 10.6

Resistivity (cm)

Thermal Conductivity (W/m ∙K)

4.2 Doped Gr

Graphene Al

Cu

106

800

4020

Current Density (A/cm2)

Graphene 10

High Performance

Tr

Transparent Electrode

for Display & Solar Cell

Super capacitor

Composite

Heat Sink

Interconnect

Larg

e A

rea

Fla

ke b

ase

Chemical Inertness

& Flexibility

Barrier

Flexible Device


3 /40

Where are we? : Gartner’s Hype Cycle

Year 2015 data: Estimation

Trends of Publications on Graphene

Publications in Science/Nature

Peak in 2011/2012 Peak in 2012

Trends of Patent filing

Science Engineering


4 /40

Properties? Properties! : Filling the gaps in properties

Ideal Properties

Engineering Properties

Actual Properties

Required Properties

• Mobility

200,000cm2/Vs ~2000cm2/Vs

• Thermal Conductivity

5300W/mK ~ 1000W/mK

• Mobility

200,000cm2/Vs > 1400cm2/Vs (Si)

• On/Off

~ 10 104 ~ 1011 (Si)


5 /40

Filling the Puzzles : All puzzles need to be filled to be commercialized.

Property 1 Property 2 Property 3

Main Property

Processibility 1 Processibility 2 Cost

Property 4 Uniformity

• Properties Processibility (Industry) Cost (?) Uniformity (Equipment)

• Everything needs to be satisfied all together

– Actual/Engineering Properties

– Processibility

– Cost: $281 for 5cm X 5cm (on Cu foil) ~ $700,000/m2

– Uniformity

Joker


6 /40

Samsung Electronics

www.Statista.com; www.IDC.com; www.SmartWatchGroup.com Wikipedia, Gartner

Semiconductor

DRAM

(39%, 1st in 2014)

NAND

(30%, 1st in 2014)

AP

(4%, 4th in 2014)

CIS

(29%, 2nd in 2014)

Mobile

Smart Phone

(31%, 1st in 2014.Q1)

Smart Watch

(23%, 1st in 2014)

Tablet

(18%, 2nd in 2014)

Appliances and other electronics

LCD TV

(22%, 1st in 2014)

French door refrigerator

(40%, 1st in 2010)

PC Monitor

(13%, 2nd in 2014)

Digital Camera

(23%, 2nd in 2014.H2)

http://www.google.co.kr/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCM2djY7agscCFSQepgod6BUH6w&url=http://www.notebookcheck.net/Samsung-Exynos-5430-Octa-SoC.128499.0.html&ei=JQS6VY33FqS8mAXoq5zYDg&bvm=bv.99028883,d.dGY&psig=AFQjCNHQjDr_6tGx3AxgURggsZu9XQYhWQ&ust=1438340514267483


7 /40

Graphene Applications

Semiconductor

Active Materials

Components

Mobile

Touch Screen

Battery

Appliances and other electronics

External Case

gate

http://www.google.co.kr/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCMGUseX-n8cCFQkVlAod8v8OcA&url=http://www.sparkcharging.com/2015/07/13/samsung-global-research-lab-discusses-potential-lithium-ion-battery-breakthrough/&ei=7F7JVcHuHomq0ATy_7uABw&bvm=bv.99804247,d.dGo&psig=AFQjCNGtWYHZMbz724y6eOvVBq_gPnHzKA&ust=1439346793489008


Growth


9 /40

Graphene Growth on Metal Catalyst

Graphene Growth on various Cu

orientations

Low temperature growth on Metal

catalyst with ICP CVD

0 200 400 600 8000.00

0.05

0.10

0.15

0.20

0.25

D/G

ra

tio

COUNTS

Y S Woo et al. Carbon, 64 315 (2013) H-J Shin et al. APL, 102, 163102 (2013)


10 /40

Direct Growth

Growth of h-BN on and underneath

of Ni

Graphene can be grown on

Semiconductor

Y S Woo et al. Carbon, 64 315 (2013) S Park et al. ACS Nano, 9, 633 (2015)

Ge


Wafer-scale Integration of

Graphene Tunneling Barristor


12 /40

How to Achieve Low Off Current

Ion/Ioff~102 , D=2.2V/nm

X. Li et al. Science (2008)

F. Xia et al. Nano Lett.. (2010)

w=5nm, Ion/Ioff~106, μ=100-200cm2/Vs

F. Schwierz, Nature Nanotechnology(2012)

L. Ci, Nature Materials(2012)

Quantum Confinement: GNR

Symmetry Breaking: Bilayer h-BCN


13 /40

Doping : DFT simulations on metal doped graphene Work functions

eV Graphene Ni Co Pd Al Ag Cu Au Pt

WF Metal 5.47 5.44 5.67 4.22 4.92 5.22 5.54 6.13

WF Simulation 4.48 3.66 3.78 4.03 4.04 4.24 4.40 4.74 4.87

WF Exp 4.6 3.9 4.3 4.8

-W

W

G Giovannetti et al., PRL, 101 026803 (2008)


14 /40

Tunneling Transistor : h-BN, Ion ~ 70pA/m2, Ioff ~ 12pA/m2, Ion/Ioff = 50 @ Vb = 0.2V

L Britnell et al., Science 335 947 (2012)

Gate

Ion/Ioff ~ 5

With MoS2, Ion/Ioff = 7000


15 /40

Graphene Barristor : Si, Ion ~ 10A/m2, Ion/Ioff = 105

Epoxy for Focused Ion Beam(TEM sample preparation)

Silicon Silicon

Epoxy for Focused Ion Beam(TEM sample preparation)

A B

Graphene

Graphene

Graphene Silicon

Graphene Silicon

Schottky

Height ON OFF

H Yang et al., Science 336 1140 (2012)


16 /40

Graphene Barristor : Half adder & 1:1 Matching btw work function and Fermi level changes

H Yang et al., Science 336 1140 (2012)


17 /40

Barrier Materials

• Exploring Barrier Materials: IGZO • Various Barrier Materials explored:

– 2D materials: MoS2, WS2

– Semiconductor: Si

– Graphene Family: Graphene Fluoride

Barrier On/Off (Ion)

U. Manchester

Science (2012) MoS2

104

(0.1 A/m2)

SAIT

Science (2012) Si

105

(0.1 A/m2)

U. Manchester

Nature Nano (2013) WS2

106

(a few A/m2)

UCLA

Nature Mat (2013) MoS2

103

(50 A/m2)

HRL

EDL (2013)

Graphene

Fluoride

105

(5 A/m2)

Drain

Source IGZO

Gate

Graphene

Insulator

Pt/Cr

Drain

Al2O3

C

In

Ga

Zn

O

H

Glass

Ni

IGZO Graphene

Al2O3

Pt

Cr


18 /40

Tunneling Barristor : Working Principles: Barrier Thickness Modulations

• Conventional Fabrication Processes • Barrier Thickness Modulations

– Modulated thickness of tunneling Barrier

SEM Graphene

IGZO Source

Drain

Gate

A

Vg

Vd

Fabricated on (15cm)2 glass

-ΔWG

ΔWM

t

Graphene IGZO Metal

eVd +ΔWG

OFF ON


19 /40

IV Curves : High On/Off even at 0.1 VDS

• Statistics • Device Behavior

– Ion/Ioff > 106 @ 0.1 V

±

±

-0.4 -0.2 0.0 0.2 0.410

-14

10-12

10-10

10-8

10-6

J

(

A/

m2)

Vd (V)

Vg:

-3V

-2V

-1V

0V

1V

2V

3V

0

2

4

6

8

10

1 2 3 4 5 60

50

100

150

200

Joff

= 0.47 nA/m2

Co

un

t

Jon

Joff

log (J (pA/m2))

Jon

= 89 nA/m2

1 2 3 4 5 60

50

100

150

200

Co

un

t

2,062 devices

log (Ion

/Ioff

)

Ion

/Ioff

= 3,010 398.7

9 10 11 12 13 14 15 16 17 180

10

20

30

40

Co

un

t

Ion

/Ioff

Ion

/Ioff

=13.7 0.039

796 devices


20 /40

Barrier Design : Barrier Modulation with metal work function

• Exploring Barrier Materials

– Mo: Small response to gate and high off

– Pt: Small on current

– Ni: Small off current and high on current

• Barrier Modulation with Metal

– Large Barrier

Low IOn

– Small Barrier

High IOff

ΔWM

t

10-13

10-12

10-11

10-10

10-9

10-8

10-7

10-6

10-5

1.40.90.7

On

Off

J (

A/

m2)

WM

(eV)

7.0 15,000 2,500 1,700

0.1

ION

/IOFF

=

10 15 20

t (nm)Mo Ni Au Pt

Pt

-3 -2 -1 0 1 2 310

-13

10-12

10-11

10-10

10-9

10-8

10-7

10-6

10-5

Vg (V)

J (

A/

m2)

Mo

Ni Au Pt


21 /40

Inverter

• Logic Inverter • p-type Barrier: Ge

Graphene

Ge Al2O3

Pt/Cr

Drain

Source Ge

Gate

Graphene

Insulator

Glass

-3 0 3

10-8

10-7

J (

A/

m2)

Vg(V)

Vsd

= 0.1V

-0.5 0.0 0.5

-0.6

-0.3

0.0

0.3

0.6

Vg:

-3V

-2V

-1V

0V

1V

2V

3V

J (

A

/m

2)

Vb (V)

VDD

Vout Vin

G

G

p

n

Al

-1 0 1

0.0

0.2

0.4

0.6

0.8

1.0

VDD

= 0.1 V

Vo

ut (V

)

Vin

(V)

VDD

= 1 V

-1 0 1

0

1

2

3

Gain

Vin

(V)

VDD

= 1 V

VDD

= 0.1 V

0.0 0.5 1.0

0

1

2

3

Ga

in

VDD

(V)


ALD on Graphene

23 /40

Graphene Incorporated Device Challenges

ALD High-k Film on Graphene

X. Wang et al. , JACS, 130(26), 8152 (2008)

:Non-conformal growth of high-k dielectric films Gate Dielectric

Gate

p-Si

S D Graphene

Materials

- Direct Growth

- Analysis Tools

Transfer

- Lamination

- Delamination

- Residue

Interface

- ALD

- Metal contact

24 /40

ALD HfO2 Films on Graphene : The effects of various surface modifications

S-J Jeong, et al. (Submitted)

25 /40

Downscaling and Electrical Evaluation of ALD HfO2 Films on Graphene


26 /40

Graphene Tunnelling Transistors


27 /40

Direct Growth of Metal Oxide Films on Graphene

S-J Jeong, et al. (In preparation)

28 /40

Surface Morphology Evolution of pALD and cALD-Al2O3 thin films on Graphene


29 /40

Electrical Evaluation of pALD Al2O3 Films on Graphene in a Wafer Scale



Organic Light Emitting Transistor

31 /40

Emission type of AMOLED

• Thin-film transistor based on an organic semiconductor

– The organic light-emitting field-effect transistor (OLET) emits light during transistor operation.

– Line emission at recombined area

Bottom emission Top emission

Adv. - Simple fabrication process

- Low power consumption

- High colour purity - High resolution

Dis-Adv. - Physical limitation

- Low resolution (<1000dpi)

- Complexity of the fabrication process

Needs Need to improvement light efficiency

Need to adapt large size device such as TV

a) Bottom Emission b) Top Emission

http://www.oled.at/wp-content/uploads/2013/11/emission-oled.gif

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Graphene Electrode : 97.7% transparent and controllable work function with doping

• Device performance with graphene electrode is similar to that with ITO

• Transparency ~ 97.7%

• Work function can easily modulated by chemical and electric field

Shin et al., J. Am. Chem. Soc., 132, 15603-15609, 2010

Yu et al., Nano Lett.., 9, 3430-3434, 2009 Ahn et al., Nature Photonics, 6, 105-110, 2012

33 /40

Vertically Stacked OLED and Graphene : Graphene is used both electrode of OLED and channel in TFT

• Controlling the number of injection hole by gate bias

– if Gate bias < 0, Graphene W/F increased speed of hole injection is faster

– if Gate bias > 0, Graphene W/F decreased speed of hole injection is slower

• Hole injection and recombination can be controlled by gate bias.

• Graphene together work as channel and electrode

• Hole injection layer

5.2 eV

?? eV

4.5 eV 5.0 eV

3.0 eV

4.5 eV

Operating part (GB with Graphene channel)

Emitting part (EL with Graphene electrode

Graphene HIL

EF EF

EF

Gate bias < 0 Gate bias = 0 Gate bias > 0

34 /40

Operation of OLEB (OLE Barristor) : Drain current and luminescence efficiencies can be controlled by gating

• P3HT

• PEDOT:PSS

-10 -8 -6 -4 -2 0-5.0x10

-4

-4.0x10-4

-3.0x10-4

-2.0x10-4

-1.0x10-4

0.0

Vgs=-10

Vgs=-5

Vgs=0

Vgs=5

Vgs=10

I ds

-10 -8 -6 -4 -2 0

0.01

0.1

1

Vgs=-10

Vgs=-5

Vgs=0

Vgs=5

Vgs=10

Lu

min

esce

nce (

cd

/m2)

Vds

-10 -8 -6 -4 -2 0-7.0x10

-4

-6.0x10-4

-5.0x10-4

-4.0x10-4

-3.0x10-4

-2.0x10-4

-1.0x10-4

0.0

Vgs=-10

Vgs=-5

Vgs=0

Vgs=5

Vgs=10

I ds

-10 -8 -6 -4 -2 01E-6

1E-5

1E-4

1E-3

0.01 Vgs=-10

Vgs=-5

Vgs=0

Vgs=5

Vgs=10

Lu

min

es

ce

nc

e (

cd

/m2)

Vds

5.2 eV

?? eV

4.5 eV 5.0 eV

3.0 eV

4.5 eV


Graphene for Si True Ohmic Contact

36 /40

Source/Drain Contact : Contact Resistance became serious portion of total resistance of devices

• Contact resistance of logic devices

– From 32 nm, contact resistance is higher

than channel resistance.

– 9.1% of PMOS’s and 37.5% of NMOS’s

contact resistances are due to Schottky

barrier between contact metal silicide and Si.

• Total Resistance of Device

– Channel Resistance is getting smaller as the device getting smaller

– Specific contact resistance is constant and contact resistance is getting bigger as the contact area is getting smaller

Gate Dielectric

Gate

p-Si n+

S

n+

D

RTotal = RC(S/n+) + R(p-Si) + RC(n+/D)

IEEE Trans Elec Dev 55, 1259 (2008)

37 /40

De-pinning : Some may de-pin Si surfaces but hard to control its thickness (< 1 nm)

• 0.5nm MgO Ohmic contact & contact resistance reduction by 100 times

• De-pinning by inserting interfacial layer

– 1nm SiN Ohmic contact & contact

resistance reduction by 106 times

J. Appl. Phys. 105, 023702 (2009) Appl. Phys. Lett. 96, 052514 (2010)

38 /40

Graphene for De-pinning : AFM results show that Graphene improved contact resistances.

• Demonstrated that Schottky barrier height reduction

– Contact resistance was measured with AFM

(Atomic Force Microscopy) and was 10-8 ~

10-9 cm2 (n-Si 1017 cm-3).

• De-pinning for Graphene on fully saturated Si

– 1:1 relationship btw work function & Schottky

barrier height

– Fully saturated Si Surface with 0.5 nm

Separation with Graphene

J. Appl. Phys. 105, 023702 (2009)

Science 336, 1140 (2012)

Gra

ph

en

e F

erm

i Leve

l

Ch

an

ge

Sc

ho

ttk

y B

arr

ier

He

igh

t

Nano Letters 13, 4001 (2013)

39 /40

Graphene for Ohmic Contact : Ohmic Contact between Ni and Si with Graphene insertion

• Schottky Contact for Metal/Si

• Interface Issues

• Ohmic contact was demonstrated

– 1:1 relationship btw work function & Schottky

barrier height

– Some cases shows Schottky but can be

corrected

Science 336, 1140 (2012) Graphene

SiO2

Si

40 /40

Summary

• Graphene Propoerties

– High mobility, conductance, current density, transparency, chemical inertness

– Surface area, thermal conductivity, ultimate strength

• Applications

– New device concept: Gate-Tunable Schottky Diode / Barristor

– High current on-off ratio (>105) achieved

– OLET

– S/D Contacts

• Too early to say what will happen: The Long Game

– Nature, Editorials, May 2011

– It typically takes any technology some 20 years to emerge from the lab and be

commercialized.

Contact: [email protected]

Documents

Graphene for Electronic Applications · Samsung Confidential Seongjun Park Device Lab. Device & System Research Center Samsung Advanced Institute of Technology (SAIT) Graphene for