january 9, 2013 ieee eds dl@vit, vellore, india · 2013-04-17 · dubai, uae (year 2010) 828 m...

Future of nano CMOS Technology

January 9, 2013

Hiroshi Iwai, Tokyo Institute of Technology

1

IEEE EDS DL@VIT, Vellore, India

1900 “Electronics” started.

Device: Vacuum tubeDevice feature size: 10 cm

1970 “Micro-Electronics” started.

Device: Si MOS integrated circuitsDevice feature size: 10 µm

Major Appl.: Amplifier (Radio, TV, Wireless etc.)

Major Appl.: Digital (Computer, PC, etc.)

Technology Revolution

Technology Revolution

2000 “Nano-Electronics” started.

Device: Still, Si CMOS integrated circuitsDevice feature size: 100 nmMajor Appi.: Digital (µ-processor, cell phone, etc.)

Technology Revolution??

Maybe, just evolution or innovation!

Now, 2012 “Nano-Electronics” continued.

Device: Still, Si CMOS integrated circuitsDevice feature size: 10 nmMajor Appl.: Digital (µ-processor, cell phone, etc.)

Future, “Nano-Electronics” still continued?

Device: Still, Si CMOS integrated circuits?Device feature size: ? nm, what is the limit?

Application: New application?

Technology Revolution?

What is special or new for Nano-Electronics?

In 1990’s, people expected completely new mechanism or operational principle due the nano size, like quantum mechanical effects.

However, no fancy new operational principle was found.

At least for logic application, there is no success story for “Beyond CMOS devices” to replace Si-CMOS.

λ>>LDiffusive transport

λ<LBallistic transport

λ~LQuasi-Ballistic transport

Lλ ：Mean free pathsource drain

RM

Back scatteringfrom drain

Ballistic transport will neverHappen for MOSFET because of back scattering

With decreasing channel length,Drain current increase continue.

Also, 1D quantum conduction, or ballistic conduction will not happen.

Ballistic conduction will not happeneven decreasing channel lengh.

(1D quantum conduction: 77.8µS regardless of the length and material).

First Computer Eniac: made of huge number of vacuum tubes 1946Big size, huge power, short life time filament

Today's pocket PCmade of semiconductor has much higher performance with extremely low power consumption

dreamed of replacing vacuum tube with solid‐state device

8

1960: First MOSFET by D. Kahng and M. Atalla

Top View

Al Gate

Source

Drain

Si

Si

Al

SiO2

Si

Si/SiO2 Interface is extraordinarily good

9

1970,71: 1st generation of LSIs

DRAM Intel 1103 MPU Intel 4004

10

Most Recent SD Card

128GB (Bite) = 128G X 8bit= 1T(Tera)bit

1T = 1012 = １Trillion

Brain Cell：10～100 BillionWorld Population：7 Billion

Stars in Galaxy：100 Billion

In 2012

2.4cm X 3.2cm X 0.21cm

Volume：1. 6cm³ Weight：2g

Voltage：2.7 - 3.6V

Old Vacuum Tube：5cm X 5cm X 10cm, 100g, 50W

128 GB = 1Tbit

What are volume, weight, power consumption for 1Tbit

Old Vacuum Tube：5cm X 5cm X 10cm

1Tbit = 10,000 X 10,000 X 10,000 bitVolume = (5cm X 10,000) X (5cm X 10,000)

X (10cm X 10,000)= 0.5km X 0.5km X 1km

500 m

1,000 m

1Tbit

Burji KhalifaDubai, UAE(Year 2010)

828 m

Indian TowerMumbai, India(Year 2016)

700 m

700 m

Pingan IntenationalFinance CenterShanghai, China(Year 2016)

Old Vacuum Tube：100W

1Tbit = 1012bitPower = 0.05kWX1012=50 TW

Nuclear Power Generator1MkW=1BW We need 50,000 Nuclear Power Plant for

just one 128 GB memory

In Japan we have only 54 Nuclear Power Generator

Last summer Tokyo Electric Power Company (TEPCO) can supply only 55BW.

We need 1000 TEPCO just one 128 GB memory

Imagine how many memories are used in the world!

So progress of integrated circuits is extremely important for power saving.

Brain: Integrated Circuits

Hands, Legs：Power device

Stomach：PV device

Ear, Eye：Sensor

Mouth：RF/Opto device

16

17

Near future smart-society has to treat huge data.

Demand to high-performance and low power CMOS become much more stronger.

18

MemoryMemory[19%][19%]

MicrocompMicrocomp..[21%][21%]

Logic ICLogic IC[27%][27%]

Analog ICAnalog IC[15%][15%]

OthersOthers[18%][18%]

MemoryMemory[13%][13%]

MicrocompMicrocomp..[14%][14%]

Logic ICLogic IC[30%][30%]

Analog ICAnalog IC[10%][10%]

Emerging areasEmerging areas[33%][33%]

313 billion dollar (US) in 2011

1,528 billion dollar (US) in 2025

（Gartnerの市場予測）

Semiconductor Device Market will grow 5 times in 12 years, even though, it is very matured market!!

Gartner: By K. Kim, CSTIC 2012

Downsizing1. Reduce Capacitance

Reduce switching time of MOSFETsIncrease clock frequency

Increase circuit operation speed2. Increase number of Transistors

Parallel processingIncrease circuit operation speed

Thus, downsizing of Si devices is the most important and critical issue.19

Downsizing contribute to the performance increase in double ways

20

(1970) 10 µm 8 µm 6 µm 4 µm 3 µm 2µm 1.2 µm

0.8 µm 0.5 µm 0.35 µm 0.25 µm 180 nm 130 nm 90 nm

Averaged downsizing rate (in the past 42 years): ~ 0.7X every 3 years

Total reduction in 19 generations: Gate Length ~ 1/500, Area ~ 1/250,000

65 nm 45 nm 32 nm 22 nm (2012)

Feature Size/Technology Node

Gate oxide

Gate metal

Source Drain

1V 0V0V

Substrate 0V DepletionRegion (DL)

1V

0V 0V

tox and Vdd have to be decreased for betterchannel potential control IOFF Suppression

0V < Vdep＜1V

0V

0V < Vdep＜1VChannel

0V

0V

0V0V

0.5V

Large IOFF

Region governed By drain bias

Region governed by gate bias

tOX thinning

DL touch with SRegion (DL)

Large IOFF

No toxthinning

Vdd

Vdd

21

Problem for downsizing

LLgate gate and tand toxox(EOT) scaling trend(EOT) scaling trendA. Toriumi (Tokyo Univ), IEDM 2006, Short Course

t ox(

(

22

Gate oxideGate oxide

Small Cox Low inversion electron densitySmall ION

Large Cox High inversion electron densityLarge ION

Inversion layer Inversion layer

ttoxox thinningthinning

1V

1V

tOX thinning

23

Tunnelingdistance

3 nm

What would be the limit of downsizing!

Source DrainChannel

25

Vg

Id

Vth (Threshold Voltage)

Vg=0V

SubthreshouldLeakage Current

Subtheshold leakage current of MOSFET

Subthreshold CurrentIs OK at Single Tr. level

But not OKFor Billions of Trs.

ONOFF

Ion

Ioff

Subthresholdregion

26

Vg (V)1

0.3 V

0.5 V 1.0 V

Ion

Ioff

Id (A/µm)

10-7

10-5

10-11

10-9

Vd

Vth

0.15 V

0 0.5

Subthreshold leakage current will limit the downsizing

Electron EnergyBoltzmann statics

Exp (-qV/kT)

27

Subthreshold Leakage (A/µm)

Ope

ratio

n Fr

eque

ncy

(a.u

.)

e)

100

10

1

Source: 2007 ITRS Winter Public Conf.

The limit is deferent depending on application

How far can we go for production?

10µm 8µm 6µm 4µm 3µm 2µm 1.2µm 0.8µm 0.5µm

0.35µm 0.25µm 180nm 130nm 90nm 65nm 45nm 32nm

1970年

22nm 16nm 11.5 nm 8nm 5.5nm? 4nm? 2.9 nm?

Past 0.7 times per 3 years

Now

In 40 years: 18 generations,Size 1/500, Area 1/250,000

Future

・At least 4,5 generations to 8 ~ 5 nm

29

1V0V

0V

S

0V

0V ＜V＜1V

1V0V

0V

0V

0VS D

G

G

G

Suppression of subthreshold leakage by surrounding gate structure

Planar Surrounding gate

Planar Ｆｉｎ Nanowire

Source DrainGate

Wdep

1

Leakage current

S D

Planar FETFin FET Nanowire FET

Because of off-leakage control,1V

0V

0V0V

0VS

D

GG

31

Fin Tri-gate Ω-gate All-around

G G G

G

GNanowire structures in a wide meaning

More Moore to More More MooreMore Moore to More More Moore

65nm 45nm 32nm

Technology node

M. Bohr, pp.1, IEDM2011 (Intel)P. Packan, pp.659, IEDM2009 (Intel)C. Auth et al., pp.131, VLSI2012 (Intel)T. B. Hook, pp.115, IEDM2011 (IBM)S. Bangsaruntip et al., pp.297, IEDM2009 (IBM)

Lg 35nm Lg 30nm

Main stream(Fin,Tri, Nanowire)

22nm 15nm, 11nm, 8nm, 5nm, 3nm

Alternative

Alternative (III-V/Ge) Channel FinFET

Emerging Devices 32

Tri-Gate

Now Future

Si channelSi

Others

(ETSOI)

Planar

Si is still main stream for future !! ET: Extremely Thin

HighHigh--k gate dielectricsk gate dielectrics

Continued research and development

SiO2 IL (Interfacial Layer) is used at Si interface to realize good mobility

Technology for direct contact of high-k and Si is necessary

Remote SiO2-IL scavengingHfO2 (IBM)

EOT=0.52 nm

Si

La-silicate

MG

Direct contact with La-silicate (Tokyo.Tech)

T. Ando, et al., p.423, IEDM2009, (IBM) T. Kawanago, et al., T-ED, vol. 59, no. 2, p. 269, 2012 (Tokyo Tech.)

K. Mistry, et al., p.247, IEDM 2007, (Intel)

TiN

HfO2

Si

SiO2

EOT=0.9nmHfO2/SiO2(IBM)

T.C. Chen, et al., p.8, VLSI 2009, (IBM)

Hf-based oxides

45nmEOT:1nm

32nmEOT:0.95nm

22nmEOT:0.9nm

15nm, 11nm, 8nm, 5nm, 3nm,

K. Kakushima, et al., p.8, IWDTF 2008, (Tokyo Tech.)

EOT=0.37nm EOT=0.40nm EOT=0.48nm

0.48 → 0.37nm Increase of Id at 30%

[1] C. Auth et al., pp.131, VLSI2012 (Intel).[2] K. Mistry et al., pp.247, IEDM2007 (Intel).[3] H.-J. Cho et al., pp.350, IEDM2011 (Samsung).[4] S. Saitoh et al., pp.11, VLSI2012 (Toshiba).[5] S. Bangsaruntip et al., pp.297, IEDM2009 (IBM).

[6] T. Yamashita et al., pp.14, VLSI2011 (IBM).[7] A. Khakifirooz et al., pp.117, VLSI2012 (IBM).

IIONON and Iand IOFFOFF benchmarkbenchmark

[8] G. Bidal et al., pp.240, VLSI2009 (STMicroelectronics).[9] S. Sato et al., pp.361, ESSDERC2010 (Tokyo Tech.)[10] K. Cheng et al., pp.419, IEDM2012 (IBM)

1

10

100

1000

10000

0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2ION [mA/µm]

I OFF

[nA

/µm

]NMOS

Intel [1]Bulk 32nmVDD=0.8V

Intel [1]Tri-Gate 22nmVDD=0.8V

Intel [2]Bulk 45nmVDD=1V

Toshiba [4]Tri-Gate NWVDD=1V

Samsung [3]Bulk 20nmVDD=0.9V

IBM [5]GAA NWVDD=1V

IBM [6]FinFET 25nmVDD=1V

IBM [7]ETSOIVDD=0.9V

IBM [7]ETSOIVDD=1V

STMicro. [8]GAA NWVDD=0.9V


Tokyo Tech. [9]Ω-gate NWVDD=1V

IBM [10]ETSOIVDD=0.9VIeff

1

10

100

1000

10000

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6ION [mA/µm]

I OFF

[nA

/µm

]

PMOSIntel [1]Bulk 32nmVDD=0.8V

Intel [1]Tri-Gate 22nmVDD=0.8V

Intel [2]Bulk 45nmVDD=1V

IBM [7]ETSOIVDD=1VSamsung [3]

Bulk 20nmVDD=0.9V

IBM [5]GAA NWVDD=1V

IBM [6]FinFET 25nmVDD=1V

IBM [7]ETSOIVDD=0.9V


IBM [10]ETSOIVDD=0.9VIeff

・Lg and EOT are larger than ITRS requirements

・Implementation of Tri-gate and lower Vth/Vdd since 22nm

C. Auth et al., pp.131, VLSI2012 (Intel).

K. Mistry et al., pp.247, IEDM2007 (Intel).P. Packan et al., pp.659, IEDM2009 (Intel).

Comparison with ITRSComparison with ITRS

0

0.2

0.4

0.6

0.8

1

1.2

1.4

2006 2008 2010 2012 2014 2016 2018 20200

0.2

0.4

0.6

0.8

1

1.2

1.4

Year

VD

D(V

)

VDD

Vth

ITRS2007~2011

Intel

45nm 32nm

22nm

Intel45nm32nm

22nm

Multi-GateBulk Planar

Vth (V

)

0

5

10

15

20

25

30

35

40

2006 2008 2010 2012 2014 2016 2018 20200.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Year

L g(n

m)

EO

T (nm)

Intel45nm32nm 22nm

ITRS2007~2011

Intel

45nm 32nm

22nmMulti-Gate

Bulk PlanarITRS2007

EOT

LgITRS2009~2011

<80

56/9

2.05/1.5

1.1

~0.5

-

HfZrO2

22/30 (nFET/pFET)

GAA NW

STMicro. (VLSI2008)

85

65/105

0.83/0.95

1

0.3~0.4

1.5

Hf-based

35/25 (nFET/pFET)

GAA NW

IBM (IEDM2009)

Intel(IEDM2007, 2009)

Intel (VLSI2012)

Toshiba (VLSI2012)

IBM (IEDM2012)

Samsung (IEDM2012)

Tokyo Tech (ESSDERC2010)

StructureBulk Planar Tri-Gate

22nm Tri-Gate NW ETSOI Bulk Planar Ω-gate NW45nm 32nm

Lg (nm) 35 30 30 14 22 20 65

Gate Dielectrics Hf-based Hf-based SiO2 HfO2 HfO2 ? SiO2

EOT (nm) 1 0.95 0.9 3 ~1 - 3

Vth (V) ~0.4 ~0.3 ~0.2 -0.15 (nFET) 0.3~0.4 ~0.3 -0.2 (nFET)

VDD (V) 1 1 0.8 1 0.9 0.9 1

ION (mA/um) nFET/pFET 1.36/1.07 1.53/1.23 1.26/1.1 0.83 (nFET) 0.59/0.62 (Ieff) 1.2/1.05 1.32 (nFET)

DIBL (mV/V)

nFET/pFET~150 ~200 46/50 <50 - 104/115 62

SS (mV/dec) - ~100 ~70 <80 - 87 70<80

56/9

2.05/1.5

1.1

~0.5

-

HfZrO2

22/30 (nFET/pFET)

GAA NW

STMicro. (VLSI2008)

85

65/105

0.83/0.95

1

0.3~0.4

1.5

Hf-based

35/25 (nFET/pFET)

GAA NW

IBM (IEDM2009)

Intel(IEDM2007, 2009)

Intel (VLSI2012)

Toshiba (VLSI2012)

IBM (IEDM2012)

Samsung (IEDM2012)

Tokyo Tech (ESSDERC2010)

StructureBulk Planar Tri-Gate

22nm Tri-Gate NW ETSOI Bulk Planar Ω-gate NW45nm 32nm

Lg (nm) 35 30 30 14 22 20 65

Gate Dielectrics Hf-based Hf-based SiO2 HfO2 HfO2 ? SiO2

EOT (nm) 1 0.95 0.9 3 ~1 - 3

Vth (V) ~0.4 ~0.3 ~0.2 -0.15 (nFET) 0.3~0.4 ~0.3 -0.2 (nFET)

VDD (V) 1 1 0.8 1 0.9 0.9 1

ION (mA/um) nFET/pFET 1.36/1.07 1.53/1.23 1.26/1.1 0.83 (nFET) 0.59/0.62 (Ieff) 1.2/1.05 1.32 (nFET)

DIBL (mV/V)

nFET/pFET~150 ~200 46/50 <50 - 104/115 62

SS (mV/dec) - ~100 ~70 <80 - 87 70

Benchmark of device characteristicsBenchmark of device characteristics

The down scaling of MOSFETs is still possible for at least another 10 years!

2. Thinning of high-k gate oxide thicknessbeyond 0.5 nm

3. Metal(Silicide) S/D

1. Wire channel

4 important technological items for down scaling.New structures

New materials

4. III-V/Ge channel, for the moment, however, very difficult to replace Si

These technologies are very difficult and not every company can success in the development timely.

In the past, technology comes with the purchase of equipment, but any more.

Thus, some of the companies are in the threat of dropping off.

There are so many rooms for the universities to contribute to the development of Si world.

Wire channel

40

Si nanowire FET as a strong candidate

1. Compatibility with current CMOS process

2. Good controllability of IOFF

3. High drive current

1D ballisticconduction

Multi quantumChannel High integration

of wires

k

E

量子チャネル

量子チャネル量子チャネル量子チャネル

バンド図

Quantum channelQuantum channel


k

E

量子チャネル

量子チャネル量子チャネル量子チャネル

バンド図



Off電流のカットオフ

Gate:OFFDrain Source

cut-off

Gate: OFFdrainsource

Off電流のカットオフ

Gate:OFFDrain Source

cut-off

Gate: OFFdrainsource

Wdep

1

Leakage current

S D

Increase the Number of quantum channels

Energy band of Bulk Si

Eg

By Prof. Shiraishi of Tsukuba univ.

Energy band of 3 x 3 Si wire

4 channels can be used

Eg

41

Compact modeling of nanowire MOSFETs is very difficult

43By Profs. Oshiyama and Iwata, U. of Tokyo

Diameter dependence

By Profs. Oshiyama and Iwata, U. of Tokyo

Wire cross section dependence.

What cross section gives best solution forSCE suppression and drive current?.

45

λ>>LDiffusive transport

λ<LBallistic transport

λ~LQuasi-Ballistic transport

Lλ ：Mean free pathsource drain

Mobility Theory

Real nanoscaleMOSFETs

Compact model for circuit designer is very important

Prof. K. Natori of TIT

46

0

10

20

30

40

50

0 0.1 0.2 0.3 0.4 0.5 0.6

300K VG-Vt=0.1V

300K VG-Vt=0.4V

300K VG-Vt=0.7V

300K VG-Vt=1.0V

4K VG-Vt=0.1V

4K VG-Vt=0.4V

4K VG-Vt=0.7V

4K VG-Vt=1.0V

Current (

µA)

Drain Bias (V)


47

F(x)/h は、正速度フラックス

G(x)/h は、負速度フラックス( )

( )

0

0

2 ( ) ( ) ( ) 0

2 ( ) ( ) ( ) 0

BdF xqEx F x G xm dx qEx

BdG xqEx G x F xm dx qEx

εε

εε

+ + − =+

− + + − =+

( )

( )

0 0

0 0

22 ( ) ( ) ( ) ( ) 0

22 ( ) ( ) ( ) ( ) 0

B DdF xqEx F x G x F xm dx qEx qEx

B DdG xqEx G x F x G xm dx qEx qEx

εε ε ε

εε ε ε

∗

∗

+ + − + =+ + −

− + + − + =+ + −

( )0

00 0 0 0 0

2( )

2 ln

D qET

qExB D D qE mD Bε

εε

=+⎛ ⎞+ + + ⎜ ⎟

⎝ ⎠

弾性散乱域

光学フォノン放出域

ソースからドレインへの透過確率（エネルギー εに対して）

散乱の導入に係る計算式散乱の導入に係る計算式

物理パラメータB0の値は移動度対応した値

物理パラメータD0の光学フォノンエネルギー緩和時間に対応した値


48

0

5

10

15

20

25

30

35

40

0 0.1 0.2 0.3 0.4 0.5

VG-Vt=0.1V, Bal.

VG-Vt=0.1V, Q-Bal.

VG-Vt=0.4V, Bal.

VG-Vt=0.4V, Q-Bal.

VG-Vt=0.7V, Bal.

VG-Vt=0.7V, Q-Bal.

VG-Vt=1.0V, Bal.

VG-Vt=1.0V, Q-Bal.

Current [µA]

Drain Bias [V]


49

0.E+00

2.E-05

4.E-05

6.E-05

8.E-05

0.0 0.5 1.0Vd (V)

Id (A

)

Vg – Vth = 1V

0.8V

0.6V

0.4V

0.2V

ExperimentQuasi ballistic

Lg=65nm, Tox=3nm

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

-1.5 -1.0 -0.5 0.0 0.5 1.0

0.E+00

1.E-05

2.E-05

3.E-05

4.E-05

5.E-05

6.E-05

7.E-05

-1.0 -0.5 0.0 0.5 1.00

10 20 30 40 50 60 70

Dra

in C

urre

nt (µ

A)

Drain Voltage (V)

Vg-Vth=1.0 V

Vg-Vth= -1.0 V

0.8 V

0.6 V

0.4 V

0.2 V

(a)

10-12

Gate Voltage (V)

pFET nFET

(b)

10-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Dra

in C

urre

nt (A

)

Vd=-50mV

Vd=-1V

Vd=50mV

Vd=1V

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

-1.5 -1.0 -0.5 0.0 0.5 1.0

0.E+00

1.E-05

2.E-05

3.E-05

4.E-05

5.E-05

6.E-05

7.E-05

-1.0 -0.5 0.0 0.5 1.00

10 20 30 40 50 60 70

Dra

in C

urre

nt (µ

A)

Drain Voltage (V)

Vg-Vth=1.0 V

Vg-Vth= -1.0 V

0.8 V

0.6 V

0.4 V

0.2 V

(a)

10-12

Gate Voltage (V)

pFET nFET

(b)

10-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Dra

in C

urre

nt (A

)

Vd=-50mV

Vd=-1V

Vd=50mV

Vd=1V

On/Off>106、60uA/wire

Recent results to be presented by ESSDERC 2010 next week in Sevile

Wire cross-section: 20 nm X 10 nm

010203040506070

1 10 100 1000Gate Length (nm)

I ON

(µA

/ w

ire)

nMOSpMOS

(5)

(5)

(10)

(10)(12)

(12x19)

(12)

(12x19)

(13x20)

(9x14)(10)

(10)

(10)

(8)

(8)

(16)

(13)

(34)

(3)(3)

(30)

(19)

VDD: 1.0~1.5 V

括弧内は寸法を示す

010203040506070


I ON

(µA

/ w

ire)

nMOSpMOS

010203040506070


I ON

(µA

/ w

ire)

nMOSpMOS

(5)

(5)

(10)

(10)(12)

(12x19)

(12)

(12x19)

(13x20)

(9x14)(10)

(10)

(10)

(8)

(8)

(16)

(13)

(34)

(3)(3)

(30)

(19)

VDD: 1.0~1.5 V


(12)

010203040506070


I ON

(µA

/ w

ire)

nMOSpMOS

(5)

(5)

(10)

(10)(12)

(12x19)

(12)

(12x19)

(13x20)

(9x14)(10)

(10)

(10)

(8)

(8)

(16)

(13)

(34)

(3)(3)

(30)

(19)

VDD: 1.0~1.5 V


010203040506070


I ON

(µA

/ w

ire)

nMOSpMOS

010203040506070


I ON

(µA

/ w

ire)

nMOSpMOS

(5)

(5)

(10)

(10)(12)

(12x19)

(12)

(12x19)

(13x20)

(9x14)(10)

(10)

(10)

(8)

(8)

(16)

(13)

(34)

(3)(3)

(30)

(19)

VDD: 1.0~1.5 V


010203040506070


I ON

(µA

/ w

ire)

nMOSpMOS

(5)

(5)

(10)

(10)(12)

(12x19)

(12)

(12x19)

(13x20)

(9x14)(10)

(10)

(10)

(8)

(8)

(16)

(13)

(34)

(3)(3)

(30)

(19)

VDD: 1.0~1.5 V


010203040506070


I ON

(µA

/ w

ire)

nMOSpMOS

010203040506070


I ON

(µA

/ w

ire)

nMOSpMOS

(5)

(5)

(10)

(10)(12)

(12x19)

(12)

(12x19)

(13x20)

(9x14)(10)

(10)

(10)

(8)

(8)

(16)

(13)

(34)

(3)(3)

(30)

(19)

VDD: 1.0~1.5 V


(12)

本研究で得られたオン電流

(10x20)102µA

Our Work

Bench Mark

Y. Jiang, VLSI 2008, p.34H.-S. Wong, VLSI 2009, p.92S. Bangsaruntip, IEDM 2009, p.297C. Dupre, IEDM 2008, p. 749S.D.Suk, IEDM 2005, p.735G.Bidel, VLSI 2009, p.240

Si nanowireFET

Planer FETS. Kamiyama, IEDM 2009, p. 431P. Packan, IEDM 2009, p.659

1.2～1.3V

1.0～1.1V

Lg=500～65nm

IIONON/I/IOFF OFF Bench markBench mark

This work

53

0

2

4

0

2

40

5

10

15

x 1019

x (nm)y (nm)

Electron density (/cm3)

024681012

02

46

810

120

5

10

15

x 1019

x (nm)y (nm)

Electron density (/cm3)

(a) (b) width=12nmwidth=4nm

0

2

4

0

2

4500

550

600

650

x (nm)y (nm)

Mobility (cm2/Vs)

024681012

02

46

810

12700

750

800

850

900

x (nm)y (nm)

Mobility (cm2/Vs)


0

2

4

0

2

4500

550

600

650

x (nm)y (nm)

Mobility (cm2/Vs)

024681012

02

46

810

12700

750

800

850

900

x (nm)y (nm)

Mobility (cm2/Vs)


0 .E + 0 0

1 .E + 1 9

2 .E + 1 9

3 .E + 1 9

4 .E + 1 9

5 .E + 1 9

6 .E + 1 9

0 2 4 6 8Distance from SiNW Surface (nm)

6543210

角の部分

平らな部分

電子濃度(x1019cm-3)Electron Density

Edge portion

Flat portion

0

2000

4000

6000

8000

10000

12000

2008 2010 2012 2014 2016 2018 2020 2022 2024 2026

Year

I ON

(µA/

µm)

SiNW (12nm×19nm)

MGFDbulk

ION∝Lg-0.5×Tox

-1(20)

(11)

(33)

(15)

(26)

今回用いたIONの仮定

1µm当たりの本数

コンパクトモデルの完成

S/D寄生抵抗低減技術

pMOSの高性能化

低EOT実現技術

Compact model

Small EOT for high-k

P-MOS improvement

Low S/D resistance

# of wires /1µm

Assumption

ITRSNan

owire

Primitive estimation !

HP MP SP

TOX,E (nm) 0.9 0.9 0.9

LGATE (nm) 30 34 34

IOFF (nA/um) 20-100 5-20 1-5

Tri-gate has been implemented at 22nm node, enabling further scaling

C. Auth et al., pp.131, VLSI2012 (Intel)

TriTri--gate implementation for transistors gate implementation for transistors

57

PMOS channel under the gate

S/D region showing the SiGe epitaxy

A fin width of 8nm to balance SCE and Rext

A fin height of 34nm to balance drive current vs. capacitance


TriTri--gate width/height optimizationgate width/height optimization

58


TriTri--gate Igate Idd--VVgg characteristics and Vcharacteristics and Vthth

・SS of 69 and 72mV/dec for NMOS and PMOS, respectively

・DIBL of 46 and 50mV/V for NMOS and PMOS, respectively

・Vth of 22nm is about 0.1V lower than that of 32nm

59

A. Khakifirooz et al., pp.117, VLSI2012 (IBM)

・Lg = 22nm ETSOI

・Si channel thickness of 6 nm

・DIBL of 75 mV/V and 130mV/V for NFET and PFET

Extremely Thin SOI (ETSOI)Extremely Thin SOI (ETSOI)

RSDwith silicide

RSDwith silicide

ETSOI 6nmBOX

Poly-Si Metal/high-k

60

TriTri--gate Igate IONON and Iand IOFFOFF characteristicscharacteristics

HP SP LP ULP

ION (mA/um) NMOS/PMOS 1.08/0.91 0.71/0.59 0.41/0.37 0.35/0.33

IOFF 100nA/um 1 nA/um 30 pA/um 15 pA/um

ION/IOFF ~105 ~106 ~108 ~108

Vdd = 0.75 V

C.-H. Jan et al ., pp.44, IEDM2012 (Intel)

NMOS PMOS

ION/IOFF > 105

S. Saitoh et al., pp.11, VLSI2012 (Toshiba)

・Lg = 14nm Tri-Gate NW

・High SCE immunity at Lg of 14nm

・Vth tuning by applying Vsub with thin BOX of 20nm

TriTri--Gate NanowireGate Nanowire

Vsub

H.-J. Cho et al., pp.350, IEDM2011 (Samsung)

・Lg = 20nm bulk planar CMOS

・Gate last integration

・In-situ doped S/D for better SCE

Bulk PlanarBulk Planar

Extremely Thin SOI (ETSOI)Extremely Thin SOI (ETSOI)

・Hybrid CMOSSi Channel nFETStrained SiGe Channel pFET・RO delay improvement over FinFET with FO = 2

K. Cheng et al., pp.419, IEDM2012 (IBM)

S. Bangsaruntip et al., pp.297, IEDM2009 (IBM)

・Lg = 25~35nm GAA NW

・Hydrogen anneal provide smooth channel surface

・Competitive with conventional CMOS technologies

・Scaling the dimensions of NW leads to suppressed SCE

Gate All Around Nanowire (GAA NW)Gate All Around Nanowire (GAA NW)

65

G. Bidal et al., pp.240, VLSI2009 (STMicroelectronics)

SiNHMTop Gate

Bottom Gate

Channel

iPtSi

・Gate all around structure

・Lg of 22~30nm

・Bulk wafer-based integration

・High drive currents by special stress and channel orientation design

Gate All Around Nanowire (GAA NW)Gate All Around Nanowire (GAA NW)

ΩΩ--gate Si Nanowiregate Si NanowireS. Sato et al., pp.361, ESSDERC2010 (Tokyo Tech.)

19 nm

12 nm

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

-1.5 -1.0 -0.5 0.0 0.5 1.010-12

Gate Voltage (V)

pFET nFET

10-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Dra

in C

urre

nt (A

)

Vd=-50mV

Vd=-1V

Vd=50mV

Vd=1V

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

-1.5 -1.0 -0.5 0.0 0.5 1.010-12

Gate Voltage (V)

pFET nFET

10-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Dra

in C

urre

nt (A

)

Vd=-50mV

Vd=-1V

Vd=50mV

Vd=1V

0 0.5 1 1.5 2ION (mA/µm)

Lg=65nm

0 0.5 1 1.5 2ION (mA/µm)

Lg=65nm

Lg=65nm

Poly-Si

SiO2

SiNSiN

SiO2

NW

・Conventional CMOS process

・High drive current

(1.32 mA/µm @ IOFF=117 nA/µm)

・DIBL of 62mV/V and SS of 70mV/dec for nFET

ShortShort--channel effectchannel effectT. Skotnicki, IEDM 2009 Short Course (STMicroelectronics)

S. Bangsaruntip et al., pp.297, IEDM2009 (IBM), K. Tachi et al., pp.313, IEDM2009 (CEA-LETI)

Decreasing the diameter of NW

Problems in MultiProblems in Multi--gategate

Improvedshort-channel control

Severe mobility degradation

69

K. Uchida et al., pp.47, IEDM2002 (Toshiba)

Problems in SOIProblems in SOI

Mobility is also decreased with decreasing the Si thickness of SOI transistor similar to the NW transistor.

70

When wire diameter becomes less than 10 nm, sudden drop of Id

Problem for nanowire

IdDiameter

10 nm2. Decrease of DOS

1. Electron Scattering of every surface

If diameter cannot be scaled, SCE cannot be suppressed.

Then, again aggressive EOT scaling of high-k is necessary.

K. Kim, pp.1, IEDM2010 (Samsung) 1.21.1

1

0.9

0.8

0.7

0.6

0.5

EO

T [n

m]

202020152010Year

12

10

8

6

4

2

0

Body Thickness [nm

]

Multi-Gate

Planar

ITRS2011

Fin width

Trend 1

Trend 2Trend 3 ?

EOT Scaling TrendsEOT Scaling Trends

Wire/fin mitigates EOT thinning trend (Trend 1 Trend 2)Because of better SCE control.

However, ION severely degrade with wire/fin width reduction

Therefore, EOT trend will become accelerated again(Trend 2 Trend 3) Thus, high-k becomes important again.72

High-k beyond 0.5 nm

Limit in tLimit in toxox thinningthinning

R.Chau, et al., (Intel) IWGI 2003

74

Gate oxide should be thicker than mono atomic layer

0.8 nm gate oxide thickness MOSFETs operate0.8 nm Distance of 3 Si atoms 2 mono layers

Limit in tLimit in toxox thinningthinningR.Chau, et al., (Intel) IWGI 2003

1 0.010.1

1

10

100

1000

0.1

0.01

0.001

Pow

er D

ensi

ty [W

/cm

2 ]

Gate Length [µm]

Active Power

Passive PowerGate

Leakage

Gate Leakage Power Density becomes significantly large with Lg reduction, and thus, with tox thinning!!

W.F.Clark, (IBM) VLSI 2007 Short Course

75

To use high‐k dielectrics

Thin SiO2

Thick high‐k dielectrics

Almost the same electric characteristics

However, very difficult and big challenge!

K: Dielectric Constant

5 times thicker

Small leakageCurrent

K=4K=20

SolutionSolution

SiO2 High‐k

76

Equivalent Oxide Thickness (EOT)Equivalent Oxide Thickness (EOT)

Silicon Substrate

S D

Silicon Substrate

S D

SiO2

Poly-Si

C Poly

COX

CSi

High-kCOX

CSi

Equivalent Oxide Thickness (EOT): gate dielectrics itself, Cox

Capacitance Equivalent Thickness (CET): entire gate stack,

Metal gate can eliminate the poly-Si depletion.

Inversion CET = Tinv ≈ EOT + 0.4nm with metal gate electrode

Metal

Cmetal

Poly-Si(1020cm-3)

K. Natori, et al., (Tsukuba Univ) SSDM 2005, p.286

CMetal(EOT: 0.1 nm)

Depletion

Cmetal is finite because of quantum effect. In other words electron is not a point charge located at the interface but distributed charge.

(EOT: 0.3 nm)

Combination of high-k and metal gate is important

77

Si-sub.

Metal

SiO2-IL

High-kSmall interfacial state density at high-k/Si

Oxygen diffusion control for prevention of EOT increase and oxygen vacancy formation in high-k

Thinning or removal of SiO2-IL for small EOT

Flat metal/high-k interface for better mobility

O

Workfunction engineering for Vth control

Interface dipole control for Vth tuning

Suppression of oxygen vacancy formation

Control of interface reaction and Si diffusion to high-k

Oxygen concentration control for prevention of EOT increase and oxygen vacancy formation in high-k

Suppression of metal diffusion

Endurance for high temperature process

Remove contaminationintroduced by CVD

Reliability: PBTI, NBTI, TDDB

Suppression of gate leakage current

Suppression of FLP

78

Issues in high-k/metal gate stack

0 10 20 30 40 50Dielectric Constant

4

2

0

-2

-4

-6

SiO2

Ban

d D

isco

ntin

uity

[eV]

Si

XPS measurement by Prof. T. Hattori, INFOS 2003

Conduction band offset vs. Dielectric Constant

Band offset

Oxide

Leakage Current by Tunneling

79

R. Hauser, IEDM Short Course, 1999Hubbard and Schlom, J Mater Res 11 2757 (1996)

Gas or liquidat 1000 K

H

Radio activeHe

Li BeB C N O F Ne

① Na Mg Al Si P S Cl Ar

② ① ① ① ① ① ① ① ① ① ① K Ca Sc Ti V Cr Mn Fc Co Ni Cu Zn Ga Ge As Se Br Kr ① ① ① ① ① ① ① ① ① ① Rh Sr Y Zr Nb Mo Tc Ru Rb Pd Ag Cd In Sn Sb Te I Xe ③ ① ① ① ① ① ① ① Cs Ba

HfTa W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

Fr Ra Rf Ha Sg Ns Hs Mt

La Ce Pr Nd PmSmEu Gd Tb Dy Ho Er TmYｂ Lu Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Candidates

Na Al Si P S Cl Ar

② ① ① ① ① ① ① ① ① ① K Sc Ti V Cr Mn Fc Co Ni Cu Zn Ga Ge As Se Br Kr ① ① ① ① ① ① ①

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

②

③

Unstable at Si interfaceSi + MOX M + SiO2①

Si + MOX MSiX + SiO2

Si + MOX M + MSiXOY

Choice of High-k elements for oxide

HfO2 based dielectrics are selected as the first generation materials, because of their merit in1) band-offset, 2) dielectric constant3) thermal stability

La2O3 based dielectrics are thought to be the next generation materials, which may not need a thicker interfacial layer

80

SiO2-ILHfSix (k~4)

VO

IO

IOVO

VO

IOIO

VOHfO2

Si substrate SiO2-IL(k~4)

LaSix

VO

IOVO

IO

VO

IOLa2O3silicate

La-rich Si-rich

Si substrate

High PO2Low PO2 High PO2Low PO2

SiO2 IL formation

Si substrate

silicate formation

Si substrate

HfO2 case La2O3 case

Direct contact can be achieved with La2O3 by forming silicate at interfaceControl of oxygen partial pressusre is the key for processing.

Our approach

K. Kakushima, et al., VLSI2010, p.69

Direct high-k/Si by silicate reaction

82

1837184018431846Binding energy (eV)

Inte

nsity

(a.u

)

Si sub.

Hf SilicateSiO2

500 oC


Inte

nsity

(a.u

)

Si sub.

Hf SilicateSiO2

500 oC

SiOx-IL

HfO2

W

1 nm

k=4

k=16

SiOx-IL growth at HfO2/Si Interface

HfO2 + Si + O2→ HfO2 + Si + 2O*→HfO2+SiO2

Phase separator

SiOx-IL is formed after annealingOxygen control is required for optimizing the reaction

Oxygen supplied from W gate electrode

XPS Si1s spectrum

D.J.Lichtenwalner, Tans. ECS 11, 319

TEM image 500 oC 30min

H. Shimizu, JJAP, 44, pp. 6131

83

La-Silicate Reaction at La2O3/Si

La2O3

La-silicate

W

500 oC, 30 min

1 nm

k=8~14

k=23


Inte

nsity

(a.u

)

as depo.

300 oC

La-silicate

Si sub.

500 oC


Inte

nsity

(a.u

)

as depo.

300 oC

La-silicate

Si sub.

500 oC

La2O3 + Si + nO2→ La2SiO5, La2Si2O7,

La9.33Si6O26, La10(SiO4)6O3, etc.

La2O3 can achieve direct contact of high-k/Si

XPS Si1s spectraTEM image

Direct contact high-k/Si is possible

84Year

Pow

er p

er M

OSF

ET (P

)

P∝L

g 3

(Scaling)

EOT Limit0.7~0.8 nm

EOT=0.5nm

TodayEOT=1.0nm

Now

45nm node

One order of Magnitude

Si

HfO2

Metal

SiO2/SiON

Si

High-k

Metal

Direct ContactOf high-k and Si

Si

MetalSiO2/SiON

0.5～0.7nm

Introduction of High-kStill SiO2 or SiONIs used at Si interface

For the past 45 yearsSiO2 and SiON

For gate insulator

EOT can be reduced further beyond 0.5 nm by using direct contact to SiBy choosing appropriate materials and processes.

85

Substrate

Moving Mask

SourceElectron Beam

Flux

Deposited thin film

準備室

絶縁膜堆積室フラッシュランプアニール室

金属膜堆積室

ロボット搬送室

ALD室

RTA室

Robot

EB Evaporation Flash Lamp Anneal

ALD

RTA

Sputter

EB Evaporation

Flash Lamp Anneal

ALDRTAEntrance

Entrance

Sputter

High-k/metal gate stackfilm deposition cluster tool

87

L=0.5~100µm (8 kinds)W=10, 20, 50, 100µm(4 kinds)

30 different Trs

26 c

hips

1cm

1cm

1cm×1cm

p-Si

S Dn+ Sn+SiO2

88

Shutter movement

Chip

Si Si SiSi

Metal Metal Metal Metal

Thin Thick

high-k

15cm

0.0E+00

5.0E-04

1.0E-03

1.5E-03

2.0E-03

2.5E-03

3.0E-03

3.5E-03

0 0.2 0.4 0.6 0.8 1

Vg=0VVg=0.2VVg=0.4VVg=0.6VVg=0.8VVg=1.0VVg=1.2V

0 0.2 0.4 0.6 0.8 1

Vg=0VVg=0.2VVg=0.4VVg=0.6VVg=0.8VVg=1.0VVg=1.2V

0 0.2 0.4 0.6 0.8 1

Vg=0VVg=0.2VVg=0.4VVg=0.6VVg=0.8VVg=1.0VVg=1.2VI d

(V)

Vth=-0.04VVth=-0.05VVth=-0.06V

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

0 0.5 1 1.5 2 2.5 3

EOT ( nm )

Cur

rent

den

sity

( A

/cm

2 )Al2O3HfAlO(N)HfO2HfSiO(N)HfTaOLa2O3Nd2O3Pr2O3PrSiOPrTiOSiON/SiNSm2O3SrTiO3Ta2O5TiO2ZrO2(N)ZrSiOZrAlO(N)

Gate Leakage vs EOT, (Vg=|1|V)

La2O3

HfO2

89

90

2

1.5

1

0.5

0

Cap

acita

nce

[µF/

cm2 ]

-1 -0.5 0 0.5 1Gate Voltage [V]

10kHz 100kHz 1MHz

20 x 20µm2 1.5

1

0.5

0

Cap

acita

nce

[µF/

cm2 ]

-1.5 -1 -0.5 0 0.5Gate Voltage [V]

20 x 20µm2

10kHz 100kHz 1MHz

2

1.5

1

0.5

0

Cap

acita

nce

[µF/

cm2 ]

-1.5 -1 -0.5 0 0.5Gate Voltage [V]

20 x 20µm2

10kHz 100kHz 1MHz

FGA500oC 30min FGA700oC 30min FGA800oC 30min

A fairly nice La-silicate/Si interface can be obtained with high temperature annealing. (800oC)

However, high-temperature anneal is necessary for the good interfacial property

91

① silicate-reaction-formedfresh interface

metal

Si sub.

metal

Si sub.

La2O3 La-silicateSi Si

Fresh interface with silicate reaction

J. S. Jur, et al., Appl. Phys. Lett., Vol. 87, No. 10, (2007) p. 102908

② stress relaxation at interface by glass type structure of La silicate.

La atomLa-O-Si bonding

Si sub.

SiO4tetrahedron network

FGA800oC is necessary to reduce the interfacial stress

S. D. Kosowsky, et al., Appl. Phys. Lett., Vol. 70, No. 23, (1997) pp. 3119

Physical mechanisms for small DitPhysical mechanisms for small Dit

92

No interfacial layer can be confirmed with Si/TiN/W

MIPSW TiN/W

Kav ~ 8 Kav ~ 12 Kav ~ 16

Si 2nm2nm2nm

HK

MG

La2O3Si/TiN/W

La2O3/silicate/n-Si CV

-0.5-1.0-1.5 0.0 0.5Gate voltage (V)

3

2

1

0

Cap

acita

nce

dens

ity (µ

F/cm

2 )

W/La2O3(4nm)/n-Si600oC, 30min

∆Vfb

Cfb

1MHz

1kHz

0.0E+00

5.0E-07

1.0E-06

1.5E-06

2.0E-06

2.5E-06

3.0E-06

1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07

Gp/ω

(F/c

m2 )

0.0

0.5

1.0

2.0

2.5

(×10-6)3.0

ω (rad/s)

1.5

10 103 104 105 106 107102

400

500

600

Dit, Dslow(FG anneal)

Dit

, Dsl

ow(c

m-2

/eV

)

1014

1013

1012

1011

Annealing temperature (oC)as 200 400 600 800 1000

Dit

Dslow

Dit

Dslow

Annealing temperature (oC)

10-11

σ it,

σ slo

w(c

m2 )

10-12

10-13

10-14

10-15

∆Vfb

(V)

-0.1

-0.2

-0.3as 200 400 600 800 1000

0.0

Dslow=2.8x1013cm-2/eV

∆Vfb=CLa2O3/qDslow

⎟⎠⎞

⎜⎝⎛−=

λσσ silicate

slowtexp0 (λ=0.8nm)

Slow trap state

σslow

σit

La2O3

silicate (tsilicate)

Dit

DslowVg

Ef

n-Si

CLa2O3

It is important to change the La2O3 to La-silicate completely

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

600 700 800 900 1000As depo

～～

Annealing temperature (oC)

EOT

(nm

)

Annealed for 2 sLa2O3(3.5 nm)

W(60 nm)

TiN/W(12 nm)

TiN/W(6 nm)

TiN(45nm)/W(6nm)

00.5

11.5

22.5

33.5

44.5

-1 -0.5 0 0.5

Vg (V)

Cg

(uF/

cm2 )

Experiment

Cvc fittingTheory

EOT=0.55nm

TaN/(45nm)/W(3nm)900oC, 30min

EOT=0.55nm

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.5 0.55 0.6 0.65 0.7

Flat

-ban

d vo

ltage

(V)

EOT（nm)

TaN(45nm)/W(3nm)

900oC, 30min

Qfix=1×1011 cm-2

Fixed Charge density: 1×1011 cm-2

0

20

40

60

80

100

120

140

160

180

0 0.5 1 1.5 2

EOT = 0.53nm

L/W = 20/20µm

T = 300K

Nsub = 3×1016cm-3

Eeff [MV/cm]

Elec

tron

Mob

ility

[cm

2 /Vse

c]Si-sub

SiO2S D

Si-sub

Si-sub

La2O3W AlTaN/ 熱処理

151cm2/VsEeff=1MV/cm150cm2/Vs

0 0.2 0.4 0.6 0.8 1.0

Drain Voltage (V)

5010

015

020

025

0

Dra

in C

urre

nt (µ

A)

Vg= 0.4V

Vg= 0.6V

Vg= 0.8V

Vg= 1.0V

Vg= 0.2VVg= 0 V

L/W = 20/20µm

T = 300K

Nsub = 3×1016cm-3

300

EOT = 0.53nm

EOT=0.53nm

10-5

10-4

10-3

10-2

10-1

100

101

103

104

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Gate voltage (V)

Gat

e cu

rrent

(A/c

m2 )

102

ITRSの要求値

x1/100

Wg/Lg=20/20µmEOT=0.55nm

TaN/W/LaSiOx/nFET

0 0.2 0.4 0.6 0.8 1.0

Drain Voltage (V)

0.2

0.4

0.6

0.8

1.0

Dra

in C

urre

nt (m

A)

Vg= 0.4V

Vg= 0.6V

Vg= 0.8V

Vg= 1.0V

Vg= 0.2V

Vg= 0 V

L/W = 5/20µm

T = 300K

Nsub = 3×1016cm-3

0

20

40

60

80

100

120

140

0 0.5 1 1.5 2 2.5

EOT = 0.40nm

L/W = 5/20µm

T = 300K

Nsub = 3×1016cm-3

Eeff [MV/cm]El

ectr

on M

obili

ty [c

m2 /V

sec]

EOT=0.40nm

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

0.3 0.4 0.5 0.6 0.7 0.8

ITRS requirement

J gat

1 V

(A/c

m2 )

EOT (nm)

Benchmark of LaBenchmark of La--silicate dielectricssilicate dielectrics

Gate leakage is one order of magnitude lower than that of ITRS.

Electron mobility is comparable to record mobility with Hf-based oxides.

T. Ando, et al., (IBM) IEDM 2009, p.423

0

50

100

150

200

250

300

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1EOT (nm)

Mob

ility

(cm

2 /Vse

c)

at 1 MV/cm

Open : Hf-based oxidesSolid : La-silicate oxide

L.-Å. Ragnarsson, et al., (IMEC) Microelectron. Evol. 88, no. 7, pp. 1317–1322, Jul. 2011.

T. Kawanago, et al., (Tokyo Tech.) T-ED, vol. 59, no. 2, p. 269, 2012

Si benchmark (nMOSFET)Si benchmark (nMOSFET)

102

EOT Mobility Vth SS DIBLGate stack Ref.

0.45nmTiN/Cap/HfO2 115cm2/Vs

(at 1x1013cm-2)IMEC

MEE20110.3V

(Lg=10um)


(at 1x1013cm-2)IBM

VLSI2011~0.4V

(Lg=24nm) 90mV/dec 147mV/V

0.59nmMetal/HfO2 130cm2/Vs

(at 1MV/cm)0.45V

(Lg=1um) 75mV/decSematechVLSI2009

0.65nmMetal/Hf-basedSamsungVLSI2011

0.3~0.4V(Lg=~30nm) 90mV/dec 100mV/V

0.95nmMetal/Hf-basedIntel

IEDM2009~0.3V

(Lg=30nm) 100mV/dec ~200mV/V

0.62nmW/La-silicateTokyo Tech.T-ED2012

-0.08V(Lg=10um) ~70mV/dec

155cm2/Vs (at 1MV/cm)


(at 1MV/cm)IBM

VLSI2009

0 0.2 0.4 0.6 0.8 1.0

Drain Voltage (V)

5010

015

020

025

0

Dra

in C

urre

nt (µ

A)

Vg= 0.4V

Vg= 0.6V

Vg= 0.8V

Vg= 1.0V

Vg= 0.2VVg= 0 V

L/W = 20/20µm

T = 300K

Nsub = 3×1016cm-3

300

EOT = 0.53nm

0

20

40

60

80

100

120

140

160

180

0 0.5 1 1.5 2

EOT = 0.53nm

L/W = 20/20µm

T = 300K

Nsub = 3×1016cm-3

Eeff [MV/cm]El

ectr

on M

obili

ty [c

m2 /V

sec]

Recent results by my group.

substrate

①La gas feed ②Ar purge ③H2O feed ④Ar purge

Laligand H

O

substrate substrate substrate

1 cycle

La

C 3H7

3

L a

C 3H7

3

L a

C 3H7

3

CLaN

NH

C3H7

C3H7

La(iPrCp)3 La(FAMD)3

Precursor (ligand)

ALD is indispensable from the manufacturing viewpoint- precise control of film thickness and good uniformity

K. Ozawa, et al., (Tokyo Tech. and AIST) Ext. Abstr. the 16th Workshop on Gate Stack Technology and Physics., 2011, p.107.

104

ALD of La2O3

S D

1) High injection Velocity of carriers

2) High mobility of carriers

Both 1) and 2) are important

Arming higher performance at lower supply voltage

Problems: Technologies and CostInterfacial properties at the gate insulator/semiconductor

Contact resistance at Source/Drain and semiconductor

Different semiconductors for n- and p- channel FETs

Integration on Si wafer

vinj

III-V (n-channel) or Ge (p-channel)

105

Why high mobility channel materials?

Ge,IIIGe,III--V bulk properties V bulk properties

S. Takagi., IEDM2011, Short course (Tokyo Uni)106

Metal S/D InGaAs‐OILch= 55nm, EOT 3.5nmVDS=0.5V(Tokyo Uni.)[5]

InGaAs NanowireLg= 200nm, Tox 14.8nmVDS=0.5V(Hokkaido Uni.)[4]

InGaAs FinFETLch=130nmEOT 3.8nmVDS=0.5V (NUS)[3]

InGaAs Tri‐gateLg=60 nm,EOT 12AVDS=0.5V (Intel) [2]

InGaAs GAALch=50nm, Dielectric: 10nm Al2O3VDS=0.5V (Purdue Uni.) [1]

Ge Tri‐gateLg=183nm, EOT 5.5nmVD=‐1V (NNDL Taiwan)[9]

Ge GAA Lg= 300nm, dielectric: GeO2(7nm)‐HfO2(10nm)VD= ‐0.8V (ASTAR Singapore)[8]

Ge FinFETLg=4.5 mm, Dielectric: SiON, VDS=‐1V(Stanford Uni.)[7]

GOI Tri‐gateLg: 65nm. EOT 3.0nmVD=‐1V (AIST Tsukuba)[6]

Si‐bulk 45nmIntel VDD=1V

I OFF(A/µm)

ION (mA/µm)

nMOS pMOS

ION (mA/µm)[1] J. J. Gu et al., pp.769, IEDM2011 (Purdue).[2] M. Radosavljevic et al., pp.765, IEDM201(Intel).[3] H. –C. Chin et al., EDL 32, 2 (2011) (NUS)[4] K. Tomioka et al., pp.773, IEDM2011 (Hokkaido Uni).

[6] K. Ikeda et al., pp.165, VLSI2012 (AIST, Tsukuba).[7] J. Feng et al., IEEE EDL 28(2007)637 (Stanford Uni)[8] J. Peng et al., pp.931, IEDM2009 (ASTAR Singapore)[9] S. Hsu et al., pp.825, IEDM2011 (NNDL Taiwan)

[5] S. H. Kim et al., pp.177, VLSI2012 (Tokyo Uni)

Si‐bulk 45nmIntel VDD=1V[11]

Si‐FinFET 32nmIntel VDD=0.8V [10]


[10] C. Auth et al., pp.131, VLSI2012 (Intel).

[11] K. Mistry et al., pp.247, IEDM2007 (Intel).



MultiMulti--gate IIIgate III--V and Si benchmarkV and Si benchmark

107

ION/IOFF Benchmark of Ge pMOSFET

108

Planar(metal S/D, Strain, Buffer…)

FinFET Tri‐gateGate‐all‐around

MOSFETNanowire

material InGaAs Ge InGaSn InGaAs Ge InGaAs Ge InGaAs Ge InGaAs(multishell)

Ge

Dieletric/EOT

Al2O3/ 3.5 nm

7.6 Ao

HfO2+ Al2O3+GeO2

5nm ALDAl2O3

5nm ALD Al2O3

SiON 1.2 nm5.5 nm(Al2O3+GeO2)

10nm‐ALD Al2O3

HfO2:11nm

HfAlO14.8 nm

3.0 nm(ALD Al2O3)

Mobility ‐ ~600(cm2/Vs)

e: 200h: 400

~700(µS/µm)

‐ ‐ ‐ 701(µS/µm)

‐ ~500(µS/µm)

~850(cm2/Vs)

Lch (nm) 55W/L=

30/5 µm50 µm 100 4.5 µm 60 183 50 200 200 65

DIBL(mV/V)

84 ‐ ‐ 180 ‐ ~50 ‐ 210 ‐ ‐ ‐

SS(mV/dec)

105 ‐61pMOS33nMOS

145 750 90 130 150 160 ‐ ‐

ION(µA/µm)

278(VD=0.5V)

3(VD=‐0.2V)

4 (n,p)(VD=0.5V)

‐ 10(VD=0.5V)

400(VD=0.5V)

235(VD=‐1V)

180(VD=0.5V)

604(VD=‐0.5V)

100(VD=0.5V)

731(VD=‐1V)

ResearchGroup

Tokyo UniVLSI 2012

Tokyo UniVLSI 2012

Stanford Uni VLSI 2012

Purdue Uni IEDM 2009

Stanford Uni ELD 2007

IntelIEDM 2011

NNDL Taiwan

IEDM 2011

Purdue Uni IEDM 2011

ASTARSingapore IEDM 2009

Hokkaido Uni, IEDM

2011

AIST Tsukuba VLSI 2012

150K

120K

(cm2/Vs)

Ns: 5e12

III-V/Ge benchmark for various structures

109

2012 2016 2018 2020 2022

Lg (nm)

Vdd (V)

EOT (nm)

Mobility enhancementfactor due to strain

CV/I (ps)

BulkFD SOI∗1: MG

Year of Production

∗1: Thicker EOT for MG(Multiple gate : Fin/Tri gate, nanowire)

2024 2026

Cg Ideal(fF/µm)

BulkFD SOI

MGBulk

FD SOIMGBulk

FD SOIMG

Vt,sat (mV)

2014

22 18 15.3 12.8 10.6 8.9 7.4 5.9

0.87 0.82 0.77 0.73 0.68 0.64 0.61 0.570.84 0.73 0.61

0.8 0.72 0.63 0.540.76 0.68 0.62 0.56 0.50 0.45

1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8

0.658 0.611 0.576

0.57 0.47 0.380.38 0.30 0.24 0.20

0.29 0.24 0.19 0.16 0.13 0.10

289 302 310222 227 234 242

217 223 225 228 231 237

0.529 0.429 0.3930.455 0.409 0.362 0.320 0.284 0.238

NMOS

Manufacturing solutionsexist or is being optimized

Manufacturing solutionsare known

Manufacturing solutionsare NOT known110

ITRS 2011 for Si (HP: High Performance Logic)

2012 2016 2018 2020 2022

Lg (nm)Equivalent

Injection velocity Vinj (107 cm/s)

BulkFD SOI

MG

Year of Production 2024 2026

Id,sat(mA/µm)

BulkFD SOI

MG

BulkFD SOI

MGBulk

FD SOIMG

Rsd (Ω-µm)

2014

CV2

(fJ/µm)

Isd,leak (nA/µm)

22 18 15.3 12.8 10.6 8.9 7.4 5.91.09 1.18 1.33

1.37 1.51 1.63 1.831.68 1.82 2.05 2.26 2.38 2.67

1.685 1.805 1.916 2.030 2.152 2.308

1.6701.367 1.4961.654 1.791 1.9421.530

100 100 100 100 100 100 100 100232 183 149

274 228 187 153257 218 186 160 133 104

0.47 0.38 0.32 0.260.38 0.31 0.25 0.21 0.17 0.14

0.490.68 0.57

Manufacturing solutionsexist or is being optimized

Manufacturing solutionsare known

Manufacturing solutionsare NOT known

111

ITRS 2011 for Si (HP),contd

2018 2022 2024 2026

Lg (nm)

Vdd (V)

EOT (nm)Mobility enhancement

factor due tochannel material

Year of Production 2020

14 11.7 9.3 7.4 5.80.63 0.61 0.58 0.56 0.540.68 0.62 0.56

8 8 8 8 80.50 0.45

4 4 4 4 4GeIII-V

0.28 0.24 0.20 0.16 0.130.41 0.36 0.30 0.25 0.21Ge

III-VCg Ideal(fF/µm)

229 230 238 245 251230 231 241 249 254Ge

III-VVt,sat (mV)

0.13 0.11 0.09 0.07 0.060.21 0.17 0.13 0.10 0.08Ge

III-VCV/I (ps)


112

ITRS 2011 for III-V/Ge

2018 2022 2024 2026

Lg (nm)

Year of Production 2020

14 11.7 9.3 7.4 5.84.29 4.58 5.32 5.93 6.642.26 2.44 2.86 3.19 3.63Ge

III-V

2.200 2.343 2.523 2.703 2.8841.769 1.932 2.121 2.330 2.555Ge

III-V

131 113 96 82 70149 126 105 85 72Ge

III-V

0.18 0.15 0.13 0.11 0.090.23 0.20 0.16 0.14 0.11Ge

III-V

Equivalent Injection velocity

Vinj (107 cm/s)

Id,sat(mA/µm)

Isd,leak (nA/µm) 100 100 100 100 100Rsd

(Ω-µm)

CV2

(fJ/µm)


113

ITRS 2011 for III-V/Ge, Contd

Carbon‐based FET

Gate length (nm)10010Cu

t‐off frequ

ency ( GHz)

L. Liao, et al., Nature ,Vol.467 p.305.

F. Schwlerz, Nature Nano ,Vol.5 p.487.

GaAs mHEMT(20nm) SiMOSFET

(29nm)GaAs pHEMT(100nm)

100

1000

10

CNT

Graphene

J. P. Colinge et al., Nature Nano. 5(2010)225

A. D. Franklin et al., pp.525, IEDM2011 (IBM)


Junctionless Transistor

All‐spin logic device

1000

M. Lemme, Nanotech workshop ,2012

Input and output related via Spin-coherent channel

Emerging devices(future scaling trends)Emerging devices(future scaling trends)Carbon nanotube Graphene

A. Seabaugh, IEDM 2011 Short Course (University of Notre Dame)

Low IOFF, Low VDD, SS<60mV/decade

Tunnel FETTunnel FET

Band to band tunneling

VDD 0.3~0.35VTFET 8x faster at the same power“parameter variation is not a significant factor for differentiation between MOSFET and TFET”


TFET vs. MOSFET at low VTFET vs. MOSFET at low VDDDD

116

A. Villalon, pp.49, VLSI 2012 (CEA-LETI)

190mV/dec

Tunnel FET (Si)Tunnel FET (Si)

X in Si1-xGex is optimized to allow for efficient BTBT

Gate Voltage (V)

Reducing SiGe Body thickness improvesSubthreshold swing.

LG= 200nm

130mV/dec

ION/IOFF~105

117

VDS=1V

K. Tomioka et al., pp.47, VLSI2012 (Hokkaido University)

SS=110mV/decSS=21mV/dec

VDS= 1V

HfAlOx

Gate

NW Diameter= 30nmSS of TFET is function of VG due to Zener tunnel current

Tunnel FET (IIITunnel FET (III--V)V)

Conventional FET limitSS= 60 mV/dec

Minimum SS= 21 mV/dec is reached due to optimized series resistance of contact, undoped InAs and InAs/SiION/IOFF~106 at VDS= 1.0V (ION= 1Aµ/µm) 118

K. Tomioka et al., pp.47, VLSI2012 (Hokkaido University)


Device structureDevice structure

119


measured III-V channel TFETs

Tunnel FET performance comparisonTunnel FET performance comparison

Is the average swing when VTH=VDD/2VOFF=0

Most common SS which is the inverse of ID-VGS slopeat the steepest part

SMIN:

SEFF:

VGS

I D

Ith

IOFF

VTHVoff

Average SS:

VTH=VDD/2

Effective SS:

VOFF=0

120

Near-ideal subthreshold slope, close to 60 mV/dec at room temperature, and extremely low leakage currents

ION/IOFF~1x106Silicon nanowire is uniformly doped


Gate material is oppositepolarity polysilicon

Lg= 1µm

10nm

30.5nm

Lg= 1µmWwire= 30nm

Nanowire Junctionless TransistorNanowire Junctionless Transistor

(-1<Vg<1)IOFFis smaller than 10-15 A

K. Banerjee, UC Santa Barbara, G-COE PICE International Symposium on Silicon Nano Devices in 2030

Carbon nanotube and GrapheneCarbon nanotube and Graphene

SWCNT : single wall carbon nanotubeGNR : graphene nano ribbon

Carbon materials for FET applications ・ an ultra-thin body for aggressive channel length scaling・ excellent intrinsic transport properties similar to carbon nanotubes・ pattern the desired device structures

A. D. Franklin et al., pp.525, IEDM2011 (IBM)

SubSub--10nm carbon nanotube transistor10nm carbon nanotube transistor

Transistor operation with Lch of 9nm

Z. Chen et al., pp.509, IEDM2008 (IBM)

Graphene FieldGraphene Field--effect Transistoreffect TransistorJ. B. Oostinga et al., Nature Materials 7 (2008) 151

・Ambipolar Characteristics

・Bi-layer graphene and double gates can open the gap

H. Wang et al., pp.88, IEDM2012 (MIT)

2D material : single layer MoS2D material : single layer MoS22

・Mobility of 190 cm2/Vsec・Ion of 1 µA/µm at VDD = 1V

Candidate : MoS2, MoSe2, WS2, WSe2, MoTe2, WTe2

Advantage Issues

TFETLower Vdd

Lower IOFF

Integrationhigher ION

CNT FETHigher transport velocity

Lg scaling

High density and alignment, reproducibility,

integration

Graphene FETRF application

Large area manufacturingNOT a direct replacement

for Silicon logic

MEMS Extremely low leakage Ultra-low digital logic

EnduranceSlow speed, scalability

Junctionless FET CMOS process compatibility

Worse gate control in short-channel

Spin FETLow power, suitable for

memory (nonvolatile info storage)

Low efficiency of spin injection

Summary of Emerging Technology pro/consSummary of Emerging Technology pro/cons

T. Marukame et al., pp.215, IEDM2009 (Toshiba)

Magnetic tunnel junction on S/D

Read/write are enabled by using ferromagnetic electrodes and Spin-polarized current

Lg = 1µm

Spin transfer Torque Switching MOSFETSpin transfer Torque Switching MOSFET

[1] G. Zhou et al., pp. 782, vol. 33, no. 6, EDL 2012 (University of Notre Dame)

IIONON and Iand IOFFOFF of TFETsof TFETs

C. Auth et al., pp.131, VLSI2012 (Intel).K. Mistry et al., pp.247, IEDM2007 (Intel).

0.01

0.1

1

10

100

1000

10000

0.01 0.1 1 10ION [mA/µm]

I OFF

[nA

/µm

]

TFET VDS=1V

Si MOSFET

IntelBulk 32nmVDD=0.8V

IntelTri-Gate 22nmVDD=0.8V

Intel Bulk 45nmVDD=1V

TFET VDS=0.75V

TFET VDS=1.05V

128

ION/IOFF of ~1010

T. K. Liu et al., pp. 43, VLSI2012 (UC Berkeley)

ON

-sta

te re

sist

ance

[Ohm

]

Number of Operation Cycles

Ultra-low-power digital logic applications.

Frequency of 1, 5, 25kHz under operation

Mechanical Switch: MEMS relayMechanical Switch: MEMS relay

129

Metal (Silicide) S/D

Extreme scaling in MOSFET Lphy

Dop

antC

onc. δ δGate

σ σ

Met

al C

onc.

Gate

Lphy = Leff- Atomically abrupt junction- Lowering S/D resistances- Low temperature process for S/D

Metal Schottky S/D junctions

- Dopant abruptness at S/D- Vt and ION variation- GIDL

Schottky Barrier FET is a strong candidate for extremely scaled MOSFET S DChannel

S DChannel

n+-Sin+-Si

Metal Silicide

Metal Silicide

132

Surface or interface controlDiffusion species:

metal atom (Ni, Co)Rough interface at silicide/Si- Excess silicide formation- Different φBn presented

at interface- Process temperature

dependent composition

Diffusion species: Si atom (Ti)Surface roughness increases- Line dependent

resistivity change

Line widthof 0.1 µm

H. Iwai et al., Microelectron. Eng., 60, 157 (2002).

Top view

Epitaxial NiSi2

O. Nakatsuka et al., Microelectron. Eng.,83, 2272 (2006).

Si(001) sub.Annealing: 650 oC

133

Si substrate

Ni-silicide

Si substrate

Si substrate

Ni-silicide

Si substrate

Deposition of Ni film

Deposition fromNiSi2 source Annealing Flat interface

Roughinterface

No Si substrateconsumption

Annealing

Deposition of Ni-Si mixed films from NiSi2 source

- No consumption of Si atoms from substrate- No structural size effect in silicidation process- Stable in a wide process temperature range

134

SEM views of silicide/Si interfaces

NiSi2 source

Ni source (50nm)

rough

rough

rough flat

flat

flat

STI 500nm

NiSi2 source (50nm)

500nm

500nm

STI

500nmSTI STI

500nmSTI500nmSTI600oC , 1min

700oC , 1min

800oC , 1min

- Rough interfaces- Consumed Si substrate - Thickness increase ~100 nm

Ni source

- Atomically flat interfaces- No Si consumption- Temperature-independent

Si substrate

Ni-silicide

Ni source

Ni-silicide

Si substrate

NiSi2 source

STI

135

Ideal characteristics (n = 1.00, suppressed leakage current)

Suppressed reverse leakage current- Flat interface and No Si substrate consumption- No defects in Si substrate

Ni

NiSi2

-0.8 -0.6 0.0 0.2Diode voltage (V)

-0.4 -0.210-5

10-4

10-3

10-2

Dio

de c

urre

nt (A

/cm

2 )

1.001.08

n

0.659NiSi2

0.676NiφBn (eV)Source

1.001.08

n

0.659NiSi2

0.676NiφBn (eV)Source

Generation current

RTA：500oC, 1min

Schottky diode structures

Leakage currentAl contact

Ni source

Al contact

NiSi2 source

Si substrate

Si substrate

NiSi2 source Applied Voltage (V)

Cur

rent

den

sity

(A/c

m2 )

136

Ni silicide Ni

200nm

Si Fin

Fins width：20nm50nm

Si Fin Ni silicide

Growth length

SiO2

NWs width：20nm

SiO2 Ni silicide

Ni silicide

Si NW

50nm

200nmGrowthlength

(a) (b)

137

Conclusions

Si-MOSFET is the most fundamental and smallest functional device available for manufacturing.

It is really amazing to keep the evolution for so many generations without being replaced by any other device.

138

The device downsizing of Si-MOSFET will be ended within 10 ~ 20 years because Ioffincrease at the size of sub-5nm.

In order to reach the limit, R&D for nanowire, high-k for sub-5nm EOT, silicide S/D are necessary.

There are many rooms for the universities to contribute to the development.

139

Finally, even after the end of Si-MOSFET downsizing, Si-CMOS technology will still be the mainstream IC technology for a long period, as no other device technology seems to be developed into a comparable integration scale as the present CMOS technology in foreseeable future.

However, new device research other thanSi-CMOS is also very important.

140

1900 1970 2000 2020

ElectronicsMicro-Electronics

Nano-Electronics

Vacuum tube Si MOS IC Si CMOS IC

2100

Leap

Bio device (brain, even insect): 4 Billion Years from single cell. Difference of history

MOS IC: only 40 Years Bio device

Thank you for your attention!

141

january 9, 2013 ieee eds dl@vit, vellore, india · 2013-04-17 · dubai, uae (year 2010) 828 m...

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