Scaling and Beyond for Logic and Memories. Which … and Beyond for Logic and Memories. Which...

Scaling and Beyond for Logic and Memories. Scaling and Beyond for Logic and Memories. Which perspectives?Which perspectives?

September 26th, 2012 Minatec, Grenoble - France

Hiroshi Iwai and Barbara de Salvo

Frontier Research Center, Tokyo Institute of TechnologyCEA-LETI

ISCDG 2012, Short Course

1

Scaling and Beyond for LogicScaling and Beyond for Logic

September 26th, 2012 Minatec, Grenoble - France

ISCDG 2012, Short Course

2

Part IPart I

More Moore approach

Advance Si-based CMOS devices and technologies

Technology benchmark

Challenges

Alternative channel material devicesTechnology benchmark

III-V, Ge-based devices

Emerging technologies(Tunnel FET, Junctionless FET, Carbon-based FET, MEMS,Spin-based Logic)

Conclusions

OutlineOutline

3

More Moore approach



Challenges




Conclusions

OutlineOutline

4

Planar to MultiPlanar to Multi--gate, New highgate, New high--kk

5

Fin Tri-gate Ω-gate All-around

G G G

G

G

Off-leakage is the obstacle for downsizing.

1. New channelstructure

Solutions

2. Thinning gate oxide New high-k

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 6

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

SiO2 IL (Interfacial Layer) is used at Si interface to obtain 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%

7

[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).

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

STMicro. [8]GAA NWVDD=1.1V

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



Tokyo Tech. [9]Ω-gate NWVDD=1V

[9] S. Sato et al., pp.361, ESSDERC2010 (Tokyo Tech.)8

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

YearV

DD

(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

9

Benchmark of device characteristicsBenchmark of device characteristics

<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 (VLSI2012)

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 1 0.9 1

ION (mA/um) nFET/pFET 1.36/1.07 1.53/1.23 1.26/1.1 0.83 (nFET) 1.65/1.25 1.2/1.05 1.32 (nFET)

DIBL (mV/V)

nFET/pFET~150 ~200 46/50 <50 75/130 104/115 62

SS (mV/dec) - ~100 ~70 <80 <90 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 (VLSI2012)

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 1 0.9 1

ION (mA/um) nFET/pFET 1.36/1.07 1.53/1.23 1.26/1.1 0.83 (nFET) 1.65/1.25 1.2/1.05 1.32 (nFET)

DIBL (mV/V)

nFET/pFET~150 ~200 46/50 <50 75/130 104/115 62

SS (mV/dec) - ~100 ~70 <80 <90 87 70

10

More Moore approach



Challenges




Conclusions

OutlineOutline

11

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

12

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

13


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

14

NMOS PMOS


TriTri--gate Igate IONON and Iand IOFFOFF characteristicscharacteristics

HP MP SP

ION (mA/um) NMOS/PMOS 1.26/1.1 1.07/0.95 0.88/0.78

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

ION/IOFF ~105 ~106 ~106

ION/IOFF of 105~106

15

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 at thin BOX of 20nm

TriTri--Gate NanowireGate Nanowire

Vsub

16

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

17

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

18

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)

19

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

SiNHMTop Gate

Bottom Gate

Channel

NiPtSi

・Gate all around structure

・Lg of 22~30nm

・High drive currents by special stress and channel orientation design

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

20

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

・High drive current

(1.32 mA/µm @ IOFF=117 nA/µm)

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

21

More Moore approach



Challenges




Conclusions

OutlineOutline

22

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

23

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.

24

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.

25

Advantages of metal S/D- atomically abrupt junction- low parasitic resistance- reduced channel dopantconcentrationIssues in metal S/D- two different φB for p/n-ch FETs- underlap/overlap to the gate- narrow process temperature window

L. Hutin, pp.45, IEDM2009 (CEA-LETI)

S D

BOX

Dopant Segregationlayer

Si

Metal S/D is considered for alternativechannel material such as InGaAs and Ge

S.-H. Kim, IEDM (2010) 596

Ni is used both onInGaAs and Ge to

form alloy.

K. Ikeda, VLSI (2012) 165

Metal S/DMetal S/D

26

More Moore approach



Challenges




Conclusions

OutlineOutline

27

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

S. Takagi., IEDM2011, Short course (Tokyo Uni) 28

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

InGaAs NanowireLg= 200nm, Tox 14.8nm

VDS=0.5V(Hokkaido Uni.)[4]

InGaAs FinFETLch=130nmEOT 3.8nm

VDS=0.5V (NUS)[3]

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

InGaAs GAALch=50nm, Dielectric: 10nm Al2O3

VDS=0.5V (Purdue Uni.) [1]

Ge Tri‐gateLg=183nm, EOT 5.5nm

VD=‐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 3.0nm

VD=‐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

29

ION/IOFF Benchmark of Ge pMOSFET

30

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

31

More Moore approach



Challenges




Conclusions

OutlineOutline

32

ION at LG = 50 µm pMOS: 4 µA/µmnMOS: 3.8 µA/µm

Achieving both N‐ and P‐type MOSFETon a single channel is possible

electron/hole mobility > 4000/900cm2/Vs was gained in a single channel material

In‐content of 20‐40% improves perfomance

Z. Yuan et al., pp.185, VLSI2012 (Stanford Uni)

InGaSb as channel material (stanford)

Electron MobilityHole Mobility

AlGaSb creates barrierfor both electrons and holes

SiSi

InGaSbInGaSb

33

Metal S/D and InAs buffer layer are usedas performance boosters.DIBL=84 mV/V and SS=105 mV/V was shown for Lch = 55 nm when In‐content washigher.

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

Metal S/D InGaAs MOSFET (Tokyo Uni)

34

SS: nMOS: 90 (mV/decade)pMOS: 190 (mV/decade)

Si2H6 plasma passivation is employedwhich creates Si layer at interface.

Common gate stack (gate metal and dielectric) were used for both p‐ and n‐type

High intrinsic peak GM,Sat=of ~465 μS/μm at VDS=-1.1 V was achieved for LG=250 nm.

X. Gong, et al. (National Uni of Singapore), VLSI2012, p.99.

Common InGaAs‐GeSn gate stack (NUS)

LG= 5µmVGS-VTH= 0～2.0V

35

InGaAs nanowire transistor(Hokkaido Uni)InGaAs nanowire transistor(Hokkaido Uni)T. Fukui, et al. (Hokkaido Univ), IEDM2011, p.773.

Core-multishell InGaAs nanowires grown without buffer layer on Si substrate(bottom up approach)

At Vd = 1 V peak transconductance of 500 mS/mm is achieved (roughly x3 InGaAs nanowire)

36

TriTri--gate InGaAs QWgate InGaAs QW--FET(Intel)FET(Intel)M. Radosavljevic, et al.(Intel), IEDM2011, p.765.

Steepest SS and smallest DIBL ever reported (Wfin = 30nm)

Tri-gate structure has superiority electrostatic controllability compared to ultra-thin body planar structure

37

Gate all around InGaAs MOSFET(Purdue)Gate all around InGaAs MOSFET(Purdue)P. D. Ye, et al (Purdue Univ)., IEDM2011, p.769.

DIBL was suppressed down to

Lch = 50nm and

Gm,max =701mS/mm at Vds = 1V

Inversion mode In0.53Ga0.47As MOSFET with ALD Al2O3/WN with well electrostatic properties

Wfin= 50nm

Wfin= 30nm

38

DIBL =135 mV/V and drive current

over 840 µA/µm at Lch = 130nm

and Vds = 1.5V was achieved

H.C. Chin, et al. (National Uni of Singapore)., EDL2011,Vol.32 p.146.

LCH= 130nm

InGaAs FinFET (NSU)InGaAs FinFET (NSU)

39

GeGe--nanowire pMOSFET (AIST,Tsukuba)nanowire pMOSFET (AIST,Tsukuba)

Using Ni-Ge alloy as metal S/D

Significantly reduces contact resistance

K. Ikeda, et al. (AIST, Tsukuba), VLSI2012, p.165.

High saturation current and high mobility

μeff = 855 cm2/Vs at Ns =5x1012cm-2

and saturation drain current of 731μA/μm at Vd = -1V

Lg= 65nm Wwire= 20nmVD= -1V

VD= -0.5V

VD=-0.05V

Vg-Vth= -2V

40

S-H. Hsu, et al. (NNDL,Taiwan), IEDM2011, p. 825.

Selective etching of high defect

Ge near Ge/Si interface is used which improves gate controllability.

ION/IOFF = 105 and SS= 130 mV/dec

And ION= 235 µm/µm at VD= -1V

Ge triangular pMOSFET (NNDL,Taiwan)Ge triangular pMOSFET (NNDL,Taiwan)

Ge Triangular

Ge Rectangular

Lg>2Wfin Lg<2Wfin

41

III-V (InGaAs, InAs,InGaSb,…)

Al2O3 Si-HfO2 Al2O3+HfO2 HfAlOx TaSiOx

ALD-Al2O3 is most commonly used as gate dielectric in planar or Multi-gateHfO2-only stacks have high Dit (combination of Al2O3 or Al or Si is used)

In0.53Ga0.47AsIn0.7Ga0.3As

Ge

Intel, IEDM 2010Hokkaido Uni, IEDM 2011NUS, VLSI 2012E. Kim, et al.,APL96, 012906

L. Chu, et al.,APL99, 042908

3.4 nm1.2 nm

Implementing highImplementing high--k material to IIIk material to III--V,GeV,Ge

By controlling the formation of GeOxat the interface, HfO2 and Al2O3show good results.

R. Zhang et al., VLSI2012,p16142

More Moore approach



Challenges




Conclusions

OutlineOutline

43

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

44

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

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

Tunnel FETTunnel FET

45

Band to band

tunneling

VDS=1V

SS=21mV/dec

VDS= 1V

HfAlOx

Gate

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

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

46

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

47

VDS=1V


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)

48



Device structureDevice structure

49


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

50

[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

51

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

52

Silicon nanowire is uniformly doped


Gate material is oppositepolarity polysilicon

Lg= 1µm

10nm

30.5nm

Lg= 1µmWwire= 30nm

Nanowire Junctionless TransistorNanowire Junctionless Transistor

53

n+ n+n n+ n+pS DS D

pn junctionno junction

Junctionless Conventional

IM : Conventional Inversion ModeJAM LD : Janctionless Accumulation Mode with low dopeJAM HD : Janctionless Accumulation Mode with high dope

JAM devices have reduced gate control and degraded short-channel characteristics relative to IM

Si Junctionless Transistor (Intel)Si Junctionless Transistor (Intel)R. Rios et al., EDL. 32(2011)1170 (Intel)

403020 403020 403020Lg (nm) Lg (nm) Lg (nm)

Not suitable for high-performance logic (high Ion and moderate Ioff)54

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

55

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

SubSub--10nm carbon nanotube transistor10nm carbon nanotube transistor

Transistor operation with Lch of 9nm56

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

57・ Ioff is very large No bandgap

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

58

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

59

Advantage Issues

TFETLower Vdd

Lower IOFF Lower ION

CNT FET Higher transport velocityLow density and

alignment, reproducibility, integration

Graphene FET RF application Huge IOFF

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

More Moore approach



Challenges




Conclusions

OutlineOutline

60

Conclusions for logicConclusions for logic

Alternative channel device needs more time to catch up Si.

Si based CMOS is still the mainstream for downsizing until sub-10 nm.

Emerging device technologies are still in research level.

61

New structure (fin, try, nanowire-gate, or ET-SOI). New materials for high-k gate, and metal S/D.

Fin, try, nanowire-gate structures become popular. High-k gate needs to be improved.

AcknowledgementAcknowledgement

I would like to express appreciation to Dr. Takamasa Kawanago and Mr. Darius Zade

of Tokyo Institute of Technologyfor the material preparation.

62

Appendix

63


・Steep SS

・low DIBL

・Improved Ion (strain, HK/MG)

1-55-2020-100IOFF (nA/um)

343430LGATE (nm)

0.90.90.9TOX,E (nm)

SPMPHP

1-55-2020-100IOFF (nA/um)

343430LGATE (nm)

0.90.90.9TOX,E (nm)

SPMPHP

FinFET(TriFinFET(Tri--Gate Transistors)Gate Transistors)

64

Scaling and Beyond for Logic and Memories. Which … and Beyond for Logic and Memories. Which...

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