future of nano cmos technology - 東京工業大学 · future of nano cmos technology ... what is...
TRANSCRIPT
Hiroshi Iwai
Frontier Research CenterTokyo Institute of Technology
CSTIC 2013 Keynote Talk
1
Future of Nano CMOS Future of Nano CMOS TechnologyTechnology
Kerry Hotel, Shanghai, China, March 17, 2013
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 Appl.: Digital (µ-processor, cell phone, etc.)
Technology Revolution??
Maybe, just evolution or innovation!
But very important so many innovations!
Now, 2013 “Nano-Electronics” continued.
Device: Still, Si CMOS integrated circuitsDevice feature size: near 10 nmMajor Appl.: Still Digital (µ-processor, cell phone, etc.)
But, so many important emerging applications for smart society.
Still evolution and innovation..
Future, “Nano-Electronics” still continued?
Device: Still, Si CMOS integrated circuits?
Device feature size: ? nm, what is the limit?
Application: New application?
Any Technology Revolution?
Questions for future
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.
Of course, I do not deny the importance of Beyond CMOStechnology development. It is becoming very importantas CMOS approach its limit.
λ>>LDiffusive transport
λ<LBallistic transport
λ~LQuasi-Ballistic transport
Lλ :Mean free pathsource drain
RM
Back scatteringfrom drain
Ballistic transport will never happen for MOSFET because of back scattering at drain
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
10
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
11
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 Center
Shanghai, 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!
Brain: Integrated Circuits
Hands, Legs:Power device
Stomach:PV device
Ear, Eye:Sensor
Mouth:RF/Opto device
18
19
Near future smart-society has to treat huge data.
Demand to high-performance and low power CMOS become much more stronger.
20
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
23
(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 Drain1V 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
24
Problem for downsizing
LLgate gate and tand toxox(EOT) scaling trend(EOT) scaling trendA. Toriumi (Tokyo Univ), IEDM 2006, Short Course
t ox(
(
25
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
Our Work at TIT: HighOur Work at TIT: High--k k
28
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
29
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)
30Subthreshold 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
32
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
Our work at TIT: Our work at TIT: 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
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 36
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
STMicro. [8]GAA NWVDD=1.1V
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
STMicro. [8]GAA NWVDD=1.1V
IBM [10]ETSOIVDD=0.9VIeff
Supply voltage affects very much!
<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
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
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
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 since 22nm node, enabling further scaling
C. Auth et al., pp.131, VLSI2012 (Intel)
TriTri--gate implementation for transistors gate implementation for transistors
・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
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
C. Auth et al., pp.131, VLSI2012 (Intel)
TriTri--gate width/height optimizationgate width/height optimization
Intel’s fin is triangle shape!
C.-H. Jan et al ., pp.44, IEDM2012 (Intel)
TriTri--gate Igate Idd--VVgg characteristics and Vcharacteristics and Vthth
・SS of 71 and 72 mV/dec for HP NMOS and PMOS, respectively
・DIBL of 30 and 35 mV/V for NMOS and PMOS, respectively
・Vth of 22 nm is about 0.1 ~0.2 V lower than that of 32nm
Very good Vth control!
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)Also, ET-SOI works very good!
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)
DrainDrain--induced barrier loweringinduced barrier loweringT. Skotnicki, IEDM 2010 Short Course (STMicroelectronics)
SubSub--threshold Slopethreshold SlopeT. Skotnicki, IEDM 2010 Short Course (STMicroelectronics)
110 mV/dec
85 mV/dec
75 mV/dec
65 mV/dec
95 mV/dec
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
Significant µ degradationat diameter < 10 nm
Need to decrease diameter for SCH
J. B. Chang et al., pp.12, VLSI2012 (IBM)
Impact of Si thickness in FinFETImpact of Si thickness in FinFET
・Replacement Gate process
・TaN/HfO2 gate stack
・Reduced gm and higher Vthwith decreasing Fin width
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.
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.
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
57
By Profs. Oshiyama and Iwata, U. of Tokyo
Wire cross section dependence.
What cross section gives best solution forSCE suppression and drive current?.
J. B. Chang et al., pp.12, VLSI2012 (IBM)
VVthth variabilityvariability
nFETs pFETs
Significant increase in Vth variability with decreasing Fin width
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 2
Trend 3 ?
EOT Scaling TrendsEOT Scaling Trends
Smaller wire/fin width is necessary for SCE suppression
But mobility and ION severely degrade with wire/fin width reduction
Therefore even in multi-gate structures, EOT scaling should be accelerated to provide SCE immunity
Limit in tLimit in toxox thinningthinning
R.Chau, et al., (Intel) IWGI 2003
63
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
64
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
65
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, CoxCapacitance 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
66
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 Pm Sm Eu 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
67
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
68
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
69
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
71
1837184018431846Binding energy (eV)
Inte
nsity
(a.u
)
Si sub.
Hf SilicateSiO2
500 oC
1837184018431846Binding energy (eV)
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 image500 oC 30min
H. Shimizu, JJAP, 44, pp. 6131
72
La-Silicate Reaction at La2O3/Si
La2O3
La-silicate
W
500 oC, 30 min
1 nm
k=8~14
k=23
1837184018431846Binding energy (eV)
Inte
nsity
(a.u
)
as depo.
300 oC
La-silicate
Si sub.
500 oC
1837184018431846Binding energy (eV)
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 spectra TEM image
Direct contact high-k/Si is possible
Cluster Chambers for HKMG Gate Stack
Flash Lamp Anneal
EB Deposition: HK Sputter: MG
ALD: HK
Robot
RTA
Entrance
77
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
78
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
79
80
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
81
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
82
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)
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.
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)
92
EOT Mobility Vth SS DIBLGate stack Ref.
0.45nmTiN/Cap/HfO2 115cm2/Vs
(at 1x1013cm-2)IMEC
MEE20110.3V
(Lg=10um)
0.52nmTiN/Cap/HfO2 110cm2/Vs
(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)
0.55nmTiN/Cap/HfO2 140cm2/Vs
(at 1MV/cm)IBM
VLSI2009
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.
93
ALD of La2O3
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
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]
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).
Si‐FinFET 22nmIntel VDD=0.8V [10]
Si‐FinFET 22nmIntel VDD=0.8V [10]
MultiMulti--gate IIIgate III--V and Si benchmarkV and Si benchmark
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
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
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)
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
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)
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
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
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)
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
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
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,p161
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)
J. P. Colinge et al., Nature Nano. 5(2010)266
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”
A. Seabaugh, IEDM 2011 Short Course (University of Notre Dame)
TFET vs. MOSFET at low VTFET vs. MOSFET at low VDDDD
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
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)
K. Tomioka et al., pp.47, VLSI2012 (Hokkaido University)
A. Seabaugh, IEDM 2011 Short Course (University of Notre Dame)
Device structureDevice structure
A. Seabaugh, IEDM 2011 Short Course (University of Notre Dame)
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
[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
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
MEMS relayMEMS relay
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)
Near-ideal subthreshold slope, close to 60 mV/dec at room temperature, and extremely low leakage currents
ION/IOFF~1x106Silicon nanowire is uniformly doped
J. P. Colinge et al., Nature Nano. 5(2010)225
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
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
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
ConclusionsConclusions
HKMG: Continuous innovation has enabled EOT scaling to 9 Ao, however, new material could be needed for further EOT scaling.
New device structures (FinFET, Tri-gate) are replacing conventionalPlanar CMOS
Same performance at lower supply voltage
The combination of III-V channel materials with a multi-gate structure appears to be a promising direction.(Higher performance in lower operating voltage)
Recent advances in new channel material shows promising device performances but still far to cacth up Si-CMOS.
Device demonstration on emerging technologies (such as Tunnel FET, Junctionless FET, Carbon-based FET..) is increasing, But more time is needed for implementation of these technologies in future generation devices as mature technologies.
La-based high-k material
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
Vth control by back-gate bias
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
Planar still works well at 20nm
G. Bidal et al., pp.240, VLSI2009 (STMicroelectronics)
SiNHMTop Gate
Bottom Gate
Channel
NiPtSi
・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)
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
135Year
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
SiHigh-k
Metal
Direct ContactOf high-k and Si
Si
MetalSiO2/SiON
0.5~0.7nm
Introduction of High-kStill SiO2 or SiON
Is 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.