past and future trends 0f integrated circuit …past and future trends 0f integrated circuit...
TRANSCRIPT
Past and Future Trends 0f Integrated Circuit Technology
October 25, 2010
Hiroshi Iwai, 1
@Prithvi Narayan Campus, Trivhuvan Univ.,Pokhara, Nepal
Frontier Research CenterTokyo Institute of Technology
Founded in 1881, Promoted to Univ. 1929Tokyo Institute of Technology
International StudentsInternational Students
Asia 847Europe 78 North America 12
South America 24Oceania 5
Africa 16
Total 982
Country Students
China 403
S. Korea 130
Indonesia 64
Thailand 55
Vietnam 60
Malaysia 28
(As of May. 1, 2005)
• There were many inventions in the 20th century:
Airplane, Nuclear Power generation, Computer,
Space aircraft, etc
• However, everything has to be controlled by electronics
• Electronics
Most important invention in the 20th century
• What is Electronics: To use electrons,
Electronic Circuits
Importance of Electronics
Lee De Forest
Electronic Circuits started by the invention of vacuum tube (Triode) in 1906
Cathode(heated) Grid
Anode(Positive bias)
Thermal electrons from cathodecontrolled by grid bias
Same mechanism as that of transistor
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
7
J.E.LILIENFELD
J. E. LILIENFELD
DEVICES FOR CONTROLLED ELECTRIC CURRENTFiled March 28, 1928
8
ElectronSemiconductor
Gate Electrode
Gate InsulatorNegative bias
Positive bias
Capacitor structure with notch
No current
Current flows
Electricfield
9
Source Channel Drain
0V
N+-Si P-Si
N-Si
0V
1V
Negative
Source Channel DrainN-Si1V
N+-Si P-Si
Surface Potential (Negative direction)
Gate Oxd
ChannelSource Drain
Gate electrode
S D
G
0 bias for gate Positive bias for gate
Surface
Electron flow
10
However, no one could realize MOSFET operation for more than 30 years.
Because of very bad interface property between the semiconductor and gate insulator
Even Shockley!
11
Very bad interface property between the semiconductor and gate insulator
Even Shockley!
eGe
GeO Electric Shielding
CarrierScattering
Interfacial Charges
Drain Current was several orders of magnitude smaller than expected
12
1947: 1st transistor W. Bratten,
W. ShockleyBipolar using Ge
However, they found amplification phenomenon when investigatingGe surface when putting needles.This is the 1st Transistor: Not Field Effect Transistor, But Bipolar Transistor (another mechanism)
J. Bardeen
13
1958: 1st Integrated Circuit Jack S. Kilby
Connect 2 bipolar transistors in theSame substrate by bonding wire.
14
1960: First MOSFET by D. Kahng and M. Atalla
Top View
Al Gate
Source
Drain
Si
Si
断面
Al
SiO2
Si
Si/SiO2 Interface is extraordinarily good
15
1970,71: 1st generation of LSIs
DRAM Intel 1103 MPU Intel 4004
16
MOS LSI experienced continuous progress for many years
1960s IC (Integrated Circuits) ~ 10
1970s LSI (Large Scale Integrated Circuit) ~1,000
1980s VLSI (Very Large Scale IC) ~10,000
1990s ULSI (Ultra Large Scale IC) ~1,000,000
2000s ?LSI (? Large Scale IC) ~1000,000,000
Name of Integrated Circuits Number of Transistors
17
Gate ElectrodePoly Si
Gate InsulatorSiO2
Drain
SiSubstrate
Source
Channel N‐MOS (N‐type MOSFET)
Gate ElectrodePoly Si
Gate InsulatorSiO2
SubstrateSi
Use Gate Field Effect for switching
ee
18
19
CMOS
Complimentary MOS
Inverter
PMOS
NMOS
When NMOS is ON, PMOS is OFFWhen PMOS is ON, NMOS is OFF
CMOS Technology: Indispensible for our human society
Al the human activities are controlled by CMOS
living, production, financing, telecommunication, transportation, medical care, education, entertainment, etc.
Without CMOS:
world economical activities immediately stop.
Cellarer phone dose not exists
Needless to say, but….
There is no computer in banks, and
20
1900 1950 1960 1970 2000
VacuumTube
Transistor IC LSI ULSI
10 cm cm mm 10 µm 100 nm
In 100 years, the size reduced by one million times.There have been many devices from stone age.We have never experienced such a tremendous reduction of devices in human history.
10-1m 10-2m 10-3m 10-5m 10-7m
Downsizing of the components has been the driving force for circuit evolution
21
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.22
Downsizing contribute to the performance increase in double ways
2323
Scaling Method: by R. Dennard in 1974
1
1Wdep
1 1
I
00 V 1
X , Y , Z : K, V : K, Na : 1/K
K
K
KWdep
Wdep V/Na: K
KI00 KV
I : K
K=0.7 for example
Wdep: Space Charge Region (or Depletion Region) Width
Wdep has to be suppressedOtherwise, large leakagebetween S and D
Leakage current
S D
By the scaling, Wdep is suppressed in proportion,and thus, leakage can be suppressed.
Good scaled I-V characteristics
Potential in space charge region ishigh, and thus, electrons in source areattracted to the space charge region.
2424
Drive current
Power per chip
Integration (# of Tr)
Scaling K : K=0.7 for example
Id = vsatWgCo (Vg‐Vth)
N
K‐1(αK‐2)K (K1 )2= α
Switching speed KK/K= K
Id per unit Wg = Id / Wg= 1
Wg (tox –1)(Vg‐Vth)= Wgtox
‐1(Vg‐Vth)= KK‐1K=Kin saturation
Co: gate C per unit area
Cg = εoεoxLgWg/tox
Id per unit Wg
Clock frequency
K
1
τ
Id
K
Id/µm
f 1/K f = 1/τ = 1/K
N α/K2
P α
Gate capacitance Cg K
Chip area Achip α
Lg, WgTox, Vdd
Geometry &Supply voltage
K
KK/K = K
τ= CgVdd/Id
α: Scaling factor
α/K2
fNCV2/2
= 1/K2 , when α=1
= 1, when α=1
Downscaling merit: Beautiful!
In the past, α>1 for most cases
2525
k= 0.72 =0.5 and α =1
Vdd 0.7Single MOFET
Lg 0.7Id 0.7Cg 0.7P (Power)/Clock
0.73 = 0.34 τ (Switching time) 0.7
Chip N (# of Tr) 1/0.72 = 2
P (Power)
k= 0.7 and α =1
Vdd 0.5Lg 0.5Id 0.5Cg 0.5P (Power)/Clock
0.53 = 0.125 τ (Switching time) 0.5
1/0.7 = 1.4f (Clock)1
N (# of Tr) 1/0.52 = 4
P (Power)1/0.5 = 2f (Clock)1
2626
10 -3
10 -2
10 -1
10 0
10 1
10 2
1970 1980 1990 2000
MPU Lg (µm)X
j (µm)
Minimum logic Vdd (V)
Id/µm(mA/µm)
tox (µm)
10 -3
10 -1
10 1
10 3
1970 1980 1990 2000
chip size (mm2)
Number of tr
ansistors
power (W
)
MIPSclock frequency (MHz)
Id/µm
Id
1 101
10‐1K (10 –2) f 1/K(10 2) 103
P α(10 1) 105
N α/K2(10 5) 104Achip α 101
Change in 30 years
Lg K 10 ‐2tox K(10 –2) 10‐2
Vdd K(10 –2) 10‐1
Idealscaling
RealChange
Idealscaling
RealChange
Idealscaling
RealChange
= fαNCV2
Past 30 years scaling
N, f increaseMerit:
Demerit: P increase
Vdd scaling insufficient
Additional significantincrease inId, f, P
Actual past downscaling trend until year 2000
Vd scaling insufficient, α increased N, Id, f, P increased significantly
Source. Iwai and S. Ohmi, Microelectronics Reliability 42 (2002), pp.1251-1268
Late 1970’s 1µm: SCE
Early 1980’s 0.5µm: S/D resistance
Early 1980’s 0.25µm: Direct‐tunneling of gate SiO2
Late 1980’s 0.1µm: ‘0.1µm brick wall’(various)
2000 50nm: ‘Red brick wall’ (various)
2000 10nm: Fundamental?
Period Expected Cause limit(size)
Many people wanted to say about the limit. Past predictions were not correct!!
27
Historically, many predictions of the limit of downsizing.
VLSI text book written 1979 predict that 0.25 micro‐meter would be the limit because of direct‐tunneling current through the very thin‐gate oxide.
29C. Mead L. Conway
VLSI textbook
Finally, there appears to be a fundamental limit 10 of approximately quarter micron channel length, where certain physical effects such as the tunneling through the gate oxide ..... begin to make the devices of smaller dimension unworkable.
30
Potential Barrier
Wave function
Direct‐tunneling effect
31
G
SD
Gate Oxide
Gate OxideGate Electrode
Si Substrate
Direct tunneling leakage current start to flow when the thickness is 3 nm.
Direct tunnelingcurrent
Direct tunneling leakage was found to be OK! In 1994!
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
1.6
1.2
0.8
0.4
0.0
‐0.4
0.0 0.5 1.0 1.5
Vd (V)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
0.4
0.3
0.2
0.1
0.0
‐0.1
0.0 0.5 1.0 1.5
Vd (V)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
0.08
0.06
0.04
0.02
0.00
‐0.02
0.0 0.5 1.0 1.5
Vd (V)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
0.03
0.02
0.01
0.00
0.01
‐0.4
0.0 0.5 1.0 1.5
Vd (V)
Id (m
A / μ
m)
Lg = 10 µm Lg = 5 µm Lg = 1.0 µm Lg = 0.1µm
Gate electrode
Si substrate
Gate oxide
MOSFETs with 1.5 nm gate oxide
32
G
S D
Lg
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
1.6
1.2
0.8
0.4
0.0
-0.40.0 0.5 1.0 1.5
Vd (V)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
1.6
1.2
0.8
0.4
0.0
-0.40.0 0.5 1.0 1.5
Vd (V)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
0.4
0.3
0.2
0.1
0.0
-0.10.0 0.5 1.0 1.5
Vd (V)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
0.4
0.3
0.2
0.1
0.0
-0.10.0 0.5 1.0 1.5
Vd (V)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
0.08
0.06
0.04
0.02
0.00
-0.020.0 0.5 1.0 1.5
Vd (V)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
0.08
0.06
0.04
0.02
0.00
-0.020.0 0.5 1.0 1.5
Vd (V)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
0.03
0.02
0.01
0.00
0.01
-0.40.0 0.5 1.0 1.5
Vd (V)
Id (m
A/ μ
m)
Vg = 2.0V
1.5 V
1.0 V
0.5 V
0.0 V
0.03
0.02
0.01
0.00
0.01
-0.40.0 0.5 1.0 1.5
Vd (V)
Id (m
A/ μ
m)
Lg = 10 µm Lg = 5 µm Lg = 1.0 µm Lg = 0.1µm
Gate leakage: Ig ∝ Gate Area ∝ Gate length (Lg)
Id
Drain current: Id ∝ 1/Gate length (Lg)
Lg small, Then, Ig small, Id large, Thus, Ig/Id very small
33
G
S D
Ig Id
Never Give Up!
There would be a solution!
Think, Think, and Think!
Or, Wait the time!Some one will think for you
No one knows future!
Do not believe a text book statement, blindly!
34
Qi Xinag, ECS 2004, AMD35
5 nm gate length CMOS
H. Wakabayashi et.al, NEC
IEDM, 2003
Length of 18 Si atoms
Is a Real Nano Device!!
5 nm
36
Tunnelingdistance
3 nm
Atomicdistance
0.3 nm
Below this, no one knows future!
What is the limit prediction now!
37
Limit for MOSFET operation
Ultimate limitation
10 ‐5
10 ‐4
10 ‐3
10 ‐2
10 ‐1
100
101
102
1970 1990 2010 2030 2050
MPU LgJunction depthGate oxide thickness
Direct-tunneling
ITRS Roadmap(at introduction)
Wave length of electron
Distance between Si atomsSize (µ
m), Voltage(V)
Min. V supply
10 nm3 nm
0.3 nm
ULTIMATELIMIT
However,Gate oxide thickness2 orders magnitude smallerClose to limitation!!
Lg: Gate length downsizing will continue to another 10‐15 years 38
By Robert Chau, IWGI 2003
0.8 nm Gate Oxide Thickness MOSFETs operates!!
0.8 nm: Distance of 3 Si atoms!!
39
So, we are now in the limitation of downsizing?
Do you believe this or do not?
40
There is a solution!To use high‐k dielectrics
Thin gate SiO2Thick gate high‐k dielectrics
Almost the same electric characteristics
However, very difficult and big challenge!Remember MOSFET had not been realized without Si/SiO2!
K: Dielectric Constant
Thick
Small leakageCurrent
41
42
Historical trend of high-k R& D
1st FET LSIPMOS NMOS CMOS
IC
Gate insulator
Gate electrode
1960 1970 1980 1990 2000 05
MOSFETGate Stackin production
SiO2 SiOxNy
DoublePoly SiAl N+Poly Si
Silicide above Poly Si electrode TiSi2 CoSi2WSi2MoSi2 NiSi
MOSFET
DRAM Capacitor
NV Memory
Analog/RF
Al2O3, ZrO2
Ni3Si4 Stack NO(Ni3Si4/SiO2)
R&D for high-k
NO, AO (Al2O3/SiO2)
Recent new high-kPure Si Period
(O)NO, Ni3Si4
(O)NO, Ni3Si4Ta2O5 , Al2O3,
Ta2O5 ,
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
43
44
PMOS
High‐k gate insulator MOSFETs for Intel: EOT=1nm
EOT: Equivalent Oxide Thickness
45
0 V
1.1 V
V > 1 Ve
V > 1 Vh
OxideSi
CB
VB
-6
-4
-2
0
2
4
6
Ene
rgy
(eV
)
SiO2
4.4
3.5
1.1
2.4
1.8
0.3
3.0
-0.1
2.3
Si3N4Ta2O5
SrTiO3
BaZrO3
ZrO2
Al2O3
Y2O3
La2O3
ZrSiO4HfSiO4
4.9
2.82.3
2.6 3.4
1.51.5
3.43.3
1.4
3.4
0.8
Si HfO2
1.9
2.1
LaAlO3
J Robertson, J Vac Sci Technol B 18 1785 (2000)
Band Offsets Calculated value
Dielectric constantSiO2; 4Si3N4: ~ 7Al2O3: ~ 9
Y2O3; ~10Gd2O3: ~10
HfO2; ~23La2O3: ~27
HfO2 was chosen for the 1st generationLa2O3 is more difficult material to treat
0 10 20 30 40 50Dielectric Constant
4
2
0
-2
-4
-6
SiO2
Ban
d D
isco
ntin
uity
[eV]
Si
kB *φ : Figure of Merit of High-k
T. Hattori, INFOS , 2003
SiO2 3.9AlxSiyOz(Ba,Sr)TiO3 200-300BeAl2O4 8.3-9.43CeO2 16.6-26CeHfO4 10-20CoTiO3/Si3N4EuAlO3 22.5HfO2 26-30Hf silicate 11La2O3 20.8LaScO3 30La2SiO5MgAl2O4
NdAlO3 22.5PrAlO3 25Si3N4 7SmAlO3 19SrTiO3 150-250Ta2O5 25-24Ta2O5-TiO2TiO2 86-95TiO2/Si3N4Y2O3 8-11.6YxSiyOzZrO2 22.2-28Zr-Al-OZr silicate(Zr,Sn)TiO4 40-60
C.A. Billmann et al.,, MRS Spring Symp., 1999,R.D.Shannon, J. Appl. Phys., 73, 348, 1993S. De Gebdt, IEDM Short Coyuse, 2004
Dielectric constant value vs. Band offset (Measured)
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
47
48
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 image 500 oC 30min
H. Shimizu, JJAP, 44, pp. 6131
49
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 spectraTEM image
Direct contact high-k/Si is possible
EOT = 0.48 nm
Transistor with La2O3 gate insulator
Our results
50
Direct contact of high-k/Si with La-silicate foramtion
※EOT:Equivalent oxide thickness
Foramtion of high-k quality La-silicate using the reaction of La2O3 and Si substrate
Originality
Si
High-k
SiOx intefaciallayer (0.5~0.7nm)
EOT scaling→limitted by IL
Si
High-k
Si
High-k
silicate
Issues in Dit, realiabilityµeff, etc.
High-k/SiO2/Si Direct contact of high-k/Si Direct contact of high-k/Siwith high quality silicate
Nice FET operation→EOT scaling
thin layer of silicate at high-k/Si interface
High quality La-silicate
La2O3
La-silicate
W
1 nm
k=8~14
k=23
La2O3 + Si + nO2→ La2SiO5, La9.33Si6O26, La10(SiO4)6O3, La2Si2O7, etc.
La2O3/Si after 500 oC 30min
Proper oxygen atom supply to form high quality Si-rich La-silicate
SiSiO2
HfO2
Si
La2O3
・HfO2 formesSiO2 at interface
・µeff degradation・defects in silicate(hysteresis)・large Dit (1013cm-2/eV)
La-richsilicateLa2SiO5
K. Kakushima, et al., ESSDERC ’08, Edinburgh
Si-richsilicatek=8~14
La-rich Si-rich
0.00E+00
5.00E-05
1.00E-04
1.50E-04
2.00E-04
2.50E-04
3.00E-04
3.50E-04
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2-0.4 0 0.4 0.8 1.2
0.1
0.2
0.30.35
Gate voltage (V)
Tran
scon
duct
ance
(mS)
Vd=50mV
W/L=50/2.5µm
0.00.00E+00
5.00E-05
1.00E-04
1.50E-04
2.00E-04
2.50E-04
3.00E-04
3.50E-04
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2-0.4 0 0.4 0.8 1.2
0.1
0.2
0.30.35
Gate voltage (V)
Tran
scon
duct
ance
(mS)
Vd=50mV
W/L=50/2.5µm
0.0
11%up
EOT=0.48nm
FET operation of EOT=0.37nm
0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1
Dra
in c
urre
nt (m
A) 3.5
2
1
0
3
(a) EOT=0.37nm (b) EOT=0.43nm (c) EOT=0.48nm
W/L=2.5/50µmPMA 300oC (30min)
Vth=-0.04V Vth=-0.03V Vth=-0.02V
14%up4%up
0 0.2 0.4 0.6 0.8 1Drain voltage (V)
0 0.2 0.4 0.6 0.8 1Drain voltage (V)
0 0.2 0.4 0.6 0.8 1Drain voltage (V)
compensation regioninsufficient
W/L=50/2.5µm
0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1
Dra
in c
urre
nt (m
A) 3.5
2
1
0
3
(a) EOT=0.37nm (b) EOT=0.43nm (c) EOT=0.48nm
W/L=2.5/50µmPMA 300oC (30min)
Vth=-0.04V Vth=-0.03V Vth=-0.02V
14%up4%up
0 0.2 0.4 0.6 0.8 1Drain voltage (V)
0 0.2 0.4 0.6 0.8 1Drain voltage (V)
0 0.2 0.4 0.6 0.8 1Drain voltage (V)
compensation regioninsufficient
W/L=50/2.5µm
EOT scaling below 0.5nm is still useful
Direct contact of high-k/Si using La2O3/silicate
K. Kakushima, et al., Microelectron. Reliab., 50, 790 (2010)
Improvement in both drain current and transconductance
(2) Direct high-k/Si using La-silicate/Si with high µeff
0
50100
150200
250
300350
400
0 0.2 0.4 0.6 0.8 1Eeff(MV/cm)
µ eff(
cm2 /V
s)
universal
0.0E+00
5.0E-05
1.0E-04
1.5E-04
2.0E-04
2.5E-04
3.0E-04
3.5E-04
4.0E-04
-0.8 -0.4 0.0 0.4 0.8 1.2 1.61.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
0.0E+00
1.0E-03
2.0E-03
3.0E-03
4.0E-03
5.0E-03
6.0E-03
0 0.2 0.4 0.6 0.8 1
00.20.40.60.811.2
Ids
(A)
Vd (V) Vg (V)
Ids
(A)
EOT=1.26 nmVth=-0.08 VSS=66.4mV/dec
L/W=2.5/50µm
W/La2O3/La-silicate/nFET, 500oC for 30min
Fairly nice properties can be achieved even with direct high-k/Si interface (EOT~1.2)
High peak µeff of 300cm2/Vs with 500oC annealing→ nice proerties of Si-rich La-silicate/Si interface
EOT=1.26nm
K. Kakushima, et al., ESSDERC ’08, Edinburgh
(3) Origin of degradations at EOT<1.3nm
1012 1013100
1000
200
300400500
Ns0.5
µadd
EOT = 1.69 nm
EOT = 0.93 nm
Ns (cm-2)µ e
ff, µ
add
(cm
2 /Vs)
2000
Coulomb scattering from high-k at EOT<1.3nm
Additional scattering of ~Ns0.5
←remote Coulomb scattering (Coulomb scattering in bulk Si ∝Ns
1)
Inversion density,
-1.4-1.2
-1-0.8-0.6-0.4-0.2
00.2
EOT (nm)
La2O3/silicate nFET, W/L=50µm/2.5µm
1011
1012
Dit
(cm
-2/e
V)
507090
110130150170
S.S
(mV/
dec)
V fb,
V th
(V) Vth
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2
Charge pumping @500kHz
Vfb
K. Kakushima, et al., Solid-State Electron., 54, 715 (2010)
Matthiessen’s rule
Defects from metal electrode
metal
Si sub.
EOTlim
density defects
effectivedistance
interface trap generation
high-kVo defect
metal defect metal
Vo
Metal atom diffusions to degrade the µeffin EOT<1.3nm
0
100
200
300
400
0.6 1.2 1.80EOT (nm)
µ eff
(cm
2 /Vs)
W/La2O3/silicate nFETAnnealed at 500 oC
peak µeff
µeff @ 0.8 MV/cm
W/L=50/2.5µm
EOTlim
nice Silicate/Siproperties
K. Kakushima, et al., Solid-State Electron., 54, 715 (2010)
Low Dit at high-k/Si interface at EOT>1.3nm
57
Vfb
(V)
-0.5-0.4-0.3-0.2-0.1
00.10.2
0.8 1.0 1.2 1.4 1.6 1.8 2.0
w/ Mg
w/o Mg
PMA500oC
EOT (nm)
W
Si
La
W
Si 2nm
a.u.
Mg
TEM EDX
Gate Metal Induced Defects Compensation
Suppression of aggressive shift in Vfb
Metal GateMgO
La2O3Si
58
Challenge for thinning High‐k
W/HfO2
µ eff
(cm
2 /Vs)
EOT (nm)
500 oC annealed
0.4 1.0 1.6
350
250
50
150
100
200
300
0W/La2O3 @300oC
W/La2O3Open: peak mobilityFill: 0.8MV/cm
EOT=0.5nm
1.41.20.80.6
500 oC annealedW/HfO2
µ eff
(cm
2 /Vs)
EOT (nm)
500 oC annealed
0.4 1.0 1.6
350
250
50
150
100
200
300
0W/La2O3 @300oC
W/La2O3Open: peak mobilityFill: 0.8MV/cm
EOT=0.5nm
1.41.20.80.6
500 oC annealed
µ eff( c
m2 /V
s)
050
100150200250300350
0 0.2 0.4 0.6 0.8 1.0
w/ Mg (EOT=1.09nm)
w/o Mg (EOT=1.04nm)
universal
µ eff( c
m2 /V
s)
050
100150200250300350
0 0.2 0.4 0.6 0.8 1.0
w/ Mg (EOT=1.09nm)
w/o Mg (EOT=1.04nm)
universal
PMA500oC
Metal GateMgO
La2O3Si
Degradation of mobility
Some solution
(5) µeff recovery with Mg incorportationVf
b(V
)
-0.5-0.4-0.3-0.2-0.1
00.10.2
0.8 1.0 1.2 1.4 1.6 1.8 2.0
w/ Mg
w/o Mg
PMA500oC
EOT (nm)µ ef
f( c
m2 /V
s)
050
100150200250300350
0 0.2 0.4 0.6 0.8 1.0
w/ Mg (EOT=1.09nm)
w/o Mg (EOT=1.04nm)
universal
µ eff( c
m2 /V
s)
050
100150200250300350
0 0.2 0.4 0.6 0.8 1.0
w/ Mg (EOT=1.09nm)
w/o Mg (EOT=1.04nm)
universal
PMA500oC
Eeff (MV/cm)
Incorprotation of Mg into La-silicate can recover the µeff
Suppression of Vfb shift at small EOT
µeff recovery
Mg incorporation into La-silicate
T. Koyanagi, K. Tachi, K. Okamoto, K. Kakushima, et al, Jpn. J. Appl. Phys., 48, 05DC02 (2009)
PreparationRoom
E-Beam Evaporation8 different target
Flash LampAnnealMicro to mille-seconds
Sputter for metal5 different target
Robot room
Cluster tool for high-k thin film deposition
61
Si Nanowire FET
62
Introduction of SiNW FETs
DrainDrain
SourceSource
GateGate
NanowireNanowire BOXBOX
DrainDrain
SourceSource
GateGate
NanowireNanowire BOXBOX
Effective electrostatic control of 1-D channel due to the gate all-around structure.
Low Ioff can be achieved.
Source DrainGate Gate
SourcePlanar FET
Multi Gate FET
Nanowire FETSource Drain
Gate
UTB SOI FET
63
Toward a Reduction of Power Supply Voltage
Gate Voltage (V)
Dra
in C
urre
nt (l
in.) Vd: high
Dra
in C
urre
nt (l
og.)
Vd: low
SiNW FET
Conventional FET
SiNW FET
Conventional FET
Higher drivability
Reduction of VDDand low power consumption
Lower IOFF
Vth Vth
Required ION can be achieved with lower overdrive voltage.
Capacity for reduction of Vth
required ION
1
10
100
1000
10000
0 1000 2000 3000 4000
bulkFinFETSiNWFETGeNWFETITRS(Planer)ITRS(SOI)ITRS(DG)
Bulk
DG
dia~3nm
dia~10nm
ITRS (SOI)
ITRS (DG)
ITRS(Bulk)
Si Nanowire
Ion (uA/um)
Ioff
(nA
/um
)
1
10
100
1000
10000
0 1000 2000 3000 4000
bulkFinFETSiNWFETGeNWFETITRS(Planer)ITRS(SOI)ITRS(DG)
1
10
100
1000
10000
0 1000 2000 3000 4000
bulkFinFETSiNWFETGeNWFETITRS(Planer)ITRS(SOI)ITRS(DG)
Bulk
DG
dia~3nm
dia~10nm
ITRS (SOI)
ITRS (DG)
ITRS(Bulk)
Si Nanowire
Ion (uA/um)
Ioff
(nA
/um
)Off Current
64
Nanowire FETNanowire FET
Nanowire FET
ITRS 2009
Multiple Gate (Fin)FET
Bulk → Fin → Nanowire
Siナノワイヤ
FinBulk or SOI
Si Nanowire
66
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
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
Quantum channelQuantum channel
Quantum channelQuantum channel
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
67
Maximum number of wires per 1 µm
Surrounded gate type MOS
Front gate type MOS 165 wires /µm
33 wires/µm
High-k gate insulator (4nm)Si Nano wire (Diameter 2nm)
Metal gate electrode(10nm)
Surrounded gate MOS
30nm
6nm6nm pitchBy nano-imprint method
30nm pitch: EUV lithograpy
68
Device fabrication
Si/Si0.8Ge0.2superlatticeepitaxy on SOI
Anisotropicetchingof these layers
Isotropicetchingof SiGe
Gate depositions S/D implantationSpacer formationActivation annealSalicidation
BOXSi
SiGeSi
SiGeSi
SiGeSiN
BOX BOX
BOX
Gate
BOX
Gate
Gate etchingStandardBack-Endof-LineProcess
HfO2 (3nm)TiN (10nm)Poly-Si (200nm)
C. Dupre et al.,IEDM Tech. Dig., p.749, 2008
7
SiN HM
Process Details :
The NW diameteris controllabledown to 5 nm by self limited oxidation.
( )
Cross-section
50nm
SiN HM
Wire direction : <110>50 NWs in parallel3 levels vertically-stackedTotal array of 150 wires EOT ~2.6 nm
NWs
8
3D-stacked Si NWs with Hi-k/MG
BOX
500 nm
Sou
rce
Dra
in
Gate
Top view
<110>
SiNW Band structure calculation
Cross section of Si NW
[001] [011] [111]D=1.96nm D=1.94nm D=1.93nm
First principal calculation,
Si nanowire FET with 1D Transport[001] [011] [111]0.86 0.94 0.89
OrientationDiameter (nm)
[001] [011] [111]3.00 3.94 1.93
OrientationDiameter (nm)
ZG G GZ ZWave Number
ZG G GZ ZWave Number
Ener
gy (e
V)
0
-1
0
1
Ener
gy (e
V)
0
-1
0
1
(a)
(b)
Small mass with [011]
Large number of quantum channels with [001]
10 nm diameter Si(100)NW( 2341 atoms)
20 nm diameter Si(100)NW ( 8941 atoms )
Atomic models of a Si quantum dot and Si nanowires
6.6 nm diameter SiQD( 8651 atoms)
2 6
26
( , , ) ( , , )n m nm
x y z C x m x y zx
ψ ψ=−
∂≈ + ∆
∂ ∑
1( ) ( ) ( ) ( )
Mesh
m n m i n ii
d x y zψ ψ ψ ψ=
≈ ∆ ∆ ∆∑∫ r r r r r
Real-Space Finite-DifferenceSparse MatrixFFT free (FFT is inevitable in the conventional plane-wave code)
Kohn-Sham eq. (finite-difference)
3D grid is divided by several regionsfor parallel computation.
Higher-order finite difference
Integration
MPI_ISEND, MPI_IRECV
MPI_ALLREDUCE
RSDFT – suitable for parallel first-principles calculation -
MPI ( Message Passing Interface ) library
)()()(ˆ)]([21 2 rrrr nnn
PPnlocs vv φεφρ =⎟
⎠⎞
⎜⎝⎛ ++∇−
CPU0
CPU8CPU7CPU6
CPU5CPU4CPU3
CPU2CPU1
Higher-order finite difference pseudopotential methodJ. R. Chelikowsky et al., Phys. Rev. B, (1994)
10-10
10-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
|Vnew-Vold|^2
50403020100iteration
Convergence behavior for Si10701H1996
e.g.) The system over 10,000 atoms → Si10701H1996(7.6 nm diameter Si dot)
Massively Parallel Computing
Computational Time (with 1024 nodes of PACS-CS)
6781 sec. × 60 iteration step = 113 hour
Based on the finite-difference pseudopotential method (J. R. Chelikowsky et al., PRB1994)
Highly tuned for massively parallel computers
Computations are done on a massively-parallel cluster PACS-CS at University of Tsukuba.
(Theoretical Peak Performance = 5.6GFLOPS/node)
with our recently developed code “RSDFT”
Iwata et al, J. Comp. Phys., to be publishedReal-Space Density-Functional Theory code (RSDFT)
Grid points = 3,402,059Bands = 22,432
1.0
0.9
0.8
0.7
0.6
0.5
(eV
)
-0.6
-0.4
-0.2
0.0
(eV
)
1.2
1.1
1.0
0.9
0.8
0.7
(eV
)
-0.8
-0.4
0.0
0.4
(eV
)
3.4
3.2
3.0
2.8
2.6
(eV
)
-1.5
-1.0
-0.5
0.0
0.5
(eV
)
1.0
0.8
0.6
0.4
0.2
0.0DO
S ( S
tate
s / e
V a
tom
)
-12 -10 -8 -6 -4 -2 0 2(eV)
1.0
0.8
0.6
0.4
0.2
0.0DO
S ( S
tate
s / e
V a
tom
)
-12 -10 -8 -6 -4 -2 0 2(eV)
1.0
0.8
0.6
0.4
0.2
0.0DO
S ( S
tate
s / e
V a
tom
)
-10 -8 -6 -4 -2 0 2 4 6(eV)
Band Structure and DOS of Si(100)NWs (D=1nm, 4nm, and 8nm)
D = 4 nmSi341H84(425 atoms)KS band gap = 0.81eV
D=4nm D=8nmD=1nm
D=8 nmSi1361H164 (1525 atoms) KS band gap=0.61eV
D=1 nmSi21H20(41 atoms)KS band gap=2.60eV
KS band gap of bulk (LDA) = 0.53eV
Band structure of 8-nm-diameter Si nanowire near the CBM
1.0
0.9
0.8
0.7
0.6
0.5
(eV
)
0.300.250.200.150.100.050.00
・KS band gap = 0.608 eV (@Γ)
kz
kx
ky
82 meV (96 meV)
kx
Each band is4-dgenerate. 23 meV (24 meV)
)()()(22 2
2
*
2
2
2
2
2
*
2
rr Φ−=Φ⎥⎦
⎤⎢⎣
⎡
∂∂
−⎟⎟⎠
⎞⎜⎜⎝
⎛∂∂
+∂∂
− CBMlt zmyxm
εεhh
Effective mass equation
The band structure can be understood thatelectrons near the CBM in the bulk Si are Confined within a cylindrical geometry.
Si12822H1544(14,366 atoms)・10nm diameter、3.3nm height、(100)・Grid spacing:0.45Å (~14Ry)・# of grid points:4,718,592・# of bands:29,024・Memory:1,022GB~2,044GB
Si12822H1544
Top View Side View
Si nano wire with surface roughness
SiNW Band compact model
Landauer Formalism for Ballistic FET
From xmax to xmin
[ ][ ]∑
⎭⎬⎫
⎩⎨⎧
−+−+
⎟⎟⎠
⎞⎜⎜⎝
⎛=
i BiD
BiSi
BD TkE
TkEgqTkGI
/)(exp1/)(exp1ln
0
00 µ
µ
µS
µD
xO xmax xmin
Qf
Qb
k
Energy
µSµD
E0
E1
E2min
E2max
qVD
E2min
Qf
Qb
0
5
10
15
20
25
30
35
40
0 0.1 0.2 0.3 0.4 0.5
Drain Bias (V)
Current (uA)
IV Characteristics of Ballistic SiNW FET
T=1KT=300K
Vg-Vt=1.0 V
0.7 V
0.3 V
0.05 V
Small temperature dependency35µA/wire for 4 quantum channels
Model of Carrier Scattering
ChannelOpticalPhonon
Initial ElasticZone
Optical PhononEmission Zone
ε~kBT
ε*
Source
TransmissionProbability : Ti
Elastic Backscatt.Elastic Backscatt.+(Optical Phonon Emission)
x00x
V(x)
F(0)
G(0)
Linear Potential Approx. : Electric Field E
TransmissionProbability to Drain
To Drain
0Drain fromInjection )0()0()0()(
=⎟⎟⎠
⎞−=
FGFT ε
Résumé of the Compact Model
.)( 0
G
bfStG C
qVV
+=
−−−
µµα
.
22
ln
2
⎪⎭
⎪⎬⎫
⎪⎩
⎪⎨⎧
−+
++=
oxox
oxox
oxG
ttrttr
Cεπ
0 1 1 ( ( ))( ) ( ) ( )1 exp 1 exp 1 exp
f b i i ii i S i S i D
B B B
q dkQ Q g T k dkk k kk T k T k T
επ ε µ ε µ ε µ
∞
−∞ −∞
⎤⎡ ⎧ ⎫⎥⎢ ⎪ ⎪
⎪ ⎪ ⎥⎢+ = − −⎨ ⎬ ⎥⎢ ⎧ ⎫ ⎧ ⎫ ⎧ ⎫− − −⎪ ⎪+ + + ⎥⎢ ⎨ ⎬ ⎨ ⎬ ⎨ ⎬⎪ ⎪⎢ ⎥⎩ ⎭ ⎩ ⎭ ⎩ ⎭⎣ ⎩ ⎭ ⎦
∑ ∫ ∫
.ln
2
⎟⎠⎞
⎜⎝⎛ +
=
rtr
Cox
oxG
επDDS qV=− µµ
Unknowns are ID, (µS-µ0), (µD-µ0), (Qf+Qb)
[ ]( , ) ( , )i s D ii
qI g f f T dε µ ε µ επ
= −∑ ∫h
( )0
00 0 0 0 0
2( )
2 ln
D qET
qExB D D qE mD Bε
εε
=+⎛ ⎞+ + + ⎜ ⎟
⎝ ⎠
PlanarGate
GAA
(Electrostatics requirement)
(Carrier distributionin Subbands)
I-VD Characteritics (RT)
Electric current 20~25 µANo satruration at Large VD
0
5
10
15
20
25
30
35
40
45
0 0.1 0.2 0.3 0.4 0.5 0.6
Drain Bias [V]
Current [uA]
VG-Vt=0.1V,Bal.
VG-Vt=0.1V,Qbal
VG-Vt=0.4V,Bal.
VG-Vt=0.4V,Qbal.
VG-Vt=0.7V,Bal.
VG-Vt=0.7V,Qbal.
VG-Vt=1.0V,Bal.
VG-Vt=1.0V,Qbal.
SiNW FET Fabrication
SiNW FET Fabrication
Sacrificial Oxidation
SiN sidewall support formation
Ni SALISIDE Process (Ni 9nm / TiN 10nm)
S/D & Fin Patterning
Gate Oxidation & Poly-Si DepositionGate Lithography & RIE EtchingGate Sidewall Formation
30nm
30nm
30nm
Oixde etch back
Standard recipe for gate stack formationBackend
(a) SEM image of Si NW FET (Lg = 200nm) (b) high magnification observation of gate and its sidewall.
88
Fabricated SiNW FET
30nm
Poly-Si
SiN
Nanow
ire
SiN support
SiNW
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
1 10 100 1000Gate Length (nm)
I ON
(µA
/ w
ire)
nMOSpMOS
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
(12)
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
1 10 100 1000Gate Length (nm)
I ON
(µA
/ w
ire)
nMOSpMOS
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
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
1 10 100 1000Gate Length (nm)
I ON
(µA
/ w
ire)
nMOSpMOS
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
(12)
本研究で得られたオン電流
(10x20)102µA
Our Work
Bench Mark
Bench MarkBench MarkThis work Ref[11] Ref[12] Ref[13] Ref[14] Ref[15] Ref[4]
NW Cross-section (nm) Rect. Rect. Rect. Cir. Cir. Elliptical Elliptical NW Size (nm) 10x20 10x20 14 10 10 12 13x20
Lg (nm) 65 25 100 30 8 65 35EOT or Tox (nm) 3 1.8 1.8 2 4 3 1.5
Vdd (V) 1.0 1.1 1.2 1.0 1.2 1.2 1.0Ion(uA) per wire 60.1 102 30.3 26.4 37.4 48.4 43.8
Ion(uA/um) by dia. 3117 5010 2170 2640 3740 4030 2592Ion(uA/um) by cir. 1609 2054 430 841 1191 1283 825
SS (mV/dec.) 70 79 68 71 75 ~75 85DIBL (mV/V) 62 56 15 13 22 40-82 65
Ion/Ioff ~1E6 >1E6 >1E5 ~1E6 >1E7 >1E7 ~2E5
Ref[11] by Stmicro Lg=25nm,Tox=1.8nmThis work Lg=65nm,Tox=3nm
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ナノワイヤFET
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
95
1. Increase of Inversion Carrier Density
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
97
Evaluation of Inversion carrier extracted using advanced split-CV measurement
Higher inversion carrier density was obtained with smaller dimensions.
The result of two-dimensional simulation in the previous slide supports these experimental results.
0.E+00
5.E-15
1.E-14
2.E-14
0 20 40 600 20 40 600
5
10
15 Th
e am
ount
of
Inve
rsio
n C
arrie
r@
V g-V
th=1
.0V
(fC)
(a)
0.E+00
5.E-07
1.E-06
2.E-06
2.E-06
0 20 40 60 80 100 1200 20 40 60 SOI 0
1
2
1.5
0.5
Inve
rsio
n C
arrie
rD
ensi
ty@
V g-V
th=1
.0V
(µC
/cm
2 )
(b)
Peripheral Length (nm)
A(10x9)
B(12x19)C(12x28) A(10x9)
B(12x19)
C(12x28)
(hNWxwNW)nm2 (hNWxwNW)nm2
Peripheral Length (nm) H. Irie et al., Solid State Devices and Materials, 2005.
64 channels
98
2. Enhancement of Effective Carrier Mobility
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 !
Our roadmap for R &D Source: H. Iwai, IWJT 2008
Current Issues
III-V & Ge NanowireHigh-k gate insulatorWire formation technique
CNT:
Width and Chirality control Growth and integration of CNT
Graphene:Graphene formation technique Suppression of off-current
Very small bandgap or no bandgap (semi-metal)
Control of ribbon edge structure which affects bandgap
Chirality determines conduction types: metal or semiconductor
100
Si NanowireControl of wire surface property
Compact I-V model
Source Drain contactOptimization of wire diameter
Brain Ultra small volumeSmall number of neuron cellsExtremely low power
Real time image processing(Artificial) Intelligence3D flight control
Sensor
InfraredHumidityCO2
Mosquito
Dragonfly is further highperformance
System andAlgorism becomes more important!
But do not know how?