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1
Basic MOSFET I-V characteristic(1/3)
• High circuit operation speed large ION
small Subthreshold Slope (SS)• Low power consumption small IOFF
(Silicon-on-insulator or Fully deplete device)
2
Basic MOSFET I-V characteristic(2/3)
• Linear region drain current • Large ION
small L (technology node) 14nm large mobility Ge , strained channel large COX (small EOT) High-K metal gate
3
Basic MOSFET I-V characteristic(3/3)
• Subthreshold slope (SS) the applied gate voltage difference when ION
has increases one order• Low large Cox (low EOT)
small CD (high channel doping or FINFET)
4
CMOS Technology Trend
22nm2011
2009
FinFETS
• Current Si-based technology scaling innovations▬ Mobility booster: Uniaxial Compressive Strain SiGe S/D for p-FET▬ Gate leakage reduction: High-k / Metal Gate▬ Short Channel Effect suppression: FinFETs
• High mobility substrate:
— Ge
55
Characteristics of (111) Ge n+/p Diodes
The high resistivity substrates have ideality factor (~ 1.1) but low on/off ratio.The high on/off ratio ~ 105 of low resistivity substrates is probably due to the reduction of diffusion current.
-2 -1 0 1 210-4
10-2
100
102
n~1.13~105
Dio
de
curr
ent(
A/c
m2)
Diode Voltage(V)
Substrate resistivity 0.05~0.3 ohm-cm 15~20 ohm-cm
n~1.26
5
66
Transfer and Output Characteristics of (111) Ge n-MOSFET
The S.S. is ~140mV/decade with on/off ratio ~ 8×104 for Is. Ideal output characteristics
-1.0 -0.5 0.0 0.5 1.0 1.5 2.010-5
10-4
10-3
10-2
10-1
100
101
Resistivity: 0.05~0.3 ohm-cm
VD=1V
VD=0.05V
S.S.~140 mV/decade
Drain current Source Current
Gate voltage (V)
Cu
rren
t (
A/
m)
~8X104
0.0 0.5 1.0 1.5 2.00
1
2
3
4
5
6
7
8
Vgs-Vt=0V
Vgs-Vt=2V
D
rain
cu
rren
t (
A/
m)
Drain voltage (V)
6
77
Effective Electron Mobility of (111) Ge n-MOSFET
The peak mobility reaches 2200 cm2/V-s owing to the suppression of Coulomb scattering using low doping Ge substrates.As substrate doping concentration increases, lower electron mobility is observed.
0.1100
1000
edge device
center device
Ge (111) n-MOSFET
Resistivity:15~20 ohm-cm (2x1014
cm-3)
Si universal
Resistivity:0.05~0.3 ohm-cm (1x1017
cm-3)
W=120mL=50mV
DS=50mV
@RT
0.5
Mo
bili
ty (
cm2 /V
s)
Electric field (MV/cm)
7