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