178
Strain-Engineered MOSFETs
mobility, N t is the volume oxide trap density, and E fn is the quasi-Fermi level.
By substituting the drain current expression, Equation (6.52) can be rewritten as
S f
kTW
f L
q
Q N E
( )
(
)
( )
I
s c eff s
t
fn
3
2
D
= λ
± λ µ
γ
(6.53)
S
ID (A
2
/Hz)
V gs = 0.7 V
V gs = 0.8 V
V gs = 1.2 V
V gs = 1.4 V
V gs = 1.6 V
10 2
Frequency (Hz)
10
–20
10
–19
10
–18
10
–17
10
3
FIGURE 6.20
Variation of drain current noise power spectral density of strained Si n-MOSFET with
W/L = 10 µm/1 µm at V ds = 0.05 V.
0.0
10
–25
10
–24
10
–23
10
–22
10
–21
S
ID (A
2
/Hz)
10
–20
10
–19
10
–18
10
–17
0.5
V gs (V)
1.0
1.5
W = 10 µm L = 1 µm
W = 5 µm L = 1 µm
W = 10 µm L = 2 µm
2.0
FIGURE 6.21
Variation of drain current noise power spectral density for three devices with W/L =
10 µm/1 µm, W/L = 5 µm/1 µm, and W/L = 10 µm/2 µm at V ds = 0.05 V and f = 150 Hz.