EE115C – Winter 2007
Digital Electronic Circuits
Lecture 4:
MOS Capacitance
CMOS Manufacturing
EE115C – Winter 2007
2
Announcements
±
Starting next week: Wed (3-4pm) discussions
–
Moved to MS-5118
±
Homework #1 posted
–
Due Thu, Jan 25 @ 2pm
±
Seminar next Monday, Jan 22
–
54-134 Eng IV, 1-2pm
Extending and Expanding Moore's Law --
Challenges and Opportunities
Shekhar Borkar
Intel Microprocessor Technology Lab

This
** preview**
has intentionally

**sections.**

*blurred***to view the full version.**

*Sign up*EE115C – Winter 2007
3
Agenda
±
Last Lecture
–
Subthreshold MOS IV characteristics
●
Modes of Operation:
Off, Linear,
Velocity Saturation
, Saturation
–
MOS RC Model
±
Today
–
MOS Capacitances
–
Delay Analysis
EE115C – Winter 2007
4
MOS Transistor: Regions of Operation
Linear
Relationship
-4
0
0.5
1
1.5
2
2.5
0
0.5
1
1.5
2
2.5
x 10
Velocity
Saturation
V
DS
(V)
I
D
(A)
V
DS
= V
GT
V
DSAT
= V
GT
Saturation
Linear
V
DS
= V
DSAT
±
Define
V
GT
= V
GS
–V
T
V
DSAT
≈
L
·
ξ
c

EE115C – Winter 2007
5
B
D
G
I
D
S
()
DS
GT
D
V
V
V
V
L
W
k
I
⋅
+
⋅
−
⋅
⋅
⋅
=
λ
1
2
'
2
min
min
for
V
GT
≤
0:
I
D
=0
with
V
min
= min (
V
GT
,
V
DS
,
V
DSAT
)
for
V
GT
≥
0:
define
V
GT
=
V
GS
–
V
T
Regions of Operation:
Simply look at the Min function…
Sat Lin V-Sat
A Unified Model for Manual Analysis
EE115C – Winter 2007
6
Also Sub-Threshold Conduction…
Typical values for S:
60 – 100 mV/decade
The Slope Factor
ox
D
nkT
qV
D
C
C
n
e
I
I
GS
+
=
1
,
~
0
S
is
∆
V
GS
for
I
D
2
/
I
D
1
=10
0
0.5
1
1.5
2
2.5
10
-12
10
-10
10
-8
10
-6
10
-4
10
-2
V
T
Linear
Exponential
Quadratic
V
GS
(V)
I
D
(A)
0
11
GS
DS
qV
qV
nkT
kT
DD
S
II
e
e
V
−
=−
×
+
⋅

This
** preview**
has intentionally

**sections.**

*blurred***to view the full version.**

*Sign up*EE115C – Winter 2007
7
B
D
G
I
D
S
()
DS
GT
D
V
V
V
V
L
W
k
I
⋅
+
⋅
−
⋅
⋅
⋅
=
λ
1
2
'
2
min
min
for
V
GT
≤
0 (sub-V
TH
):
with
V
min
= min (
V
GT
,
V
DS
,
V
DSAT
)
for
V
GT
≥
0 (Lin, Sat, V-Sat):
define
V
GT
=
V
GS
–
V
T
Summary:
Deep Submicron MOS I-V Model
Sat Lin V-Sat
0
11
GS
DS
qV
qV
nkT
kT
DD
S
II
e
e
V
−
=−
×
+
⋅
EE115C – Winter 2007
8
.MODEL Parameters MOS1 (Basic Parameters)
±
.MODEL Modname NMOS/PMOS <VT0=
VT0
…>