1.introduction vlsi
TRANSCRIPT
-
7/28/2019 1.Introduction VLSI
1/59
1bkdas
VLSI Technology
by
SANKHA CHAKRAPAREEK
-
7/28/2019 1.Introduction VLSI
2/59
2bkdas
Introduction (Lecture 1)
History of VLSI
MOS Transistor - Introduction
Transistor scaling and Moores law - BKD
VLSI Technology
MOS Technology (Lecture 2 & 3) MOS Transistor Characteristics and Short Channel Effects
Fabrication of CMOS structure
VLSI Design (Lecture 4 & 5)
Complexities involved and key design issues
VLSI Design flow (analog, digital, RF, CPLD, FPGA)
Role of design engineer in IC industry
Manufacturing trends & ITRS Roadmap
-
7/28/2019 1.Introduction VLSI
3/59
3bkdas
Introduction to VLSI
(Lecture 1)
Sources:
International TechnologyRoadmap For Semiconductors -http://public.itrs.net/
INTEL-
http://www.intel.com/technology/silicon/index.htm
-
7/28/2019 1.Introduction VLSI
4/59
4bkdas
High
Low
FailureR
ate
Cost
1 mm
1-5 nm High
Low
Minimum
FeatureSize
Complex
ity
1930-
1950s
1960s
1970-90
VACUUM TUBES
SEMICONDUCTOR BASEDTRANSISTORS
PLANAR TRANSISTORS
ICs LSI, VLSI
SMART STRUCTURES (MEMS)1995-
NANO STRUCTURES
2010-
-
7/28/2019 1.Introduction VLSI
5/59
5bkdas
First Computer
The BabbageDifference Engine
(1832)
25,000 parts
cost: 17,470
-
7/28/2019 1.Introduction VLSI
6/59
6bkdas
ENIAC - The First Electronic Computer
(1946)
-
7/28/2019 1.Introduction VLSI
7/59
7bkdas
First TransistorPoint Contact Germanium Transistor
Shockley, Brattain & Bardeen - Bell Labs, 1948
Nobel Prize - 1956
-
7/28/2019 1.Introduction VLSI
8/59
8bkdas
Planar Process
p-n Junction Formation
p-Si
oxidise Lithography Etch P-Diffuse
n-SiMask
Light
n+
p-Si
ox
p+
p n+
n n
n+
b e c
Bipolar transistor
-
7/28/2019 1.Introduction VLSI
9/59
9bkdas
First Integrated Circuits
First IC Jack Kilby, 1958, Texas
Instruments, Nobel Prize 2000
-
7/28/2019 1.Introduction VLSI
10/59
10bkdas
Early Integrated Circuits
Bipolar logic
1960s
ECL 3-input Gate
Motorola 1966
-
7/28/2019 1.Introduction VLSI
11/59
11bkdas
Intel 4004 Micro-Processor
1971
1000 transistors
1 MHz operation
-
7/28/2019 1.Introduction VLSI
12/59
12bkdas
IC Processor
INTEL Pentium IV IBM Corp. Power PC
-
7/28/2019 1.Introduction VLSI
13/59
13bkdas
INTEL Montecito 90nm1.72 billion transistors
INTEL Prescot 90nm125 million transistors
IC Processor
-
7/28/2019 1.Introduction VLSI
14/59
14bkdas
0.57 m2 cell size
>0.5 billion transistors
110 mm2 chip size
Fully functional 70 Mbit
SRAM chips have been
fabricated.
IC SRAM Chip
-
7/28/2019 1.Introduction VLSI
15/59
15bkdas
Transistor Shockley, Brattain &Bardeen (Bell
Labs) in 1948 NL 1956
Bipolar transistor Schockley in 1949First bipolar digital logic gate Harris in 1956
First monolithic IC Jack Kilby in 1958 NL 2000
First commercial IC logic gates Fairchild 1960
TTL1962 into the 1990s
ECL1974 into the 1980s
Evolution of
Integrated Circuits
-
7/28/2019 1.Introduction VLSI
16/59
16bkdas
Transistor Bardeen et al.(Bell Labs) in 1947
MOSFET transistor - Lilienfeld (Canada) in 1925
and Heil (England) in 1935
CMOS1960s, but plagued with manufacturingproblems
PMOS in 1960s (calculators)
NMOS in 1970s (4004, 8080) for speed
CMOS in 1980s preferred MOSFET technology
because of power benefits
BiCMOS, Gallium-Arsenide, Silicon-Germanium
SOI, Copper-Low K,
Evolution of Integrated
Circuits
-
7/28/2019 1.Introduction VLSI
17/59
17bkdas
Integrated Circuits
SSI Small Scale Integrated CircuitsLess than 10 gates e.g., 7404 inverter
MSI Medium Scale Integrated Circuits
Less than 1000 gates e.g., 74161 counter
LSI Large Scale Integrated CircuitsLess than 10,000 gates e.g., 8bit -
processor
VLSI Very Large Scale Integrated Circuitsmore than 10,000 gates e.g., 64bit -
processor
-
7/28/2019 1.Introduction VLSI
18/59
18bkdas
MOS Structure
metal orn+- polysilicon
p-silicon
+
+
+
+
+
+
+
+
+
oxide
Gate charge
Depletion layer charge
or Bulk charge
In a metal-oxide-silicon structure, a depletion layer
forms below the metal gate. For p-type silicon
substrate, a positive charge develops on metal side
and depletion layer is negatively charged.
-
7/28/2019 1.Introduction VLSI
19/59
19bkdas
MOS Structure
M O p-Si
++++
Accumulation,VGB VT
++++
+
+++
++++
Depletion0 < VGB < VT
-
7/28/2019 1.Introduction VLSI
20/59
20bkdas
MOS Transistor
p- Si
n+ poly-Si
n+ n+
depletion
region
VG
VD
Wdep n-channel
Gate
Drain
Source
VS
L channel length
oxide
-
7/28/2019 1.Introduction VLSI
21/59
21bkdas
NMOS transistor (NMOSFET) behaves as a resistor when VDS is low: Drain current I
Dincreases linearly with V
DS
Resistance RDS
between SOURCE & DRAIN depends on VGS
RDS
is lowered as VGS
increases above VT
NMOS Transistor
-
7/28/2019 1.Introduction VLSI
22/59
22bkdas
VDS= VGSVT Inversion-layer is pinched-offat the drain end
VGS
> VT
: Pinch-off
Electrons are swept into the drain by the E-field when theyenter the pinch-off region and saturation occurs.
NMOS Transistor
-
7/28/2019 1.Introduction VLSI
23/59
23bkdas
MOS Transistor
Cut-off :
Linear region :
Saturation :
Back gate effect :
DST
DS
GSoxnD V)V2
V
V(CL
W
I
0ID
2
TGSoxnD )VV(CL2
WI
)2V2()0V(V)V(V pBSpBSGS
TBS
GS
T
0
1
2
3
4
5
6
0 0.5 1 1.5 2 2.5
VDS (V)
X 10-4
VGS = 1.0V
VGS = 1.5V
VGS = 2.0V
VGS = 2.5V
Linear Saturation
VDS = VGS - VT
cut-
off
-
7/28/2019 1.Introduction VLSI
24/59
24bkdas
Without a gate voltage applied, no current can flow
between the source and drain regions.
Above a certain gate-to-source voltage (thresholdvol tageVT), a conducting layer of mobile electrons isformed at the Si surface beneath the oxide. These
electrons can carry current between the source and drain.
G
NMOS Transistor
n
p
oxide insulatorgate
n
D
S
-
7/28/2019 1.Introduction VLSI
25/59
25bkdas
MOSFET as a Resistive Switch
For digital circuit applications, the MOSFET is eitherOFF (VGS< VT) or ON (VGS= VDD). Thus, we only need
to consider two IDvs. VDScurves:
1. the curve forVGS< VT
2. the curve forVGS= VDD
ID
VDS
VGS= VDD (closed switch)
VGS< VT (open switch)
Req
-
7/28/2019 1.Introduction VLSI
26/59
26bkdas
For current to flow, VGS > VT
Enhancement mode: VT > 0 Depletion mode: VT < 0
Transistor is ON when VG=0V
For current to flow, VGS < VT
Enhancement mode: VT
< 0
Depletion mode: VT > 0
Transistor is ON when VG=0V
NMOS & PMOS Transistor
p-type Si
n+ poly-Si
NMOS
n+ n+
n-type Si
p+ poly-Si
PMOS
p+ p++ + + + +
-
7/28/2019 1.Introduction VLSI
27/59
27bkdas
As compared to an n-channel MOSFET, the signs of all the voltages
and the currents are reversed:
PMOS Transistor
-
7/28/2019 1.Introduction VLSI
28/59
28bkdas
W
L
MOS
TransistorStructure
-
7/28/2019 1.Introduction VLSI
29/59
29bkdas
Source
DrainGate (contact not shown)
MOS Structure
-
7/28/2019 1.Introduction VLSI
30/59
30bkdas
Transistor
for 90nm
process
InProduction
MOS Structure
After Intel Corp
-
7/28/2019 1.Introduction VLSI
31/59
31bkdas
After Intel Corp
After Intel Corp
Transistor Scaling
-
7/28/2019 1.Introduction VLSI
32/59
-
7/28/2019 1.Introduction VLSI
33/59
33bkdas
Generation:
Intel386 DXProcessor
Intel486 DX
Processor
PentiumProcessor
Pentium IIProcessor
1.5 1.0 0.8 0.6 0.35 0.25
Benefit of Transistor Scaling
smaller chip area lower cost
more functionality on a chip better system performance
-
7/28/2019 1.Introduction VLSI
34/59
34bkdas
Moores Law
In 1965, Gordon Moore predicted that thenumber of transistors that can be integrated on
a die would double every 18 to 14 months (i.e.,
grow exponentially with time).
Amazingly visionary million transistor/chip
barrier was crossed in the 1980s.
2300 transistors, 1 MHz clock (Intel 4004) - 1971
16 Million transistors (Ultra Sparc III)
42 Million, 2 GHz clock (Intel P4) - 2001
140 Million transistor (HP PA-8500)
-
7/28/2019 1.Introduction VLSI
35/59
35bkdas
40048008
80808085 8086
286386
486Pentium procP6
0.001
0.01
0.1
1
10
100
1000
1970 1980 1990 2000 2010
Year
Transistors(M
T)
2X growth in 1.96 years!
Transistors on lead microprocessors double every 2 years
Courtesy, Intel
Moores Law
-
7/28/2019 1.Introduction VLSI
36/59
36bkdas
Moores Law
90 nm Montecito processor breaks through billion transistor
mark ahead of trend line with 1.72B transistors
After Intel Corp
-
7/28/2019 1.Introduction VLSI
37/59
37bkdas
64
256
1,000
4,000
16,000
64,000
256,000
1,000,000
4,000,000
16,000,000
64,000,000
10
100
1000
10000
100000
1000000
10000000
100000000
1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 2010
Year
K
bitcapacity/
chip
1.6-2.4 m
1.0-1.2 m
0.7-0.8 m
0.5-0.6 m
0.35-0.4 m
0.18-0.25 m
0.13 m
0.1 m
0.07 m
encyclopedia2 hrs CD audio30 sec HDTV
book
page
4X growth every 3 years!
DRAM Chip
human memoryhuman DNA
Moores Law
-
7/28/2019 1.Introduction VLSI
38/59
38bkdas
Moores Law
Processor power will keep doubling every two years.
After Intel Corp
-
7/28/2019 1.Introduction VLSI
39/59
41bkdas
Moores Law
Transistor physical gate length will reach ~15 nm beforeend of this decade, and ~10 nm early next decade.
After Intel Corp
-
7/28/2019 1.Introduction VLSI
40/59
42bkdas
After Intel Corp
Moores Law
-
7/28/2019 1.Introduction VLSI
41/59
43bkdas
Moores Law
After Intel Corp
-
7/28/2019 1.Introduction VLSI
42/59
44bkdas
40048008
80808085
8086286
386486Pentium proc
P6
1
10
100
1970 1980 1990 2000 2010
Year
Diesize(mm)
~7% growth per year
~2X growth in 10 years
Die size grows by 14% to satisfy Moores Law
Courtesy, Intel
Moores Law
Die Size
-
7/28/2019 1.Introduction VLSI
43/59
45bkdas
Lead microprocessors frequency doubles every 2 years
P6Pentium proc
486386
28680868085
8080
80084004
0.1
1
10
100
1000
10000
1970 1980 1990 2000 2010
Year
Frequency(Mhz)
2X every 2 years
Courtesy, Intel
Moores Law
Clock Frequency
-
7/28/2019 1.Introduction VLSI
44/59
46bkdas
Lead Microprocessors power continues to increase
P6Pentium proc
486
3862868086
80858080
80084004
0.1
1
10
100
1971 1974 1978 1985 1992 2000Year
Power(Watts)
Courtesy, Intel
Power delivery and dissipation will be prohibitive
Moores Law
Power Dissipation
-
7/28/2019 1.Introduction VLSI
45/59
47bkdas
40048008
8080
8085
8086
286386
486
Pentium procP6
1
10
100
1000
10000
1970 1980 1990 2000 2010
Year
PowerDensity(W/cm2)
Hot Plate
Nuclear
Reactor
Rocket
Nozzle
Power density too high to keep junctions at low temp
Courtesy, Intel
Moores Law
Power Density
-
7/28/2019 1.Introduction VLSI
46/59
49bkdas
1.E-07
1.E-05
1.E-03
1.E-01
1.E+01
68 72 76 80 84 88 92 96 00 04
Year
CostUS$/t
ransistor
Moores Law
Moores Law meansDecreasing Costs:Packing more transistors into
less space has dramatically
reduced their cost and the cost
of the products they populate.
-
7/28/2019 1.Introduction VLSI
47/59
51bkdas
Lithography
Node (nm)
250 180 130 90 65 45
Process P856 P858 Px60 P1262 P1264 P1266
Ist Year ofProduction
1997 1999 2001 2003 2005 2007
Gate Length
(nm)
200 130
-
7/28/2019 1.Introduction VLSI
48/59
52bkdas
Transistor
for 90nm
process
InProduction
Moores Law
After Intel Corp
-
7/28/2019 1.Introduction VLSI
49/59
53bkdas
Moores Law
15nm Research Transistor
After Intel Corp
-
7/28/2019 1.Introduction VLSI
50/59
54bkdas
Moores Law130 nm node
70 nm length
Production-2001
90 nm node
50 nm length
Production-2003
65 nm node
30 nm length
Production-2005
45 nm node
20 nm lengthProduction-2007
32 nm node
15nm length
Production-2009
After Intel Corp
-
7/28/2019 1.Introduction VLSI
51/59
55bkdas
Moores Law - Future
Future High-k Dielectricfor Reduced Gate Leakage
30nm Tri-gate Transistor
After Intel Corp
-
7/28/2019 1.Introduction VLSI
52/59
56bkdas
Silicon Nanowires
Source: Morales & Lieber,Science 279, 280 (1998)
Moores Law - Future
After Intel Corp
-
7/28/2019 1.Introduction VLSI
53/59
57bkdas
Moores Law - Future
Intel SiliconOptical ModulatorConvergence of
silicon and optical
communications
MEMS-basedRF Switches
After Intel Corp
-
7/28/2019 1.Introduction VLSI
54/59
58bkdas
Processed Silicon Wafer in 2000
-
7/28/2019 1.Introduction VLSI
55/59
59bkdas
Why Scaling? Technology shrinks by ~0.7 per generation
With every generation can integrate 2x more functions ona chip; chip cost does not increase significantly
Cost of a function decreases by 2x
But How to design chips with more and more functions?
Design engineering population does not double every two
years Hence, a need for more efficient design methods
Exploit different levels of abstraction
Moores Law & IC Design
-
7/28/2019 1.Introduction VLSI
56/59
60bkdas
Design Levels
n+n+
S
GD
+
DEVICE
CIRCUIT
GATE
MODULE
SYSTEM
-
7/28/2019 1.Introduction VLSI
57/59
-
7/28/2019 1.Introduction VLSI
58/59
62bkdas
Investment into IC Manufacture
-
7/28/2019 1.Introduction VLSI
59/59
IC Manufacture Trend
Source ITRS