Introduction to ICs and Transistor Fundamentals
Brief History Transistor Types Moore’s Law Design vs Fabrication
First Programmable Electronic Computer
Electrical Numerical Integrator and Calculator (ENIAC) is created by the US army in 1947
Build out of 18,000 vacuum tubes, ENIAC consumed 200kW and suffered a failure on average every 6 hours
A Brief History 1958: First integrated circuit
Flip-flop using two transistors Built by Jack Kilby at Texas Instruments
2003 Intel Pentium 4 mprocessor (55 million transistors) 512 Mbit DRAM (> 0.5 billion transistors)
2006 Intel Duo Core mprocessor (151 million transistors)
55% compound annual growth rate over 48 years No other technology has grown so fast so long
Driven by miniaturization of transistors Smaller is cheaper, faster, lower in power! Revolutionary effects on society
Annual Sales
1018 transistors manufactured in 2003 100 million for every human on the planet
0
50
100
150
200
1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002
Year
Global S
emiconductor B
illings(B
illions of US
$)
VLSI Applications VLSI is an implementation technology for electronic
circuitry - analogue or digital
It is concerned with forming a pattern of interconnected switches and gates on the surface of a crystal of semiconductor
Microprocessors personal computers Microcontrollers Memory - DRAM / SRAM Special Purpose Processors - ASICS (CD players, DSP
applications) Optical Switches
Has made highly sophisticated control systems mass-producable and therefore cheap
Invention of the Transistor
Vacuum tubes ruled in first half of 20th century. Large, expensive, power-hungry, unreliable
1947: first point contact transistor
First Transistor and Integrated Circuit The first transistor used germanium and was
created by a team lead by William Shockley at Bell Labs in 1947
Shockley later shared the Noble prize in physic for his work on the transistor
Shockley semiconductor was founded in Palo Alto in 1955. Bob Noyce and Gordon Moore were hired by Shockley to being work on a silicon transistor
In 1957, Noyce, Moore and 6 others leave to found Fairchild semiconductor
The first IC proposed independently by Bob Noyce at Fairchild and Jack Kilby at Texas Instruments in 1959
TI used germanium while Fairchild used silicon with incorporated wires
In 1968 Noyce and Moore leave Fairchild to found Intel. Intel is short for INTegrated ELectronics
Transistor Types Bipolar junction transistors (BJT)
npn or pnp silicon structure Small current into very thin base layer
controls large currents between emitter and collector
Base currents limit integration density
Cont..
Field Effect Transistors (FET) n-channel FET and p-channel FET Also known as unipolar transistor Operates on the principle that
semiconductor conductivity can be increased or decreased by the presence of electric field
Cont…
MOS transistor Metal Oxide Semiconductor Field Effect
Transistors (MOSFET) Complementary Metal Oxide Semiconductor
(CMOS)
Cont…
MOSFET nMOS and pMOS MOSFETS Voltage applied to insulated gate controls
current between source and drain Low power allows very high integration
Cont…
CMOS Uses complementary and symmetrical pairs
of p-type and n-type MOSFETs for logic functions
Extremely useful for digital circuitry design (act as a simple switches w/o having pull-up resistors)
Main advantage : much smaller power dissipation
Cont…
CMOS operation (NMOS)
Cont…
CMOS operation (PMOS)
Cont…
Complementary MOS (CMOS)
D
G G
S
D
D
S
NMOS PMOS
BG
D
S
G
S
D
B
NMOS with bulk contact PMOS with bulk contact
G = GateD = DrainS = SourceB = Bulk
OutIn
VDD
PMOS
NMOS
CMOS inverter circuit
1970’s processes usually had only nMOS transistors Inexpensive, but consume power while idle
1980s-present: CMOS processes for low idle power
MOS Integrated Circuits
Intel 1101 256-bit SRAM Intel 4004 4-bit Proc
The integrated circuit from an Intel 8742, an 8-bit microcontroller that includes a CPU running at 12 MHz, 128 bytes of RAM, 2048 bytes of EPROM, and I/O in the same chip.
Intel Duo Core processor, CPU speed max 3 GHz with almost 2 billion transistors
Moore’s Law 1965: Gordon Moore plotted transistor
on each chip Transistor counts have doubled every 18 - 24
months As of 2006, chip areas range from a few square
mm to around 350 mm2, with up to 1 million transistors per mm2. Integration
Levels
SSI: 10 gates
MSI: 1000 gates
LSI: 10,000 gates
VLSI: > 10k gates
Fit straight line on semilog scale
Moore's Law
Intel 4004 (1971)108 KHz2300 Transistors10um Technology
Pentium 42 GHz>40,000,000 Transistors0.18um Technology
Empirical Evidence of Moore’s Law
Integrated Processor: Starting with Intel's 486 processor series, cache memory is included Increase in the number of transistors Integrated processor chips - L1 cache + L2 cache. Multi-chip package: Pentium Pro and Pentium II L2 added in the same silicon from 2nd Gen Celeron processors.
Computer clock frequency and the number of instructions per second (MIPS) keep increasing but have become very inaccurate indicators of processor power. parallel processing is used in many alternative forms.
Two important numbers in wafer fabrication: wafer size and feature size Wafer size increase to enable higher volume capacity Features size reduced to enable more die/chip per wafer
Advantage of integration's economies of scale more and more of the circuit's components onto one die cost/integration curve begins to drop as integration increases. at some point the effects of defect density kick in and drive costs up more transistors increase the power density of the chip.
Add more functionality (or complexity) to the die Reduce the size of the die while keeping the same functionality/complexity. Shrinking of features size
improve the processor's clock speed or lower its power dissipation
Corollaries Many other factors grow exponentially
Ex: clock frequency, processor performance
Year
1
10
100
1,000
10,000
1970 1975 1980 1985 1990 1995 2000 2005
4004
8008
8080
8086
80286
Inte l386
Inte l486
Pentium
Pentium Pro/II/III
Pentium 4
Clock S
peed (MH
z)
Design versus Fabrication Design
Inexpensive Software based Small setup
area Related with
design skill
Fabrication Costly Hardware and
software based Huge setup
area Related with
chemical process