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

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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