MIT, Spring 2003

6.012 Microelectronic Devices and Circuits

Jesús del AlamoDimitri Antoniadis, Judy Hoyt, Charles SodiniPablo Acosta, Susan Luschas, Jorg Scholvin,

Niamh Waldron

Lecture 1 – 6.012 overview

February 4, 2003

• Contents:– Overview of 6.012

• Reading Assignment: – Howe and Sodini, Ch. 1

Overview of 6.012

• Introductory subject to microelectronic devices and circuits

• Microelectronics is cornerstone of:– Computer revolution– Communications revolution

1.E-06

1.E-04

1.E-02

1.E+00

1.E+02

1.E+04

1.E+06

1.E+08

1900 1920 1940 1960 1980 2000

Year

Cal

cula

tions

per

sec

ond/

$100

0

mechanicallogic

electromechanicallogic

vacuum tubelogic

discrete transistor logic

IC logicfrom R. Kurzweil in "The Age of Spiritual Machines ", 1999

In last 30 years, computer performance per dollar has improved more than a million fold!

Microelectronics:cornerstone of computing revolution

In last 20 years, communication bandwidth through a single optical fiber has increased by ten-thousand fold.

Microelectronics: cornerstone of communications revolution

Si digital microelectronics today

• A thick web of interconnects, many levels deep.

• High density of very small transistors.

Take the cover off a microprocessor. What do you see?

Intel’s Pentium IV

Interconnects

Today, as many as 8 levels of interconnect using Cu.

Transistor size scaling

0.1

1

10

1970 1975 1980 1985 1990 1995 2000Year

Tech

nolo

gy g

ener

atio

n (

µm

)

size of human blood cell

size of a virus

2-orders of magnitude reduction in transistor size in 30 years.

data for Intel processors

Evolution of transistor density

Moore’s Law: doubling of transistor density every 1.5 years

4-orders of magnitude improvement in 30 years.

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1970 1975 1980 1985 1990 1995 2000

Year

Num

ber o

f tra

nsis

tors

1.4x/year

Intel processors

2x/1.5year

Benefits of increasing transistor integration

• system performance

• cost-per-function,

• power-per-function, and

• system reliability.

Exponential improvements in:

Experimental SOI microprocessor from IBM

Clock speed

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1970 1975 1980 1985 1990 1995 2000

Year

Freq

uenc

y (H

z)

4-orders of magnitude improvement in 30 years.

Intel processors

Transistor cost

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1970 1975 1980 1985 1990 1995 2000

Year

Tran

sist

or c

ost (

$)

3-order of magnitude reduction in 30 years.

Intel processors

Cost per function

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1970 1975 1980 1985 1990 1995 2000

Year

$/M

Hz

Intel processors

4-order of magnitude reduction in 30 years.

Keys to success of digital microelectronics:I. Silicon

• Cheap and abundant

• Amazing mechanical, chemical and electronic properties

• Probably, the material best known to humankind

Keys to success of digital microelectronics:II. MOSFET

MOSFET = switchMetal-Oxide-Semiconductor

Field-Effect Transistor

Good gain, isolation, and speed

Keys to success of digital microelectronics:III. MOSFET scaling

1

10

100

1000

0.1 1 10

Gate length (µm)

Gat

e de

lay

(ps)

MOSFET performance improves as size is decreased:• Shorter switching time• Lower power

consumption

Keys to success of digital microelectronics:IV. CMOS

• “Complementary” switch activates with V<0.• Logic without DC power consumption.

CMOS: Complementary Metal-Oxide-Semiconductor

Keys to success of digital microelectronics:V. Microfabrication technology

• Tight integration of dissimilar devices with good isolation

• Fabrication of extremely small structures, precisely and reproducibly

• High-volume manufacturing of complex systems with high yield.

DSP core from IBM

Keys to success of digital microelectronics:VI. Circuit engineering

• Simple device models that:– are based on physics– allow analog and digital circuit design– permit assessment of impact of device variations on circuit

performance

• Circuit design techniques that:– are tolerant to logic level fluctuations, noise and crosstalk– are insensitive to manufacturing variations– require little power consumption

Content of 6.012

• Deals with microelectronic devices…– Semiconductor physics– Metal-oxide-semiconductor field-effect transistor

(MOSFET)– Bipolar junction transistor (BJT)

• … and microelectronic circuits– Digital circuits (mainly CMOS)– Analog circuits (BJT and MOS)

“One shouldn’t work on semiconductors, that is a filthy mess; who knows if they really exist!”

Wolfgang Pauli, 1931

“To the electron –

may it never be of any use to anybody.”

favorite toast at annual dinners at Cavendish Laboratory, early 1900’s