Engineering materials for electrical engineers

Introduce fundamental concepts in Materials Science and how they are used in ECE You will learn about: • material structure • how structure dictates properties • how electronic & physica

ECE 331: Introduction to Materials for

Electrical Engineers

Course Objective

Introduce fundamental concepts in Materials Science and how they are used in ECE

You will learn about:

• material structure

• how structure dictates properties

• how electronic & physical properties are related

This course will help you to:

• use materials properly

• realize new design opportunities with materials

• understand the physics of semiconductor devices

ECE 331 – Intro to Materials for ECE

Materials in ECE are: semiconductors, metals (e.g

Al contacts), polymers (e.g encapsulants for LEDs) and insulators (ceramics such as silicon dioxide in FETs))

Materials in ECE are single crystals, polycrystals,

amorphous layers and nanostructures

Si electronics is the world’s largest manufacturing industry), but it is the most important one and will

ECE331 Wi11 lecture 1

remain so!

ECE 331 – Intro to Materials for ECE

III-V examples

GaAs

InP

InAs

AlGaAs

InGaAs

InGaAsP

G N

InGaN

III - V

•Know your periodic table!

•Find your old chemistry notes!

Materials Roadmap for Device Technologies: the

Bandgap vs Lattice Constant Relationship

III-V electronics

ECE applications are

expanding across

III V electronics

CD Lasers Fiber pump lasers Space solar

expanding across this entire space!

CMOS BiCMOS

CMOS, BiCMOS,

Terrestrial solar,

Power CMOS

Telecomm Optoelectronics thermophotovoltaics

ECE331 Wi11 lecture 1

TECHNOLOGY ROADMAPS:

New Age for ECE Materials and opportunities

• Electronics:

Roadmaps are calling for unusual properties not

obtainable using conventional materials or processes

• Electronics:

- Nanoscale patterning

- optical interconnects

- speed enhancing materials

• Optoelectronics: Optoelectronics:

- tunable light emission/detection wavelengths

- seamless integration with electronic systems

• Alternative Energy:

- clean, renewable, cheap, safe, autonomous

- Biocompatiblity and medicine

The Materials Selection Process

1 Pick Application Determine required Properties

Properties: mechanical, electrical, thermal, magnetic, optical, deteriorative.

2 Properties Identify candidate Material(s)

Material: structure, composition.

3 Material Identify required Processing

Processing: changes structure and overall shape

ex: casting, sintering, vapor deposition, doping

forming, joining, annealing.

ECE331 Wi11 lecture 1

• Electrical Resistivity of Copper:

Adapted from Fig 18.8, Callister 7e.

(Fig 18.8 adapted from: J.O Linde,

Ann Physik 5, 219 (1932); and

C.A Wert and R.M Thomson,

Physics of Solids, 2nd edition,

McGraw-Hill Company, New York,

1970 )

4

5

2

3

sistivit -8 0

Ohm-1

2

e (1 0

0

• Adding “ impurity ” atoms to Cu increases resistivity.

T (°C)

0

• Space Shuttle Tiles:

Silica fiber insulation

of Copper:

decreases when you add zinc!

Adapted from chapter-opening photograph,

300 200

Chapter 19, Callister

7e (Courtesy of

Lockheed Missiles and Space Company, Inc.)

100

0

Adapted from

Fig 19.4W, Callister

6e (Courtesy of

Lockheed Aerospace

Adapted from Fig 19.4, Callister 7e.

(Fig 19.4 is adapted from Metals Handbook:

Properties and Selection: Nonferrous alloys

Composition (wt% Zinc)

ECE331 Wi11 lecture 1

Ceramics Systems, Sunnyvale, CA) (Note: "W" denotes fig is on CD-ROM.)

and Pure Metals, Vol 2, 9th ed., H Baker,

(Managing Editor), American Society for Metals, 1979, p 315.)

100 mm

• Magnetic Permeability

vs Composition:

• Magnetic Storage:

Recording medium

Adding 3 atomic % Si makes Fe a better

recording medium!

is magnetized by recording head.

g

Fe+3%Si F

Adapted from C.R Barrett, W.D Nix, and

A.S Tetelman, The Principles of

Engineering Materials, Fig 1-7(a), p 9,

Fig 20.23, Callister 7e.

(Fig 20 23 is from J U Lemke MRS Bulletin

Magnetic Field

Engineering Materials, Fig 1 7(a), p 9,

1973 Electronically reproduced

by permission of Pearson Education, Inc., Upper Saddle River, New Jersey.

(Fig 20.23 is from J.U Lemke, MRS Bulletin,

Vol XV, No 3, p 31, 1990.)

• Transmittance:

Aluminum oxide may be transparent, translucent, or

opaque depending on the material structure

single crystal

polycrystal:

low porosity

high porosity

Adapted from Fig 1.2,

Callister 7e.

(Specimen preparation, P.A Lessing; photo by S Tanner )

ECE331 Wi11 lecture 1

Tanner.)

Photovoltaics and the role of materials

Conversion of radiant heat to electricity:

Thermophotovoltaics

Interconnect Grid Finger

Front Contact

p

n InPAs window

p InPAs BSF

S i I l ti I P

n InPAs Buffer

p/n InGaAs TJ

n/p InGaAs Emitter/Bas e

Semi-Insulating InP SiN/Gold Back Surface Reflector

23

SEM Micrograph Of Processed Ternary

MIM Structure

19 20 21 22 23

26.7°C 26.7°C

25.6°C

• Efficiency ~18%

• With addition of a a front

surface filter

15 16 17 18 19

25.6°C

surface filter

– 0.9 W/cm 2 power density

- h = 20.6% at a radiator temperat re of 1058°C 850 900 950 1000 1050 1100

Radiator Temperature (°C )

temperature of 1058°C.

Wide Bandgap Semiconductors – GaN:

Energy-Efficient Solid State Lighting (SSL) gy g g ( )

• Al-Ga-In-N spans uv-blue-green-red-near ir spectrum

50% of elec used by lighting:

National SSL Initiative: by 2020:

• save $115B

ECE331 Wi11 lecture 1

50% of elec.used by lighting: • eliminate 258M metric ton of C

emission

• Use the right material for the job

Course Goals:

• Use the right material for the job.

• Understand the relation between properties, structure, and processing.

• Recognize new design opportunities offered

by materials selection.

• Appreciate the relationship between devices

• Appreciate the relationship between devices, their characteristics and their constituent materials