Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L L/α...

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Roadmap of Microelectronic Industry

Transcript of Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L L/α...

Page 1: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Roadmap of Microelectronic Industry

Page 2: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Scaling of MOSFET

Reduction of channel length L L/α

Integration density α2

Speed α; Power/device 1/α2

Power density unchanged; Voltage 1/α

Equivalent thickness of gate oxide 1/

Page 3: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Gate Dielectric film in ULSI MOSFET

p-Si

n+ n+

GateGate oxide

Page 4: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Equivalent Gate Oxide Thickness

tEq= tx SiO2/x

x: dielectric constant of insulator X

SiO2 = 3.2

Use high-x insulator

Page 5: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Possible epitaxial dielectric films on

Si r

On Si(100)(rectangular)

On Si(111)(triangular)

Si3N46-9 amorphous Hex., a = 7.6 Å,

mismatch 1%, 900°C

-Al2O3 9 Cubic, a = 7.91Å mismatch 3.5%, 800°C

Same as on (100)

CeO226 Cubic, a = 5.45 Å

mismatch 0.4%, < 550°C Same as on (100)

ZrO2

(Y-stb)

25 Cubic, a ~ 5.2 Å mismatch 3%, 730°C

?

HfO225 Amorphous Amorphous

Page 6: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Metallization target parameters

(current)

Page 7: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Electromigration EffectsVoid Pile-up

Electron wind and field-driven atomic migration

Page 8: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Lower levels: fine connections to individual devices

Upper levels: thicker/wider common connections

Cu metallization: reducing wire resistance

Low-k dielectrics: reducing parasitic capacitance

RC delay issue

Multi-level Metallization

Page 9: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Lithography: shorter wavelength (deep UV, X-

ray, electron/ion beams) source, optics, resist materials

Gate insulator: with high dielectric constant (high-k), high dielectric strength, effective barrier to impurity (e.g., B) migration

Si-on-insulator (SOI): reducing capacitive coupling between devices, power consumption, effective heat dissipation

Page 10: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Double-gate FET

Double-gate FET by selective epitaxial growth

Page 11: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Single-electron Tunneling (SET) TransistorCoulomb blockade effect

Devices based on quantum effects in nano-structured materials

quantum dots/wire, nano-wires (e.g., carbon nanotubes), molecular devices, …

Page 12: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Index of Single-wall Carbon Nanotubes

(SWNT)

Armchair (n, n)

 

Zigzag (n, 0)

General (m, n)

Page 13: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Electronic properties of SWNTs

SWNTs: 1D crystal

If m - n = 3q metallic

Otherwise semiconductor

Zigzag, dt = 1.6nm

=18, dt = 1.7nm

=21, dt = 1.5nm

=11, dt = 1.8nm

Armchair, dt = 1.4nm

STM I-V spectroscopy

Bandgap of semiconducting SWNTs:

tdCCat

gE

= 1.42 Å, 5.4 eV, overlap integral

CCa t

Page 14: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Doping of semiconductor SWNTs

N, K atoms n-type; B atoms, oxygen p-type

SWNT CMOS inverter & its characteristics

SWNT Transistors

Page 15: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Molecular diodes and nonlinear devices

Molecule with D--A structure C16H33Q-3CNQ

Highly conductive zwitterionic D+--A- state at 1-2V forward bias Reverse conduction state D---A+ requires bias of 9V

I-V curve of Al/4-ML C16H33Q-3CNQ LB

film/Al structure

AD

Page 16: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Ultimate Physical Limits

Thermodynamic limit: energy consumption in handling 1 bit of information = kT log 2 18 meV = 3 10-21 J at RT

Current products: Pentium 4, power consumption 30 W, consists > 2.5 106 devices operating at > 4 108 Hz, energy cost per bit of operation 10-15 J

Demonstrated in laboratory: energy cost of operating a single-molecule switch is ~ 10-19 J

Page 17: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Real Materials and their Processing

Particles, lines and rigid bodies vs. real materials:

each material has its own characteristics

Material-specific properties determine the function

and processing details of a material

Comprehensive knowledge of materials processing

requires ~ 5-10 years of learning and practice:

Interdisciplinary between physics, chemistry, electronics, materials science, economics…

Advantage and role of physicist

Page 18: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Graduate Attributes(Southern Cross University, Australia)

• Intellectual rigour

• Creativity

• Ethical understanding, sensitivity, commitment

• Command an area of knowledge

• Lifelong learning --- ability of independent & self-

directed learning

• Effective communication and social skills

• Cultural awareness

(From: S. Yeo, CDTLink, NUS, July 2004)

Page 19: Roadmap of Microelectronic Industry. Scaling of MOSFET Reduction of channel length L  L/α Integration density  α 2 Speed  α; Power/device  1/α 2 Power.

Final Exam

24 Nov, two hours

One A4 cheat sheet allowed, both sides

What will be in the exam?

Basic principle, processes…, mainly after

Chapter 5