INTRODUCTION xxiv
Figure .4: Chip power density is increasing exponentially with time.
answer? Is the control of electron spin rather than the total charge in the channel of the device
(the emerging field of spintronics) the holy grail? Are architectures based on single electron
transistors a high density, low power alternative?
The future is murky, and we as scientists and engineers have to help clarify it. This book seeks
to provide an understanding of the materials, devices, and technology of the various alternatives
being considerred, with detail appropriate to the maturity of the technology. A bias towards
compound semiconductors is obvious, as Si-based devices have been exclusively addressed over
the years in various forms. We hope that this book serves a function to academics teaching course
materials, engineers and researchers in the field tackling the murky future, and today’s graduate
students who will be the great engineers of tomorrow.
Watts/cm
2
Watts/cm
2
1
10
100
1000
1.5μm1 μm 0.7 μm 0.5 μm 0.35 μm 0.25 μm 0.18 μm 0.13 μm 0.1 μm 0.07 μm
i386i386
i486i486
PentiumPentium®®
PentiumPentium®®ProPro
PentiumPentium®®IIII
Hot plateHot plateHot plateHot plate PentiumPentium®®IIIIII
Rocket
Nozzle
RocketRocket
NozzleNozzle
Rocket
Nozzle
RocketRocket
NozzleNozzle
Nuclear ReactorNuclear ReactorNuclear ReactorNuclear ReactorNuclear ReactorNuclear Reactor
PentiumPentium®® 44
Power doubles every 4 yearsPower doubles every 4 years
55 - -year projection: 200W total, 125 W/cmyear projection: 200W total, 125 W/cm^2 2 !!
P=VI: 75W @ 1.5V = 50 A!P=VI: 75W @ 1.5V = 50 A!