Intel’s Low Power Technology
With High-K Dielectric
Balapradeep Gadamsetti
Why this is required?

Continuation of Moore’s Law

Transistor scaling with increased
performance and Reduced Power
Consumption
Introduction

Silicon Industry is scaling SiO2 for the
past 15 years and still continuing.

SiO2 is running out of atoms for further
scaling but still scaling continues.
What is a Transistor ?
A simple switch
- current flows from source
to drain when gate is at certain
voltage; otherwise it doesn’t flow
Gate dielectrics (SiO2) are only a few atomic layers thick at this
thickness even being insulator current leaks through.
Now Leakage Power became an Issue !!
Seeking new materials to drive
Moore’s Law
Replacing SiO2 a challenge?
Materials chosen for replacing SiO2 should be thicker (to reduce
leakage power) but should have a “high-K” value.
What is High-K ?
A measure of how much charge a material can hold.
“AIR” is the reference with “K=1”.
"High-k" materials, such as hafnium dioxide (HfO2), zirconium
dioxide (ZrO2) and titanium dioxide (TiO2) inherently have a
dielectric constant or "k" above 3.9, the "k" of silicon dioxide.
Dielectric reduces Leakage power
Problem’s with High-K

Threshold Voltage Pinning- high-K and Polysilicon gate are
incompatible due to Fermi level pinning at the High-K and
Polysilicon interface which causes high threshold voltages
in transistors

Phonon scattering - High-K/ Polysilicon transistors exhibit
severely degraded channel mobility due to the coupling of
phonon modes in high-K to the inversion channel charge
carriers.
Both the above problems limit the
transistor switching speed !!!
High-K and PolySi are Incompatible
Mobility degradation in High-k\PolySi
Phonon Scatterings
Solution- Metal Gates
Metal gate electrodes are able to decrease phonon
scatterings and reduce the mobility degradation
problem.
Challenges with Metal Gates
Requires metal gate electrodes with “CORRECT”
work functions on High-K for both nMOS and
pMOS transistors for high performance.
Work functions for nMOS and pMOS
Breakthroughs with Metal Gates

N-Type metal and P-Type metal with the
CORRECT work functions on high-K have been
engineered.

High-K\metal-gate stack achieves nMOS and
pMOS channel mobility close to SiO2's.

High-K\metal-gate stack shows significantly
lower gate leakage than SiO2.
High-Metal-gate reduces leakage
pMOS mobility graph
nMOS mobility graph
Conclusion

Intel achieved 20 percent improvement in
transistor switching speed

Reduced transistor gate leakage by over 10
fold.

Integration of more than 400 million transistors
for dual-core processors and more than 800
million for quad-core in Intel® 45nm high-k
metal gate silicon technology.
References

http://www.intel.com/technology/silicon/
high-k.htm

http://www.physorg.com/news80.html

http://www.eetimes.com/conf/iedm/show
Article.jhtml?articleID=18305166&kc=50
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