Intel’s Low Power Technology With High-k dielectric

Intel’s Low Power Technology

• With High-K Dielectric

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.

• 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.

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.

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/showArticle.jhtml?articleID=18305166&kc=5012