Alpha-Power Law MOSFET Model and its

Applications to CMOS Inverter Delay

By Ken Kimura

CMOS Models

• Long Channel (Conventional) – width and length long enough so that edge

effects from the four sides can be neglected

• Short Channel – width and length short enough

such that the edge effects can not be neglected

Shot Channel MOS Device Characteristics

• Channel Length Modulation

• Threshold Voltage Roll-off

• Narrow Gate Width Effects

• Reverse Short Channel Effects

• Punch Through

• Mobility Degradation

• Velocity Saturation

Long Channel CMOS Device

Short Channel CMOS Device

Short Channel CMOS Device

2.000E+04

5.000E+04

0 0.5 1 1.5 2 2.5

Ch

ann

el E

lect

ric

Fie

ld (

V/c

m)

Channel Length (um)

MOSFET Channel Electric Field by Process

Short Channel CMOS Modeling

Short Channel CMOS Modeling

Short Channel CMOS Modeling

Effect on Delay Calculation

Effect of Source and Drain Resistance

Source: Intel’s Revolutionary 22 nm Transistor Technology, Bohr, Mistry, May, 2011

Questions?

Strained Silicon

Source: The Invention of Uniaxial Strained Silicon Transistors at Intel, Bohr, Jan 2007

Source: IBM's Strained Silicon Breakthrough

Conventional vs Tri-Gate Device

Source: Intel’s Revolutionary 22 nm Transistor Technology, Bohr, Mistry, May, 2011

Details of Tri-Gate Device

References

• T Sakurai and R Newton, “Alpha-Power Law MOSFET Model and its Applications to CMOS Inerter Delay and Other Formulas”, IEEE Journal of Solid State Circuits, Vol 25, No 2, April 1990 • M Bohr and K Mistry, “Intel’s Revolutionary 22nm Transistor Technology”, May 2011 • N Weste and D Harris, “CMOS VLSI Design”, 4th ed, Addison-Wesley, 2011 • D Neamen, “Semiconductor Physics and Devices”, 4th ed, McGraw-Hill, 2011 •M Bohr, “Source: The Invention of Uniaxial Strained Silicon Transistors at Intel”, Jan 2007 •IBM's Strained Silicon Breakthrough, http://www.research.ibm.com/resources/press/strainedsilicon/