Systematic Study of Thick Strained Silicon NMOSFETs for Digital Applications

This work investigates NMOSFETs on thick biaxially strained silicon for digital logic applications. Strain and long channel mobility enhancement are shown to be maintained for strained films as thick as 300 nm, 15 times thicker than the equilibrium critical thickness, and misfit-dislocation induced off-current leakage is shown to be completely eliminated for t Si equiv 100 nm. Significant performance enhancement is achieved: short channel DC NMOS drive current is up to 18% higher than comparable unstrained silicon devices and thin strained silicon devices