Schottky Barrier Height Reduction and Drive Current Improvement in Metal Source/Drain MOSFET with Strained-Si Channel

Abstract

The use of strain to reduce contact resistance and improve the drive current of the Schottky barrier source/drain metal-oxide-semiconductor (MOS) transistor is proposed. The advantages of this approach were shown by theoretical calculation based on the non-equilibrium Green's function formalism. Furthermore, the interface dipole theory was firstly applied to the calculation in order to clarify the effects of strain and Fermi-level pinning on the Schottky barrier height. The calculated results indicate that bi-axial strain can reduce the Schottky-barrier height and increase complementary metal-oxide-semiconductor (CMOS) transistor drive current without disturbance of Fermi-level pinning, whereas hydrostatic strain has no effect on the barrier height because of the pinning. These results indicate the combination of the metal source/drain structure with a bi-axially strained Si channel can be beneficial for improving the drive current of nanoscale metal-oxide-semiconductor field-effect transistor (MOSFET).