IMPACT OF MECHANICAL STRESS ON MOBILITY & DEVICE CURRENT OF PLANAR MOSFET

Abstract

Strain engineering is used to enhance device performance commensurately with the physical scaling in contemporary technology. Therefore, strain engineering is an integral part of a state-of-the-art CMOS technology flow. Strain engineering is used to introduce favourable mechanical stress in the channel to enhance CMOS performance. In the era of nano-technology devices are working in the near ballistic regime. In this regime of operation performance of device depends on the injection velocity (V) and backscattering ratio (r), so here we analyze how these parameters depends on stress. It is observed that uniaxial tensile stress reduces the backscattering ratio due to modulation in KT-layer thickness and carrier mean free path for backscattering. Tensile stress also splits the valley degeneracy, which change the probability of occupancy of carrier in different valley. It also improve injection velocity near the virtual source end by reducing the carrier effective mass. Impact of drive current under uniaxial strain is analyzed in term of mean-free-path, KT-layer thickness, ballistic efficiency and injection velocity.