Effects of uniaxial mechanical stress on drive current of 0.13 (mu)m MOSFETs

We study the effects of both external mechanical stress and intrinsic stress due to trench isolation on drive currents of 0.13 (mu)m-node MOSFETs. The drive current, I/sub dsat/, of PMOS is enhanced by about 13% while that of NMOS is reduced by about 9% upon applying a uniaxial compressive stress along the channel of L/sub physical/=85 nm. The shifts in linear drive current, I/sub dlin/, are larger. By applying the external stress, we have simultaneously reproduced, for both PMOS and NMOS, the I/sub dsat/ and I/sub dlin/ shifts due to different gate-trench-isolation distances. We find that the shifts by the applied stress, (delta)I/sub dsat//I/sub dsat0/ and (delta)I/sub dlin//I/sub dlin0/, decrease with decreasing gate length. The change in total resistance, (delta)(V/sub ds//I/sub dlin/), is a linear function of gate length. Because of the mobility dependence on external stress, we have also been able to extract source-drain series resistance, R/sub sd/, by simply bending the wafer.