First Principles Calculations of the Effect of Stress in the I-V Characteristics of the CoSi2/Si Interface

We present ab initio-based electronic transport calculations on the effect of uniaxial and bi-axial stress on the CoSi2/n Si interface resistivity for the three main silicon crystallographic directions. For the [001] case, we identify two distinctive low and high bias conduction regimes for both compressive and tensile stress. In these regimes, the current is dominated by electronic transmission pathways near the Γ point for bias up to ~0.1V, while for higher bias it is dominated by transmission at the (±1/2, ±1/2) conduction band valleys of the Brillouin zone, which results in a contact resistivity decrease of up to 30% at 0.2V bias. This effect is less pronounced for the [110] direction, and negligible for the [111] case due to the symmetry of the Si conduction band valleys along these directions. This study provides insight into stress-based optimization pathways for contact resistivity reduction of silicide interfaces in next generation semiconductor devices.