Effects of Si/SiO₂ interface stress on the performance of ultra-thin-body field effect transistors: a...

First-principles density functional theory (DFT) based device simulations are performed for Si ultra-thin-body (UTB) field effect transistors with the explicit SiO₂ atoms in the gate dielectric. In order to evaluate the Si/SiO₂ interface stress effects on the UTB device performance, the interface stress tensor is extracted from the Si/SiO₂ atomic structure by DFT calculations. The influence of the interface stress on the transport properties is examined through full quantum mechanical non-equilibrium Green's function calculations. Based on the analysis of the band structure and transfer characteristics, we demonstrate that the interface stress can characterize the overall effects of the SiO₂ gate dielectric on the device performance in the nanoscale regime.