Abstract:
Conduction band structure of silicon under uniaxial110 stress is studied with two band
k·p perturbation theory. Splitting energy of conduction band minima and electron effective mass as a function of stress and direction electron mobility in uniaxial stressed silicon are obtained with relax time approximate theory. Intervalley scattering, intravalley scattering, and ionized impurity scattering are considered in calculation. It is demonstrated that as uniaxial110 stress is applied on silicon crystal, a significant anisotropy in electron mobility can be observed. Among crystal directions001, 110, and1
10, electron mobility along110 direction under uniaxial110 tensile stress has a profound enhancement, which increase from 1 450 cm
2·Vs
-1 to 2 500 cm
2·Vs
-1 as stress change from 0 to 2 GPa. Electron mobility enhancement is mainly due to uniaxial stress induced conduction effective mass reduction, while suppression of intervalley scattering plays a minor role.