Electron Transport in Engineered Substrates: Strain and Orientation Effects

First, we focus on the on the electronic mobility in inversion layers of devices built on (100), (110), and (111) Si, with channels along various directions, and under biaxial and uniaxial strain. The Kubo-Greenwood formula has been used to calculate the mobility accounting for scattering with phonons and surface roughness. The subband structure has been computed from self-consistent Poisson-Schrodinger solutions using ellipsoidal, nonparabolic valleys (electrons) or using the triangular-well approximation using a 6-band k·p model (holes). We shall discuss the most promising combination of orientations and strains which constitutes an optimum choice to maximize simultaneously both the electron and hole mobilities.