A real time Green's functions formalism is used to study the electron transport in a uniformly-doped strained-Si surface channel on a relaxed Si1-xGex buffer. Our theoretical mobility results, for Ns = 1012 cm-2 and for several Ge concentrations in the substrate, are in good agreement with the available experimental data. We find that the low-field electron mobility is affected strongly by rather high fixed-oxide charge, interface-trap and surface-roughness scattering, in addition to non-polar optical phonon scattering. Significant mobility enhancement with increasing Ge fraction in the substrate is observed only for low values of Ns. The weighting coefficients a and b for the inversion and depletion charge densities in the definition of the effective transverse electric field Eeff are not found to be considerably affected by the strain. Strain induced increase of the population of the higher lying sub-bands from the Δ2-band leads to a reduction of the inversion layer capacitance Cinv.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry