Relationship between empirical and theoretical mobility models in silicon inversion layers

The theoretical and empirical expressions most commonly used for modeling the variation of the low field surface mobility of MOSFETs are discussed. It is shown that both approaches may be reconciled, and a new physical definition of the parameters of the empirical model is presented, In particular, we propose an analytical formula of the factor θ₂ characterizing the quadratic dependence of the reciprocal mobility on the inversion charge. Both the formula and experiment agree and show that θ₂ does not only depend on the surface roughness scattering term, but also on phonon scattering