Image and exchange-correlation effects in double gate silicon-on-insulator transistors

Abstract

We have studied the influence of the image and exchange-correlation effects in double-gate silicon on insulator (DGSOI) devices, in the calculation of both charge distribution and of electron mobility. We find that the image and exchange correlation potentials produce a greater confinement of the carriers and, according to the uncertainty principle, a greater phonon scattering rate, which produces a decrease in electron mobility. We have also observed that the influence of image and exchange-correlation potentials on electron mobility, while almost negligible for bulk silicon inversion layers, becomes increasingly important as the silicon thickness decreases, due to the effect of volume inversion in DGSOI inversion layers. It is thus essential to take these effects into account in order to correctly evaluate the inversion charge distribution and the electron mobility in DGSOI inversion layers.