High-resolution mobility spectrum analysis of magnetoresistance in fully-depleted silicon-on-insulator MOSFETs

Multi-carrier transport in planar fully-depleted silicon-on-insulator (FD-SOI) MOSFETs has been investigated employing magnetic-field dependent geometrical magnetoresistance measurements and high-resolution mobility spectrum analysis. The results indicate that electronic transport in the 10 nm thick Si channel layer is due to two distinct and well-defined electron species. Although self-consistent Schrödinger–Poisson numerical calculations indicate significant localization of the total electron population near the back and front interfaces, the results of mobility spectrum analysis suggest that the mobility distributions associated with these spatially localized populations are strongly coupled through carrier scattering processes, and do not have independent and distinguishable mobility distributions. The two detected electron mobility distributions are thus evidence of sub-band modulated transport in 10-nm thick Si planar FD-SOI MOSFETs. The mobility maximum of the dominant carrier was found to occur under gate bias conditions that result in a minimum perpendicular effective electric field.