Mobility And Screening Effect In Heavily Doped Accumulation-Mode Metal-Oxide-Semiconductor Field-Effect Transistors

Measurements made on heavily doped n-channel accumulation-mode planar metal-oxide-semiconductor field-effect transistors (MOSFETs) reveal that the channel mobility can reach values significantly higher than the bulk mobility at the same doing level. This effect is attributed to a screening effect: in the accumulation channel, the high concentration of the majority carriers brings about an electrostatic screening effect that reduces impurity coulomb scattering. As a result, mobility values that can reach twice the value expected in the bulk material are observed in the accumulation channel. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4745604]