Mobility and Effective Electric Field in Nonplanar Channel MOSFETs

The universal relationship of effective carrier mobility (mu_eff ) versus effective perpendicular electric field (E _eff ) in the channel was studied in nonplanar channel (NPC) mosfets. In general, E _eff is determined by bulk charge density ( Q _B), inversion charge density ( Q _i), and eta . The variable eta was shown to have a dependence on channel structure and was extracted from several NPC mosfets, such as pure double-gate (DG), gate-all-around (GAA), and silicon-on-insulator (SOI) Fin mosfet s. We derived E _eff expressions for the NPC mosfets for a given channel doping concentration. It was shown that large parasitic source/drain (S/D) resistance should be corrected to obtain accurate mu_eff. In the GAA structure, extracted eta decreased with increasing radius of the body wire. Width weight sum was applied to extract eta in the SOI FinFETs that consist of DG and GAA structures. From the mu_eff versus E _eff relation obtained by the C- V method, we could verify the validity of our approach.