Silicon-on-nothing MOSFETs: performance, short-channel effects, and backgate coupling

Silicon-on-nothing (SON) transistors with gate length varying from 0.25 μm down to 80 nm exhibit excellent performance and scalability. The silicon-on-insulator (SOI)-like architecture with thin fully depleted Si film and ultrathin buried oxide results in attenuated short-channel effects (charge sharing, DIBL and fringing fields), high current, and electron mobility. A new model accounts for the intrinsic mechanisms of operation in SON MOSFETs: i) substrate depletion governed by source and drain via doping modulation, ii) relatively low coupling between the front- and backgates, iii) role of ultrathin buried oxide. The proposed model reproduces the variations of the threshold voltage and subthreshold swing and is useful for further device optimization.