Analytic description of short-channel effects in fully-depleted double-gate and cylindrical, surrounding-gate MOSFETs

Short-channel effects in fully-depleted double-gate (DG) and cylindrical, s urrounding-gate (Cyl) MOSFETs are governed by the electrostatic potential a s confined by the gates, and thus by the device dimensions. The simple but powerful evanescent-mode analysis shows that the length lambda, over which the source and drain perturb the channel potential, is 1/pi of the effectiv e device thickness in the double-gate case, and 1/4.810 of the effective di ameter in the cylindrical case, in excellent agreement with PADRE device si mulations. Thus for equivalent silicon and gate oxide thicknesses, evanesce nt-mode analysis indicates that Cyl-MOSFETs can be scaled to 35% shorter ch annel lengths than DG-MOSFETs.