Analysis of Halo Implanted MOSFETs

MOSFETs with heavily doped regions at one or both ends of the channel exhibit qualitative differences in electrical behavior compared to devices with laterally uniform channel doping. These differences include a distinct peakiness in the transconductance near threshold, asymmetries in capacitances, and a surprising decrease in the statistical variation of the peak gain factor as channel length decreases. Historically, accurate modeling of such devices is best done with sectional MOSFET models. Here we present an analytic model of the behavior of the current and transconductance of a (unilaterally or bilaterally) halo implanted MOSFET and show that it predicts the decrease in variation of gain factor with channel length.