A Subthreshold Surface Potential and Drain Current Model for Lateral Asymmetric Channel (LAC) MOSFETs

摘要

A drift-diffusion theory based subthreshold drain current model for lateral asymmetric channel (LAC) MOSFET is presented. In this, an accurate analytical subthreshold surface potential model, in which the contribution of the varying depth of the channel depletion layer due to source and drain junctions have been accounted for is used. A physically-based empirical modification of the channel conduction layer thickness, originally proposed for relatively long-channel conventional devices, is also made for such short-channel asymmetrically doped devices. Very good agreement of both surface potential and drain current is observed between the model calculation and the prediction made by the 2-D numerical simulation using Dessis of ISE-TCAD. The performance prediction of the subthreshold analog circuits based on this model is also found to agree well with that by the numerical simulator.