In short channel devices, the dependence of subthreshold current on drain induced barrier lowering, substrate bias, channel length, and temperature is modeled. NMOS devices down to effective channel length of 0.13 mum are considered The model, based on drift-diffusion theory, accurately predicts such dependence as verified by results obtained using this model when compared with those obtained with numerical device simulators. (C) 2002 Elsevier Science Ltd. All rights reserved.