We present a phenomenological model for subsurface leakage current in MOSFETs biased in accumulation. The subsurface leakage current is mainly caused by source-drain coupling, leading to carriers surmounting the barrier between the source and the drain. The developed model successfully takes drain-to-source voltage (VDS), gate-to-source voltage ( VGS), gate length ( LG), substrate doping concentration ( Nsub), and temperature ( $T$ ) dependence into account. The presented analytical model is implemented into the BSIM6 bulk MOSFET model and is in good agreement with technology-CAD simulation data. © 1963-2012 IEEE.