Substrate current is a good indicator for the hot-carrier and electrostatic discharge related reliability of MOSFET. This paper develops an improved and analytic model for such a Current based on the length of and maximum electric field in the high-field region near the drain junction. The present model is compared against several existing substrate current models reported in the literature. and results from device simulation and measurements are also included in support of the model development. (C) 2002 Elsevier Science Ltd. All rights reserved.