This paper presents an improved model to simulate I - V characteristics of submicron SiC MESFETs, designed for microwave power applications. The proposed model adequately addresses a non-ideal Schottky behavior, commonly observed in submicron devices, by adjusting the device biasing through simulation variables. Swarm optimization technique has been applied to investigate gate length (L-g) dependent performance of various SiC MESFETs models. It has been found that the proposed model provides an improved accuracy, ranging from 7% to 24%, compared to the best models available in the literature. This enhanced performance is primarily associated with the extra control, provided by the proposed model to simulate the movement of the depletion region in the channel as a function of applied voltages. An attempt has been made to identify the location underneath the Schottky barrier gate, where the depletion region gets its maximum height and thus controls the saturation current of the channel. Physical and electrical parameters of various SiC MESFETs having L-g = 0.4 mu m, 0.5 mu m, 0.6 mu m and 0.7 mu m have also been assessed. An accurate assessment of the physical parameters of the device exhibits the validity of the model for submicron SiC MESFETs. (C) 2016 Elsevier Ltd. All rights reserved.