4H-SiC metal-semiconductor field effect transistors (MESFETs) with a dual-channel layer are fabricated and characterized. The higher doped lower-channel layer serves to increase the channel current while the lower doped upper-channel layer is used to improve the breakdown voltage. The thickness and doping concentration of the lower-channel layer are 0.08 mu m and 5.2 x 10(17) cm(-3) respectively, while for the upper-channel layer, the values are 0.12 mu m and 1.4 x 10(17) cm(-3) respectively. The dual-channel MESFETs with 1 mu m gate length have a saturation drain current density of 280 mu A/mu m, source-drain breakdown voltage of 145 V and maximum output power density of 4.6 W/mm. These results are improved compared to conventional single channel MESFETs fabricated in this work using the same process with a channel thickness of 0.20 mu m and doping concentration of 2.4 x 10(17) cm(-3). (C) 2006 Elsevier Ltd. All rights reserved.