A novel silicon on insulator metal semiconductor field effect transistor (SOI MESFET) structure is presented in this paper. The proposed structure includes a thin layer of nickel located in the buried oxide (BOX) of the structure which causes RF parameters to experience improved values. A thin layer of oxide in the channel under the gate edge near the drain, controls the electric field distribution and has considerable effect on the breakdown voltage. The breakdown voltage is increased by 53%. In addition, the maximum output power density is improved by 148%. The gate capacitances are reduced as a result of decreasing the depletion region extension into source and drain regions and due to the effect of metallic region in the BOX. So the proposed structure has better RF and high voltage characteristics compared to the conventional structure in terms of breakdown voltage, maximum oscillation frequency, cut-off frequency, and maximum output power density.
