A novel SOI-MESFET with parallel oxide-metal layers for high voltage and radio frequency applications

Abstract

In this paper a novel silicon on insulator metal-semiconductor field effect transistor is proposed for high voltage and radio frequency applications. This structure includes additional parallel oxide-metal layers in channel region which we called POML-SOI-MESFET. Our 2-D simulations demonstrate that the presence of parallel layers increases the breakdown voltage. Higher critical electric field of additional oxide region than Si and the effect of inserted metal layer in dispersing the potential lines at the gate edge and also at drift region, boost the breakdown voltage of the device from 13.5 V in conventional structure (C-SOI-MESFET) to 29 V in POML structure which shows 114% improvement. Maximum output power density experiences 133% enhancement by applying POML structure. Also, parallel layers improve the maximum oscillation and cut-off frequencies by 11% and 3.3%, respectively with modifying the gate-drain capacitance. Thermal analysis shows that beside these improvements, the POML maintains the thermal conductivity of the device. In order to attain the best results, POML dimensions are optimized carefully. Simultaneous improvement in breakdown voltage, cut-off frequency, maximum oscillation frequency, and maximum output power density makes our proposed structure an efficient device for applications with higher voltages and frequencies.