Novel 4H-SiC MESFET with amended minimum noise figure for high-frequency applications

Abstract

The minimum noise figure is a fundamental parameter for characterizing the noise performance of Metal Semiconductor Field Effect Transistors (MESFETs). We present a new structure of SiC-MESFET with an amended minimum noise figure. The main idea of this work is to change the channel's thickness and modify the channel's charge distribution, which leads to the modification of the curvature of the depletion region. The proposed structure consists of an asymmetrical channel thickness using a step gate. The proposed structure is an amended minimum noise figure MESFET (AMNF-MESFET). The minimum noise figure of the proposed structure is significantly improved compared to a conventional MESFET (C-MESFET). Also, the other important parameters of the AMNF-MESFET device have increased, including breakdown voltage from 160 to 210 V, cut-off frequency (f_T) from 20 to 36 GHz, and maximum oscillation frequency (f_max) from 50.55 to 61.25 GHz approximately 31%, 80%, and 21%, respectively compared to the C-MESFET. The minimum noise figure in the AMNF-MESFET is reduced from 35 to 15.5 dB at 100 GHz compared to the C-MESFET and that's a significant improvement. Therefore, the AMNF-MESFET is an excellent candidate for high voltage, high current, high-frequency, and low noise applications.