A novel 4H–SiC SOI-MESFET with a modified breakdown voltage mechanism for improving the electrical performance

Abstract

In this paper, we present the unique features exhibited by a novel 4H–SiC silicon-on-insulator (SOI) metal–semiconductor field effect transistor (MESFET) in which the active layer consists of an insulator region (ISOI-MESFET). The key idea in this work is to make the dominant breakdown voltage mechanism to be controlled by the channel breakdown and not by the gate breakdown as a result of a high electric field at the edge of the gate near the drain. We investigate the improvement in device performance with two-dimensional and two-carrier device simulation. Our simulation results show that the breakdown voltage of the ISOI-MESFET is higher than the conventional bulk-MESFET (CB-MESFET) and conventional 4H–SiC SOI-MESFET (CSOI-MESFET). In this study, we have shown that the saturation current of the proposed structure is larger than the CB-MESFET. Also, the cut-off frequency and maximum oscillation frequency of the ISOI-MESFET improve compared to the CB-MESFET. Therefore, the ISOI-MESFET has superior dc and RF performance compared to the similar device based on the conventional structures.