Design of GaN/AlGaN Heterojunction High Electron Mobility Transistor with Back Gate and Intrisnic Spacer Layer

In this paper, GaN/AlGaN heterojunction high electron mobility transistors (HEMTs) with intrinsic spacer layer and back gate have been proposed. The effect of the back gate and intrinsic GaN spacer layer on transistors’ DC and AC behavior have been studied. Performance parameters such as drain current, transconductance, cutoff frequency, maximum oscillation frequency, subthreshold swing and drain induced barrier lowering (DIBL) have been calculated for all designs. The mentioned parameters have been compared between the proposed single-gate and double-gate structures which show the improved performance of the transistor with added back gate. In addition, the effect of adding the intrinsic space layer to the proposed doube gate HEMT has been investigated. The calculation of the frequency response shows that the cut-off frequency of the proposed HEMT is 272 GHz which has considerably increased compared to the 132 GHz for the double gate HEMT without spacer layer. The results reveal that adding the back gate and the intrinsic spacer layer to the structures, both have resulted in improved DC and AC characteristics of the HEMT.