GaN based trigate HEMT with AlGaN back-barrier layer: proposal and investigation

In the present work, we have proposed a GaN based trigate high electron mobility transistor with AlGaN back-barrier (BB) layer that effectively suppress the punch-through effects as compared to the conventional device without BB layer. Furthermore, the device performance of the proposed structure has been studied by varying the distance (t (ch)) between AlGaN (barrier)/GaN (channel) to AlGaN (BB)/GaN (channel) interface from 100 nm to 500 nm. It is observed that the optimization of barrier/channel to BB/channel distance (t (ch)) is beneficial for minimizing the off-state leakage current and thereby, a high ON/OFF ratio (similar to 10(8)) and nearly ideal subthreshold slope (similar to 64-66 mV decade(-1)) is achieved. Subsequently, it is shown that the optimized distance of t (ch) = 300 nm results in superior breakdown voltage (similar to 198 V) and cut-off frequency (similar to 81 GHz), leading to excellent Johnson figure-of-merit. The proposed device promises great potential for use in next generations high-power microwave applications.