Design and Analysis of AlGaN/GaN Based DG MOSHEMT for High-Frequency Application

Abstract

In this work, AlGaN/GaN based DG MOSHEMT is designed at 0.8 µm gate length with Al2O3 gate dielectric. The key device performance parameter such as gm, AV, fT, and fmax has been investigated using 2D Mixed-Mode Sentaurus TCAD device simulation. The use of the double heterostructure helps to achieve higher on-current. We observe a double hump type feature in transconductance which is attributed to occurrence of the double 2-DEG, resulting in better device linearity. Further, the double gate structure is responsible for nearly ideal subthreshold slope (~ 59.94 mV/dec) and higher Ion/Ioff ratio (> 1016). Moreover, the device offers comparable cut-off frequency (19.25 GHz) and maximum-oscillation frequency (66.95 GHz) to the existing Al2O3/AlGaN/GaN based SG MOSHEMT alongwith tremendous improvement in terms of intrinsic gain (~ 76 dB). Furthermore, enhancement of the device performance (fT = 122.44 GHz and fmax = 163.07 GHz) is achieved by scaling down the gate length from 0.8 µm to 100 nm. These results indicate that Al2O3/AlGaN/GaN based DG MOSHEMT can be possible alternative for millimeter and microwave frequency applications.