Design and Performance Analysis of 70nm GaN HEMT with AlGaN Back Barrier for V-Band Nanoelectronics Applications

The work is focused on studying the effect of AlGaN back-barrier layer on the performance of a GaN HEMT device. The impact of adding a back barrier layer to the structure is being investigated taking different DC and RF parameters into account. The work has reported a 70nm AlGaN/GaN HEMT device using a 20nm thin AlGaN back barrier layer. The study reports that introducing a back barrier helps in enhancing the overall performance of the device in several ways. The conduction band was raised beyond the GaN channel region with the addition of the AlGaN back barrier thus creating a narrower quantum well and restricting their flow to the quantum well thereby preventing the 2DEG channel charge carriers from flowing into the buffer region. Benefits of back barrier layer inclusion in the HEMT device are excellently exhibited in terms of enhanced output drain current of 1.6A/mm; flat transconductance peak of nearly 280mS/mm; cut-off frequency and maximum frequency of 47GHz and 55GHz respectively. The device can thus be incorporated in high frequency applications upto V-band range. In addition, several other parameters are also reported that help to study the device’s linearity. A comparative analysis has been performed taking into account our proposed GaN HEMT devices with and without the inclusion of AlGaN back barrier layer considering a gate length of 200nm. The paper further illustrates the impact of AlGaN back barrier on the various device parameters by varying the gate length from 1000nm to 70nm keeping all other device dimensions constant.