Improved RF and DC performance in AlGaN/GaN HEMT by P-type doping in GaN buffer for millimetre-wave applications

Abstract

In this paper, the RF and DC performance of AlGaN/GaN HEMT having p-type doping in GaN buffer layer was analysed. Novelty of this work lies in the inclusion of P-type doping in GaN buffer of proposed GaN-HEMT. The result shows the significance of p-type doping at GaN buffer layer for enhancing the RF characteristics of the AlGaN/GaN HEMT. The use of p-type doping in GaN buffer layer increase the conduction band minima in the channel and thereby improving the transconductance of the device. The proposed HEMT achieves a peak transconductance of 330 mS/mm at VGS = −2 V and a maximum drain current of 850 mA/mm. The unity-gain cut-off frequency, small signal capacitance and conductance were also extracted to demonstrate its influence on RF performance. The proposed GaN HEMT has exhibited a unity current gain cut-off frequency of 45 GHz, which is 40% higher than that of conventional HEMT. The improved RF and DC performance of proposed HEMT makes it suitable for millimetre-wave applications.