Over 20 % improvement of current-gain cut off frequency 0.3 μm AlGaN/GaN HEMTs with ultra-low Von Schottky Drain for broadband application

This letter demonstrates firstly the novel IESD HEMT (Inserting Etched Schottky Drain HEMT) with the lower barrier height for the broadband and high temperature application of millimeter wave. The etched Schottky device is formed adjacent along AlGaN/GaN sidewalls into drain region and the turn-on voltage is almost about 0 V with the barrier height about 0.49 eV, 0.02 eV lower than that of conventional AlGaN/GaN SBD (Schottky Barrier Diode). Due to the hot electron emission effect of the inserted Schottky barrier diode, the results show that the HEMTs device can obtain better electrical characteristics with wide bandwidth in wider temperature range from 25 °C to 125 °C, specially improved on high frequency. The fabricated HEMTs show a high current density of 550 mA/mm and a high transconductance of 168 mS/mm (V_DS = 10V). Based on the nonlinear rectifying characteristics of SBD with containing RF harmonic components, the cut-off frequency f_T of IESD HEMT exceeds 75.7 GHz which is about 20 % higher than conventional AlGaN/GaN HEMT devices.