Record combination fmax · Vbr of 25 THz·V in AlGaN/GaN HEMT with plasma treatment

Abstract

A combination of high maximum oscillation frequency (fmax) and breakdown voltage (Vbr) was achieved in AlGaN/GaN high electron mobility transistors (HEMTs) with N2O plasma treatment on the access region. The breakdown voltage is improved from 37 V to 80 V due to the formation of oxide layer in the gate region. A suppressed current collapse is obtained due to plasma treatment on the gate-source and the gate-drain regions. The effect of the present passivation method is almost the same with that of the conventional SiN passivation method, meanwhile it can avoid introducing additional parasitic capacitance due to thinner thickness. The small signal measurement shows that HEMT can yield fT and fmax of 98 and 322 GHz, respectively, higher than that of 70 and 224 GHz for the non-treated HEMT. By using the plasma treatment technique, the HEMT can simultaneously exhibit high fmax and Vbr with a record fmax⋅Vbr of 25 THz⋅V.