AlGaN/GaN high electron mobility transistors based on InGaN/GaN multi-quantum-well structures with photo-chemical vapor deposition of SiO ₂ dielectrics

AlGaN/GaN metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) based on InGaN/GaN multi-quantum-well (MQW) structure has been fabricated with SiO₂ dielectric deposited via photo-chemical vapor deposition (PHCVD) using a deuterium lamp as the excitation source. High quality SiO₂ was successfully formed by PHCVD and it exhibited exactly stoichiometric as gate oxide and passivation dielectric for MQW-based MOS-HEMT. The protection offered by the passivation of PHCVD of SiO₂ may contribute to the significantly reduced current dispersion and improved RF performance. With 1-μm-long gate length at drain-voltage of 10 V, it exhibited a maximum drain current I_d(max) of 966 mA/mm and a peak transconductance g_m(max) of 127 mS/mm, while the unity gain cutoff frequency (f_T) and maximum frequency of oscillation (f_max) are 13.9 and 33.9 GHz, respectively.