AlGaN/GaN high electron mobility transistors based on InGaN/GaN multi-quantum-well structures with photo-chemical vapor deposition of SiO2 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 Id(max) of 966 mA/mm and a peak transconductance gm(max) of 127 mS/mm, while the unity gain cutoff frequency (fT) and maximum frequency of oscillation (fmax) are 13.9 and 33.9 GHz, respectively.

Graphical abstractAlGaN/GaN MOS-HEMT based on InGaN/GaN MQW structure with SiO2 dielectric deposited via photo-chemical vapor deposition.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The fabrication of AlGaN/GaN MOS-HEMT based on InGaN/GaN MQW structure. ► The formation of stoichiometric SiO2 via photo-chemical vapor deposition. ► SiO2 served as gate dielectric significantly enhances the drain driving current. ► SiO2 served as passivation layer effectively suppresses the RF dispersion. ► MQW-based MOS-HEMT is promising for high frequency and high power applications.