Low Current Collapse and Low Leakage GaN MIS-HEMT Using AlN/SiN as Gate Dielectric and Passivation Layer

Abstract

An effective passivation and gate insulator with low current collapse and improved dynamic ON-state resistance (R-ON) for GaN MIS-HEMT is demonstrated in this work. The structure of passivation and gate insulator is fabricated by 4-nm SiN as the first passivation layer and 1-nm AlN. The bilayer AlN/SiN structure integrates the advantages of SiN and AlN. SiN passivation has been proved to effectively reduce GaN surface states. AlN has high bandgap of similar to 6.2 eV which can suppress leakage current. Hence, the unfavorable effects such as trapping effect and leakage current which will induce current collapse and are effectively suppressed by using AlN/SiN bilayer thin film. A GaN MIS-HEMT with AlN/SiN passivation and gate dielectric exhibits improved I. V characteristics, low leakage current, low current collapse, and improved dynamic RON at high quiescent drain bias of 100 V.