N-polar GaN-based highly scaled self-aligned MIS-HEMTs with state-of-the-art fT.LG
product of 16.8 GHz-μm for mixed signal applications
Keywords: N-polar GaN, self-aligned HEMTs, GaN MIS-HEMTs, rf performance
In this paper, we describe a gate-first self-aligned MBE InGaN regrowth methodology for fabricating Npolar GaN-based MIS-HEMTs which exhibit ultra-low contact resistances of 23 Ω-μm, which is comparable to the lower band-gap technologies. These devices, not only show state-of-the-art fT.LG product values of 16.8 GHz- μm for 130 nm gate-length for GaN, but also show exceptional performance at low supply voltages (VDS = 500 mV), thereby making GaN competitive not only to wide band-gap materials like SiC but also to low bandgap technologies by InGaAs HEMTs and InSb by having low knee voltages, high drive currents while still demonstrating relatively large breakdown voltages for unipolar (non-CMOS like) operation.