Demonstration of Submicron-Gate AlGaN/GaN High-Electron-Mobility Transistors on Silicon with Complementary Metal–Oxide–Semiconductor-Compatible Non-Gold Metal Stack

Abstract

We have demonstrated 0.15-µm-gate-length AlGaN/GaN high-electron-mobility transistors (HEMTs) with direct-current (DC) and microwave performances for the first time using a complementary metal–oxide–semiconductor (CMOS)-compatible non-gold metal stack. Si/Ta-based ohmic contact exhibited low contact resistance (Rc=0.24 Ω.mm) with smooth surface morphology. The fabricated GaN HEMTs exhibited gmmax=250 mS/mm, fT/fmax=39/39 GHz, B Vgd=90 V, and drain current collapse <10%. The device Johnson's figure of merit (J-FOM = fT × B Vgd) is in the range between 3.51 to 3.83 THz.V which are comparable to those of other reported GaN HEMTs on Si with a conventional III–V gold-based ohmic contact process. Our results demonstrate the feasibility of realizing high-performance submicron GaN-on-silicon HEMTs using a Si CMOS-compatible metal stack.