Metal‐face InAlN/AlN/GaN high electron mobility transistors with regrown ohmic contacts by molecular beam epitaxy

Ohmic regrowth by molecular beam epitaxy (MBE) has been investigated for metal‐face InAlN/AlN/GaN high electron mobility transistors (HEMTs) for the first time. Using SiO 2 mask n + ‐GaN was regrown in the source/drain region while deposition on the mask was lifted off in buffered HF after regrowth. The lowest contact resistance measured was 0.40 ± 0.23 Ω mm by the transmission line method (TLM) in this initial study. The peak output current density of 1.25 A/mm at V gs  = 3 V and extrinsic transconductance of 264 mS/mm at V ds  = 5 V were observed in 500‐nm gate length InAlN/Al/GaN HEMTs passivated by SiN with regrowth contacts.