L_g=100 nm T-shaped gate AlGaN/GaN HEMTs on Si substrates with non-planar source/drain regrowth of highly-doped n⁺-GaN layer by MOCVD

High-performance AlGaN/GaN high electron mobility transistors (HEMTs) grown on silicon substrates by metal–organic chemical-vapor deposition (MOCVD) with a selective non-planar n-type GaN source/drain (S/D) regrowth are reported. A device exhibited a non-alloyed Ohmic contact resistance of 0.209 Ω·mm and a comprehensive transconductance (g_m) of 247 mS/mm. The current gain cutoff frequency f_T and maximum oscillation frequency f_MAX of 100-nm HEMT with S/D regrowth were measured to be 65 GHz and 69 GHz. Compared with those of the standard GaN HEMT on silicon substrate, the f_T and f_MAX is 50% and 52% higher, respectively.