Abstract

Novel heterojunction AlGaN/GaN-FET with inverted device channel is investigated.FET-heterostructures were grown by MBE on sapphire substrates. Devices were fabricated with 0,25 µ T-shaped gates,using electron beam lithography.Electron density profile under the device gate has demonstrated localization of electrons in very narrow nm-region (<10nm)at the bottom GaN/AlGaN – interface,giving direct evidence of HEMT-nature of our FET ’s.I - V-characteristics of HEMT ’s demonstrated high value of drain current Id max >1A/mm,and good extrinsic transconductance gm ext ≅140mS/mm.DC - specific output power of HEMT was 2,0W/mm.Extrinsic cut off frequency f τ ext of HEMT,determined from transconductance gm and gate-source capacitance Cgs, was 20GHz.Its intrinsic value,f τ ext ,was found to be as high as 36GHz.