Title :
Recessed-gate enhancement-mode GaN HEMT with high threshold voltage
Author :
Lanford, W.B. ; Tanaka, T. ; Otoki, Y. ; Adesida, I.
Author_Institution :
Micro & Nanotechnology Lab. & Dept. of Electr. & Comput. Eng., Univ. of Illinois, Urbana-Champaign, IL, USA
fDate :
3/31/2005 12:00:00 AM
Abstract :
Fabrication of enhancement-mode high electron mobility transistors (E-HEMTs) on GaN/AlGaN heterostructures grown on SiC substrates is reported. Enhancement-mode operation was achieved with high threshold voltage (VT) through the combination of low-damage and controllable dry gate-recessing and the annealing of the Ni/Au gates. As-recessed E-HEMTs with 1.0 μm gates exhibited a threshold voltage (VT) of 0.35 V, maximum drain current (ID,max) of 505 mA/mm, and maximum transconductance (gm,max) of 345 mS/mm; the corresponding post-gate anneal characteristics were 0.47 V, 455 mA/mm and 310 mS/mm, respectively. The RF performance is unaffected by the post-gate anneal process with a unity current gain cutoff frequency (fT) of 10 GHz.
Keywords :
III-V semiconductors; aluminium compounds; gallium compounds; high electron mobility transistors; substrates; E-HEMT fabrication; GaN-AlGaN; SiC; annealing; drain current; enhancement-mode high electron mobility transistors; low-damage controllable dry gate-recessing; maximum transconductance; post-gate anneal process; recessed-gate enhancement-mode GaN HEMT; substrates;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:20050161
