A technique for regrowing n+-GaN layers has been developed to realize nonalloyed Ohmic contacts using plasma assisted molecular beam epitaxy. The contact resistance and device performance were measured of a recessed-gate with the regrowth and of recessed-source/drain AlGaNGaN high electron mobility transistors (HEMTs). With the regrown n+-GaN layers and recessed drain/source, a low contact resistance of 0.6 Ω mm was obtained for TiAu contacts to AlGaN. The peak drain current (IDS,max) and maximum transconductance (gm,max) of the AlGaNGaN HEMTs with nonalloyed Ohmic contacts were 573 mAmm and 60 mSmm, respectively. These results demonstrate that the regrowth of highly doped GaN layers is crucial in achieving low-resistance nonalloyed Ohmic contacts for the HEMT structures.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)