AlGaN/GaN MODFETs with low ohmic contact resistances by source/drain n/sup +/ re-growth

n/sup +/ regrown source-drain regions have been used for AlGaN/GaN MODFETs to obtain a low-resistance ohmic contact and clear-cut ohmic boundaries which will potentially facilitate fabrication of deep submicron-gate devices. The process consists: 1. Formation of the SiO/sub 2/ re-growth mask by E-beam evaporation and lift-off; 2. Removal of the AlGaN layer in the ohmic region by RIE; 3. n/sup +/ GaN re-growth in the MOCVD reactor; 4. Ohmic metal deposition and annealing. A transfer ohmic contact resistance of 0.44 /spl Omega/-mm was achieved. Much improved device performance was obtained with the new ohmic scheme over the conventional scheme with the same metalisation.