Mass transport regrowth of GaN for ohmic contacts to AlGaN/GaN

Ohmic contacts were fabricated for AlGaN/GaN high-electron-mobility transistors by selective-area mass transport regrowth of GaN. The contact resistance ranged from 0.23 to 1.26 Ohm mm for different contact areas and geometries. The average resistivity of the autodoped regrown GaN was measured to 4 x 10(-3) Ohm cm. Devices with regrown contacts were fabricated, achieving a transconductance of 210 mS/mm. The technique provides a low-cost regrowth process, with applications in particular for high Al-composition AlGaN/GaN devices. (C) 2001 American Institute of Physics.