The Improvement of DC Performance in AlGaN–GaN HEFTs With Isoelectronic Al-Doped Channels

Enhancement of electrical properties of an AlGaN-GaN heterostructure was achieved through isoelectronic Al-doping of the undoped channel layer during the growth by metal-organic chemical vapor deposition. The two-dimensional electron gas mobility was increased from 3390 to 4870 cm/sup 2//V/spl middot/s at 77 K, and the crystal quality was significantly improved as Al atoms were incorporated in the undoped GaN film. The AlGaN-GaN HFETs were fabricated on this material structure and exhibited a maximum drain current of 909 mA/mm, and a maximum transconductance of 232 mS/mm, corresponding to an increase of 30% and 21%, respectively.