Novel AlGaN/GaN omega-shaped nanochannel FinFETs with fin width of 50 nm were successfully fabricated using TMAH lateral wet etching with ALD HfO2 sidewall spacer. This fin structure apparently exhibited the current spreading in the access region, which results in the suppression of the drain lag effect at high drain voltage and sharp switching performance with subthreshold swing of 57-65 mV/decade. Excellent on- and off-state state performances for the fabricated device prove that the omega-shaped gate structure not only exhibits excellent gate controllability, but also decouples the active nano channel region from the underlying thick buffer. The proposed device is very promising candidate for high-performance device applications. (C) 2016 Elsevier Ltd. All rights reserved.