Impacts of fluorine on GaN high electron mobility transistors: Theoretical study

We investigate the role of fluorine (F) in GaN‐based high electron mobility transistors (HEMTs) with first principle calculations. Formation energy calculations of F in GaN and AlN reveal that energetically favored interstitial F (Fi) and substitutional F at N sites (FN) could play important roles in the performance of HEMTs. Fiis responsible for positive threshold voltage (Vth) shift by forming F–anion and depleting 2DEG carriers. The degradation of device performance at high temperature is ascribed to the defect energy state near conduction band edge of FN. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)