The impact of subjecting a n-GaN surface to an in-situ argon plasma in an atomic layer deposition (ALD) tool immediately before deposition of an Al2O3 dielectric film is assessed by frequency dependent evaluation of Al2O3/GaN MOSCAPs. In comparison with a control with no pre-treatment, the use of a 50W argon plasma for 5min reduced hysteresis from 0.25V to 0.07V, frequency dispersion from 0.31V to 0.03V and minimum interface state density (Dit ) as determined by the conductance method from 6.8×1012 cm−2 eV−1 to 5.05×1010 cm−2 eV−1. 
A study of the impact of in-situ argon plasma treatment before atomic layer deposition of Al2O3 on GaN based metal oxide semiconductor capacitor