Surface passivation of n-GaN by nitrided-thin-Ga2O3/SiO2 and Si3N4 films.

The electrical characteristics of n-GaN/nitrided-thin-Ga2O3/SiO2 and n-GaN/Si3N4 metal-insulator-semiconductor (MIS) capacitors have been compared, and the work-function difference [lowercase_phi_synonym]ms and effective dielectric-fixed charge density Qf,eff have been determined. Oxide samples showed lower interface trap level density Dit, lower leakage current, and better reproducibility compared to the nitride samples. The superior properties of the oxide samples are partially attributed to the nitrided-thin-Ga2O3 layer (∼0.6-nm-thick). [lowercase_phi_synonym]ms and Qf,eff were determined, respectively, as 0.13 V and 1.0×1012 q cm-2 in oxide and 0.27 V and -3.6×1011 q cm-2 in nitride samples using flatband voltage versus dielectric thickness data. True dielectric-fixed charge density and location of the major amount of fixed charge are discussed based on Qf,eff, Dit, and spontaneous polarization of n-GaN. [ABSTRACT FROM AUTHOR]