In this study, conventional multiple-frequency capacitance-voltage (C-V) curves of a metal-insulator-semiconductor structure were modified into barrier capacitance-barrier voltage (C br -V br ) curves to study the interface state of an Al 2 O 3 /III-N interface. By eliminating the contribution of a serially connected insulator capacitance (C i ), the variation of C br as a function of V br could be obtained for determining the interface-state-caused dispersion precisely. This technique was used to deduce the distribution of energy-level-dependent D it and to investigate the influence of thermal oxidization on an Al 2 O 3 /AlGaN/GaN heterostructure with an in situ grown AlN/GaN cap layer. The oxidization process was performed prior to Al 2 O 3 deposition. Depositing an Al 2 O 3 layer on an oxidized wafer by using an atomic layer deposition system can considerably reduce the dispersion behavior among frequencydependent C br -V br curves. By determining the amount of frequency dispersion among the C br -V br curves, the distribution of D it was determined to be in the range between 1.4 × 10 12 and 2.6 × 10 13 eV −1 • cm −2 , which was an approximately one-order-of-magnitude reduction compared with a structure that was not subjected to the oxidization process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.