Influence of interface states on C-V characteristics of AlGaN/GaN heterostructures

We tried to assess the influence of interface states between AlGaN barrier and GaN buffer layer and interface states on C-V characteristics of the AlGaN/GaN structure. Interface donor states were modelled with discrete peak distribution in energy with certain energy with respect to the conduction band minimum and also by continuous distribution of interface traps in energy. We found that interface states shift C-V curves to more negative voltages and change the plateau of C-V curves as well as do deep levels situated in AlGaN layer and the deep levels in GaN change the slope of capacitance decrease after the two-dimensional electron gas depletion.