An improved small-signal equivalent model was introduced to eliminate the frequency dispersion phenomenon in capacitance-voltage measurement, and a new mathematic method was proposed to calculate the amount of bulk defect existing in the GaN buffer layer. Compared with photoluminescence and high-resolution X-ray diffraction data, it was identified that the main component of the bulk defect concentration was made up of the point defect concentration, rather than the edge dislocation concentration. All of these results proved the accuracy of the improved capacitance-voltage model and the feasibility of the mathematic model.

Point Defect Determination by Eliminating Frequency Dispersion in C-V Measurement for AlGaN/GaN Heterostructure. L.Li, L.Yang, J.Zhang, L.Zhang, L.S.Dang, Q.W.Kuang, Y.Hao: Solid-State Electronics, 2012, 68, 98-102