Capacitance characterization of AlN/GaN double‐barrier resonant tunnelling diodes

We report on the electrical characterization of AlN/GaN/AlN double-barrier resonant tunnelling diodes (RTDs) using steady-state current-voltage and capacitance-voltage (C-V) characteristics in a wide frequency range with 2 kHz steps. The C-V characteristics of a double-barrier RTD show different behaviour under forward and reverse polarities and a strong dependence on frequency. The monotonous growth of capacitance at forward bias was registered, while a more complicated dependence was observed at reverse voltages. In order to analyse this dependence, a self-consistent calculation of the potential profile of the structure was performed taking into account polarization effects at the AlN/GaN interfaces. The peculiarities are analysed in the model of possible charge trapping at the interface states. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)