The Instability of the CV Characteristics’ Capacitance When Measuring AlGaN/GaN-Heterostructures and the HEMT-Transistors Based on Them

AlGaN/GaN heterostructures and AlGaN/GaN/SiC HEMT-transistors’ Schottky barriers (SBs) are studied by the capacitance–voltage (CV) method and the SIMS method in order to determine the causes of the capacitance instability in some cases. It is shown that in most cases, the appearance of a capacitance peak on the CV curves at frequencies of 20 to 500 kHz is associated with the presence of leakage currents in the barrier layer and at low frequencies of 1 to 20 kHz with the generation–recombination centers.