Investigation of the trap states and their effect on the low-frequency noise in GaN/AlGaN HFETs

摘要

It has been suggested the surface defects and dislocations could act as the leakage paths affecting the low-frequency noise performance of the AlGaN/GaN heterostructure field-effect transistors. In this paper we report results of the capacitance-voltage (CV) characterization of SiO_2-passivated Al_(0.2)Ga_(0.8)N/GaN heterostructure field-effect transistors. From the measured frequency dependent CV profiling data, we identified the characteristics of the traps at the AlGaN/GaN interface adjoining the channel and on the surface along the ungated region between the gate and drain. Based on the measured data, the influence of the channel traps on the low-frequency noise spectra and the effect of the surface traps on possible leakage noise are analyzed and compared with previous studies.