DLTFS Study of Defect Distribution in InAlGaN/GaN/SiC HEMT Heterostructures

The paper introduces first results of a Deep Level Transient Fourier Spectroscopy (DLTFS) investigation, carried out on InAlGaN/GaN HEMT heterostructures grown on N-doped SiC substrate with semi-insulating epitaxial natural SiC layer and with AlGaN back barrier between an AlN nucleation layer and a GaN buffer. Authors focused their attention on defect distribution in different barrier devices formed on this heterostructure-Schottky diode, FAT transistor and transistors with different gate widths. Parameters of eleven deep levels were identified. The possibility to measure DLTFS spectra on transistors with very low capacitance was confirmed.