The p-n and n-n heterostructures, grown via low-pressure chemical vapor deposition, were investigated by using thermal admittance spectroscopy. Various types of defect were isolated and located. Data on the distribution of defects at a p-SiC/n-GaN interface yielded thermal activation energies of 0.087eV at a bias of 5V and of 0.072eV at a bias of 8V. Three bulk defects, with activation energies between 0.155 and 0.175eV, were also found. By comparing the admittance spectra of the p-type SiC substrate, one level was identified as being an Al acceptor in SiC, while the other defects were suggested to be electron traps in the GaN layer.

Interface and Bulk Defects in SiC/GaN Heterostructures Characterized using Thermal Admittance Spectroscopy. H.Witte, A.Krtschil, M.Lisker, J.Christen, M.Topf, D.Meister, B.K.Meyer: Applied Physics Letters, 1999, 74[10], 1424-6