Investigation of deep energy levels in heterostructures based on GaN by DLTS

In this paper we report our results of DLTS investigations of deep-level defects in Schottky-gate AlGaN/GaN LP-MOVPE structures grown on sapphire substrate. The exact location of heterostructure´s interface below the surface (20 nm) was determined from the concentration profile to depletion region width dependence. The free charge carrier density was calculated (n2D = 4.75÷5.09×10¹⁶ m⁻²). Four deep energy levels have been identified from selected DLTFS spectra (activation energies: E1=EC−0.545 eV, E2=EC−0.599 eV, E3=EC−0.642 eV, and E4=EC-1,118 eV).