A. M. Glowacki, C. Boit, TUB Berlin University of Technology, Berlin, Germany; R. Lossy, J. Würfl, Ferdinand Braun Institut für Höchstfrequenztechnik, Berlin, Germany

Summary: Non-degraded and degraded AlGaN/GaN HEMT devices have been characterized electrically and investigated in various operating modes using integral and spectrally resolved photon emission (PE). In non-degraded device the PE dependence on the gate voltage is similar to that known from silicon MOSFETs, although the physical origin is different. The maximum exists at the intermediate gate voltage of (around -3.6V). For the positions of the strongest degradation in degraded devices this shape is disturbed. Two or more maxima could be measured. PE spectroscopy was performed at various bias conditions. For both devices broad spectra have been obtained in a wavelength regime from visible to near-infrared, including local performance variations. Signatures of the degradation have been determined in the electrical characterization, in integral PE and in the PE spectrum.