Observation of deep traps responsible for current collapse in GaN metal-semiconductor field-effect transistors

Deep traps responsible for current collapse phenomena in GaN metal-semicond uctor field-effect transistors have been detected using a spectroscopic tec hnique that employs the optical reversibility of current collapse to determ ine the photoionization spectra of the traps involved. In the n-channel dev ice investigated, the two electron traps observed were found to be very dee p and strongly coupled to the lattice. Photoionization thresholds for these traps were determined at 1.8 and at 2.85 eV. Both also appear to be the sa me traps recently associated with persistent photoconductivity effects in G aN. (C) 1999 American Institute of Physics. [S0003-6951(99)04351-X].