Defect introduction in epitaxially grown n-GAN during electron beam deposition of Ru schottky contacts

We have used deep-level transient spectroscopy (DLTS) to study the electric al properties of defects introduced in epitaxial n-GaN during electron beam (EB) deposition of Ru Schottky contacts. DLTS revealed that EB deposition introduces at least two defects, Eel and Ee2, with energy levels at E-c - ( 0.19 +/- 0.01) eV and E-c - (0.92 +/- 0.04) eV, respectively, in the band g ap. The defect Eel has a similar signature as a radiation induced defect in GaN, speculated to be the V-N The concentrations of Eel and Ee2 both decre ase away from the interface into the GaN. The concentration of Ee2, the mor e prominent of the two defects, is estimated as about 10(16) cm(-3) at the GaN surface. The effect of the EB deposition induced defects on the current -voltage characteristics of the Schottky contacts thus formed is to introdu ce recombination and generation components to the reverse and forward curre nts, respectively. (C) 1999 Elsevier Science B.V. All rights reserved.