The impact of rapid thermal annealing on the electrical and materials characteristics of Re Schottky contacts on n-type GaN and AlxGa 1-xN (x=0.10 and 0.26) was investigated. Effective barrier heights were obtained from current-voltage and modified Norde measurements on diodes annealed at up to 800°C. For AlxGa1-xN with x>0, Schottky barrier heights were found to increase upon annealing from the as-deposited state, but decreased sharply after annealing at 600°C. Modified Norde measurements indicate that this degradation could be explained by the existence of a shunt conduction path with an associated barrier height below 0.46 V, possibly a consequence of an inhomogeneous interface after annealing at temperatures above 600°C. A new defect lying at 0.34 eV below the conduction band edge was also detected by deep level transient spectroscopy after contact degradation.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)