Improved light reflectance and thermal stability of Ag-based ohmic contacts on p-type GaN with La additive

Abstract

We investigated the effect of La additive on the improvement of light reflectance and thermal stability of Ag contacts on p-GaN. A high reflectance of over 90% at 460 nm wavelength and low specific contact resistivity of 5.5 x 10(-5) Omega cm(2) were obtained from La-containing Ag contacts annealed at 300 degrees C for 1 min, which also show better thermal stability than Ag contacts after annealing in air ambient. The experimental results reveal that the addition of La could effectively slow down Ag migration in < 1 1 1 > direction during annealing, and thus suppress the Ag agglomeration at elevated temperature, leading to a good ohmic contact with improved high reflectance and thermal stability. (C) 2013 Elsevier Ltd. All rights reserved.