Strain induced suppression of silver agglomeration of indium-containing silver contact

Abstract

The mechanism for thermally stable indium-containing silver [Ag(In)] Ohmic contact on p-type GaN has been investigated. The specific contact resistivity as low as 3.8x10(-5) Omega cm(2) and a high reflectance of 88.4% at a 460 nm wavelength were obtained by annealing Ag(0.5 wt % In) alloy contact at 450 degrees C in air ambient. The In atoms in Ag matrix made In-O chemical bonds, producing a tensile stress in the film. This compensated thermal compressive stress built in the Ag film. As a result, In atoms in Ag film play a role in preventing Ag contact from agglomeration, leading to high reflectance and good thermal stability. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3430509]