High Reliability of Ag Reflectors with AgCu Alloy for High Efficiency GaN-Based Light Emitting Diodes.

We propose an Ag reflector layer with an AgCu alloy layer as a thermally reliable reflector for high power flip-chip and vertical light emitting diodes (LEDs). By annealing the deposited Ag and Cu layers, intermixed grains and grain boundaries from the alloyed AgCu layer were formed on the LEDs, and CuO nano dots precipitated at the grain boundaries. A thick AgCu layer was deposited to cover the AgCu alloy layer.