Novel Device Design for High-Power InGaN/Sapphire LEDs Using Copper Heat Spreader With Reflector

Direct integration of InGaN/sapphire LED with a cup-shaped copper heat spreader was proposed for enhancing light extraction and heat dissipation by self-aligned photolithography and copper electroforming techniques. Based on optical simulation results, geometric design for a copper heat spreader is crucial to luminous property of an LED chip. An InGaN/sapphire LED embedded with the optimized cup-shaped copper heat spreader was demonstrated to exhibit superior light output power than a conventional LED by a factor of 2.68 times at an injection current of 1 A. Moreover, the power efficiency is remarkably increased from 4.2% to 15.7% at the same driven current. The improved device performance can be attributed to both of the enhanced light extraction of the laterally emitted light from an LED chip and efficient heat dissipation by the highly reflective and excellently thermal conductive copper heat spreader. These results suggest an efficient alternative simultaneously with two functions of thermal management and light extraction for high-power InGaN/sapphire LEDs application from chip to package design.