Improvement of The Light Output of Blue InGaN-Based Light Emitting Diodes by Using a Buried Stripe -Type n-Contact and Reflective Bonding Pad

Abstract

To enhance the light output of blue InGaN-based light emitting diodes (LEDs), a buried stripe-type n-electrode, expanded stripe-type p-electrode, and reflective p-bonding pad were employed. Flip-chip (FC) LEDs with the expanded p-electrode gave forward voltages of 2.99-3.11 V at 100 mA and series resistances of 3.28-3.94 Omega. The expanded p-electrode FCLED fabricated with 375 nm-thick window and TiO2 adhesion layers produced 22.7% higher light output at 21 A/cm(2) than conventional FCLEDs. The expanded p-electrode FCLEDs revealed better current spreading efficiency than the c-FCLED, indicating the importance of the use of an optimised window and TiO2 adhesion layers. (C) The Author(s) 2019. Published by ECS.