Improvement of Thermal Dissipation of GaN-Based Micro Cavity Light-Emitting Devices

Abstract

Double dielectric DBR based GaN-based micro cavity light emitting devices with two different structures were fabricated, and their thermal characteristics were investigated. To improve thermal dissipation, an AlN current confinement layer with a much higher thermal conductivity than SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and an electroplated copper heat sink were utilized. The thermal resistance of the device decreased from 923 K/W to 457 K/W, half of that obtained with the typically used SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> current confinement layer and bonded substrate. This is the lowest reported value in GaN-based micro cavity light-emitting devices with double dielectric DBRs. Temperature distribution and heat flux inside of the device was simulated based on a steady state quasi three-dimensional cylindrical model. The results show that heat transport in vertical direction is efficiently bypassing the bottom DBR to the copper plate. This work provides an effective method to improve thermal characteristics of GaN-based micro cavity light-emitting devices with double dielectric DBR structure.