Comparison of Properties of Thin Film AlGaInP LEDs with Composite Metal and Si Substrates

Abstract

N-side up thin-AlGaInP epilayers based on vertical light-emitting diodes (VLEDs) (light emitting area: 44 mil x 44 mil) with Si and composite metal (copper/Invar/copper; CIC) substrates were obtained by wafer bonding and epilayer transferring technologies. The coefficients of thermal expansion of the Si and CIC substrates were about 2.6 x 10(-6) /K and 6.1 x 10(-6) /K respectively. The coefficient of thermal expansion of CIC was matched to the GaAs substrate and AlGaInP epilayer. After the epilayer transferred to the CIC substrate, a small amount of bending occurred. The performance of the packaged LEDs/CIC was almost the same with that of LEDs/Si. The redshift phenomenon was from 623 to 643 nm for the CIC/LEDs while that of the LEDs/Si chip was from 625 to 643 nm with an injected current from 100 mA to 1 A and high output power (251 mW at 1 A) as compared to packaged LEDs/Si (299.5 mW at 1 A). The variation in light-emitting wavelengths of the LEDs/CIC was the same with that of the LEDs/Si. The distribution of the temperature of the LEDs on the CIC substrate was less than the LEDs on Si throughout the surface. The obtained data suggested that CIC could be extended instead of a Si substrate for high-power thin film LEDs applications. (c) The Author(s) 2019. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.