GaN/SiC Quasi-Substrates for GaN-Based LEDs

GaN/SiC templates are evaluated as quasi-substrates for GaN device technology. The GaN/SiC templates offer quasi-homoepitaxial growth conditions and benefit from general advantages of SiC substrates, i.e. vertical device design, high thermal conductivity, low processing costs, etc. The thin HVPE-deposited GaN layers significantly reduce thermal stress, bowing and cracking as compared to thick GaN/sapphire quasi-substrates. The templates are assessed from the performance of MOVPE grown UV-emitting GaN/InGaN double heterostructure LEDs. The LEDs are grown directly on the quasi-substrates using parameters established for GaN/sapphire technology. Compared to InGaN/GaN/sapphire LEDs narrower electroluminescence and higher output powers are obtained.