3C-SiC/AlN Distributed Bragg Reflector for GaN-based LEDs grown on large diameter silicon wafers

Abstract

The cost of Light Emitting Diodes (LEDs) is still impairing their sale for general lighting. In order to reduce the LED’s fabrication cost, the growth of efficient Gallium-Nitride (GaN)- based LEDs on large silicon (Si) wafers has consequently become an important research focus for the solid-state lighting industry. We are proposing here the use of thin-layers of silicon carbide (3C-SiC) with the aim not only to improve the nitride growth but also to enhance the light output from GaN-LEDs on Si. SiC has a lower lattice mismatch to GaN (3%) than Si (17%) which makes it more suitable for the integration of GaN-LEDs on Si wafers1. Furthermore, its large refractive index and low residual absorption make it an ideal material to develop photonic structures with the goal of reducing parasitic light absorption from the Si substrate.