Semiconductor LED flip-chip with dielectric coating on the mesa

A dielectric layer is formed on the mesa wall of a flip-chip LED. The dielectric layer is selected to maximize reflection of light incident at angles ranging from 10 degrees towards the substrate to 30 degrees away from the substrate. In some embodiments, the LED is a III-nitride device with a p-contact containing silver, the dielectric layer adjacent to the mesa wall is a material with a low refractive index compared to GaN, such as Al₂O₃.