InGaN-Based Light-Emitting Diodes With a Sawtooth-Shaped Sidewall on Sapphire Substrate

An InGaN light-emitting diode (LED) with a cone-shaped GaN structure and a sawtooth-shaped sapphire sidewall structure was fabricated through a laser-drilling process. The fabricated procedures consisted of a laser scribing/drilling process, a wet etching process, and a chip cleaving process. In the treated LED structure with the laser-drilling sawtooth-shaped sidewall, the light output power had a 16% enhancement compared to a conventional LED structure with a laser-scribing sidewall. A periodic high light emission intensity, with a 2.6- μm width spaced at regular intervals of 3.8 μm, was observed on the treated LED sidewall structure corresponding to the laser-drilling patterns. The LED structure consists of a laser-drilling sidewall and a cone-shaped GaN structure that increases the light extraction efficiency for high efficiency InGaN LED applications.