Enhanced Extraction Efficiency of InGaN-Based Light-Emitting Diodes Using 100-kHz Femtosecond-Laser-Scribing Technology

A femtosecond laser was focused inside a thinned sapphire substrate to scribe the substrate and separate nitride-based light-emitting diodes (LEDs). The LED scribed by using the femtosecond laser exhibits an 11% enhancement in the output power at 20 mA, compared to that scribed by using the nanosecond laser, which is attributed to the reduction in both debris and thermal damage of the sapphire substrate. Femtosecond-laser scribing also has an advantage of high-speed processing because the extremely short pulsewidth enables it to easily reach very high peak laser intensity.