ABSTRACT
Group III–nitride semiconductors and their ternary solid solutions are very promising as the candidates for both short-wavelength optoelectronics and power electronic devices. Major developments in wide-gap III–nitride semiconductors have led to the commercial production of high-brightness light-emitting diodes (LEDs). The InGaN-based LEDs have been extensively used in full-color displays, traffic displays, and various other applications such as projectors, automobile headlights, and general lighting. This chapter discusses the characteristics of GaN film grown on patterned sapphire substrate (PSS). It describes the effect of residual stress of InGaN/GaN films after sapphire lapping and polishing. The chapter deals with chip breaking using traditional diamond tip scribing. It discusses a method of LED-chip separation using the 100 kHz femtosecond laser scribing technique to improve the output power of LEDs through the reduction of both the debris and the thermal damage of sapphire substrate.
