InGaN-Based Light-Emitting Diodes with a Cone-Shaped Sidewall Structure Fabricated Through a Crystallographic Wet Etching Process

Abstract

The InGaN-based light-emitting diodes (LEDs) were fabricated through a crystallographic etching process to increase their light extraction efficiency. After the laser scribing and the selective lateral wet etching processes at the LED chip edge region, the stable crystallographic etching planes were formed as the GaN {1012e} planes and had an including angle with the top GaN (0001) plane measured as 40.3 degrees. The AlN buffer layer acted as the sacrificial layer for the lateral wet process with a 27.5 mu m/h etching rate. The continuous cone-shaped sidewall (CSS) structure of the treated LED has a larger light-scattering area and higher light extraction cones around the LED chips. The LED with the CSS structure around the chip edge region has a higher light output power compared to a conventional LED when measured in LED chip form.