An AlN Sacrificial Buffer Layer Embedded into the InGaN Light Emitting Diodes for a Chemical Lateral Etching Process

Abstract

High chemical lateral etching rate at AIN buffer/sacrificial layer embedded into GaN/patterned-sapphire substrate of InGaN-based light emitting diode (LED) was achieved. An air-void structure was observed at a truncated triangular patterned sapphire that provided an empty space to increase the lateral etching rate of the AIN sacrificial layer. A 30 μm wide lateral etched region was observed around the LED chip. After a chemical lateral wet-etching process on AlN sacrificial layer and a bottom-up N-face etching process on GaN epitaxial layer, the stable crystallographic etching planes were formed as GaN {1011} planes. The treated LED structure had a higher light-output power and a smaller divergent angle compared with conventional LED structure that had the potential application for the chemical lift-off process.