A Method for Current Spreading Analysis and Electrode Pattern Design in Light Emitting Diodes (LEDs)

Abstract

We successfully developed a 3-D electrical circuit model consisting of resistances and intrinsic diodes to analyze the current spreading effect in an InGaN/GaN multiple-quantum-well light-emitting diode. Each circuit element was formulated by physical parameters such as structural dimensions or material properties. We obtained a good agreement between the measured 2-D light intensity distribution emitted from the surface of a fabricated device and that calculated with our model. With our design tool and each epitaxial layer parameter, we investigated the correlation of the geometrical pattern of the electrode with the light intensity distribution, saturation of output power, and reliability. Our analysis method also shows that defect locations due to electrostatic discharge stress are closely related to the area of current crowding.