Failure mechanisms and reliability issues in LEDs

Abstract

The construction of LEDs is somewhat similar to microelectronics, but there are unique functional requirements, materials, and interfaces in LEDs that make their failure modes and mechanisms different. This chapter presents a definite, comprehensive and up-to-date guide to industry and academic research on LED failure mechanisms and reliability. It will help readers focus resources in an effective manner to assess and improve LED reliability for various current and future applications. In this review, we focus on the reliability of LEDs at the die and package levels. The reliability information provided by the LED manufacturers is not at a mature enough stage to be useful for the users of LEDs. This chapter provides groundwork for understanding of the reliability issues of LEDs. First, we present introduction about LED reliability and Physics of Failure (PoF) approach. We then categorize LED failures into 13 different groups related to semiconductor, interconnect, and package reliability issues. We close by identifying relationship between failure causes and associated mechanisms, issues in thermal standardization on LED reliability, critical areas of investigation, and development in LED technology and reliability.