Effect of LED Die-Attachment on Stress in GaN Eip-Layers and Anelastic Behavior(2/3)

Nowaday, GaN LED gradually replaces the traditional lighting source. Temperature is the important factor affecting photoelectric property of GaN LED and the lifetime of GaN LED. LED die-attachment process is critical to improve the thermal dissipating problem. This process determines the reliability of LED chip on thermal dissipating substrate. Hence, the process will significantly affect the LED's thermal dissipation efficiency and device reliability.This project will study how does temperature and AuSn bonding layer thickness affect the stress in GaN LED film after die-attachment process. Also, we carefully analyze the distribution of the piezoelectric field induced by the stress inside the GaN film. Futhermore, this project will discuss the tilting of the energy levels of MQWs in the GaN film before and after die-attachment process and the degree affecting LED photoelectric property. Ultimately, we will study the relationship between the GaN film quality and anelastic strain, and measuring the amount of anelastic strain as a method of testing the amount of defect in the LED film.