수직 구조 발광 다이오드에서 열 방출 향상과 Sn 확산 방지층에 대한 연구

Abstract

We demonstrated the GaN based vertical light emitting diodes with enhanced heat dissipation. This device had a new utilizing receptor which was the Cu extreme flat substrate. GaN based V-LED occurs much higher temperatures so we could design to extract much heat with Cu extreme flat substrate which has much higher thermal conductivity, 401 W/m•K. As the result, the forward voltage of Cu (Vf=3.15V) was lower than Mo (Vf=3.21V) and Si (Vf=3.28V) and this result could be connected with a reliability test. After all, the Cu substrate device (more than 600 hour) could be lost lasting than Mo (450 hour) and Si (530 hour) substrate. However, wafer bowing is a big problem in some metals with high thermal expansion coefficient. So we suggest a low temperature bonding with Au-Sn(1:9). But, there was still the Sn diffusion problem so we could need to design new Sn diffusion barrier. In this dissertation, Ni/Cu and W/Mo diffusion barriers had a hopeful outlook. More than 7 multi layers of Ni/Cu and W/Mo could block Sn diffusion at the V-LED structure. Consequently, Ni/Cu and W/Mo multi layers were confirmed a distinct possibility as a Sn diffusion barrier. In conclusion, these results clearly represent enhanced V-LED characteristics, heat dissipation and reducing wafer bow with a low temperature bonding.