ABSTRACT
In order to improve the luminous efficiency of GaN-based light-emitting diodes flip chips and optimize the distributed Bragg reflector (DBR) and its preparation process, a high-reflectivity distributed Bragg reflector (DBR) was prepared by using high-low refractivity materials SiO2/TiO2. Firstly, the reflectivity characteristics of the distributed Bragg reflector is expounded and DBR reflectors with different cycles of alternating SiO2/TiO2 are designed and prepared for photoelectric performance tests and color rendering index tests at different color temperatures. By changing the lithography exposure to improve the coating of DBR reflectors, DBR with the size of 457μm*760μm is prepared, the lithography exposure was 60mJ, the undercut length is 1.46μm, and the slope angle is 30°. The experimental results show that the reflectivity of 18-cycle DBR reflectors with in the band of 300 nm ~ 650 nm is more than 98%.
