Design and Optimization of Flip-Chip Light-Emitting Diode with High Light Extraction Efficiency

In order to improve the light extraction efficiency of flip-chip light-emitting diode (LED), we propose to prepare a SiO2 dielectric grating on the sapphire substrate surface and form a surface grating flip-chip LED structure. The surface grating flip-chip LED model is established by the CAD module of RSOFT software. Then, the LED module of RSOFT software is used to simulate and optimize the surface grating flip-chip LED. Simulation optimization and theoretical analysis show that, when p-GaN layer thickness h(p)= 220 nm, n-GaN layer thickness h(n)= 100 nm, sapphire substrate thickness h(s) =130 nm, grating period p =260 nm, grating thickness h(g) =20 nm, grating duty cycle f =0. 02, the light extraction efficiency of the surface grating flip-chip LED can reach to 49.12%, compared to the best normal flip-chip LED light extraction efficiency (30.56%), the efficiency raises by 63%. The research can provide theoretical research methods for the future design of LED with high light extraction efficiency, and provide theoretical guidance for the preparation of devices.