Preparation of Dome-Shaped SiO2/Al2O3 Composite-Patterned Sapphire Substrate for High-Performance Mini-LED Backlight Modules

High-efficiency mini-LED with a large light-emitting angle is the key to achieving high-quality high dynamic range (HDR) in liquid crystal display (LCD) displays. In this study, we adopted photolithography and ion beam-assisted electron beam evaporation to prepare a dome-shaped SiO2/Al2O3 composite-patterned sapphire substrate (CPSS). Simultaneously, inductively coupled plasma (ICP) dry etching was used to form a patterned sapphire substrate (PSS) as the contrast group. Combined with epitaxial growth and chip manufacturing processes, mini-LED flip chips prepared using CPSS and PSS were obtained, and mini-LED backlight modules were prepared. By comparison, we found that the CPSS-LED chip has higher external quantum efficiency (EQE), and higher EQE brings higher peak brightness, which improves the HDR performance. Simultaneously, we also found that the CPSS-LED chip has a larger light-emitting angle, and the mini-LED backlight module made of it shows a more uniform irradiance distribution and better light mixing effect. In short, we prepared a high-performance mini-LED backlight module using the CPSS-LED chip with both a large light-emitting angle and high EQE, which is expected to be used in future LCD displays.