Some Defects of Blue Light Emitting Diode Wafer Preparation Technology

At present, LED chip manufacturers use four processes to make LED blue chips: 1. Sapphire substrate GaN matrix LED This is a common method used by most chip manufacturers. Although the material growth and device manufacturing level are still being improved, the sapphire substrate is not conductive, has poor thermal conductivity, is difficult to slice, has poor antistatic force, and has a complex flip-chip process. It also has large lateral resistance, high operating voltage at high current density, and wastes energy. 2. Silicon carbide substrate GaN matrix LED Because the substrate is conductive and thermally conductive, it is currently dominant in semiconductor lighting chips, but its price is too high and it is difficult to slice. 3. GaN substrate GaN matrix LED This process can significantly improve the quality of epitaxial materials, but the price is too high and the device processing is difficult. 4. Silicon wafers are used as GaN material substrates This process can make the chip have good conductivity, high crystal quality, large size, low cost, and easy processing. However, there is a huge lattice mismatch and thermal mismatch between GaN epitaxial materials and silicon substrates, so it is difficult to find device-quality GaN materials on silicon substrates.