LED chips mainly include three types: sapphire substrate, silicon substrate and silicon carbide substrate
Sapphire substrate: ranked first in market share, originated from a Japanese company Patented technology. The main advantages are: good chemical stability, no visible light absorption, moderate price, and relatively mature manufacturing technology; shortcomings: poor conductivity is overcome by P and N electrodes on the same side; difficulty in mechanical cutting is overcome by laser scribing technology. However, the poor thermal conductivity does not show obvious shortcomings under low current operation, but the problem is very prominent under high current operation of power devices
Silicon substrate: The substrate is a patented technology originated from China. Advantages: high crystal quality, large size, low cost, easy processing, good electrical conductivity, thermal conductivity and thermal stability. Disadvantages: The silicon substrate absorbs light seriously, resulting in low light extraction efficiency of the silicon substrate LED
Silicon carbide substrate: second in market share. The advantages of silicon carbide are good chemical stability, good electrical conductivity, good thermal conductivity, and no absorption of visible light. The disadvantages are high price, crystal quality is difficult to be as good as sapphire and silicon, poor mechanical processing performance, and SiC substrate absorbs less than 380nm. Ultraviolet light is not suitable for the development of ultraviolet LEDs below 380nm.