A Comparison of Sapphire Substrate and Silicon Carbide Substrate

Silicon carbide has excellent thermal, mechanical, chemical and electrical properties. It is not only one of the best materials for making high temperature, high frequency, high power electronic devices, but also can be used as the substrate material based on GaN blue light emitting diodes, which has broken the situation of the sapphire unifying the whole country. Especially in the field of street lamps and outdoor lighting, it has a huge market potential. The most commonly used in the field of semiconductor SiC are 4H-SiC and 6H-SiC.

Compared with silicon carbide, the sapphire is an insulator instead of semiconductor on the structure. It can only make single sided electrode; Silicon carbide is conductive semiconductor that can do the vertical structure. The thermal conductivity of silicon carbide substrate is more than 10 times higher than the sapphire; Sapphire itself is a poor conductor of heat, and it needs to use the silver adhesives at the bottom when manufacturing devices, but the heat transfer performance of silver adhesives also has a poor heat transfer.

The electrode of chips using silicon carbide substrate is L. Two electrodes are distributed in the surface and bottom of the device, and the generated heat can be derived directly by electrode; At the same time, the substrate does not need current diffusion layer, so the light will be not absorbed by the materials in the diffusion layer, which can improve the light-extraction efficiency.

The main challenge of using silicon carbide to make photoconducting device substrate is the relatively high cost. The technical threshold and patent technology are not enough, facing the patent threat from monopolies. But the LED market has a difference about high-end, middle-end and low-end. Silicon carbide substrate LED is positioned in the high-end.

The demand of high power LED market is huge, and silicon carbide material has superior performance, big power, low energy consumption, high luminous efficiency and other significant advantages. It can well meet the demand of high power LED.