Research On SiC Substrate Etching Process For High-power GaN-based LED

Silicon carbide (SiC) is a wide bandgap semiconductor materials and ideal substrate material for GaN LED because of its chemical stability、conductivity、thermal conductivity and low lattice mismatch with GaN. During the production process for the LED chip, etching is a very important process. A lot of experiments need to be done in order to get optimized process, since there are many factors affect the etching of SiC, the orthogonal experiment can get the result with few times experiment, and widely be used.The experiment of etching SiC was design with the method orthogonal experiment. The etching rate and surface defects of SiC substrate had been studied and optimized by inductively coupled plasma (ICP), SF6and O2as the etching gas, with different etching parameters (ICP source power, ICP bias power, pressure, gas flow, gas mixing ratio) for high-power GaN LED. We got the optimized etch parameter as followed:ICP source power700w, ICP bias power400w. pressure1.5Pa, gas flow of SF6is16sccm, and gas flow of O2is4sccm. With the parameters, the etching rate of SiC is823nm/min. The results demonstrated that the surface of samples were better with defects density625个/mm2using metallurgical microscope. This work provided better process conditions for the high-power SiC-based GaN LED.