Study on doping and microwave permittivity of SiC powders

SiC powders doped with aluminum in the method of thermal diffusion were prepared at 1800°C, 1900°C, and 2000°C respectively, and the permittivity and structure of SiC powders before and after thermal diffusion were investigated. There is no obvious change in the morphology and phase structure before and after the doping processes. Both the real and the imaginary parts of the permittivities of the Al-doped SiC powders are improved much more than those of the original SiC powders, and increase with the doping temperatures. It is believed that, the high values of both the real and the imaginary parts of the permittivity are due to electric relaxation and conductivity losses as result of aluminum atoms doped in silicon carbide lattice.