Improving the dielectric properties of SiC powder through nitrogen doping

Nitrogen-doped SiC powders were synthesized by combustion synthesis using α-Si₃N₄ as solid nitrogen dopant. Results showed that β-SiC phases were produced and the introduction of α-Si ₃N₄ resulted in the decrease of particle size of β-SiC powder. The complex permittivities of the undoped and doped samples were determined in the frequency range of 8.2-12.4 GHz. The real part ε′ and imaginary part ε″ of the complex permittivity of doped SiC powder were greatly increased compared to undoped one. The mechanism of nitrogen doping on increasing the complex permittivity of SiC has been discussed, indicating that N_C defects contribute to higher permittivity.