Study on the thermal conductivity and microstructure of silicon nitride used for power electronic substrate

The thermal conductivity and microstructure of Si3N4 ceramics used for power electronic substrate were studied in present paper. Thermal conductivity of Si3N4 ceramics sintered at different temperatures varied greatly. The microstructure of the specimens was studied with X-ray diffraction, EDS and transmission electronic microscope to reveal the difference in thermal conductivity. The experimental results showed that microstructure of Si3N4 ceramics sintered at different temperatures had different components in their grain phase and grain boundary phase, while electrical properties showed not much difference with different sintering temperatures.