Research Progress in High Thermal Conductivity Silicon Nitride Ceramics Prepared by Non-Oxide Additives

The development trend of high voltage, high current and high-power density of power semiconductor devices has raised the bar for the heat dissipation capability and reliability of ceramic substrates in devices.Silicon nitride (Si3N4) ceramics, known for their high thermal conductivity and excellent mechanical properties, have emerged as a preferred thermal dissipation substrate material for high-power electronic devices.However, there is a significant gap between experimental and theoretical values of thermal conductivity in Si3N4 ceramics.The long period of heat preservation during preparation leads to excessive grain growth, compromising mechanical properties and increasing costs, which hinders large-scale application.Lattice oxygen defects act as main factor limiting thermal conductivity of silicon nitride.Researchers are exploring ways to promote the removal of lattice oxygen and the full development of bimodal morphology formation of Si3N4, by selecting non-oxide sintering additives to reduce the oxygen content in the system, adjusting the composition and properties of the liquid phase and constructing a "nitrogen-rich-oxygen-deficient" liquid