Aluminium nitride (AlN) occupies a unique niche among technical ceramics: it conducts heat like a metal while remaining an electrical insulator. With thermal conductivity of 170–200 W/m·K — comparable to some aluminium alloys — and electrical resistivity exceeding 10¹⁴ Ω·cm, AlN is the material of choice for power-electronics substrates, LED heat sinks and RF packaging where heat must be removed without creating short circuits.
Its thermal expansion coefficient (4.5×10^−6/K) closely matches silicon, minimising thermomechanical stress on mounted dies. This combination of properties has made AlN indispensable in electric vehicles, 5G base stations, laser diodes and high-power inverters where conventional alumina substrates cannot keep up with heat flux.