High thermal conductivity electrical insulator. AlN approaches metal-level heat transfer while remaining dielectric — the specifier's choice for power-electronics substrates.
Used for: power-electronics substrates · heat spreaders · IGBT modules · LED carriers · semiconductor handling · molten-metal nozzles
Aluminium nitride is a hexagonal covalent ceramic with an unusual combination of properties — high thermal conductivity (typically 170–220 W/m·K, an order of magnitude above alumina), high electrical resistivity and a coefficient of thermal expansion matched closely to silicon. It is the standard ceramic substrate for high-power electronics.
AlN’s thermal conductivity approaches that of metals while its dielectric strength remains in the kV/mm range. The CTE of ~4.5 × 10⁻⁶/K is well matched to silicon and to many semiconductor packaging materials, minimising thermal-cycling fatigue. It is non-toxic, unlike beryllium oxide.
Before AlN, beryllium oxide (BeO) was the only ceramic combining metal-level thermal conductivity with electrical insulation, but BeO dust is highly toxic. AlN matches or exceeds BeO performance for most substrate applications with no health hazard — and is now the dominant specification for IGBT and high-power-LED carriers.
Substrates and heat spreaders in IGBT modules, RF power amplifiers, laser diode carriers and high-brightness LEDs. Also used in semiconductor wafer-handling chucks, evaporation boats and selected molten-metal contact applications.
| Grade | Purity | Max temp | Density | Hardness | Typical use | Find products |
|---|---|---|---|---|---|---|
| AlN — standard | ~98% | 1400 °C inert | 3.3 | 1200 HV | General-purpose substrate, ~170 W/m·K | → Find products |
| AlN — high TC | ~99% (low O₂) | 1400 °C inert | 3.3 | 1200 HV | Premium thermal-management substrate, ~220 W/m·K | → Find products |
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AlN’s thermal conductivity is roughly 8–10× higher than 96% alumina, but its dielectric strength and CTE are also in the right band for power-semiconductor substrates. Where heat dissipation governs, AlN is the right call; for less thermally loaded parts, alumina remains cheaper.
AlN slowly hydrolyses in humid conditions, forming a thin surface aluminium-hydroxide layer that releases trace ammonia. For most packaged electronic applications this is negligible; sealed devices are unaffected.
AlN forms a protective alumina layer in air to ~700 °C. For higher-temperature oxidising service, specify with us — service ceilings depend on grade, geometry and atmosphere.
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