Aluminum Nitride, AIN Ceramic Properties Aluminum Nitride, formula AlN, is a newer material in the technical ceramics family. While its discovery occurred over 100 years ago, it has been developed into a commercially viable product with controlled and reproducible properties within the last 20 years. .Key Aluminum Nitride Properties Good dielectric properties High thermal conductivity Low thermal expansion coefficient, close to that of Silicon Non-reactive with normal semiconductor process chemicals and gases . Typical Aluminum Nitride Uses Substrates for electronic packages Heat sinks IC packages Power transistor bases Microwave device packages Material processing kiln furniture Semiconductor processing chamber fixtures and insulators Molten metal handling components General Aluminum Nitride Information Aluminum nitride has a hexagonal crystal structure and is a covalent bonded material. The use of sintering aids and hot pressing is required to produce a dense technical grade material. The material is stable to very high temperatures in inert atmospheres. In air, surface oxidation begins above 700°C. A layer of aluminum oxide forms which protects the material up to 1370°C. Above this temperature bulk oxidation occurs. Aluminum nitride is stable in hydrogen and carbon dioxide atmospheres up to 980°C. The material dissolves slowly in mineral acids through grain boundary attack, and in strong alkalis through attack on the aluminum nitride grains. The material hydrolyzes slowly in water. Most current applications are in the electronics area where heat removal is important. This material is of interest as a non-toxic alternative to beryllia. Metallization methods are available to allow AlN to be used in place of alumina and BeO for many electronic applications. Aluminum Nitride Engineering Properties* Aluminum Nitride Mechanical Units of Measure SI/Metric (Imperial) Density gm/cc (lb/ft3) 3.26 (203.5) Porosity % (%) 0 (0) Color — gray — Flexural Strength MPa (lb/in2x103) 320 (46.4) Elastic Modulus GPa (lb/in2x106) 330 (47.8) Shear Modulus GPa (lb/in2x106) — — Bulk Modulus GPa (lb/in2x106) — — Poisson’s Ratio — 0.24 (0.24) Compressive Strength MPa (lb/in2x103) 2100 (304.5) Hardness Kg/mm2 1100 — Fracture Toughness KIC MPa•m1/2 2.6 — Maximum Use Temperature (no load) °C (°F) — — Thermal Thermal Conductivity W/m•°K (BTU•in/ft2•hr•°F) 140–180 (970–1250) Coefficient of Thermal Expansion 10–6/°C (10–6/°F) 4.5 (2.5) Specific Heat J/Kg•°K (Btu/lb•°F) 740 (0.18) Electrical Dielectric Strength ac-kv/mm (volts/mil) 17 (425) Dielectric Constant @ 1 MHz 9 (9) Dissipation Factor @ 1 MHz 0.0003 (0.0003) Loss Tangent @ 1 MHz — — Volume Resistivity ohm•cm >1014 — l