Gold/Germanium Eutectic (Au88/Ge12) - Material Information

The Gold/Germanium (Au–Ge) eutectic alloy is a precision-engineered solder widely used in microelectronics and high-reliability applications. With its distinct eutectic composition of approximately 88 atomic percent gold and 12 atomic percent germanium, this alloy exhibits excellent wetting, bonding, and hermetic sealing properties. Its consistent melting point of 356 °C makes it ideal for joining components that demand high stability and low contamination.

Material Overview

The Au–Ge eutectic alloy forms a uniform microstructure characterized by fine intermetallic compounds distributed within a gold matrix. The eutectic reaction occurs at 361 °C, but the Au₈₈Ge₁₂ ratio achieves an optimized melting point of 356 °C with high thermal and chemical stability. The electrical resistivity is typically around 5.0 ??·cm, and the alloy demonstrates a thermal conductivity of approximately 30 W·m⁻¹·K⁻¹. The hardness and ductility balance make it suitable for precise metallurgical applications, while its oxidation resistance ensures long-term durability in harsh environments.

Applications and Advantages

Au–Ge eutectic alloys are widely used in semiconductor device packaging, die bonding, and optoelectronic assembly. Their eutectic behavior allows for rapid and clean joining, minimizing thermal stress on delicate components. The alloy’s superior wetting on silicon, germanium, and various metallic substrates ensures strong metallurgical adhesion. Additionally, Au–Ge joints remain void-free and thermally stable even under high cycling conditions, making them invaluable for aerospace, defense, and photonics applications. Compared with traditional tin-based solders, Au–Ge alloys provide better conductivity, minimal interdiffusion, and improved reliability over time.

Goodfellow Availability

Goodfellow supplies Gold/Germanium Eutectic (Au88/Ge12) alloys manufactured to high purity standards for precision soldering and bonding applications. Custom dimensions and compositions are available upon request to meet the requirements of microelectronic and optical component assembly. Researchers and engineers can explore options suitable for vacuum-compatible and high-temperature joining processes through the Goodfellow online catalogue.

Explore Gold/Germanium Eutectic (Au88/Ge12) - Material Information and other advanced materials in Goodfellow’s online catalogue: Goodfellow product finder.