Performance enhancement of Au-Ge eutectic alloys for high-temperature electronics

A Review of Eutectic Au-Ge Solder Joints

“…[26] It was 294 found that the thermal resistance from junction to case 295 increased from 0.92 to 1. 53 [8][9][10][11][12][15][16][17]19,20,22,28,31,[34][35][36]49] Various samples tested at room temperature are compiled in the 'Nominal' series. Dashed lines are curve fits for each series.…”

“…[48] Near eutectic compositions have an irregular lamellar type microstructure, see Figure 2(a). [8,9,12,15,16,19,20,23,27,49] Another common microstructure found in literature is colonies of Ge dispersed in a Au matrix, [8,9] see Figure 2(b). This second microstructure is especially common after thermal aging which typically coarsens the grain structure.…”

“…A. Nickel/Gold (ENIG) Most commonly, eutectic Au-Ge have been used in systems with a metallization scheme based on the electroless nickel immersion gold (ENIG) system. [8,9,11,12,15,19,20,22,[26][27][28]31,33,35,36,49] In such systems, Au-Ge typically reacts with Ni and forms Ge-Ni intermetallic compounds (IMC). Lang et al and Egelkraut et al reported the intermetallic phase to be near the stoichiometric phases NiGe and Ni 2 Ge.…”