Au-Si eutectic alloy formation by Si implantation in polycrystalline Au

Different doses of high-energy Si (0.2–4.5 MeV) were implanted in polycrystalline Au foils (35 μm thick) to form a low melting point Au–Si alloy which can be used for gold soldering. A Au–Si eutectic structure has been observed in the implanted Au foils after annealing at 400°C for 1 h. The Au–Si liquid phase was diffused in the polycrystalline Au foil along the grain boundaries which were flattened by the initial rolling procedure. The presence of this eutectic alloy was also observed on the back of the Au foil. Nuclear (d,p) reactions induced by deuterons have been used to measure the concentration of the implanted Si in various depths in the Au foils. RBS was also used as a complementary technique to probe the Au concentration. SEM pictures indicate that an eutectic structure was induced in the implanted samples.