3D characterization of the eutectic Au–Si alloy by using a nuclear microprobe

Abstract

The quantitative analysis of silicon in gold is performed in the three dimensions by the spectroscopy of protons produced in various depths by scanning a microbeam of energetic deuterons. Owing to the high Coulomb repulsion of incident deuterons by heavy nuclei (like gold), proton emission can only be induced on light elements. The incident deuterons may approach silicon nuclei at a sufficiently close distance to be broken and to give rise to an emission of energetic protons. Measuring the energy of these protons leads to a quantitative method of analysis of silicon at various depths under the surface of the irradiated material. The spatial resolution in the three dimensions of space lies around 3 microns. Application is made to the study of eutectic gold‐silicon alloys formed, in situ, and used for the soldering of gold at a low temperature (400° C).

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

“…The speed of di usion is so high (a few minutes are su cient for 35 lm thick foils) that any process of solid-state di usion may be discarded; only migration of a liquid phase is possible. The present SEM picture is almost the same as the one observed in the Si ®lm deposited on the Au foil, as reported earlier [5,8,9]. The p 0 and p 1 groups induced by 2.98 MeV deuteron on the Si-implanted (2 MeV, 2.9´10 17 at./cm 2 ) sample is depicted in Fig.…”

“…Measuring the energy of those protons leads to a quantitative method of analysis of Si at various depths under the surface of the irradiated material. The advantages for using this technique have been explained in earlier publications [8,9]. A beam of 2.98 MeV deuterons was focused (1 mm 2 ) on the Si-implanted Au foils.…”