Solid-state diffusion and point defect studies evaluated by SIMS

The applicability of secondary ion mass spectrometry to tracer diffusion study in different solids has been tested. The diffusion of B and Ge has been measured in Si single crystals under different hydrostatic pressures. The isotope effect of diffusion at different temperatures has been determined for tri‐ and tetra‐valent impurities in single‐crystal Cu and Ag. The activation volumes in Si appear non‐zero or negative, in line with an interstitial type of diffusion mechanism. The isotope effect E for Ga and Ge in Cu, and for Sn in Ag, obtained by SIMS with accuracies competitive to the best radiotracer measurements, are lower than for self‐diffusion in the noble metals, in line with simple theory based on monovacancies. Near to the melting point, E increases with temperature, which is contrary to the divacancy‐attributed tendencies reported for the isotope effect of self‐diffusion in Group 1B metals. The presently observed behaviour of polyvalent impurities at high temperatures, nevertheless, does not appear easily reconcilable with only a single vacancy diffusion mechanism.