Minority Carrier Lifetime in As-Grown Germanium Doped Czochralski Silicon

The minority carrier lifetime of as-grown germanium-doped Czochralski (GCZ) silicon wafers doped with germanium concentrations Ge=10¹⁶--10¹⁸cm^-3 is
investigated in comparison with conventional CZ silicon samples. It is found that the lifetime distribution along the ingot changes with the variation of Ge. There is a critical value of Ge = 10¹⁶cm^-3 beyond which Ge can obviously influence the lifetime of as-grown ingots. This phenomenon is considered to be associated with the competition or combination between the oxygen related thermal donors (TDs) and electrically active Ge-related
complexes. The related formation mechanisms and distributions are also discussed.