A process‐induced metastable defect inn‐type silicon is reported. The defect is found close to the wafer surface after combination of ambient gas‐flow annealing at ≊900 °C depending on subsequent cleaning procedure. The defect gives rise to a band‐gap levelEc−Et=0.25 eV observed by deep‐level transient spectroscopy after reverse‐bias cooling of the sample. Both annealing and generation of the defect proceed by 1st order processes. The activation enthalpies (&Dgr;E) and pre‐exponential factors (v) have been determined from Arrhenius analyses; the results are &Dgr;E=0.63 eV and &ngr;=1⋅1012s−1for annealing, and &Dgr;E=0.65 eV and &ngr;=6⋅1014s−1for generation. ©1995 American Institute of Physics.