This paper reports a series of X‐ray triple‐crystal diffractometry (TCD) measurements performed on annealed Czochralski‐grown silicon (ACS) single crystals to investigate in more detail the reasons for the observed broadening of double‐crystal diffractometer rocking curves described in the previous paper [Joksch, Zaumseil & Zulehner (1993). J. Appl. Cryst.26, 185–191]. It is shown that diffuse scattering by structural defects created during the high temperature heat treatment is responsible for the changes in the reflection properties. With TCD, the dominant defects are identified as stacking faults on (111) planes.