High resolution section topographs are made with synchrotron radiation using exposure times that are 1/1000 or less of those necessary with conventional x-ray sources. The imaging technique is employed to study oxygenrelated defects and their spatial distribution in a large number of annealed p-type (100) Czochralski silicon wafers. A two-step annealing in nitrogen consisted of a nucleation cycle at 800 °C and at 825 °C for 20 h followed by a denuding cycle at 1100 °C for 6 h. Denuded zones measuring from zero to 100 μm are seen in the synchrotron section topographs made after oxidation of the wafers at 1100 °C for 2 h. The denuded zone formation is found to depend strongly on the part of the crystal from which the wafer is cut. The wafers have the same interstitial oxygen concentration but different carbon concentrations. Large spatial variations up to 100 μm of the denuded zone width are observed in some wafers. Synchrotron section topographs of the wafers in which CMOS devices were fabricated showed a denuded zone only if the wafers were thremally annealed before the IC process.