Two‐dimensional periodic arrays containing 108Si pillars with heights of 600–700 nm, widths of 100 nm, and repeat spacings of 300 nm have been fabricated using electron beam lithography on Si(001) substrates. These pillars have subsequently undergone wet oxidation at 800 °C and etching in hydrofluoric acid to produce an array of sharp tips with a height of ∼4000 Å. The x‐ray diffraction from this array appears to be dominated by scattering from the bases of the tips. Correlated variations in tip shape, observed with scanning electron microscopy, produce a modulated diffuse background in the diffracted x‐ray intensity. These observations demonstrate the feasibility of using high‐resolution x‐ray diffraction for studying defects in large‐area arrays of periodic structures.