The demarcation of Sb‐doped Si buried layer structures has been investigated following silicidation‐enhanced diffusion. After Co and Ti silicidation at 700 and 800 °C, respectively, two‐dimensional perspectives of the two buriedn/pjunction interfaces have been obtained by optical microscopy of bevel‐polished and etched (or stained) cross sections. Greatly enhanced and asymmetric diffusion of Sb buried layers is observed under silicided regions, as well as at large distances from the edges of silicided stripes. Excellent correlation of micrographs with one‐dimensional experimental secondary ion mass spectrometry profiles was obtained. Metrology and shallow junction processing/characterization issues are discussed.