Two-dimensional boron diffusion has been investigated on sub-micron patterned samples implanted with 1 keV B ions and diffused at 1100 °C for different times. Carrier profiles were measured by scanning capacitance microscopy (SCM) whose depth and lateral resolution was enhanced by a double bevelling sample preparation. Implants were performed at two different doses (1×1014 and 1×1015 cm−2) into patterned wafers with several stripe widths ranging from 0.5 to 5 μm. B transient enhanced diffusion is strongly reduced with decreasing feature size, depending also on the implanted dose. The phenomenon has been related to the influence of Si self-interstitials on the B transient diffusion.