A non destructive SEM observation method has been applied to investigate the extended defects created by pulsed electron beam annealing of arsenic–implanted silicon. The defect study was performed on bevelled samples after irradiation using variable beam fluences for both a 20°C or a 450°C specimen starting temperature. Dislocation generation resulting in subgrain boundaries formation occurs during regrowth of the silicon layer which has been heated up to the melt point or higher. For the rather penetrating electron beam pulse used in this work the subgrain size and their depth extent depend on the beam fluence and the substrate temperature. For 450°C pre‐heated samples, annealing of the arsenic implant is possible without any stable extended defect creation using the 1.0 – 1.2 J.cm−2 fluence range.