During recrystallization of encapsulated silicon films on SiO2, by the graphite strip heater technique, the silicon sometimes breaks apart and agglomerates into small beads or stripes. By secondary ion mass spectroscopy analysis, it was found that a high concentration of nitrogen at the interface between the silicon and the top SiO2capping layer is needed to prevent this from occurring. Incorporation of hydrogen into the crystallization ambient was found to cause the beading to occur. The initial stages of the bead formation were investigated by scanning electron cross‐section microscopy.