Reduced pressure, chemical vapor deposited polycrystalline silicon films (5000 A˚ thick) over thermally grown SiO2on (100) silicon wafers are recrystallized by a scanning electron microscope modified electron beam annealing system. On the basis of transmission electron microscope bright‐field images and electron diffraction patterns, large grained polycrystalline silicon films of 20‐&mgr;m average grain size are obtained after electron beam annealing. Electron beam current, scanning rate, and annealing repetition are found to be important parameters in the recrystallization. Optimum values for them are from 1.6 to 1.9 mA, from 40 to 80 cm/sec, and from 5 to 10 times, respectively.