PURPOSE: To contrive improvement and the like of characteristics of an element by forming grooves in a silicon thin film in the direction that is parallel to a beam scanning direction and separating silicon thin film into several parts before performing a fusion-recrystallization process, thereby forming a protective insulating film in the grooves and on the silicon thin film.

CONSTITUTION: An SiO2 film 11 of 2μm thickness is deposited on a face-oriented single crystal silicon substrate 10 by a CVD process and then, an opening 12 which acts as a seed in the case where recrystallization is performed is formed by the use of the water solution of ammonium fluoride. Then a polycrystal silicon film 13 of 0.4μm thickness is deposited on the SiO2 film 11 and in the opening 12 by the CVD process in which the thermal decomposition of silane is used. Subsequently, grooves 14 are formed in the silicon film 13 by the use of reactive ion etching to separate the polycrystal silicon film 13 into stripes in such a way that each stripe is 30μm or less in width and the stripes are spaced about 2μm apart. The manufacturing work of this element is thus completed by forming an SiO2 film 15 of 0.5μm thickness on the silicon film as a protective insulating film. Therefore, no silicon is cohesive when it is molten through the irradiation of electron beam.