Provided is a technique of effectively removing a metallic element that
has catalytic action in terms of the crystallization of a semiconductor
film and remains in a semiconductor film obtained using the metallic
element. With the technique of the present invention, to remove a
catalytic element used to crystallize a semiconductor film having an
amorphous structure, gettering is completed by forming a region or a
semiconductor film, to which a rare gas element is added, and by having
the catalytic element move to the formed region or semiconductor film.