Apparatus and method for forming a polycrystalline silicon thin film by
converting an amorphous silicon thin film into the polycrystalline
silicon thin film using a metal are provided. The method includes: a
metal nucleus adsorbing step of introducing a vapor phase metal compound
into a process space where the glass substrate having the amorphous
silicon formed thereon is disposed, to adsorb a metal nucleus contained
in the metal compound into the amorphous silicon layer; a metal nucleus
distribution region-forming step of forming a community region including
a plurality of silicon particles every metal nucleus in a plane boundary
region occupied by the metal compound by a self-limited mechanism due to
the adsorption of the metal nucleus; and an excess gas removing step of
purging and removing an excess gas which is not adsorbed in the metal
nucleus distribution region-forming step.