PURPOSE: To increase the storage capacity of the storage device by forming an uneven part on the surface of polysilicon for storage node use by a method wherein first polysilicon is etched anisotropically by making use of a sidewall protective film as a mask, a polysilicon residue is formed and second polysilicon is deposited on it and then etched anisotropically.

CONSTITUTION: First polysilicon 9 is deposited on a semiconductor substrate 1; a spontaneous oxide film on the first polysilicon 9 is etched anisotropically. Then, while a first polysilicon sidewall protective film formed by the etching operation is used as a mask, the first polysilicon 9 is etched anisotropically; polysilicon residues 12 are formed. Then, second polysilicon 13 is deposited on the polysilicon residues 12; after that, the second polysilicon 13 is etched anisotropically. For example, a contact window 9 which reaches an n+ active region for a switching transistor formed on a p-type silicon substrate 1 is opened; after that, first polysilicon 9 is deposited.