| 摘要 |
PROBLEM TO BE SOLVED: To increase the effective area of charge storage electrode on a restricted area by a method wherein, after the formation of a polysilicon film formed of an oxide byproduct inside a contact hole, the oxide byproduct is removed to form the charge storage electrode of the porous polysilicon films. SOLUTION: After the successive formation of a field oxide film 2, a word line 4, a junction region 3, an interlayer oxide layer 5 and a bit line 6, the upper side of the whole structure is flattened by a flattening insulating film 7 to evaporate an amorphous silicon layer 8 including oxygen on a conductive layer for the charge storage electrode in the formed state of a charge storage electrode contact hole. Next, when the whole body is heat-treated, oxide byproducts 10 in SiOx form are formed between crystalline lattice among crystallized silicons 9 while crystallizing the silicon films in amorphous state. Finally, the oxide byproducts 10 are wet-removed so as to complete the charge storage electrodes 9 by the crystallized silicon only in porous polysilicon form. |
