Method of manufacturing a semiconductor device with a stacked-gate-electrode structure.

摘要

A method of manufacturing a semiconductor device comprising the steps of forming source and drain regions (40, 42) in a semiconductor substrate (10) in a spaced-apart relation, forming a floating gate (26) such that it overlies a channel region between the source and drain regions with a gate insulating film (16) formed between the floating gate and the channel region and forming a control gate (38) such that it overlies a floating gate (26) with an insulating film formed between the control gate and the floating gate. An oxidation-resistant film pattern (22) is formed over a non-monocrystalline silicon layer (18) so as to have a predetermined opening (20). With the oxidation-resistant film pattern (22) as a mask, the non-monocrystalline silicon layer with the opening is selectively oxidized to form a separation insulating film (24) whereby a floating gate is formed with a part of the non-monocrystalline silicon layer insulatingly separated and a floating gate layer portion (28) adjacent to the separation insulating film is smoothly formed.