Semiconductor devices and methods for manufacturing the same

A method for manufacturing a semiconductor device, comprising the steps in sequence of:

• forming, on a substrate, a first shielding sub-layer on the substrate and also a first spacer on a sidewall of the first shielding sub-layer;
• forming one of source and drain regions with the first shielding sub-layer together with the first spacer as a mask;
• forming a second shielding sub-layer on the substrate next to the first spacer and removing the first shielding sub-layer;
• forming the other of the source and drain regions with the second shielding sub-layer together with the first spacer as a mask;
• removing the first spacer;
• forming a first gate dielectric layer and a floating gate layer on the substrate with the second shielding sub-layer left thereon;
• forming, on the floating gate layer, a mask layer as a spacer on a sidewall of the second shielding sub-layer, and patterning the floating gate layer with the mask layer as a mask, and then removing the mask layer;
• and
• forming a second gate dielectric layer on the first gate dielectric layer and the patterned floating gate layer, and forming, on the second gate dielectric layer, a gate conductor as a spacer on the sidewall of the second shielding sub-layer.