Semiconductor device with air gap

The method according to claim wherein the forming the second conductive patterns comprises:

• forming a metal layer over the liner layer;
• silicidation-reacting the metal layer and the liner layer through annealing;
• and
• removing any unreacted metal layer.

A method of fabricating a semiconductor device, the method comprising:

• forming a plurality of conductive structures that include conductive patterns, over a substrate;
• forming protective spacers on sidewalls of the conductive structures;
• forming isolation structures that include openings, between the plurality of conductive structures;
• forming sacrificial spacers on sidewalls of the openings;
• forming, on the sacrificial spacers, first conductive patterns that are recessed in the openings;
• removing the sacrificial spacers to define air gaps;
• forming a liner layer that caps the first conductive patterns and the air gaps;
• forming second conductive patterns through silicidation of the liner layer;
• and
• forming third conductive patterns over the second conductive patterns.

A method of fabricating a memory device, the method comprising:

• forming a dielectric layer over a substrate;
• forming a plurality of bit line structures over the dielectric layer;
• forming first spacers on sidewalls of the plurality bit line structures;
• forming isolation structures, which include contact holes, between the plurality bit line structures;
• forming sacrificial spacers on sidewalls of the contact holes;
• forming second spacers on sidewalls of the sacrificial spacers;
• enlarging bottom portions of the contact holes;
• forming recessed first plugs in the enlarged contact holes;
• removing the sacrificial spacers to define air gaps;
• forming an ohmic contact layer to cap the first plugs and the air gaps;
• and
• forming second plugs over the ohmic contact layer.