Semiconductor device including air gaps and method of fabricating the same

A method of fabricating a semiconductor device, comprising:

• forming a plurality of bit line structures over a substrate,
• forming contact holes between the bit line structures;
• forming sacrificial spacers on sidewalls of the contact holes;
• forming silicon plugs recessed into the respective contact holes;
• forming air gaps by removing the sacrificial spacers;
• forming capping structures capping the air gaps while exposing top surfaces of the silicon plugs;
• forming ohmic contact layers over the silicon plugs;
• and
• forming metal plugs over the ohmic contact layers.

A semiconductor device comprising:

• a plurality of bit line structures formed over a substrate;
• storage node contact holes formed to have sidewalls of the bit line structures exposed therethrough;
• silicon plugs recessed and formed in the respective storage node contact holes;
• air gaps formed between the sidewalk of the bit line structures and the silicon plugs;
• capping layer patterns formed over the air gaps;
• passivation layers formed over the respective capping layer patterns;
• and
• metal plugs formed over the respective silicon plugs,
• wherein the air gaps are capped with the respective capping layer patterns and passivation layers.