Semiconductor device and method of fabricating the same

A semiconductor memory device, comprising:

• a substrate, comprising a plurality of active areas and a shallow trench isolation;
• a plurality of bit lines, separately disposed on the substrate, each of the bit lines comprises a conductive layer and a capping layer stacked from bottom to top, and a top portion of the capping layer comprises a plurality of protrusions;
• a bit line contact, disposed below one of the bit lines to extend into one of the active areas, wherein one of the protrusions is disposed around the bit line contact;
• a spacer, disposed on sidewalls of each of the bit lines and the bit line contact;
• and
• a storage node contact, disposed on the one of the active areas, the storage node contact and the bit lines are alternately arranged with each other.

A method of fabricating a semiconductor memory device, comprising:

• providing a substrate, comprising a plurality of active areas and a shallow trench isolation;
• forming a plurality of bit lines separately disposed on the substrate;
• forming a bit line contact below one of the bit lines, the bit line contact being extended into one of the active areas;
• forming a spacer on sidewalls of each of the bit lines and the bit line contact;
• forming a liner layer on the substrate along an outer periphery of the bit line contact, wherein the liner layer comprises a first portion embedded in the one of the bit line, and the first portion is disposed between the bit line contact and the one of the bit lines in an extending direction of the bit lines;
• and
• forming a storage node contact on the one of the active areas, the storage node contact and the bit lines are alternately arranged with each other.