Semiconductor memory device including lower contact plug protruding from sidewall spacers

A semiconductor device comprising:

• an active pattern on a substrate;
• a bit line structure on the active pattern;
• a spacer structure on a sidewall of the bit line structure;
• and
• a lower contact plug directly contacting the spacer structure,
• wherein the spacer structure includes:
• a first spacer covering a sidewall of the bit line structure;
• a second spacer directly contacting an outer sidewall of the first spacer;
• a third spacer directly contacting an upper outer sidewall of the second spacer;
• and
• a fourth spacer directly contacting a lower outer sidewall of the second spacer, and
• wherein the lower contact plug includes:
• an extension portion covered by the third and fourth spacers;
• and
• a protrusion portion extending from the third and fourth spacers, a bottom surface of the protrusion portion is disposed at a level that is lower than or equal to a level of a bottom surface of the fourth spacer.

A semiconductor device comprising:

• active patterns disposed on a substrate in first and second directions, the first and second directions being substantially parallel to an upper surface of the substrate and substantially perpendicular to each other, and each of the active patterns extending in a third direction substantially parallel to the upper surface of the substrate and having an acute angle with respect to the first and second directions;
• bit line structures disposed in the first direction, each of the bit line structures extending in the second direction on central portions in the third direction of ones of the active patterns;
• spacer structures on opposite sidewalls, respectively, in the first direction of the bit line structures;
• a contact plug structure on an end portion in the third direction of each of the active patterns;
• and
• a capacitor on the contact plug structure,
• wherein the contact plug structure includes:
• an extension portion covered by the spacer structures;
• and
• a protrusion portion protruding from the spacer structures, a bottom surface of the protrusion portion is disposed at a level that is lower than or equal to a level of a bottom surface of the spacer structures.