Semiconductor memory devices including an air gap and methods of fabricating the same

A semiconductor memory device, comprising:

• a semiconductor substrate including a first trench that defines active regions in a first region and a second trench in a second region around the first region;
• a gate electrode on the first region that crosses the active regions;
• a data storing pattern that is between the gate electrode and the active regions;
• a blocking insulating layer that is between the gate electrode and the data storing pattern and that extends over the first trench to define a first air gap in the first trench;
• and
• an insulating pattern that is spaced apart from a bottom surface of the second trench to define a second air gap in the second trench;
• wherein the first and second trenches have substantially a same depth,
• wherein the first air gap includes a first vertical height and the second air gap includes a second vertical height, and
• wherein the first vertical height is greater than the second vertical height.