Semiconductor devices and methods of manufacturing the same

A semiconductor device comprising:

• a gate pattern comprising a gate insulation layer and a gate electrode formed on a substrate;
• a source/drain region formed at substantially opposite sides of the gate pattern;
• a silicide layer formed on the source/drain region;
• an insulation layer formed on the gate pattern and the source/drain region;
• and
• a contact hole formed through the insulation layer and exposing a predetermined region of the silicide layer,
• wherein the gate pattern and the source and drain regions have a step difference between a top portion of the gate pattern and a top portion of the source and drain regions of about 250 Å or less from the substrate,
• wherein the gate pattern and the source/drain region have an aspect ratio of less than about 3:1, and
• wherein the aspect ratio is a ratio of the step difference between the top portion of the gate pattern and the top portion of the source/drain region to a width of the source/drain region.