Semiconductor devices having field effect transistors with epitaxial patterns in recessed regions

A semiconductor device comprising:

• a device isolation pattern disposed in a semiconductor substrate to define an active area;
• a gate line intersecting the active area;
• and
• an epitaxial pattern that completely fills a recess region in the active area at one side of the gate line, the epitaxial pattern including a different constituent semiconductor element than the semiconductor substrate,
• wherein the recess region includes a first inner sidewall that extends in the lengthwise direction of the gate line, a second inner sidewall that extends in the direction perpendicular to the lengthwise direction of the gate line and a third inner sidewall that is opposite the first inner sidewall and that is between the active area under the gate line and the first inner sidewall,
• wherein the active area comprises the first inner sidewall and the device isolation pattern comprises at least a portion of the second inner sidewall,
• wherein the epitaxial pattern directly contacts the first inner sidewall and the second inner sidewall of the recess region, and
• wherein the first inner sidewall is spaced apart from the device isolation pattern.