Semiconductor device including a crystal semiconductor layer, its fabrication and its operation

A semiconductor device comprising,

• a semiconductor substrate having first source/drain regions;
• an active pattern on the semiconductor substrate, the active pattern comprising a barrier pattern and a single crystalline semiconductor pattern on the barrier pattern;
• and
• a gate pattern on the single crystalline semiconductor pattern.

A semiconductor device comprising,

• a semiconductor substrate having a protruding portion from a top surface of the semiconductor substrate, the protruding portion having first source/drain regions;
• a barrier pattern on the protruding portion;
• a single crystalline semiconductor pattern on the barrier pattern, the single crystalline semiconductor pattern having second source/drain regions;
• an insulating isolation layer on the semiconductor substrate and portions of sidewalls of the protruding portion;
• and
• a gate pattern on a top surface and sidewalls of the single crystalline semiconductor pattern and on the stop surface of the insulating isolation layer, the gate pattern crossing above the single crystalline semiconductor pattern.