Semiconductor devices and methods of fabricating the same

A semiconductor device comprising:

• a fin-shaped active region protruding from a substrate;
• a field insulating layer on the substrate, the field insulating layer being on a side of a lower portion of the fin-shaped active region and absent from an upper portion of the fin-shaped active region;
• a first silicon oxide layer extending along a surface of the upper portion of the fin-shaped active region;
• a high-k insulating layer on the first silicon oxide layer and the field insulating layer;
• a barrier metal layer on the high-k insulating layer;
• a second silicon oxide layer on the barrier metal layer, the barrier metal layer extending between the second silicon oxide layer and the high-k insulating layer, and the second silicon oxide layer extending along an upper surface of the field insulating layer;
• and
• an upper gate electrode on the second silicon oxide layer, the upper gate electrode crossing the fin-shaped active region,
• wherein the barrier metal layer directly contacts the second silicon oxide layer.

A semiconductor device comprising:

• a fin-shaped active region protruding from a substrate;
• a gate insulating layer on the substrate and fin-shaped active region;
• a lower gate electrode on the gate insulating layer, the lower gate electrode comprising a barrier metal layer;
• a silicon oxide layer on the lower gate electrode;
• and
• an upper gate electrode on the silicon oxide layer, the upper gate electrode having a thickness different from a thickness of the lower gate electrode,
• wherein the fin-shaped active region has top, right, and left sides, and
• wherein the lower gate electrode, the silicon oxide layer, and the upper gate electrode extend along the top, right, and left sides of the fin-shaped active region.