Methods of forming a semiconductor device may include forming a fin-type active pattern that extends in a first direction on a substrate, the fin-type active pattern including a lower pattern on the substrate and an upper pattern on the lower pattern. A field insulating layer is formed on the substrate, the sidewalls of the fin-type active pattern, and a portion upper pattern protruding further away from the substrate than a top surface of the field insulating layer. A dummy gate pattern that intersects the fin-type active pattern and that extends in a second direction that is different from the first direction is formed. The methods include forming dummy gate spacers on side walls of the dummy gate pattern, forming recesses in the fin-type active pattern on both sides of the dummy gate pattern and forming source and drain regions on both sides of the dummy gate pattern.