A semiconductor device includes a base substrate, a buried insulating film on the base substrate, a first semiconductor substrate pattern on the buried insulating film, a second semiconductor substrate pattern on the buried insulating film, the second semiconductor substrate pattern being spaced apart from the first semiconductor substrate pattern, a first device pattern on the first semiconductor substrate pattern, a second device pattern on the second semiconductor substrate pattern, the first and second device patterns having different characteristics from each other, an isolating trench between the first semiconductor substrate pattern and the second semiconductor substrate pattern, the isolating trench extending only partially into the buried insulating film, and a lower interlayer insulating film overlying the first device pattern and the second device pattern and filling the isolating trench.