A method of manufacturing a semiconductor device includes forming a preliminary fin-type active pattern extending in a first direction, forming a device isolation pattern covering a lower portion of the preliminary fin-type active pattern, forming a gate structure extending in a second direction and crossing over the preliminary fin-type active pattern, forming a fin-type active pattern having a first region and a second region, forming a preliminary impurity-doped pattern on the second region by using a selective epitaxial-growth process, and forming an impurity-doped pattern by injecting impurities using a plasma doping process, wherein the upper surface of the first region is at a first level and the upper surface of the second region is at a second level lower than the first level.