In a semiconductor device and a method of manufacturing the same, a first insulation layer is removed from a cell area of a substrate and a first active pattern is formed on the first area by a laser-induced epitaxial growth (LEG) process. Residuals of the first insulation layer are passively formed into a first device isolation pattern on the first area. The first insulation layer is removed from the second area of the substrate and a semiconductor layer is formed on the second area of the substrate by a SEG process. The semiconductor layer on the second area is patterned into a second active pattern including a recessed portion and a second insulation pattern in the recessed portion is formed into a second device isolation pattern on the second area. Accordingly, grain defects in the LEG process and lattice defects in the SEG process are mitigated or eliminated.