A semiconductor device includes: a first semiconductor layer; a second semiconductor layer including a first dopant of a first conductivity type and a second dopant of a second conductivity type, wherein the first dopant has a doping concentration, and the first conductivity type is different from the second conductivity type; a third semiconductor layer on the second semiconductor layer, wherein the third semiconductor layer includes a third dopant including a doping concentration higher than the doping concentration of the first dopant; and an active region between the first semiconductor layer and the second semiconductor layer; wherein the second semiconductor layer includes a bottom surface facing the active region, and the active region includes a top surface facing the second semiconductor layer, and a distance between the bottom surface of the second semiconductor layer and the top surface of the active region is not less than 2 nm.