A method for fabricating a semiconductor device includes: forming a fin-type semiconductor region on a substrate; and introducing an n-type impurity into at least a side of the fin-type semiconductor region by a plasma doping process, thereby forming an n-type impurity region in the side of the fin-type semiconductor region. In the introducing the n-type impurity, when a source power in the plasma doping process is denoted by a character Y [W], the supply of a gas containing the n-type impurity per unit time and per unit volume is set greater than or equal to 5.1×10−8/((1.72.51/24.51)×(Y/500)) [mol/(min·L·sec)], and the supply of a diluent gas per unit time and per unit volume is set greater than or equal to 1.7×10−4/((202.51/24.51)×(Y/500)) [mol/(min·L·sec)].