An objective is to provide a semiconductor device capable of utilizing properties of a high-mobility electron transport layer with a thin film stacked structure having large ΔEc, high electron mobility, and simplified element fabrication process even when the substrate material and the electron transport layer greatly differ in lattice constant. The semiconductor device includes: a semiconductor substrate (1); a first barrier layer (2) on the substrate (1); an electron transport layer (3) on the first barrier layer (2); and a second barrier layer (4) on the electron transport layer (3). The first barrier layer (2) has an InxAl1-xAs layer. At least one of the first barrier layer (2) and the second barrier layer (4) has a stacked structure having an AlyGa1-yAszSb1-z layer in contact with the electron transport layer (3) and an InxAl1-xAs layer in contact with the AlyGa1-yAszSb1-z layer. The stacked structure is doped with a donor impurity.