Patent ID: 8306495

Claim:
A semiconductor device comprising: a barrier layer with a thickness that allows transmission of a plurality of electrons by direct tunneling; and a p-type semiconductor layer and an n-type semiconductor layer that are disposed so as to sandwich the barrier layer, wherein a band gap of the barrier layer is wider than band gaps of the n-type semiconductor layer and the p-type semiconductor layer, wherein an energy level of a plurality of holes at an upper end of a valence band of the barrier layer is higher than an energy level of a plurality of holes at an upper end of a valence band of the n-type semiconductor layer under a state in which a flat band voltage that makes energy bands of the n-type semiconductor layer and the p-type semiconductor layer flat is applied between the n-type semiconductor layer and the p-type semiconductor layer; and an energy level of a plurality of electrons at the upper end of the valence band of the p-type semiconductor layer is equal to or higher than an energy level of a plurality of electrons at the lower end of the conduction band of the n-type semiconductor layer in a region that is further away from a bending portion of an energy band at an interface between the barrier layer and the n-type semiconductor layer and an interface between the barrier layer and the p-type semiconductor layer, under an equilibrium state without any voltage being applied.