PURPOSE: To improve the switching characteristics of a semiconductor device and to suppress the level of a leakage current to a low value without difficulty under the control of the characteristics of a current amplification factor or the like by employing reversely a vertical transistor.

CONSTITUTION: A vertical transistor is used in a reverse direction by providing one conductive type semiconductor substrate 31, the other conductive type first semiconductor region 32, one conductive type second semiconductor region 40 formed on the surface of the region 32, an insulating layer 33 formed to cover the surface of the substrate 31, a metal electrode contacted with the surface of the region 32 through a hole 34 opened at the layer 33, the first polycrystalline Si layer 37 containing one conductive impurity contacted with the surface of the region 40 through the other hole opened at the layer 33, and the second polycrystalline Si layer 38 formed to extend on the layer 33 continuously to the layer 37 and containing one conductive type impurity of the lower density than the layer 37 forming a Schottky junction in contact with the metal electrode at the contacting part.