PURPOSE: To make reliably and easily a process of forming base contact regions in a hot-carrier transistor.

CONSTITUTION: A semiconductor device has a collector layer consisting of a one conductivity type semiconductor layer, collector barrier layers 22 and 21 consisting of an insulative semiconductor layer, a base layer 3 consisting of a one conductivity type semiconductor layer, an emitter barrier layer 4 consisting of an insulative semiconductor layer, an emitter layer consisting of a one conductivity type semiconductor layer and base-contact regions 6 which are connected to the base layer and consist of an opposite conductivity type semiconductor layer, which are laminated in order on a substrate, and base electrodes 8 are respectively formed on the regions 6.