PURPOSE: To obtain a high-frequency transistor of small consuming electric power and to perfom high-speed action by a method wherein a base region having impurity concentration of the second grade is formed in a substrate to constitute a collector region, an emitter region having concentration of the highest grade is provided therein, and a Schottky diode is formed adjoining thereto and interposing an insulating film between them.

CONSTITUTION: The P+ type base region 2 having impurity concentration of the second rank is formed by diffusion in the N type semiconductor substrate 1 to constitute the collector region, and the N++ type emitter region 3 having concentration of the highest rank is provided therein. Then the SiO2 film 4 is adhered on the whole surface thereof, and the Schottky diode region 5 is formed thereon separating slightly from the region 2 and adjoining thereto. At this time, the region thereof is constructed of the region 5 consisting of the N++ type region on the region 2 side, and of the N+ type region coming in contact therewith. After then, a contact part 8 is fixed to the region 3, a contact part 9 is to the region 2, a contact part 6 is to the high concentration part of the region 5 and a contact part 7 is to the low concentration part respectively, and the contact part 6 is connected to the part 9, and the contact part 7 is connected to the part 8.