To provide a bipolar transistor, a field effect transistor, and a complementary transistor which can be improved in both withstand voltage and operating speed, by increasing the operating speeds of the transistors by reducing the collector resistance, base resistance, or drain resistor of a high breakdown- voltage transistor, and a method for manufacturing the transistors.

A high withstand-voltage V(vertical)-NPN transistor 35 is constituted in a dielectric separating structure, using a semiconductor on insulator(SOI) substrate. A trenched groove for separating element is filled up with an arsenic glass(ASSG) film 28. As contained in the ASSG film 28 is diffused in an adjacent N-type collector region 25 which has a thickness of about 15 μm and forms and N+-type collector plug layer 29. Since the collector plug layer 29 connects the N+-type collector embedded layer 24 in the bottom face section of the collector area 25 to the N+-type collector contact region 21 on the surface of the collector region 21, the collector resistance is reduced.