TRANSISTOR

PURPOSE:To obtain a transistor of good characteristics of a safety operating region by a method wherein the side close to an emitter in a band formed resistor region with the both ends connected respectively to a base and the emitter is surrounded by a band formed region of the same conductive type as the emitter, when an inserted resistor positioned between the base and the emitter is formed on the same semiconductor substrate. CONSTITUTION:A P type base region 2 is diffusin-formed on an N type Si substrate 1, then an N type emitter region 3 is provided therein, and an N type floating emitter 4 surrounding the region 3 and an N type band formed resistor region 5 are diffusion-formed simultaneously with the formation of the region 3. Next, one end of the resistor region 5 is connected to the base region 2 via a metallic electrode 6, and the other end is connected to the emitter region 3 via the same metallic electrode 7. In this constitution, only the part closely contacted on the electrode 7 in the region 5 is surrounded by the N type band formed region 9 working as a floating emitter. Thus, the secondary breakdown is blocked by the region 9, without increasing the dimension of the substrate 1.