JPS5642368A - Semiconductor device - Google Patents

Abstract

PURPOSE:To avoid a breakdown of a transistor by limiting a collector current path of the transistor with a reverse conductivity type region formed in a collector region to the conductivity type of the collector region and thereby obtaining a current amplification factor having an abrupt attenuating property in large current region. CONSTITUTION:A P type buried layer 15 is diffused in an N type semiconductor substrate 11 becoming a collector so that it is not existed in the circular portion of a diameter D at the position corresponding to the N type emitter region to be formed later, and an N type layer 12 is epitaxially grown on the whole surface including the layer 15. Then, a P type base region 13 and a P type region 16 reaching one buried layer 15 are diffused in the surface layer, and an N type emitter region 14 is formed in the region 13. Thereafter, the surface is covered with oxide film in the normal way, a window is opened thereat, aluminum electrodes are formed on the regions 13 and 14, and aluminum electrode is coated on the back surface of the substrate 11. Further, aluminum electrode is also attached to the region 16, a bias voltage is applied thereto to be equal potential to the region 14, and the regions 11, 12 are set in reverse bias state.