Patent ID: 8232623

Claim:
A semiconductor device comprising an epitaxial semiconductor layer including in which are formed: a base diffusion layer of one conductivity type, a base lead diffusion layer of the one conductivity type, formed to overlap the base diffusion layer, an emitter diffusion layer of an opposite conductivity type, formed to overlap the base diffusion layer, and a collector diffusion layer of the opposite conductivity type, formed at an upper surface of the epitaxial layer around the base diffusion layer, wherein the collector diffusion layer includes: a first diffusion layer of the opposite conductivity type extending from the upper surface of the epitaxial layer, and a second diffusion layer of the opposite conductivity type extending from the upper surface of the epitaxial layer, formed to have a higher impurity concentration than the first diffusion layer, wherein the first diffusion layer has a region where the first diffusion layer faces the base lead diffusion layer without the emitter diffusion layer therebetween.