| 摘要 |
PURPOSE:To prevent increase of a leak current and to improve reliability by forming a third semiconductor region of high impurity concentration, which is shallower than a second semiconductor region and has the same conductivity as the second semiconductor region, in the peripheral part inside the second semiconductor region by impurity diffusion. CONSTITUTION:An n<->-type collector region 2 (a first semiconductor region) is deposited on an n<+>-type collector region 1 by epitaxial growth, etc. A p-type base region 3 (a second semiconductor region) is formed in a specified thickness on the surface of the n<->-type collector region 2 by impurity diffusion such as boron. An n<+>-type emitter region 4 is further formed on the surface inside the p-type base region 3 by impurity diffusion, and, at the same time, a shallow ring-shaped p<+>-type region 11 (a third semiconductor region) is formed by impurity diffusion in a peripheral part thereof. That is, formation of a ring-shaped p<+>-type region 11 in the peripheral part of low impurity concentration inside the p-type base region 3 prevents inversion of conductivity on the surface of the p-type base region 3. |
