| 摘要 |
PURPOSE:To make it easy to set up Zener voltage by a method wherein, when an epitaxial layer is grown on a semiconductor substrate and a base layer is formed in the surface layer of epitaxial layer and then an emitter layer is further formed in the base layer to produce a transistor, a region with the same conductive type as that of emitter layer is provided outside the base layer and inside the epitaxial layer. CONSTITUTION:An N type layer 10 to be a collector region is epitaxially grown on an N<+> type Si substrate 1 and then a P type base region 11 is diffusion- formed on the central part of surface layer. Next an N<++> type emitter region 12 to be an NPN type transistor is provided in the region 11. Later overall surface is coated with an oxide film 20 and then openings are made oppositely to the periphery of P type base region 11 while shallow N<++> type regions 13 are formed on the surface layer of exposed epitaxial layer 10 by ion implanting process. Thus a Zener diode is produced by the base region 11 and the region 13. Through these procedures, the Zener diode may fill the role thereof with no fluctuation in impurity in process to improve the yield of product. |
