| 摘要 |
PURPOSE:To obtain the element having excellent high-frequency characteristics by a method wherein, in the case of a transistor with a flat emitter-base junction, the base resistance of a base electrode and a base contact region is sufficiently lowered. CONSTITUTION:An N<+> type buried layer 27 is formed by diffusion on a P type Si substrate, an N type layer 28 is epitaxially grown on the whole surface, and a layer 32 is formed into island shape using a P type isolation layer 29. Then, an N<+> type collector wall 31 is provided at the end part of the island-shaped layer 28, and an SiO2 film 30 having a diffusion window 32 is formed. Subsequently, a polycrystalline Si film 33 is deposited on the whole surface, a BSG film 34 is provided on a part of the window 32 and the film 33, and an N<+> type polycrystalline Si film 33b is formed in the center part of the window 32. Then, the impurities in the films 33b and 34 are diffused by performing a heat treatment, a P<+> type region 35 and an N<+> type region 36 are formed in the layer 28, at the same time, the wall 31 is extended and connected to the region 27. Then, a P type base region 39' is provided closely at a point adjoining to the side of the region 35 and the wall 31, and an N<+> type region 38 is formed between the above two regions. |
