| 摘要 |
PURPOSE:To facilitate fining, and to improve high-frequency characteristics by forming an emitter electrode through self-alignment to an emitter layer. CONSTITUTION:With a bipolar transistor Tr1, an n<+> buried diffusion layer 11, an epitaxial layer 12 in which a collector is shaped, isolation diffusion layers 13 and a collector wall 14 are formed to a p type semiconductor substrate 10. The surface of a cell region in the Tr1 is protected by a pad oxide 20' and a nitride film 30 used as a mask for selective oxidation. Contact layers 40 consisting of poly Si are interposed among an emitter layer 60 and a contact layer 70 for the collector and electrodes for these layers 60, 70. A p type internal base layer 50 is connected to a p<+> type external base layer 51, and an emitter electrode 80 is connected to the n<+> type emitter layer 60. The electrode 80a is formed through self-alignment to the layer 60. Accordingly, fining is facilitated, and the area of an active region can be reduced. High-frequency characteristics can be improved on the basis of the facilitation of fining and the reduction of the area of the active region. |
