| 摘要 |
PURPOSE:To reduce the fluctuation of the transistor characteristics during the walled wash process by a method wherein the base region is formed on the substrate through the intermediary of the second oxide film which is opened so that the emitter region may be diffused through the intermediary of the oxide film. CONSTITUTION:The thick oxide film 2 is formed on the thin oxide film 3 on the substrate 1 and the multicrystal Si film 9 is further formed on the said film 3. Next boron is inplanted in the substrate through the intermediary of said films 9 and 3 to form the P type base region 4. After forming the PSG film 5 on the overall surface, said film 5 on the base region 4 is removed to etch the multicrystal Si film 9 utilizing said film 5 as a mask. Arsenic is inplanted in said region 4 through the intermediary of the thin oxide film 3 to form the N<+> type emitter 6. Through these procedures, the fluctuation of the transistor characteristics during the walled process may be reduced. |
