| 摘要 |
PURPOSE:To shorten a distance between an emitter and a base by thinning a polycrystalline silicon film only in an active element region to desired thickness in a process before an isolation groove is formed. CONSTITUTION:A polycrystalline silicon film 24 is shaped on the surface of a semiconductor substrate 21 in thickness of approximately 5,000Angstrom . The surface of said polycrystalline silicon film 24 at a position where base and emitter electrodes for a transistor must be formed is removed slightly. It is preferable that the polycrystalline silicon film 24 is removed in approximately 2,000Angstrom . An silicon nitride film 25 and an silicon oxide film 26 are applied in succession, and boron as an impurity is added into the region of the polycrystalline silicon film 24 functioning as an electrode for leading out a base. An isolation groove 27 is shaped. Accordingly, an extension in the lateral direction at a time when the isolation groove 27 between a base and an emitter can be reduced to approximately 0.4mum from approximately 0.8mum in conventional devices, thus forming the small-sized transistor having high performance. |
