| 摘要 |
PURPOSE:To make the base and emitter sufficiently minute, by forming a pattern of polysilicon, by oxidizing the pattern halfway by a finely controllable oxidizing process, and by treating in turn the oxide film and remaining polysilicon as a mask. CONSTITUTION:Using polysilicon 14' being left and an oxide film 15 formed by oxidizing halfway a first polysilicon pattern which is formed on a collector region of a substrate 1, the base and emitter sizes are essentially determined in the post-process. By making the first polysilicon 14 of doped polysilicon, it can be formed for the purpose of serving as a conductive layer in the post- process. Impurities are diffused from the first polysilicon 14 into a portion lying on the polysilicon projection which was not first doped, in order to be doped partially. The doped polysilicon is selectively etched (doped ... undoped) in order to plane the surface with a lift off method. |
