| 摘要 |
PURPOSE:To make layer resistance value equal before and after the push-in of a base diffusion region, etc. approximately, and to facilitate process control by forming a reverse conduction type diffusion layer and a glass layer to one conduction type substrate, oxidizing the whole by steam, removing an oxide layer and executing push-in treatment. CONSTITUTION:In a forming process of the base diffusion region 3 of a transistor such as an NPN transistor, an opening section is formed to an oxide film 7 on an N<-> epitaxial layer 2 functioning as a collector, diffusion treatment is conducted in a BCl3 atmosphere, and the P diffusion layer 30 and the B glass layer 17 are shaped. The layer 17 is removed, the whole is oxidized by steam at approximately 700-900 deg.C, and an oxide film 71 is formed onto the layer 30. The film 71 is removed, push-in treatment is conducted in an oxidizing atmosphere, and a P type base region 3 and an oxide film 72 on the surface are shaped. Processes after forming an emitter are conducted, but the difference of the sheet resistance value of the P type layer 30 and the base layer 3 before and after push-in treatment can be minimized through the processes, and the scattering can be reduced. Accordingly, the measurement of the sheet resistance after push-in can be unnecessitated and process control can be facilitated. |
