| 摘要 |
PURPOSE:To obtain a semicondutor element, by which the formation of an emitter and a collector with a walled structure can be realized, by a method wherein an isolation system utilizing a U-shaped groove with a deep section is utilized CONSTITUTION:An N type Si layer 1 grown epitaxially on an Si single crystal substrate 11 is performed an RIE reaction ion etching using an Si3N4 film 3 as the mask and a deep U-shaped groove 4 is formed. The inner surface of the U- shaped groove 4 is oxidized for forming an SiO2 film 5. The Si3N4 film 3 is removed once and an Si3N4 film 6 is formed according to a low-pressure CVD method. After that, the U-shaped groove is buried in with a polycrystalline Si layer 7 according to a low-pressure CVD method. A plasma etching is performed on the surface of the polycrystalline layer 7, and the whole surface thereof is flattened and, at the same time, one part of the Si3N4 film 6 is made to expose. An over-etching 6a is performed on the exposed part of the S i3N4 film 6 by hot phosphoric acid and the like, thereby making to protrude the end part 7a of the polycrystalline Si layer. After then, a thick SiO2 film 8 is formed on the surface part of the polycrystalline layer 7 according to an oxidation method. A collector and an emitter are formed as a walled structure in the insular region on the Si layer surrounded with the isolation part and a contact photo etching is performed on the SiO2 film 8 on the surface thereof for forming an electrode. In this case, a short-circuit never occurs, since the SiO2 film 8 is thick. |
