| 摘要 |
PURPOSE:To obtain a high-integrated device with high yield through a simplified process by a method wherein an epitaxial layer on a p-type Si is isolated to an island region having a buried oxidized film partly, B-ion is implated therein, an As-added polycrystalline-Si is accumulated selectively, and B and As are subjected to thermal diffusion. CONSTITUTION:An n-epitaxial layer 43 is formed on a p<->-type Si substrate 41 is which an n<+>-layer 42 is buried selectively. A double layer of SiO245 and Si3N446 is formed selectively, B-ion is then implanted by means of a resist mask to form a p<+>-isolated layer 44, and a buried oxidized film 47 is formed consecutively through wet oxidation. An opening is provided on a collector layer and an n<+>-layer 48 is formed through P-diffusion. Next, B-ion is implanted on the overall surface and a p-type internal base 49 is formed through thermal diffusion. Then, the layers 46, 45 are removed, an As-added polycrystalline-Si 50 is accumulated selectively, oxidized films 511, 522 are formed at low temperature, B-ion is then implanted to heat treatment, and thus a p<+>-type external base 52 and an n<+>-emitter 53 are formed. A window is provided selectively and an electrode is applied finally. According to this method, the emitter area can be limited, and the emitter base short circuit can be prevented, thus ensuring a high integration at high yield. |
