| 摘要 |
PURPOSE:To obtain flat surface by allowing a single crystal to grow on an Si substrate having a pattern of insulator and selectively etching polycrystal by making use of difference in impurity diffusion speed betwen single crystal and polycrystal. CONSTITUTION:A silicon is epitaxially formed opening to SiO2 2 on the Si substrate 1 and a poly-Si 3 is formed on the film 2 and a single crystal Si 1' is formed within the window. When phosphorus is diffused, it is diffused deep in the film 3 but shallow in the film 1'. The heat treatment is carried out in order to perfectly diffuse phosphorus into the film 3. Thereby, the film 4 is formed. Thereafter the layer 4 is selectively etched with a mixed solution of fluoric acid, nitric acid and acetic acid and etching is stopped when the layer 4 is almost perfectly removed. Thereby, the single crystal Si 1' is not almost etched, the substrate surface is flattened, a micro-miniature buried pattern can be obtained, disconnection can be prevented. Moreover, since there is no difference in size conversion as the reverse pattern of insulating film, a high integration density LSI can be obtained with good yield. |
