| 摘要 |
PURPOSE:To extremely reduce defects produced in a semiconductor substrate and a well by forming a material layer having oxidizing speed faster than the substrate on the substrate and well and selectively oxidizing the layer, thereby forming an interelement isolating film. CONSTITUTION:A p type well 2 is selectively formed on an n type single crystal Si substrate 1, a thermally oxidized film 3 is then grown, and a P-doped polycrystalline Si layer 4 of a material layer having an oxidizing speed faster than the substrate 1 is accumulated. Subsequently, nitrided Si patterns 51, 52 are formed on the upper part of the layer 4 corresponding to the element region forming regions of the substrate 1 and well 2. With the patterns 51, 52 as masks the layer 4 is oxidized to form a thick oxidized film 6 for isolating between the elements. In this manner great stress to the substrate 1 and well 2 can be prevented. After the patterns 51, 52 are removed, remaining polycrystalline Si layers 41', 42' are removed. Then, they are thermally oxidized to grow the oxidized films 71, 72 a becoming gate oxidized films, and interelement isolating film 8 having no overhang is simultaneously formed. |
