| 摘要 |
PURPOSE:To form an element isolating insulation region by forming a narrow groove on a silicon substrate, and by thermally oxidizing the part facing to such groove of the silicon substrate with a silicon nitride film obtained by directly nitriding a substrate used as the mask. CONSTITUTION:A groove 3 is formed by removing the area just under the aperture 2a of a silicon substrate 1 by the etching through the method such as the reactive ion etching using the mask 2 as a mask. Thereafter, an impurity introducing region 4 is formed by introducing impurity of the same conductivity type as that of impurity of a silicon substrate 3 by the ion implanting into the area under the bottom part of groove 3 of the silicon substrate 1. Moreover, after removing the mask 2, a silicon nitride film 5 is formed by direct nitriding of the surface of silicon substrate 1. At this time, an aperture 5a is formed to the area of silicon nitride film 5 corresponding to the groove 3. This silicon nitride film is also formed at the side and bottom surfaces of groove 3, but only these are removed by etching with the hot phosphoric acid. In succession, the substrate 1 is thermally oxidized with the silicon nitride film 5 having the aperture 5a used as the mask, the silicon oxide film fills the groove 3 and thereby element isolation insulating region 6 is formed. |
