| 摘要 |
PURPOSE:To finely form an element separating region of high separating capacity by attaching a side wall to a mask for selectively oxidizing to form the separating region to draw a finely selectively oxidizing region, and then etching the main surface of a semiconductor substrate exposed to the region to form a recess. CONSTITUTION:The first silicon oxide film 2 and the first silicon nitride film 3 are thinly formed on a silicon substrate 1, the second silicon oxide film 4 is formed relatively thickly thereon, patterned, and the films are allowed to remain only on an element forming region. Then, the second silicon nitride film 5, the third silicon oxide film 6 are thickly formed, and then anisotropically etched to form a side wall 7 offset to project the films 2, 3, 4 at both sides and an offset silicon nitride film 30 directly attached to the substrate 1. Subsequently, with the films 2, 3, 4 and the wall 7 as masks the main surface of the substrate 1 is etched to form a recess 8, boron implanted layer 9 is formed on the bottom, and a thick silicon oxide film 10 is formed thereon. |
