| 摘要 |
A method of manufacturing a semiconductor device is provided which, even if device dimensions decrease, prevents degradation in the operating characteristics of semiconductor elements which are isolated from each other by an element isolation region in a trench isolation structure. Implantation of ions (15) in a polycrystalline silicon layer (3) from above through a silicon nitride film (2) produces an ion-implanted polycrystalline silicon layer (16). Since the ions (15) are an ionic species of element which acts to enhance oxidation, the implantation of the ions (15) changes the polycrystalline silicon layer (3) into the ion-implanted polycrystalline silicon layer (16) having a higher oxidation rate. In subsequent formation of a thermal oxide film (21) on the inner wall of a trench (5), exposed part of the ion-implanted polycrystalline silicon layer (16) is also oxidized, forming relatively wide polycrystalline silicon oxide areas (21a).
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