| 摘要 |
PURPOSE:To form a favorable insulating isolation region in the semiconductor device by a method wherein a groove is filled up only by forming thin Si oxide films, or Si to be used as the nuclei for selective growth of poly-Si is left easily in the groove by leaving projections on the base of the groove when the groove for insulating isolation is to be formed. CONSTITUTION:After an opening 3 is formed in an SiO2 film 2 on an Si substrate 1, selective etching of the Si substrate is performed according to the reactive sputter etching method. Needle-shaped projections 4 of a large number are formed at the etched part. The needle-shaped projections 4 thereof are the needles of Si to be considered as that a material like SiO2 is readhered on the etched face, and by acting as an etching mask, the needles are formed. When the SiO2 films of about 0.2mum thickness are formed by thermal oxidation after etching like this is performed, the needle- shaped projections become to the needles 5 of SiO2 to fill up nearly the groove. Although fine gaps 6 are generated at the circumferences of the needles 5 of SiO2, when the SiO2 films having thickness of 1/2 or more of the gaps 6 are adhered according to the CVD method, flattening of the surface can be attained easily. Because the region formed by this way has a structure that the SiO2 contained therein has the fine gaps to mitigate the generation of stress when the Si substrate is heated, the region becomes suitable for the insulating isolation region of a semiconductor element. |
