Abstract: A method for isolating elements in a silicon semiconductor device is disclosed. The invention discloses the steps of: (1) forming a thermal silicon oxide layer on a silicon substrate, depositing a layer of polysilicon, and depositing a first silicon nitride layer thereon, (2) patterning an active region and a field region, and etching the thermal oxidation layer, the polysilicon layer and the first silicon nitride layer on the field region to forth an active region pattern, (3) depositing a second silicon nitride layer, and, thereupon, depositing a silicon oxide layer, (4) etching back the oxide layer by application of a reactive ion etch technique, forming a silicon oxide side wall on the side of the active region pattern, and etching back the second silicon nitride layer using the oxide side wall as a mask to expose the silicon substrate, (5) removing the oxide side wall, and performing a channel stop field ion implantation, and (6) performing a field oxidation process to form a field oxide layer.

Abstract: A method of manufacturing a semiconductor device includes the following steps. A wide groove portion is formed in a predetermined portion of one major surface of a first semiconductor substrate. A first insulating film is formed on the bottom surface of the groove portion. The major surface of the first semiconductor substrate except for the first insulating film is polished to form a mirror-polished surface on the same level as the surface of the first insulating film. One major surface of a second semiconductor substrate is bonded to the mirror-polished surface of the first semiconductor substrate and the surface of the first insulating film by direct bonding, and the resultant structure is heat-treated, thereby forming a composite semiconductor substrate. A groove having a ring-like planar shape is formed to extend from the other major surface of the first semiconductor substrate constituting the composite semiconductor substrate to the first insulating film.