| 摘要 |
PURPOSE:To prevent any parasitic channel from generating at the corner parts of the grooves in the element isolation region on the semiconductor substrate by a method wherein impurity ions having the same conductive type as that of the substrate are implanted in the element isolation region and the circumference thereof. CONSTITUTION:A resist mask 23 is provided on an SiO2 film 22 on a P type Si substrate 21 and an isotropic etching is performed to form a mask 22 having its thin circumferential part. The resist 23 is removed, an isotropic etching is performed, grooves 24 having the side surfaces 25 inclined by about 50 deg. are formed and P type impurity ions are implanted 26 and 27. The groove parts 24 are filled with an SiO2 film 28 by a CVD method, the SiO2 mask 22 is removed, the surface of the substrate is flattened, and a gate oxide film 29 and a gate electrode 30 are provided. Then, ions are implanted using the electrode 30 as a mask and the N<+> type source and the N<+> type drain are provided. Since the film thickness of the circumferential part of the mask 22 is made thinner, an impurity can be simultaneously implanted in the grooves 24 in the element isolation region and the side surfaces 25 and corners 27 of the grooves 24 by an ion-implantation of one time. As a result, any parasitic chennal can be prevented from generating at the corner parts of the grooves. |
