| 摘要 |
PURPOSE:To prevent the defect in pressure resistance by a method wherein an si substrate is oxidized selectively with an Si3N4 mask provided, O ions are implanted in the entire surface, gate oxidation is applied to a region wherefrom Si3N4 is etched, and an electrode is provided. CONSTITUTION:First N2 ions are implanted into an Si substrate 1 to provide an Si3N4 mask 6, and then selective oxidation 7 is applied. O2 ions are implanted through the film 6 to form a layer 11 below the film 6. After etching is made to the depth 12 with a hot phosphoric acid, the layer 11 is etched to the depth 13 with HF. Then residual N is removed completely and thus the faulty in pressure resistance is prevented. Gate oxidation is performed as usual thereafter, a gate electrode is provided, and thereby FET is completed. This constitution makes it possible to etch the Si3N4 film completely and thus to prevent the faulty in pressure resistance. |
