| 摘要 |
PURPOSE:To improve the yield and the reliability of an element by smoothly forming a gradient bent at a diffused layer of source and drain regions due to the reduction in As<+> ions implanted on the source and drain regions in the side surface of a gate electrode, thereby preventing the decrease in the withstand voltage due to a punch-through phenomenon and alleviating the production of hot electrons. CONSTITUTION:A PSG film 19 is covered by an ordinary CVD method on the overall surface of a semiconductor substrate 11 which contains a gate electrode 13, and a resist film 20 is covered on the upper surface. This buries a recess formed on the side surface of the film 19 to be flattened, and is necessary to form the PSG film of the desired wedge shape in next steps. Subsequently, an ion etching unit is used, a reaction gas such as trifluoromethane is used to anisotropically etch the films 20, 19 so as to allow a PSG film 21 of wedge shape to remain only on the side surface of the electrode 13. Then, As<+> is implanted in the substrate 11, the surface is flattened, a heat treatment is performed for diffusion, thereby forming a diffused layer which has a smooth gradient as compared with the gradient of the diffused layer of the source and drain regions according to the conventional method. |
