| 摘要 |
PURPOSE:To enhance the integrating degree of a semiconductor memory by selectively implanting ion with a laminated mask side-etched at the upper layer portion to form a high impurity density region for channel to improve writing efficiency in self-aligning fashion. CONSTITUTION:A gate SiO2 film 11 is coated on a p-type Si substrate 10, an Si3N4 film and an SiO2 film are sequentially laminated thereon, and two laminate films having photo resist films 14A and 14B are formed on the film 11 by a lithographic process. With the films 12A, 12B of the laminates and the films 14A, 14B as masks films 13A, 13B and film 11 are side etched to reduce the width thereof, and the film 11 is divided into films 11A, 11B having narrow width. Thereafter, the films 14A, 14B are removed, one film 13B is coated with the resist film 15, ion 16 is implanted over the other film 13A to form writing efficiency improving p<+>-type regions 17A, 17B introduced underneath the film 11A. Subsequently, a p<+>-type region 20A making contact therewith is formed by the normal process. |
