| 摘要 |
PURPOSE:To obtain a semiconductor memory device high in its integrity and its reliability, by forming a low resistance layer small in depth on the periphery of first grooves for the composing of a transistor and forming the low resistance layer large in depth on a region distant from the first grooves. CONSTITUTION:A nitriding film 51 for formation of side walls is deposited on the whole upper surface of a wafer finished with an etching process, and an anisotropic etching process is performed to make the nitriding film 51 remain on sides of opening parts formed on gate electrode formation regions 23a, 23b and to form side walls 53a, 53b on the periphery of these regions 23a, 23b. Subsequently, the side walls 53a, 53b are used as masks, and the anisotropic etching process is performed to form first grooves 55a, 55b. At that time a profile of a low resistance layer 65 is formed as follows: the function of the side walls 53a, 53b is used to make depth of ion implantation small on the periphery of the first grooves 55a, 55b for the composing of a transistor in a semiconductor memory device and to make it large on the region distant from the first grooves. This semiconductor memory device fine in its structure and high in its reliability can be obtained accordingly. |
