MANUFACTURE OF SEMICONDUCTOR MEMORY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a method by which such a semiconductor memory device that can make the refreshing time longer can be manufactured. SOLUTION: A plug 122 for a buried contact and another plug 123 for a bit line contact are formed through one time of plug ion implanting process so as to simplify the masking work. Then the length of a spacer is adjusted so as to improve the contact resistances of the plugs 122 and 123 without implanting cell plug ions. In addition, the surface resistance values of the joint surfaces of the plugs 122 and 123 are adjusted by diffusion ions of an impurity in a semiconductor substrate 100 by vapor-depositing doped pads 124 and 125. Therefore, not only the manufacturing process of a semiconductor memory device can be simplified, but also the refreshing time of the memory device can be made longer.