| 摘要 |
PURPOSE:To prevent a leakage current between adjacent memories of a high density DRAM by providing the same conductivity type diffused layer as a well to surround the well side diffused electrodes of a trench capacity formed in the well. CONSTITUTION:P-type diffused layers 13, 14 are formed to prevent a leakage current between adjacent memories 15 and 16 on the inner wall of a trench formed in a P-well on a P-type substrate 1. Since the layers 13, 14 are diffused by means for ion implanting or the like from the trench of a memory capacity, they are not thinned in its impurity concentration in the bottom of the memory capacity like the well 2, and a uniform diffused layer is formed over the whole memory capacity. Accordingly, the spread of a depleted layer can be suppressed even in the bottom of the memory capacity, and no punch-through occurs. Thus, the layers 13, 14 are so formed as to surround N-type diffused layers 4, 7 which form the first electrode of the memory capacity to prevent a leakage current between adjacent cells even in small cells 15, 16 for a high density DRAM, thereby obtaining a DRAM in which no error occurs. |
