| 摘要 |
PURPOSE:To obtain a dynamic memory preventing the occurrence of improper memory cell on account of the microminiaturization and increase in capacity of the memory by using electrostatic capacity due to buried insulating film formed within a semiconductor substrate as a memory cell capacity. CONSTITUTION:A field oxide film 24 is formed on a p type Si substrate 21. Then, nitrogen ion is selectively implanted on an MOS capacitor forming region using a mask, and a buried insulating film 25 is formed. Subsequently, phosphorus is implanted, and an n<+> type layer 26 is formed thereon. Thereafter, a polycrystalline silicon layer 28 is formed on the gate oxide film 27, a gate oxide film 29 and a polycrystalline film 30 are sequentially laminated thereon, holes are opened thereat, and n<+> type drain and bit wire 31 is formed therethrough. Then, an oxide film 32 is accumulated thereon, and a word line 33 is formed. Since the layer 26 is isolated from the layer 25 in this manner, it can eliminate the thermally produced carrier at the p-n junction and software error due to the alpha rays, thereby preventing the occurrence of improper memory cell. |
