| 摘要 |
PURPOSE:To implement high density, by surrounding a storing node, in which electric charge as a signal is stored, with a plate, further surrounding the plate with an insulating film, embedding the entire body in an Si groove, and forming memory cells in close proximity. CONSTITUTION:A sheath 8 of a CVD SiO2 film is deposited. Thereafter, a polycrystalline Si plate 9 is deposited on the entire surface. Then thermal diffusion is performed, phosphorus is added into the plate 9 and photoresist 10 is embedded. Thereafter, the resist 10 is removed. Capacitor insulating films 11 comprising double-layer films of SiO2/Si3N4 are deposited. Polycrystalline Si is further embedded in the entire surface. Phosphorus is sufficiently added in the polycrystalline Si. It is etched again into the intermediate part. Said polycrystalline Si becomes a storage capacitor electrode 12. The plate of the polycrystalline Si is surrounded with the SiO2 film, which is embedded in the Si substrate. Therefore sufficient and required impurities are added and the concentration can be increased. Thus a depletion layer is not formed in the plate, and the decrease in storage capacitance can be suppressed. |
