| 摘要 |
PURPOSE:To implement high integration density in a memory, by selectively forming the lower electrode of a capacitor, which forms capacitance, on the impurity region of a switching transistor, which is formed on a semiconductor substrate. CONSTITUTION:An oxide film 2 is formed in a P<-> Si substrate 1 by ion implantation. A first polycrystalline Si layer 5 is attached to the entire surface. An Si3N4 film 3 is formed on the entire surface other than the gate part 5. An SiO2 film 7 is grown. A window is provided in the source region of a switching transistor. After a second polycrystalline Si layer 6 is attached, a groove part is buried. The second polycrystalline Si layer 6 undergoes etch-back, and the polycrystalline Si layer 6 other than the groove part is removed. After the oxide film 7 is etched away, the entire surface is oxidized, and an oxide film 10 is formed. A third polycrystalline Si layer 9 is attached to the entire surface. A part of the third polycrystalline Si layer 9 is removed and a cell plate is provided. An interlayer insulating film 12 is formed, and the surface is flattened. A metal 11 is provided, and a contact is provided at a drain. Thus a bit line 11 is formed. Since the central part of the post part of a capacitor becomes narrow in the direction of the Si substrate, the capacitance can be made large. |
