| 摘要 |
PURPOSE:To obtain sufficient storage capacitance, by constituting a memory cell of a storage electrode formed in a trench via a capacitor insulating film and a MOS transistor using a diffusion layer as the source.drain region. CONSTITUTION:A trench 4 is formed by lithography and reactive ion etching. After a capacitor insulating film 5 is formed on the inner wall of the trench 4, a first layer polycrystalline silicon film to serve as a storage electrode 6 is deposited and etched so as to be left in the trench 4. A gate insulating film 7 is formed on the upper surface of a P-type epitaxial layer 2, and a second layer polycrystalline silicon film is deposited and processed to form a gate electrode 8. After a third polycrystalline silicon film is deposited and arsenic is ion-implanted, the film is processed to form an N-type polycrystalline silicon film 10 connecting an N-type diffusion layer 9 with a storage electrode 6. Since the trench 4 is formed in a silicon substrate 1 and the epitaxial layer 2, and a capacitor is formed in the trench, sufficient storage capacitance can be ensured. |
