| 摘要 |
PURPOSE:To assure a large storage capacity memory by forming a capacitor storage electrode and an impurity region on a trench side wall. CONSTITUTION:A low concentration p-type silicon single crystal layer 9 is epitaxially formed on a p<+>-type silicon substrate 1, whose surface is in turn thermally oxidized, and CVD oxide film is deposited on the resulting surface by a CVD process. Then, grooves, each of which has a bottom reaching the interior of the substrate 1, are formed into a lattice shape, and an insulating film is burried inside the grooves, and those grooves are removed by etching only in one direction thereof. And, an n-type impurity is doped into the grooves by an ion-implantation process to yield an n<+>-layer 7. A silicon exposure part of the grooves are oxidized to yield a capacitor insulating film 8. A polycrystalline silicon layer is deposited on the substrate and etched to yield a capacitor electrode 9. A thermal oxide film 10 is formed on the layer 2 by thermal oxidization, on which a polycrystalline silicon layer 12 is deposited, and only the layer 12 is made to remain by etching on a protrusion of the silicon 9. This is employed to form an n<+>-type impurity region 13 and a layer insulating film 14 is formed on the silicon 12, which is then patterned to form bit lines 16. Hereby, a memory cell can be made fine together with assurance of a large capacity memory. |
