PURPOSE: To highly integrate a memory cell without necessity of separating nonvolatile memory capacitors by using a polycrystalline silicon film insulated and separated from a silicon semiconductor substrate instead of the substrate.

CONSTITUTION: A silicon dioxide film 2 is formed by oxidizing by a thermally oxidizing method on a silicon semiconductor substrate 1, the first polycrystalline silicon film 3 is formed by a reduced pressure vapor phase growing method thereon, and the prescribed portion is removed by a lithographic method. Then, an extremely thin silicon dioxide film 4 to become a tunneling medium is oxidized at 700°C in acidic water atmosphere to form a silicon nitride film 5 by a reduced pressure vapor phase growing method. After the second polycrystalline silicon film 6 is formed by the known reduced pressure vapor phase growing method, the prescribed portion is removed by lithographic technique and etching technique to manufacture a nonvolatile memory capacitor.