Capacitor having ferroelectric film for nonvolatile memory cell, and method of manufacturing the same

Claim 1

A capacitor in a nonvolatile memory cell comprising: a lower electrode formed on a semiconductor substrate; a ferroelectric thin film formed on said lower electrode; and an upper electrode formed on said ferroelectric thin film, said capacitor further having; a first protective layer consisting of one or more layers formed between said semiconductor substrate and said lower electrode, and composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride, Group Va transition metal nitride, silicon nitride, nickel and palladium; and a second protective layer consisting of one or more layers formed on said upper electrode, and composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride, Group Va transition metal nitride, nickel and palladium.

Claim 4

A method of manufacturing a capacitor in a nonvolatile memory cell, comprising the steps of: forming, on a semiconductor substrate, a first protective layer consisting of one or more layers composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride, Group Va transition metal nitride, silicon nitride, nickel and palladium; forming a lower electrode layer on said first protective layer; forming a lower electrode by patterning said lower electrode layer and said first protective layer; forming a ferroelectric thin film layer on said lower electrode, and patterning said ferroelectric thin film layer to thereby form a ferroelectric thin film; forming an insulator layer on the entire surface, and then forming an opening in said insulator layer at a position above said ferroelectric thin film; forming an upper electrode layer on said insulator layer inclusive of said opening; forming a second protective layer consisting of one or more layers formed on said upper electrode layer, and composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride, Group Va transition metal nitride, nickel and palladium; and forming an upper electrode by patterning said second protective layer and said upper electrode layer.

Claim 5

A method of manufacturing a capacitor in a nonvolatile memory cell, comprising the steps of: forming, on a semiconductor substrate, a first protective layer consisting of one or more layers composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride, Group Va transition metal nitride, silicon nitride, nickel and palladium; forming a lower electrode layer on said first protective layer; forming a lower electrode by patterning said lower electrode layer and said first protective layer; forming a ferroelectric thin film layer on said lower electrode, and patterning said ferroelectric thin film layer to thereby form a ferroelectric thin film; forming an insulator layer on the entire surface, and then forming an opening in said insulator layer at a position above said ferroelectric thin film; forming an upper electrode layer on said insulator layer inclusive of said opening, and then patterning said upper electrode layer to thereby form an upper electrode; and forming, on said upper electrode, a second protective layer consisting of one or more layers and composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride. Group Va transition metal nitride, nickel and palladium, and then patterning said second protective layer in such a manner that the surface of said upper electrode is covered with said second protective layer.

Claim 6

A method of manufacturing a capacitor in a nonvolatile memory cell, comprising the steps of: forming, on a semiconductor substrate, a first protective layer consisting of one or more layers composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride, Group Va transition metal nitride, silicon nitride, nickel and palladium; forming a lower electrode layer on said first protective layer; forming a ferroelectric thin film layer on said lower electrode layer; patterning said ferroelectric thin film layer, said lower electrode layer and said first protective layer to thereby form a ferroelectric thin film and a lower electrode; forming an insulator layer on the entire surface, and then forming an opening in said insulator layer at a position above said ferroelectric thin film; forming an upper electrode layer on said insulator layer inclusive of said opening; forming a second protective layer consisting of one or more layers formed on said upper electrode layer, and composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride, Group Va transition metal nitride, nickel and palladium; and forming an upper electrode by patterning said second protective layer and said upper electrode layer.

Claim 7

A method of manufacturing a capacitor in a nonvolatile memory cell, comprising the steps of: forming, on a semiconductor substrate, a first protective layer consisting of one or more layers composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride, Group Va transition metal nitride, silicon nitride, nickel and palladium; forming a lower electrode layer on said first protective layer; forming a ferroelectric thin film layer on said lower electrode layer; patterning said ferroelectric thin film layer, said lower electrode layer and said first protective layer to thereby form a ferroelectric thin film and a lower electrode; forming an insulator layer on the entire surface, and then forming an opening in said insulator layer at a position above said ferroelectric thin film; forming an upper electrode layer on said insulator layer inclusive of said opening, and then patterning said upper electrode layer to thereby form an upper electrode; and forming a second protective layer consisting of one or more layers formed on said upper electrode layer, and composed of a material selected from those of Group IVa transition metal, Group Va transition metal, Group IVa transition metal nitride, Group Va transition metal nitride, nickel and palladium, and then patterning said second protective layer in such a manner that the surface of said upper electrode is covered with said second protective layer.