Capacitor and method for manufacturing the same
View Patent ↗The capacitor of the present invention comprises: an opening part formed in an interlayer insulating film on a semiconductor substrate; a lower electrode made of a polycrystalline silicon with an uneven surface part; a chemical oxide film formed on the uneven surface part of the lower electrode; an silicon oxynitride film which is obtained by modifying the chemical oxide film by nitriding processing; a capacitive insulating film made of a metal oxide film formed on the silicon oxynitride film; and an upper electrode formed on the capacitive insulating film.
1. A capacitor manufacturing method, comprising the steps of:
forming an opening part in an interlayer insulating film on a semiconductor substrate;
forming a lower electrode made of polycrystalline silicon with an uneven surface part in an inner wall of said opening part;
forming a chemical oxide film by oxidizing a surface of said lower electrode having said uneven surface part by using an oxidize solution;
modifying said chemical oxide film into a silicon oxynitride film by nitriding the surface of said uneven surface part of said lower electrode through said chemical oxide film;
forming a capacitive insulating film made of a metal oxide film on said silicon oxynitride film; and
forming an upper electrode on said capacitive insulating film.
2. The capacitor manufacturing method according to claim 1 , wherein, in said step of forming said chemical oxide film, said uneven surface part of said lower electrode is cleaned for exposing a silicon clean surface of said uneven surface part and, subsequently, a wet treatment is performed by a chemical liquid with an oxidizing effect as said oxidize solution.
3. The capacitor manufacturing method according to claim 1 , wherein, in said step of forming said upper electrode, a titanium nitride film is formed as said upper electrode at depositing temperatures of 650° C.-700° C.
4. The capacitor manufacturing method according to claim 1 , wherein hydrogen peroxide water, ozone water, or nitrate water is used as said oxidize solution.
5. The capacitor manufacturing method according to claim 1 , wherein said step of forming said upper electrode is performed after applying a heat treatment on said capacitive insulating film in an oxidation atmosphere.