Method for making semiconductor integrated circuits
AssigneeHitachi, Ltd.
InventorsYasuhiro Shimamoto, Hiroshi Miki, Masahiko Hiratani
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Abstract
A capacitor having an equivalent thickness of 3.0 nm or less, with a sufficient static capacitance and less leakage current in a reduced size, constituted by stacking an interfacial film 21 having a physical thickness of 2.5 nm or more for suppressing tunnel leakage current and a high dielectric film 22 comprising tantalum pentaoxide on lower electrode 19, 20 comprising rugged polycrystal silicon film, the interfacial film 21 comprising a nitride film formed by an LPCVD method, for example, from Al2O3, a mixed phase of Al2O3 and SiO2, ZrSiO4, HfSiO4, a mixed phase of Y2O3 and SiO2, and a mixed phase of La2O3 and SiO2.
Claims23
A method of fabricating a semiconductor integrated circuit in which a memory cell is constituted with a memory cell selection transistor and an information storage capacitor connected in series therewith, the information storage capacitor comprises a polycrystal silicon lower electrode rugged at the surface comprising a cylindrical polycrystal silicon film having an opening at an upper portion and semi-spherical silicon crystal formed on the surface thereof, a capacitor insulative film comprising a first dielectric film comprising tantalum as a main ingredient and a second dielectric film disposed between the polycrystal silicon lower electrode and the first dielectric film, and an upper electrode formed being opposed to the polycrystal silicon lower electrode with the capacitor insulative film being disposed therebetween, wherein the method includes the steps of:
- depositing an insulative film after forming the memory cell selection transistor and forming grooves by aperturing,
- forming an amorphous silicon film to the inside of the grooves,
- forming a semi-spherical silicon crystal on the surface of the silicon film,
- introducing phosphorus to the surface of the semi-spherical silicon crystal,
- forming the second dielectric film by a deposition method to the surface introduced with phosphorus,
- forming an amorphous tantalum pentaoxide film on the surface of the second insulation film,
- crystallizing the amorphous tantalum pentaoxide film in an oxidative atmosphere at 700° C. or higher, and
- depositing titanium nitride above the crystallized tantalum pentaoxide film so as to embed the inside of the grooves.
Dependencies are inferred from the claim text.