Method for manufacturing a semiconductor device

Abstract

A method for manufacturing a semiconductor device, wherein a thin film of tantalum oxide is formed as a dielectric film in a capacitor element, increases capacitance per unit area and reduces a leakage current in the capacitor element of DRAM memory cells. The method includes steps of forming a polysilicon film constituting a lower electrode of the capacitor element, removing a natural oxide film from the surface of the polysilicon film, nitriding the surface of the polysilicon by rapid thermal nitriding (RTN) using lamp-annealing, forming a tantalum oxide film, densifying and nitriding consecutively the tantalum oxide film, and forming an upper capacitor electrode thereon. The capacitor element formed by the method has a large capacitance per unit area Cs=13.8 fF/.mu.m.sup.2.

Dependencies are inferred from the claim text.