Heat treatment of a tantalum oxide film

Abstract

A method of manufacturing a tantalum oxide film having a high dielectric constant suitable for use in a high density DRAM, and a small leakage current. After forming a tantalum oxide film in amorphous state which includes moisture and impurities such as organic substances, and before crystallizing the film, the tantalum oxide film in amorphous state is subjected to a first heat treatment at a temperature which is higher than the formation temperature of the tantalum oxide film in amorphous state and which is lower than the temperature of crystallization of the tantalum oxide film in amorphous state. As a result of the first heat treatment, the moisture and the impurities such as organic substances existing in the film are surely removed from the film. Accordingly, in a subsequent heat treatment for crystallization at a high temperature, there arises no phenomenon in which crystallization of the film proceeds while impurities in the film are being removed. In other words, the crystallized tantalum oxide film obtained is free from stresses and defects.

Dependencies are inferred from the claim text.