| abstract |
The subject is a plasma-enhanced CVD process for depositing a silicon oxide film on a substrate by using an organosilicon compound such as tetraethoxysilane and oxygen or ozone as the essential reactants. The disclosed CVD method uses a plasma containing oxygen ions, and the density of oxygen ions impinging on the substrate surface is cyclically decreased and increased with a short period such as, e.g., 1 sec. In extreme cases which are rather preferable, the effect of the oxygen plasma is cyclically nullified and returned to a maximum to thereby alternate plasma CVD and plain thermal CVD. The obtained film is comparable in film properties to silicon oxide films deposited by known plasma CVD methods and, when the substrate has steps such as aluminum wiring lines, is better in step coverage and gap filling capability. The film exhibits a still better profile when hydrogen peroxide gas or an alternative hydrogen containing gas is added to the reactant gas mixture. |