Effect of fluorine in chemicalhyphen;vaporhyphen;deposited tungsten silicide film on electrical breakdown of SiO2film

摘要

The effect of fluorine in chemicalhyphen;vaporhyphen;deposited tungsten silicide film on electrical breakdown of SiO2film was investigated. Fluorine diffuses into the SiO2film through the upper layer of poly Si above 800thinsp;deg;C. At 1000thinsp;deg;C, fluorine diffuses into the SiO2film to a concentration on the order of 1020cmminus;3. Electrical breakdown field of the SiO2film degrades remarkably at 1000thinsp;deg;C. However, it was clear that the diffusion of fluorine was blocked by a thin chemicalhyphen;vaporhyphen;deposited Si3N4layer on the SiO2film. In this case, the degradation of SiO2film was not observed. From the above results, it is concluded that the diffusion of fluorine included in the chemicalhyphen;vaporhyphen;deposited tungsten silicide film is one of the causes in degradation of electrical breakdown of the SiO2film when the chemicalhyphen;vaporhyphen;deposited tungsten silicide film was used as a gate electrode in metal oxide semiconductor integrated circuits.