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An Electron Microprobe Auger Spectroscopy was applied to investigate interactions between Al film and thermally grown silicon dioxide (SiO2) in order to examine the failure occurred for very thin Al film on SiO2 surface during heating and stressing tests. It was found that the oxidation mechanism of Al film was different on Al film surface from that at the interface between Al and SiO2 during heating in vacuum at 400-500°C for 30 min. Also, the depth of penetration of Al into SiO2 was found to be unexpectedly large. As a result of stressing test, chained hillocks appeared along the direction of electron flow in the case of very thin Al film. This Phenomenon may be due to diffusion of Si into Al film by heating during device process.

The effect of fluorine in chemical‐vapor‐deposited tungsten silicide film on electrical breakdown of SiO2 film was investigated. Fluorine diffuses into the SiO2 film through the upper layer of poly Si above 800 °C. At 1000 °C, fluorine diffuses into the SiO2 film to a concentration on the order of 1020 cm−3. Electrical breakdown field of the SiO2 film degrades remarkably at 1000 °C. However, it was clear that the diffusion of fluorine was blocked by a thin chemical‐vapor‐deposited Si3N4 layer on the SiO2 film. In this case, the degradation of SiO2 film was not observed. From the above results, it is concluded that the diffusion of fluorine included in the chemical‐vapor‐deposited tungsten silicide film is one of the causes in degradation of electrical breakdown of the SiO2 film when the chemical‐vapor‐deposited tungsten silicide film was used as a gate electrode in metal oxide semiconductor integrated circuits.

Tungsten silicide films were formed by the chemical vapor deposition method using the reaction WF/sub 6/ and Si/sub 2/H/sub 6/. The deposition rate, resistivity, composition, stress, crystal structure, and content of impurities were studied and compared with tungsten silicide films deposited by reaction of WF/sub 6/ and SiH/sub 4/. The tungsten silicide films made using Si/sub 2/H/sub 6/ have a higher deposition rate and higher Si concentration than those made by using SiH/sub 4/ at the same substrate temperature. For these reasons, the tungsten silicide films made by using Si/sub 2/H/sub 6/ were found to have a resistivity that is a little higher and, after annealing, a stress that is smaller than that made by SiH/sub 4/.