Interfacial Reactions Between Amorphous W-Si Thin Films and Polycrystalline Overlayers. Thomas Perepezko, W. Technical Report
Interfacial Reactions Between Amorphous W-Si Thin Films and Polycrystalline Overlayers [pdf]Paper  abstract   bibtex   
Interactions between amorphous metal thin films and either a substrate or an overlayer can limit their effectiveness as diffusion barriers. We have found in previous studies that Au and Al polycrystalline thin films in contact with amorphous W-Si lowers the crystallization temperature of the a-(W-Si) by at least 100C. In contrast Cu and Mo have no apparent effect on the stability of the amorphous layer. The mechanisms leading to premature crystallization are not well understood. Amorphous W Si was deposited by D.C. sputtering .72 .28 onto single crystal Si substrates. 04verlayers of Al were then evaporated onto the W-Si. Using Auger electron spectroscopy depth profiling coupled with cross-section TEM, we have studied interfacial reactions between the amorphous layer and polycrystalline Al. Auger profiling results show that in the case of Al overlayers, W and Si diffuse out of the a-(W-Si) into the Al where WA 1 2 forms. These results can be explained in the context of three binary diffusion couples, W-Si, W-Al, Al-Si, and the individual interactions associated with these couples.

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