Template-induced formation of α-W and size-dependent properties of tungsten thin films

✍ Scribed by M.X. Liu; Y.L. Huang; F. Ma; K.W. Xu

• Book ID: 103843718
• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 606 KB
• Volume: 139
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/j.mseb.2007.01.042

✦ Synopsis

Tungsten thin films with different thicknesses were deposited on Si substrate and Mo seed-layer by magnetron sputtering. X-ray diffraction (XRD) analyses and field emission scanning electronic microscopy (FESEM) observations show that stable ␣-W in equiaxial-grain shape is preferred on Mo layer driven by template effect while the metastable ␤-W with non-equiaxed grain structure appears to form on silicon substrate. Additionally, residual stress and electronic resistivity depend upon the film thickness considerably, but with different mechanisms. For the case of ␤-W, electronic resistivity and residual tensile stress increase with decreasing film thickness indeed because of reduced grain size. Whereas, for ␣-W case, at film thicknesses equal to or smaller than tens of nanometers, the constraint of coherent interface between ␣-W and Mo will dominate and enhance the resistivity and residual compressive stress.