The crystallization of Cr–Si–Ni–Al amorphous films—nucleation and growth of intermetallic phase Cr(Al,Si) 2

• Published in: Intermetallics 2003-08, Vol.11 (8), p.779-785
• Main Authors: Dong, Xianping, Wu, Jiansheng, Mao, Lizhong
• Format: Article
• Language: English
• Subjects: A. Nanostructured intermetallics; B. Electrical resistance and other properties; B. Phase transformations; C. Thin films
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/S0966-9795(03)00079-7

When sputtered amorphous Cr–Si–Ni–Al films with an atomic ratio [Si]/[Cr]>2 were heated up to temperature of 600 °C, they were found to crystallize into two phases: the intermetallic phase Cr(Al,Si) 2 and the pure silicon phase; the growth rate of the crystalline phases at the initial stage of reaction was faster than that at the final stage, resulting from the combined redistribution of Cr, Si, Al and Ni elements between the initial crystalline phases and the parent amorphous phase. The formation of the crystalline phases resulted in a significant increase of both the electrical resistivity and the temperature coefficient of resistance (TCR) for the annealed Cr–Si–Ni–Al films. In particular, the intermetallic Cr(Al,Si) 2 particles, which were embedded in the amorphous matrix, were responsible for achieving a zero TCR. Moreover, the deviation between the TCR 25 125 (TCR averaged between 25 °C and 125 °C) and the TCR −55 25 (TCR averaged between −55 °C and 25 °C) in the annealed Cr–Si–Ni–Al films with small TCR was diminished.