The role of aluminum in the crystallization of Cr–Si–Ni resistive films

The microstructure and electrical properties of both annealed Cr–Si–Ni and Cr–Si–Ni–Al films with an atomic ratio [Si]/[Cr]>2 were investigated. When sputtered amorphous Cr–Si–Ni and Cr–Si–Ni–Al films were heated up to temperature of 600 °C, they all were found to crystallize through two distinct stages. The first stage was due to the primary crystallization of nanocrystalline CrSi2 and Si phase for Cr–Si–Ni films (or Cr(Si,Al)2 and Si phase for Cr–Si–Ni–Al films), while the second stage was due to crystallization of the residual solute-enriched amorphous phase into CrSi2 (or Cr(Si,Al)2) and Si phase. The addition of Al into amorphous Cr–Si–Ni films caused the coarsening of the primary crystallization phase, resulting in a significant increase of both the electrical resistivity and the temperature coefficient of resistance (TCR) for the annealed films. Meanwhile, the subsequent crystallization of the residual solute-enriched amorphous phase was affected, resulting from the combined redistribution of Cr, Si, Al and Ni elements between the primary and parent amorphous phases.