Fast in situ X-ray analysis of Ni silicide formation.

Metal silicides are the preferred contact materials for metal-oxide semiconductor (MOS) structures. With further technology development, the materials changed within the last decades toward lower resistivity and lower thermal budget. Currently NiSi partly further stabilized with Pt or Pd is the material of choice. The understanding of phase transformation processes and structural features is of great importance for production process optimization. Here we present a fast laboratory-based in situ X-ray diffraction method with two different experimental arrangements (Bragg-Brentano and grazing incidence) optimized concerning the materials texture. Its application is demonstrated for the transformation of Ni to different Ni silicide phases starting with a 46 nm thick Ni layer sputtered on a Si(001) substrate and covered with TiN. Activation energies for the Ni to Ni2Si (1.55 ± 0.13) eV and the Ni2Si to NiSi transition (1.30 ± 0.15) eV are measured by repeating fast diffraction scans over a limited angular range under isothermal conditions and analyzing the diffraction peak height versus time. [ABSTRACT FROM AUTHOR]