AVS 50th International Symposium
    Electronic Materials and Devices Thursday Sessions
       Session EM-ThM

Paper EM-ThM3
Ni-Si Thin Films Reactions at Low Temperatures: Phase Identification and Sequence Characterization

Thursday, November 6, 2003, 9:00 am, Room 321/322

Session: Materials for Interconnects and Contacts to Semiconductors
Presenter: C. Coia, École Polytechnique de Montréal, Canada
Authors: C. Coia, École Polytechnique de Montréal, Canada
C. Lavoie, IBM Research
M. Tremblay, École Polytechnique de Montréal, Canada
C. Detavernier, IBM Research
F.M. d'Heurle, IBM Research
P. Desjardins, École Polytechnique de Montréal, Canada
Correspondent: Click to Email
The phase formation sequence upon thermal annealing of 5 to 20-nm-thick Ni layers on Si(001) has been investigated using a combination of in-situ synchrotron x-ray diffraction (XRD), diffuse elastic light scattering, and electrical resistance complemented by post-annealing transmission electron microscopy and XRD analyses. In addition to the generally reported Ni@sub 2@Si, NiSi, and NiSi@sub 2@ phases, we observe the formation of several metal-rich silicide compounds at low temperatures. The complete sequence is identified as Ni-Ni@sub 31@Si@sub 12@-Ni@sub 2@Si-Ni@sub 3@Si@sub 2@-NiSi-NiSi@sub 2@ with the possible brief appearance of Ni@sub 3@Si preceding Ni@sub 31@Si@sub 12@. The sequence observed for Ni reaction with B- and P-doped Si(001) starts at higher temperatures and occurs over a narrower range in temperature than for undoped Si(001), n-doping having a stronger influence thus showing the larger increase in temperature. Quantitative analyses of XRD peak intensities during isothermal anneals are used to determine rate limiting mechanisms and reaction kinetics. In complementary experiments, 200-nm-thick single-phase layers were obtained for each of the stable phases present in the Ni-Si binary phase diagram in order to determine their physical and chemical properties. The phase formation sequence in these thicker layers of fixed composition suggests that the phases still grow sequentially with the first phase being the Ni@sub 31@Si@sub 12@.