MAT Summer 2011 Seminar-M. Alper Sahiner
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  • MAT Summer 2011 Seminar-M. Alper Sahiner

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MAT Summer 2011 Seminar
Application of Synchrotron Based EXAFS as a Structural Local Probe to
Material Related Problems of CMOS Thin Films
M. Alper Sahiner
Chair and Associate Professor
Seton Hall University, Physics Department, South Orange, New Jersey 07079, USA
Solutions to material related problems of the next generation CMOS devices require sensitive
structural probing techniques. Our approach to local structural characterization in these
materials is a non-destructive, sensitive local probe: Extended x-ray absorption fine-structure
spectroscopy (EXAFS). In this talk, quantitative applications of EXAFS applied to major
materials problems of semiconductor industry will be presented. First application is on the
local structural characterization of Hf based advanced gate stacks thin films using
(EXAFS). Al2O3 or La2O3 capped HfO2 and HfSiOx films on silicon substrates were
analyzed by EXAFS in order to reveal subtle structural modifications due to variations
annealing mechanism during the preparation of the films. The local structure of Al2O3
capped films, as probed through EXAFS analysis, exhibit sensitivity to whether or not (N2
or NH3 ambient) PDA is performed after the initial HfO2 layer deposition. The second
application is on the local structural characterization of novel contact materials (nickel
silicides) on N2+ implanted Si(100) substrates using EXAFS. The crystal phases of nickel
silicides that are stabilized on Si (100) substrates (NiSi or NiSi2) upon varying implant doses
and post deposition annealing conditions were identified. The third application is on the
problem of the clustering and deactivation of the high dose silicon dopants. In arsenic and
antimony implanted silicon wafers our EXAFS results are shown to be sensitive to subtle
changes in structure of the clusters and precipitates formed under various post-synthesis
treatments. For all of these applications we use quantitative analysis with calculated EXAFS
functions for the possible local structures and then apply non-linear least squares
fitting to the experimental data in order to reveal the exact local configurations. Detailed
EXAFS modeling of the data acquired at the National Synchrotron Light Source of
Brookhaven National Laboratory will be presented and the local structure and synthesis
relations will be discussed.
Wednesday, 1 June 2011, FENS G015, 11.00