Transcript Document

Experimental Work - Atom Probe Tomography
At Iowa State University
S. Dumpala, S. Broderick, A. Bryden, K. Kaluskar and K. Rajan
Study of Growth of Different Oxidized Layers : APT
Atom Probe Tomography
ReaxFF Simulations
(Model System – Oxidation of Aluminum)
• Oxidation of Aluminum at 450 C,
2.5 x 10-3 Torr for 10 min.
U. Khaliov, et al. J. Phys. Chem.C, 115, 2011
• Growth behavior of ultrathin silica layers by
laser detonation hyperthermal atomic beam
source (1-15 eV) of atomic and molecular oxygen
• Study of occurrence of pure Si, SiOx,
and SiO2 and growth directions of oxidized (black
arrows) and silica layers (red arrows)
• Chemical composition and
atomic structure from 3D image of
elemental mapping with atomicscale resolution
Study of Interfaces
Mass and Charge distributions –
ReaxFF Simulations
Diffusion Profiles - APT
Bulk Al2O3 phase
Bulk Al phase
O
Al
O
Possible Link
Al
U. Khaliov, et al. J. Phys. Chem.C, 115, 2011
Effect of Growth Temperature
APT
ReaxFF Simulations
U. Khaliov, et al. J. Phys. Chem.C, 116, 2012
Environmental Chamber- APT
Possible Experimental Studies - Oxidation
• Different Temperatures up to 800 C
• Different pressures ranges (low 10 -5 torr)
• Different gas phase chemistries
• Different time scales
• Different sample orientations
Mass Spectra - APT
Diffusion Profiles
Study of Interfaces
Ion Evaporation Map
Use APT to study compound
formation, bond strengths (crystal
structure changes), evaporation
physics/ionic dissociation, and
charge states of bonded atoms.
Experimental Studies at Maryland
• 10 coupons each with 36 Si (100) micro tips (6x6 rows) were sent to
University of Maryland to obtain the samples of known fluence and
energy spectrum to evaluate the change in surface morphology
Typical Silicon Coupon