Real time x-ray studies during nanostructure formation on silicon via low energy ion beam irradiation using ultrathin iron films

Osman El-Atwani, Birck Nanotechnology Center, Purdue University
Anastassiya Suslova, Purdue University
Alexander DeMasi, Purdue University
Sean Gonderman, Purdue University
Justin Fowler, Purdue University
Mohamad El-Atwani, Purdue University
Karl Ludwig, Purdue University
Jean Paul Allain, Birck Nanotechnology Center, Purdue University

Date of this Version



Appl. Phys. Lett. 101, 263104 (2012)


Copyright (2012) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Appl. Phys. Lett. 101, 263104 (2012) and may be found at The following article has been submitted to/accepted by Applied Physics Letters. Copyright (2012) Osman El-Atwani, Anastassiya Suslova, Alexander DeMasi, Sean Gonderman, Justin Fowler, Mohamad El-Atwani, Karl Ludwig and Jean Paul Allain. This article is distributed under a Creative Commons Attribution 3.0 Unported License.


Real time grazing incidence small angle x-ray scattering and x-ray fluorescence (XRF) are used to elucidate nanodot formation on silicon surfaces during low energy ion beam irradiation of ultrathin iron-coated silicon substrates. Four surface modification stages were identified: (1) surface roughening due to film erosion, (2) surface smoothing and silicon-iron mixing, (3) structure formation, and (4) structure smoothing. The results conclude that 2.5 x 10(15) iron atoms in a 50 nm depth triggers surface nanopatterning with a correlated nanodots distance of 25 nm. Moreover, there is a wide window in time where the surface can have correlated nanostructures even after the removal of all the iron atoms from the sample as confirmed by XRF and ex-situ x-ray photoelectron spectroscopy (XPS). In addition, in-situ XPS results indicated silicide formation, which plays a role in the structure formation mechanism. (C) 2012 American Institute of Physics. []


Nanoscience and Nanotechnology