Diffuse Small Angle X-Ray Scattering From Thin Film Structures In the Distorted Wave Born Approximation
The differential scattering cross section for diffuse scattering of X-rays from thin
film structures is discussed within the framework of the distorted wave Born ap-
proximation (DWBA). In contrast to the standard Born approximation (BA), the
distorted wave approach succeeds in calculating scattering from surfaces near the
critical angle of reflection. The method is particularly useful for studying average
Compromises made in the derivation of the model substantially simplify the
final expression, but also limit its range of validity, which depends on the surface
root mean square roughness σ and the momentum transfer between the incident
and scattered X-rays perpendicular to the surface, Qz . The approximation is valid
so long as (Qz x σ) << 1.
However, this is also the only regime where it is necessary to
go beyond the simpler Born approximation.
A computer simulation software based on the DWBA is implemented in Python.
The implemented DWBA depends on the fractal dimension of the surface features
through a parameter h (D = 3 − h) and an in-plane correlation cut off length ζ.
The various effects of changing key model parameters, among them ζ and h, is
demonstrated. Comparison between experimental data and the DWBA model
looks promising although there are some challenges in relation to determining
the fractal dimension.
Finally, the feasibility of implementing the DWBA model in a multi-parameter
fitting algorithm is discussed.
Place, publisher, year, edition, pages
Institutt for fysikk , 2011. , 69 p.
ntnudaim:6641, MTNANO Nanoteknologi, Nanoelektronikk
IdentifiersURN: urn:nbn:no:ntnu:diva-13379Local ID: ntnudaim:6641OAI: oai:DiVA.org:ntnu-13379DiVA: diva2:438129
Breiby, Dag Werner, FørsteamanuensisFløystad, Jostein