Local density profiles in thin films and multilayers from diffuse x-ray and neutron scattering

AbstractMany advanced ceramics are formed by colloidal consolidation using techniques such as sedimentation, centrifugation, or pressure filtration. In all these, the minimization of density variations of various colloidally-consolidated cakes has not been examined systematically until recently. Schilling et al. used γ-ray densitometry to study the density variations in a sedimented cake and showed that the sediment of a flocculated alumina suspension exhibited significant density variations within the cake whereas the sediment of a dispersed alumina suspension showed a constant density profile. Auzerais et al. used a medical X-ray computer tomography (CT) to study the settling of dispersed and flocculated silica suspensions and obtained similar results: The sedimented cake of a dispersed silica suspension was fairly uniform whereas those of flocculated silica suspensions exhibited significant density variations. However, Shih et al. examined pressure-filtered cakes of flocculated alumina suspensions with γ-ray densitometry and showed that the density profiles of pressure-filtered cakes of flocculated alumina suspensions were uniform, in contrast to their sedimentation counterparts which showed significant density variations. These studies illustrate that how the local density varies within a consolidated cake depends not only on the suspension conditions but also on how the suspensions are consolidated, e.g., the consolidation pressure.

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Structure and Property Characterization of Porous Low-k Dielectric Constant Thin Films using X-ray Reflectivity and Small Angle Neutron Scattering

MRS Proceedings ◽

10.1557/proc-612-d4.1.1 ◽

2000 ◽

Vol 612 ◽

Cited By ~ 3

Author(s):

Eric K. Lin ◽

Wen-li Wu ◽

Changming Jin ◽

Jeffrey T. Wetzel

Keyword(s):

Thin Films ◽

Neutron Scattering ◽

Small Angle ◽

Small Angle Neutron Scattering ◽

Coefficient Of Thermal Expansion ◽

Scattering Data ◽

Connectivity Matrix ◽

X Ray ◽

Porous Thin Films ◽

Low K

AbstractHigh-resolution X-ray reflectivity and small angle neutron scattering measurements are used as complementary techniques to characterize the structure and properties of porous thin films for use as low-k interlevel dielectric (ILD) materials. With the addition of elemental composition information, the average pore size, porosity, pore connectivity, matrix density, average film density, film thickness, coefficient of thermal expansion, and moisture uptake of porous thin films are determined. Examples from different classes of materials and two analysis methods for small angle neutron scattering data are presented and discussed.

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Fourier Reconstruction of Density Profiles of Thin Films Using Anomalous X-Ray Reflectivity

EPL (Europhysics Letters) ◽

10.1209/0295-5075/21/6/010 ◽

1993 ◽

Vol 21 (6) ◽

pp. 691-696 ◽

Cited By ~ 60

Author(s):

M. K Sanyal ◽

S. K Sinha ◽

A Gibaud ◽

K. G Huang ◽

B. L Carvalho ◽

...

Keyword(s):

Thin Films ◽

Density Profiles ◽

X Ray ◽

Fourier Reconstruction

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A Three-phase Model for the Structure of Porous Thin Films Determined by X-ray Reflectivity and Small-Angle Neutron Scattering

MRS Proceedings ◽

10.1557/proc-612-d5.22.1 ◽

2000 ◽

Vol 612 ◽

Cited By ~ 3

Author(s):

Wen-li Wu ◽

Eric K. Lin ◽

Changming Jin ◽

Jeffrey T. Wetzel

Keyword(s):

Thin Films ◽

Neutron Scattering ◽

Small Angle ◽

Small Angle Neutron Scattering ◽

Coefficient Of Thermal Expansion ◽

Average Pore Size ◽

Silicon Substrates ◽

Average Pore ◽

X Ray ◽

Wide Range

AbstractA methodology to characterize nanoporous thin films based on a novel combination of high-resolution specular x-ray reflectivity and small-angle neutron scattering has been advanced to accommodate heterogeneities within the material surrounding nanoscale voids. More specifically, the average pore size, pore connectivity, film thickness, wall or matrix density, coefficient of thermal expansion, and moisture uptake of nanoporous thin films with non-homogeneous solid matrices can be measured. The measurements can be performed directly on films up to 1.5 µm thick while supported on silicon substrates. This method has been successfully applied to a wide range of industrially developed materials for use as low-k interlayer dielectrics.

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