Authors

A. P. Warren; T. Sun; B. Yao; K. Barmak; M. F. Toney;K. R. Coffey

Comments

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"This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in the linked citation and may be found originally at Applied Physics Letters."

Abbreviated Journal Title

Appl. Phys. Lett.

Keywords

SURFACE SELF-DIFFUSION; X-RAY-SCATTERING; THIN-FILMS; MULTILAYERS; ENERGY; Physics, Applied

Abstract

Synchrotron x-ray scattering was used to study the evolution of interface roughness with annealing for a series of Cu thin films. The films were encapsulated in SiO2 or Ta/SiO2 and prepared by sputter deposition. Specular x-ray reflectivity was used to determine the root mean square roughness for both the upper and the lower Cu/SiO2 (or Cu/Ta) interfaces. The lateral roughness was studied by diffuse x-ray reflectivity. Annealing the films at 600 degrees C resulted in a smoothing of only the upper interface for the Cu/SiO2 samples, while the lower Cu/SiO2 interfaces and both interfaces for the Ta encapsulated films did not evolve significantly. This difference in kinetics is consistent with the lower diffusivity expected of Cu in a Cu/Ta interface (compared to a Cu/SiO2 interface) and the mechanical rigidity of the lower Cu/SiO2 interface. As a function of roughness wavelength, the upper Cu/SiO2 interfaces exhibited a roughness decay with annealing that was only 12.5% of that expected for classical capillarity driven smoothening of a free surface.

Journal Title

Applied Physics Letters

Volume

100

Issue/Number

2

Publication Date

1-1-2012

Document Type

Article

Language

English

First Page

4

WOS Identifier

WOS:000299126800101

ISSN

0003-6951

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