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Using Metallic Interlayers to Stabilize Metal-Metal Interfaces


EMSL Project ID
19805

Abstract

The objective of the proposed research is to investigate the potential for ultrathin metal interlayers to stabilize the metal-metal interface in thin-film structures. A closely coupled combination of experimental observations and model calculations will be used to identify those metals which when deposited in monolayer amounts at the interface make possible stable, epitaxial interfaces in systems that are otherwise characterized by interdiffusion and disorder. The interlayer materials, unlike surfactants, remain at the interface to promote chemical, thermal, and structural stability. The interlayer should be atomically thin, unlike conventional diffusion barriers, to minimize the impact on any electronic properties of the bi-layer structure. Simple model calculations based on quantum approximate techniques (BFS method) will be used to guide the choice of interlayer materials, depending on the film-substrate combination under study. Experimental observations will be used to expand the database of BFS parameters, and so refine the model. The extension of the interlayer concept to sputtered thin films, typical of industrial processes will also be investigated.

The measurements will characterize the degree of ordered growth or interdiffusion at the interface using high-energy ion backscattering and channeling, low energy electron diffraction, low-energy ion scattering, and x-ray photoelectron diffraction. Core-level photoelectron binding energies will serve to identify compound formation at the interface. The collaborative effort with scientists at EMSL will supplement on-going experiments at Montana State University. The work will benefit the efforts at EMSL in the area of Science of Interfacial Phenomena. In particular, better understanding and modeling of the electronic and geometric structure of intermetallic surfaces and metal-metal interfaces will contribute to the development of bimetallic catalysts and thin-film magnetic structures (GMR). Results from the experiments will also be used to build a database for model atomistic calculations, capable of predicting interface evolution and alloy formation, and in this way improve the capability to predict and design alloys with specific surface and interface structures and properties.

Project Details

Project type
Large-Scale EMSL Research
Start Date
2006-10-01
End Date
2009-09-30
Status
Closed

Team

Principal Investigator

Richard Smith
Institution
Montana State University

Team Members

Hui Chen
Institution
Montana State University

Andreas Comouth
Institution
Montana State University

Weerasinghe Priyantha
Institution
Montana State University

Related Publications

?Interface Intermixing of Al/Fe and Fe/Al Multilayer Systems and the role of Ti as a Stabilizer Layer Using Rutherford Backscattering Spectrometry (RBS) and X-ray Reflectrometry (XRR)?, W. Priyantha , H. Chen , M. Kopczyk , R.J. Smith, A. Kayani, A. Comouth , M. Finsterbusch , P. Nachimuthu , D. McCready, J. Appl. Phys. 103, 014508 (2008).
Priyantha WA, RJ Smith, H Chen, M Kopczyk, M Lerch, C Key, P Nachimuthu, and W Jiang. 2009. "Fe-Al interface intermixing and the role of Ti, V, and Zr as a stabilizing interlayer at the interface." Journal of Applied Physics 105(5):Art. No. 053504.