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Title:Preparation and characterization of metal/sapphire and metal/polyimide thin film laminates
Author(s):Peddada, Satyanarayana Rao
Doctoral Committee Chair(s):Birnbaum, Howard K.
Department / Program:Materials Science and Engineering
Discipline:Materials Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Metallurgy
Engineering, Materials Science
Abstract:The aim of this research program was to understand the effect of thermal cycling on metal/insulator (sapphire and polyimide, PI) thin film laminates through studies of microstructure and microchemistry. Systems studied were: Ti/sapphire, Au/Cu/Ti/PI/Si and Cr/Cu/Cr/PI/Si. In the Ti/sapphire system, there was an additional interest to understand the effect of growth temperature on growth orientation and crystal quality of the films. The three material systems were characterized by a number of analytical techniques such as cross-section TEM (XTEM), plan-view TEM, SEM, Auger Electron Spectroscopy and X-ray diffraction. Of these, XTEM was the most extensively used.
In the Ti/sapphire system, single crystals formed in the temperature range 245-750$\sp\circ$C with the respective close packed planes and directions parallel. The crystal quality improved with an increase in the growth temperature up to 750$\sp\circ$C. The interface was observed to be sharp with no reaction layer formation even at a growth temperature of 950$\sp\circ$C. On annealing in D$\sb2$ gas at 325$\sp\circ$C for 48 hours, the Ti film transformed to TiD$\sb2,$ but no mechanical failures were observed.
In the Ti/PI system, on annealing in D$\sb2$ gas at 325$\sp\circ$C for 48 hours, the interface remained sharp to a large extent, but a discontinuous reaction zone consisting of an oxide, $\rm Ti\sb5O\sb9,$ formed at the interface due to a reaction between Ti and moisture in the PI. On annealing in D$\sb2$ gas, spontaneous edge delamination was observed at the Ti/PI interface. There was no extensive diffusion of Ti or Cu into PI even in samples annealed at 400$\sp\circ$C for 48 hours.
In the Cr/PI system, the interface remained sharp after annealing at 325$\sp\circ$C irrespective of the ambient atmosphere. Tensile cracks formed due to residual thermal stresses. There was no significant diffusion of Cr or Cu into PI on annealing at 325$\sp\circ$C for 48 hours.
Issue Date:1991
Rights Information:Copyright 1991 Peddada, Satyanarayana Rao
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9210950
OCLC Identifier:(UMI)AAI9210950

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