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Title: Effects of disorder state and interfacial layer on thermal transport in copper/diamond system

The characterization of Cu/diamond interface thermal conductance (h{sub c}) along with an improved understanding of factors affecting it are becoming increasingly important, as Cu-diamond composites are being considered for electronic packaging applications. In this study, ∼90 nm thick Cu layers were deposited on synthetic and natural single crystal diamond substrates. In several specimens, a Ti-interface layer of thickness ≤3.5 nm was sputtered between the diamond substrate and the Cu top layer. The h{sub c} across Cu/diamond interfaces for specimens with and without a Ti-interface layer was determined using time-domain thermoreflectance. The h{sub c} is ∼2× higher for similar interfacial layers on synthetic versus natural diamond substrate. The nitrogen concentration of synthetic diamond substrate is four orders of magnitude lower than natural diamond. The difference in nitrogen concentration can lead to variations in disorder state, with a higher nitrogen content resulting in a higher level of disorder. This difference in disorder state potentially can explain the variations in h{sub c}. Furthermore, h{sub c} was observed to increase with an increase of Ti-interface layer thickness. This was attributed to an increased adhesion of Cu top layer with increasing Ti-interface layer thickness, as observed qualitatively in the current study.
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [1] ;  [2] ;  [1]
  1. Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22413133
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 7; Other Information: (c) 2015 U.S. Government; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ADHESION; COMPOSITE MATERIALS; CONCENTRATION RATIO; COPPER; DIAMONDS; INTERFACES; LAYERS; MONOCRYSTALS; NITROGEN; SUBSTRATES; THERMAL CONDUCTIVITY; THICKNESS; TITANIUM; VARIATIONS