Ni-mediated reactions in nanocrystalline diamond on Si substrates

Author(s)
Semir Tulić, Thomas Waitz, Oleksandr Romanyuk, Marián Varga, Mária Čaplovičová, Gerlinde Habler, Viliam Vretenár, Mário Kotlár, Alexander Kromka, Bohuslav Rezek, Viera Skákalová
Abstract

Nanocrystalline diamond (NCD) films grown on Si substrates by microwave plasma enhanced chemical vapor deposition (MWPECVD) were subjected to Ni-mediated graphitization to cover them with a conductive layer. Results of transmission electron microscopy including electron energy-loss spectroscopy of cross-sectional samples demonstrate that the oxide layer on Si substrates (∼5 nm native SiO2) has been damaged by microwave plasma during the early stage of NCD growth. During the heat treatment for graphitizing the NCD layer, the permeability or absence of the oxide barrier allow Ni nanoparticles to diffuse into the Si substrate and cause additional solid-state reactions producing pyramidal crystals of NiSi2 and SiC nanocrystals. The latter are found impinged into the NiSi2 pyramids but only when the interfacial oxide layer is absent, replaced by amorphous SiC. The complex phase morphology of the samples is also reflected in the temperature dependence of electrical conductivity, where multiple pathways of the electronic transport dominate in different temperature regions. We present models explaining the observed cascade of solid-state reactions and resulting electronic transport properties of such heterostructures.

Organisation(s)
Physics of Nanostructured Materials, Department of Lithospheric Research
External organisation(s)
Universität Wien, Czech Academy of Sciences, Slovak University of Technology in Bratislava, Czech Technical University in Prague (CTU)
Journal
RSC Advances
Volume
10
Pages
8224-8232
No. of pages
9
ISSN
2046-2069
DOI
https://doi.org/10.1039/d0ra00809e
Publication date
02-2020
Peer reviewed
Yes
Austrian Fields of Science 2012
Materials physics, Electron microscopy
ASJC Scopus subject areas
,
Portal url
https://ucris.univie.ac.at/portal/en/publications/nimediated-reactions-in-nanocrystalline-diamond-on-si-substrates(c8e924a2-b4f3-41d6-aa82-714bca4bb2b0).html