Dual Silicon Oxycarbide Accelerated Growth of Well‐Ordered Graphitic Networks for Electronic and Thermal Applications

Abstract

While effective in circumventing the transfer process of graphene films from metals to insulating substrates, graphene chemical vapor deposition (CVD) methods which grow directly on the surface of insulating substrates suffer from slow growth rates, lack of covalent bonding between both graphene layers within the film and the entire film and its substrate, and the inability to grow films beyond nanoscale thickness. An atmospheric pressure chemical vapor deposition (APCVD) process is described utilizing preplaced silicone rubber and continuously fed tetraethyl orthosilicate (TEOS) as dual silicon oxycarbide (SiOC) sources to facilitate fast surface coverage (30 s) and z‐thickness growth (136 nm min−1) of graphitic coatings consisting of a network of covalently bonded graphene layers directly on quartz while providing strong adhesion between the coating and the substrate via a semiconductive transition layer. This process can produce graphitic networks for a wide range of products including transparent conducting and semiconductive nanoscale graphene films, anisotropic micrometer‐scale coatings with in‐plane thermal conductivity >1000 W m−1 K−1 and standalone flakes with >40 µm thickness for thermal management applications.

Applications of Ceramic/Graphene Composites and Hybrids

“…However, conventional CVD processes require a long time to grow nanoscale graphene films that generally show poor adhesion to the ceramic substrate, whereas micrometer-scale films with a larger thermal mass and better bonding to the substrate are needed for demanding thermal management applications such as wide band gap semiconductor devices. Recently, an atmospheric pressure CVD (APCVD) method by using dual silicon oxycarbide (SiOC) sources has been developed for depositing ∼10 μm thick graphitic networks on porous Al 2 O 3 and AlN ceramics, Figure 19 (a.1) [ 262 , 263 ]. The graphitic deposits on Al 2 O 3 showed better adhesion than those obtained by conventional CVD, while delamination was detected for the AlN/graphitic coating structures.…”

“…The graphitic deposits on Al 2 O 3 showed better adhesion than those obtained by conventional CVD, while delamination was detected for the AlN/graphitic coating structures. The developed structures presented sufficient thermal mass and superior thermal conductivity, 1000 W⋅m −1 ⋅K −1 for the in-plane and 6 W⋅m −1 ⋅K −1 for the cross-plane directions, measured for a 6 μm thin layer by the time-domain thermo-reflectance method [ 262 ]. The thermal management performance was checked by Joule heating using a setup based on a thick film resistor attached to a DBC substrate, as shown in ( Figure 19 (a.2)).…”

Evaluation of Warpage and Residual Stress of Precision Glass Micro-Optics Heated by Carbide-Bonded Graphene Coating in Hot Embossing Process

“…From the Si 2p spectrum, the binding energies of C-Si, C-Si-O and C-O-Si-O-C bonds are located at 103.0 eV, 103.6 eV and 104.3 eV respectively. A few previous studies [ 5 , 27 , 28 ] have confirmed that the carbon coatings dominated by sp 2 sites exhibit low external stress, excellent mechanical and electrical performances. Besides, the existence of sp 3 sites contributes to the high toughness of the CBG coating.…”

Highly Oriented Graphitic Networks Grown by Chemical Vapor Deposition as Thermal Interface Materials

“…Chemical vapor deposition (CVD) is an effective method to synthesize graphite/graphene thin films on different solid substrates. 24,25 Compared with other approaches, it presents superiorities on dispersive powder and porous materials. Largescale production of graphene coating has been developed in recent years by either continuous or semi-continuous processes.…”

“…Largescale production of graphene coating has been developed in recent years by either continuous or semi-continuous processes. 25,26 Many works have also been reported on the direct CVD of graphitic materials for thermal management applications on different substrates. 25,27 However, to the best of authors' knowledge, graphitic fillers produced by the CVD approach have not been yet explored for TIMs.…”