Silicon Oxycarbide Accelerated Chemical Vapor Deposition of Graphitic Networks on Ceramic Substrates for Thermal Management Enhancement

Abstract

Ceramic materials such as aluminum oxide (Al 2 O 3 ) and aluminum nitride (AlN) are commonly implemented as heat sinks for a variety of applications. However, the thermal conductivity of these ceramics is too low to act as effective thermal management materials in power electronics applications. With high lateral thermal conductivity, graphitic films would be ideal materials to enhance the thermal management abilities of ceramics. Current direct chemical vapor deposition (CVD) methods can only grow several layers of graphene on ceramic substrates with poor adhesion to the substrate. We demonstrate a simple atmospheric pressure chemical vapor deposition (APCVD) method to deposit micrometerscale graphitic networks directly on the surface of ceramics making use of dual silicon oxycarbide (SiOC) sources. The graphitic networks have good adhesion to aluminum oxide and can provide sufficient thermal mass combined with superior hear transfer properties for effective thermal management enhancement of ceramic substrates.

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.…”

“… ( a ) Example of thermal management results for thick graphitic networks on porous Al 2 O 3 and AlN ceramics processed by APCVD: ( a.1 ) SEM images of the graphitic networks, ( a.2 ) Schematics of the Joule heating test setup, based on a thick film resistor attached to a DBC substrate, and backside hot spot temperature profiles of both the coated Al 2 O 3 and bare AlN DBC substrates; and ( a.3 ) temperature distribution during heating of both coated substrates. Adapted with permission from reference [ 263 ], copyright (2019) American Chemical Society. ( b ) Schematics of the APCVD procedure used to develop thermal conductive fillers for silicone oil-based non-curing TIM: highly oriented thick graphitic network flakes delaminated from quartz substrates and graphitic network-coated Al 2 O 3 spherical particles.…”

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

“…28,30 With the increase in growth time, the 2D peak became flat and broad with an increasing G/2D peak ratio, showing an increase in the graphitic layers and the formation of a graphitic network. 31 With a coating duration of 20 min, the 2D peak was flattened even more, showing a much thicker graphitic structure. The thick graphitic flake delaminated from quartz had some similarities in spectrum to the graphitic layer grown on alumina for 20 min, for instance, the flattened peaks and lack of 2D peak.…”