Nanocrystalline Diamond Lateral Overgrowth for High Thermal Conductivity Contact to Unseeded Diamond Surface

• DOI: 10.1149/ma2024-01321567mtgabs
• Publication Date: 2024-08-19T15:25:35Z
• Authors: Daniel Francis; Xiaoyang Ji; Sai Charan Vanjari; Marko Tadjer; Tatyana Feygelson; James Spencer Lundh; Hannah Masten; Joseph Spencer; Alan G. Jacobs; Travis J. Anderson; Karl D. Hobart; Bradford Pate; Martin Kuball; Felix Ejeckam
• Keywords: Nanocrystalline material

We demonstrate diamond lateral overgrowth as a way of increasing the thermal conductivity thin layers diamond. The technique can be used growing on top semiconductors, creating layer high in direct contact with semiconductors and allowing for encasement GaN As we move to higher power densities, requirements heat removal become extreme. best passive remove from semiconductor is have spreader near source. Having under substrate good. epi better having bottom still. As-grown non-diamond substrates nano-diamond seeds starting material. function grain size (Especially small material) [1]. If increase junction, junction more efficiently spread away source before rejecting it into surrounding In experiment, start bare silicon wafer seeded then grow about one micron coat few nanometers SiN. Then pattern SiN 2μm wide features facilitate coalescence LOG-NCD over thick microwave-plasma CVD NCD film (800W, 15Torr, 750°C, 0.3% CH4/H2) patterned initiating directly exposed areas host NCD. growth does not initiate nitride without seeds. acts nucleating center regrowth. regrown spreads crystals first growth. edge closest area expand forming conformal surface. This creates large unseeded area. Figure 1 transmission electron microscope (TEM) image sample. TEM, split two regions. left has no patterning, called-out 100nm wide. right patterned, grains are between 1,000 2,000nm measured this samples using TDTR method. method uses laser many times larger diameter than thickness film. such, probe out-of-plane conductivity. initial had an average 100W/mK. second patterns Tc 130W/mK. above 260W/mK 10X un-patterned Since columnar, difference diamonds was 2X. Lateral measurements would likely show even changes With sizes 100 nm 250 (as case diamond), in-plane will dominated by quality grain/grain interfaces dimensions rather lattice. [1] microns 100s nm. means that regime where boundaries. such increased further improved improving crystal - parameter which controlled conditions. Typically, grown 1% methane / hydrogen ratio lower [2]. However concentrations important establish damage underlying semiconductor. Here, concentration balanced achieve both low substrate. References: J. Anaya, et. al “Control ultra-thin nanocrystalline films through boundary properties”, Acta Materialia, Volume 103, 2016, Pages 141-152, ISSN 1359-6454 Gu, C., Jin, Z., Lu, X., Zou, G., Zhang, Fang, R., 1997. deposition Thin Solid Films, 311(1-2), pp.124-127.