Thickness dependent thermal conductivity measurements were made on aluminum nitride (AlN) thin films grown by two methods on the (0001) surfaces of silicon carbide (SiC) and sapphire substrates with differing surface roughness. We find that the AlN layer itself makes a small contribution to the overall thermal resistance. Instead, the thermal boundary resistance (TBR) of 5.1±2.8 m2-K/GW between the AlN and substrate is equivalent to 240 nm of highly dislocated AlN, or 1450 nm of single crystal AlN. An order-of-magnitude larger TBR was measured between AlN films and SiC substrates with increased surface roughness (1.2 nm vs. 0.2 nm RMS). High resolution TEM images reveal near-interface planar defects in the AlN films grown on the rough SiC that we hypothesize are the source of increased TBR.
- Heat Transfer Division
Dependence of Thermal Conductivities of the AlN Film in the LED Architecture on Surface Roughness and Lattice Mismatch
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Su, Z, Malen, JA, Freedman, JP, Davis, RF, Leach, JH, & Preble, EA. "Dependence of Thermal Conductivities of the AlN Film in the LED Architecture on Surface Roughness and Lattice Mismatch." Proceedings of the ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. Volume 1: Heat Transfer in Energy Systems; Thermophysical Properties; Theory and Fundamental Research in Heat Transfer. Minneapolis, Minnesota, USA. July 14–19, 2013. V001T03A004. ASME. https://doi.org/10.1115/HT2013-17116
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