Growth and performance analysis of BAlN alloy thin film on Al substrate as a heat spreader for effective thermal management applications on white-based high-power LED

Abstract

The BAlN thin-film alloy with different thicknesses (∼160–330\xa0nm) is successfully developed on commercial aluminium substrates (5052 grade) using RF reactive sputtering technique at room temperature in Al/B/AlN stacking sequence. The structural, thermal properties and surface topography are studied after annealing at 400\xa0°C in a nitrogen ambient for 1\xa0h. The presence of cubic BAlN thin film is established with the presence of (200) and (220) crystal planes and confirmed by the XRD results. The aluminium nitride (AlN) and boron nitride phases are also confirmed by a clear and very shallow FTIR band reflection spectra between ∼\u2009512\xa0cm−1 and 912\xa0cm−1; furthermore, the developed BAlN alloy is confirmed from the Raman shift at ∼\u2009602\xa0cm−1 and ∼\u2009912\xa0cm−1. The observed continuous thin-film structure with low peak & valley range, low surface roughness with particle size in the range from 80 to 200\xa0nm is indicative of a good surface with lower roughness and a huge decrease in thermal resistance (Rth-tot) by up to 40% in BAlN 2 compared to that of bare Al substrate is achieved. However, similar work with (AlN/B) stacking sequence shows lower improvement in total thermal resistance (Rth) to about 23%; this evidenced the novelty of the work where a material with well-reduced interfacial thermal resistance to about 71% is fabricated at low bond line thickness compared to bare aluminium substrate. It has the capability for good heat spreading at both lower and higher current densities towards efficient and effective thermal management in LED and other devices.