Performance analysis of MgO/ZnO multilayer thin film as heat spreader on Al substrates for high-power LED thermal management applications

Abstract

Towards improving structural, surface, and thermal properties of MgO heat spreader, ZnO thin film was interstacked into MgO. This would improve heat dissipation and keeping the temperature as well as the junction temperature of LEDs in safe operating conditions and make the MgO/ZnO multilayer thin film as a reliable heat spreader material in thermal management application. XRD measurements, FESEM, and AFM analysis were employed in examining the structure, morphology, particle size, and topography of the spin-coated monolithic MgO and multilayer MgO/ZnO thin films, respectively. Improvement in crystal size, reduction in residual stress, lattice strain, and dislocation density were recorded for MgO/ZnO multilayer films. Similarly, introduction of ZnO into MgO resulted an improvement in surface morphology with large particle size (76 nm) and decrease in surface roughness from 19.1 to 9.6 nm. From thermal transient analysis, a noticeable difference in junction temperature raise (ΔTJ = 27.07 °C) and high difference in total thermal resistance (ΔRth-tot = 5.3 K/W) were recorded for LED fixed on 6:4 L MgO:ZnO thin film-coated aluminum substrate. Introduction of ZnO into MgO improves the structure and surface qualities as well as thermal performance of MgO thin film and LEDs mounted on them. The optimized multilayer MgO/ZnO ceramic-ceramic composite thin film could be employed for efficient, reliable, and longer life LEDs thermal management as heat spreader.