Influence of Deposition Techniques on the Thermal Boundary Resistance of Aluminum Thin-Films

The influence of film deposition techniques on the thermal boundary resistance of an aluminum (Al)/silicon (Si) interface was investigated in this study. Al films 100 nm in thickness were deposited on Si(100) wafers using an e-beam evaporator and a direct current (DC) magnetron sputtering system. Their microstructural characteristics were inspected using scanning electron microscopy with energy dispersive spectroscopy, atomic force microscopy, and X-ray diffraction. The thermal boundary resistance values of the samples were measured using the time-domain thermoreflectance technique and numerically analyzed based on the transient Fourier heat conduction equation. A non-equilibrium molecular dynamics (MD) study was carried out to understand the effect of the atomic disorder at the film/substrate interface. Results show that the film produced by DC sputtering has a rougher surface than that of the e-beam evaporated one and a higher thermal boundary resistance. This is in agreement with the qualitative trend observed from the MD simulation that showed increases in thermal boundary resistance with the depth of atom intermixing.