Thermal conductivity measurement of AlN films by fast photothermal method

Abstract

Aluminum nitride (AlN) films were deposited by reactive direct current Magnetron Sputtering (dcMS) on Si (100) substrates, with different thicknesses, in Ar-N2 gas mixture. The films were characterized by X-ray diffraction (XRD), profilometry, scanning electron microscopy and UV-Visible Ellipsometry. The effect of the thickness on the thermal conductivity of AlN films was investigated using a fast IR pyrometry device. The XRD measurements show that AlN films are texturated along (002) direction. Moreover, X-ray rocking curve measurements indicate that the crystalline quality of the AlN is improved with the increase of film thickness. Optical analyses by IR spectroscopy and UV-Visible Ellipsometry demonstrate a high optical band gap of pure AlN films with semi-transparent behaviour in the IR range (1 to 7 μm). The effective thermal conductivity of the AlN films is strongly dependent on the film thickness. An effective thermal conductivities between (80 ± 05) and (175 ± 15) W.m−1.K−1 were measured for 260 and 8000 nm thick AlN film.