Thin Films of Kanthal and Aluminum for Electromagnetic Wave Absorption
The miniaturization of electronic circuits and the scientific interest in the high frequency behavior of materials have led to extensive research on thin film conduction and loss mechanisms. With the purpose of studying the loss mechanisms and their relation to microstructure and thickness effects, Kanthal and aluminum thin films with thicknesses in the range of 5 200 nm were deposited by PVD in a polymeric unheated substrate. The experimental results showed that Kanthal films exhibit a maximum absorption of 48% for a thickness of 29 nm, while aluminum films have a maximum absorption of 25% for a thickness of 7.5 nm (for a deposition rate of 0.5 Å.s-1) and 23% for a thickness of 10.0 nm (for a deposition rate of 5 Å.s-1). The absorption of aluminum is only due to electric losses, while the absorption of Kanthal (an iron, copper and aluminum alloy) is attributed to electric and magnetic losses.
S. M. Leal Da Silva and C. L. Ferreira, "Thin Films of Kanthal and Aluminum for Electromagnetic Wave Absorption", Journal of Nano Research, Vol. 14, pp. 155-163, 2011