Ongoing active development of modern radio frequency electronic devices operating in the millimeter (V) band, such as fifth-generation wireless communications, demands new materials to control electromagnetic interference, compatibility, and reliability of such systems. This work investigates feasibility absorptive non-reflective thin coatings deposition on dielectric substrates using simultaneous magnetron co-deposition. For this, electromagnetic waves propagation in the millimeter band through in micrometer-thick Al–Si films of varied composition was studied. The co-deposition process was controlled by the ratio of sputtered atoms fluxes. Graded segregation was observed under certain parameters of the co-deposition process, resulting in a depth gradient of an aluminum content, as confirmed by the secondary ion mass spectrometry study. A qualitative model was proposed involving aluminum-induced silicon recrystallization happening in the course of a known aluminum interlayer exchange process. The observed Al–Si segregation effect in micrometer-thick films allows for preparation of the non-reflective and absorptive material for operation in the V-band with reflection losses more than 10 dB and transmission losses around 5 dB in the bandwidth of up to 20 GHz.
Gradient magnetron co-sputtered μm-thick Al–Si films on dielectric substrates for operation in the millimeter-wave band
Note: This paper is part of the APL Special Collection on Advances in 5G Physics, Materials, and Devices.
Alexey A. Serdobintsev, Victor V. Galushka, Ilya O. Kozhevnikov, Anton M. Pavlov, Andrey V. Starodubov; Gradient magnetron co-sputtered μm-thick Al–Si films on dielectric substrates for operation in the millimeter-wave band. Appl. Phys. Lett. 18 October 2021; 119 (16): 161906. https://doi.org/10.1063/5.0058572
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