Study of Resistive Thin-Film Coatings for Application in Millimeter-Band Vacuum Power Amplifiers

In this paper, the electrical characteristics of resistive thin films and the amplification properties of resistive wall amplifiers are studied based on large signal theory. To optimize amplification performance and reduce interaction length, different frequency bands and operating voltages require films with different electrical properties and thicknesses and a reasonable distribution of the respective lengths of the resistive walls and slow-wave structures. To obtain ZnO x thin films with the required conductivities and thicknesses, reactive DC magnetron sputtering was employed. By controlling the partial pressure of oxygen and the annealing temperature during the preparation process, it is possible to control the number of oxygen deficiencies in the material and the quality of crystallization, which significantly influence the electrical properties. The experiments provide a parameter reference for the preparation of resistive films for millimeter-wave frequency band resistive wall amplifiers.

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Gradient magnetron co-sputtered μ m-thick Al–Si films on dielectric substrates for operation in the millimeter-wave band

Serdobintsev

Галушка

Kozhevnikov

et al. 2021

Applied Physics Letters

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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.

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Study of Resistive Thin-Film Coatings for Application in Millimeter-Band Vacuum Power Amplifiers

Cited by 6 publications

References 48 publications

Prototyping of electromagnetic components of sub-terahertz vacuum electron devices

Prototyping of electromagnetic components of sub-terahertz vacuum electron devices

Theoretical and Experimental Study of Resistive Thin Film for Application in Resistive Wall Amplifiers

Gradient magnetron co-sputtered μ m-thick Al–Si films on dielectric substrates for operation in the millimeter-wave band

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