This research is focused on the development of a new technology for the fabrication of high-frequency surface acoustic wave (SAW) filters based on diamond and lithium niobate (LiNbO3) materials. LiNbO3 films are in situ deposited at 490 °C on polycrystalline diamond substrates by radio-frequency magnetron sputtering; a multistep growth process is proposed to deposit oriented LiNbO3 films with a smooth surface. Conventional interdigital transducers are fabricated on top of the piezoelectric LiNbO3 layer by standard optical lithography. We report experimental results for a SAW bandpass filter operating at a frequency above 2.30 GHz. We have observed that Rayleigh SAW modes are excited within this structure, with extremely high phase velocities (up to 12000m∕s). This latter result illustrates the greatest advantage of using diamond as an acoustic substrate. It allows the fabrication of SAW devices operating in the gigahertz frequency range using standard optical lithography.
Lithium niobate (LiNbO 3 ) films have been grown at 490 C on diamond-coated silicon substrates by radio-frequency magnetron sputtering. A multi-step process was developed to produce thick layers on diamond with a good structure and a smooth morphology. To assess the structural quality of our films, we performed X-ray diffraction, transmission electron microscopy and atomic force microscopy of the films. The structure is conserved whatever the film thickness. A delay line structure of wavelength of 28 mm was realized and transducers were deposited on top of LiNbO 3 . The objective was to verify the high velocity in such a multi-layered structure. The first results indicated a SAW velocity estimated of 8200 m/s and a coupling factor was k 2 around 1%. The film growth, the technology and the electrical measurements are described in this paper.
The influence of a pulse humidity impact on the electrophysical parameters of Pt= LiNbO 3 -film=Pt:Ti=SiO 2 =Si structures is investigated. A continuous transformation of the current-voltage, charge-voltage, and transient characteristics with the reaction time $1 s and the recovery time $10 s (under a low humidity impact), as well as a transformation of the threshold switching type (under a high humidity impact), are observed. The peculiarities of current-voltage loops and transient currents correspond to the relay-race charge transfer.The efficiency of dynamic methods for studying the influence of fast humidity changes on the electrophysical characteristics of LiNbO 3 films is demonstrated, and the possible applications to high-speed humidity sensing are considered.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.