Acoustic wave device comprising alternating polarisation domains

Abstract

The invention relates to an acoustic wave device comprising a ferroelectric material layer (C) and a substrate (S). A layer of ferroelectric material is located between a first electrode (E1) and a second electrode (E2) deposited on the surface of the substrate or is an integral part of the substrate, the layer of ferroelectric material comprising a positive first polarization region ( D1) and a negative second polarization region (D2). For the field of surface wave sensors, the structure can preferably be made into conversion regions with pitches on the order of hundreds of nanometers, so as to be suitable for high-frequency (on the order of one gigahertz) applications.

Description

technical field [0001] The present invention relates to acoustic wave devices, and more particularly to surface wave sensors capable of operating at very high frequencies on the order of several gigahertz. Background technique [0002] Typically, currently manufactured sensors use a comb-like structure based on interdigitated electrodes, using two, four or eight electrodes for each wavelength λ, where λ corresponds to the central operating frequency of the sensor, depending on the application needs. In various sensors, the ratio of the area of ​​the metallized surface on the substrate to the area of ​​the free surface is generally used in the range of about 0.25 to 0.75. [0003] However, a new type of sensor has emerged, the so-called small-gap sensor, in which the free surface is very small in order to obtain the smallest possible distance between two adjacent electrodes. The advantage of this type of sensor is that the largest possible electrode width per cycle can be ob...

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Problems solved by technology

[0005] Moreover, when electrodes that are closely spaced apart are energized, the constituent metals of said electrodes, in this case aluminum (the most used), convert electrical energy into heat and have a tendency to creep, making it possible to make different Electrode short circuit (in the case of Rayleigh waves)

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