Fabrication of High Frequency Bulk Acoustic Wave Resonator Using Thinned Single-Crystal Lithium Niobate Layers

Other Surface-Acoustic-Wave Based Instruments

“…The reasoning underlying the original design was the use of a low-acoustic-loss substrate (often sapphire) to generate multiple echoes in a delay line application [13]. Recently, the focus has shifted towards high-Q resonators [14]. The acoustic wave is launched by a thin piezoelectric slab deposited on the low-loss (non-piezoelectric) substrate.…”

“…Thickness-shear modes (needed for operation in the liquid phase) can only be achieved with piezoelectric single crystals. Methods to bond thin single crystals (mostly LiNbO 3 ) to rigid substrates include the smartcut approach [15] and the room-temperature metal-metal diffusion approach [14].…”

Periodically Poled Acoustic Wave-Guide and Transducers for Radio-Frequency Applications

“…These experiments were followed by the fabrication of PPT-based wave-guides. One more time, technology advances allowing for room-temperature reliable bonding of heterogeneous material based on metal-metal compression and lapping/polishing operations (Gachon et al, 2008), PPTs built on single crystal LiNbO 3 Z-cut layers were bounded atop Silicon and lapped down to a few tens of µm to develop RF passive devices compatible with silicon-based technologies (Courjon et al, 2008). Once again, a good agreement between theory and experiments was emphasized.…”

High-Overtone Bulk Acoustic Resonator

“…substrate exhibit Q factors of 53,000 at 1.5GHz using the Gold bonding technique [5] and Q.f product above 8.10 13 with an 800nm thickness for the piezoelectric layer by Smart Cut approach [18]. Understanding losses phenomena helps to design high quality factor devices.…”

“…HBAR have been particularly developed along different approaches to take advantage of their extremely high quality factor and very compact structure. Until now, many investigations have been carried out using piezoelectric thin films (Aluminum Nitride -AlN, Zinc Oxide -ZnO) atop thick wafers of silicon or sapphire [5] but recent developments showed the interest of thinned single-crystal-based structure in that purpose [6]. Although marginal, their application has been mainly focused on filters and frequency stabilization (oscillator) purposes [7], but the demonstration of their effective implementation for sensor applications has been achieved recently [8].…”