GaN-based surface acoustic wave filters for wireless communications

Surface acoustic waves in semi-insulating Fe-doped GaN films grown by hydride vapor phase epitaxy

“…6,8 The electromechanical coupling coefficient of GaN layers with different thickness and different resistivities were reported in a large range from 0.015% to 4.3%, and it was pointed out that the high resistivity of GaN layer might be preferable for improving the performances of SAW devices. 7,9,10,14,17,18 Therefore, it could be inferred that higher electromechanical coupling coefficients could be realized and more modes with high velocities could emerge in high-resistivity GaN films with thickness much larger than the SAW wavelength. However, GaN films used for SAW devices in reports were generally prepared through metal organic chemical vapor deposition or molecular beam epitaxy, and their thicknesses were only several microns which were usually smaller than the SAW wavelength.…”

“…In this work, Fe-doped GaN epitaxial films with wurtzite structure were grown on (0001) sapphire substrate, and the crystal orientation GaN is parallel to sapphire [11][12][13][14][15][16][17][18][19][20]. Two Fe-doped GaN samples of different thickness were employed in our experiment, and their thickness are respectively 33 lm (sample 1) and 15lm (sample 2).…”

“…Each delay line consists of two symmetric IDTs, and each IDT includes 50 pairs of electrode finger. The propagation of the SAW is made to along the or [11][12][13][14][15][16][17][18][19][20] direction of GaN. The transmission and reflection parameters of delay lines were measured by vector network analyzer (Agilent E5071C).…”

ZnO film for application in surface acoustic wave device

“…to λ for these two films are 17.2% and 20.6%. Two peaks are observed: the first one (mode 0) at low frequency range is rather weak and is attributed to a Rayleigh mode wave [9], whereas the one at the higher frequency (mode 1) is quite strong and attributed to a Sezawa mode wave. When h/λ < 0.15, the Rayleigh mode wave appears to dominate the reflection and transmissions of the SAW signals.…”

“…It can be grown in thin film form by rf magnetron sputtering on a variety of substrates, including silicon, making it the most promising material to be integrated with control electronic circuitry. Other advantages of using ZnO films for SAW devices include easy integration with microsensors and microactuators on the same substrate; excellent bonding with various substrate materials, in particular silicon; high temperature stability [4]; and low cost of deposition. Modern microfabrication technology has allowed the production of SAW devices using ZnO films with high resonant frequencies.…”