Novel concepts for GaAs/LiNbO/sub 3/ layered systems and their device applications

Rotter, M.; Ruile, W.; Scholl, Gerd; Wixforth, Achim

doi:10.1109/58.818767

Cited by 17 publications

(7 citation statements)

References 14 publications

(6 reference statements)

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“…Analogously, changes of the charge conductivity in a 2-dimensional electron gas (2DEG) modify the SAW device performance. For practical applications, materials with a large K 2 are needed, like hybrid AlGaAs/GaAs/LiNbO 3 structures [39] or ZnO/MgZnO quantum wells on sapphire substrates [40], in which external voltages are applied by split gates. In these cases, SAWs travel through the 2DEG, though the input and output IDTs must be deposited on nonconductive material, thus requir-…”

Section: Integration Of Saw With 2degmentioning

confidence: 99%

Nitride‐based surface acoustic wave devices and applications

Calle

Pedrós

Palacios

et al. 2005

phys. stat. sol. (c)

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A review of the fabrication techniques of surface acoustic wave (SAW) devices in nitrides, and their most relevant device properties, is presented. Several acoustic modes are observed in the transfer functions of the filters: besides the Rayleigh wave, guided modes (Sezawa) arise when the sound velocity in the nitride layer is lower than in the substrate, and pseudobulk modes may also appear. The effect of the substrate characteristics will be addressed, including the anisotropy found in nitride devices grown on sapphire due to the crystal structure mismatch. Regarding applications, some results in the sensor and photonics fields are summarized. Finally, two novel devices will be discussed: a SAW-assisted photodetector, based on the integration of a SAW generator and a UV photodetector, and a DC controlled SAW filter, obtained by the fabrication of a SAW device on a 2DEG AlGaN/GaN heterostructure.1 Introduction Surface acoustic wave (SAW) devices are a convenient solution for high frequency filters in mobile communication systems due to their stability, reliability and compactness [1]. SAW devices are also ideal for gas sensing, with industrial, environmental and biomedical applications [2,3]. Furthermore, SAW sensors offer the additional feature of wireless transmission, and therefore the feasibility of operation in harsh environments [4,5]. Whereas acoustic wave devices are typically fabricated on quartz or LiNbO 3 , other materials where devices exhibit novel or improved characteristics are highly desired. Thin-film piezoelectric semiconductors offer the potential for integration and compatibility with the electromechanical systems and electronic technologies. In particular, III-nitrides, specially AlN, combine high SAW velocity and electromechanical coupling coefficients, while showing excellent thermal stability. The device operation frequency can be increased either by reducing the device patterns or by using substrates with high sound velocity. These properties pave the way for the development of SAW devices operating in the GHz range. Moreover, the interaction of surface waves with electrons and photons, together with the direct bandgap of AlGaN, opens a wide window for new applications in micro and optoelectronics.A brief introduction to propagation of acoustic waves in nitride films is given in Sect. 2. Several acoustic modes are observed in the transfer functions: Rayleigh wave, guided modes when the sound is slower in the nitride layer than in the substrate (e.g., GaN/sapphire or AlN/diamond), and pseudobulk modes. On the other hand, anisotropic propagation is found when using sapphire substrates, due to the crystal structure mismatch. A review of the fabrication techniques of nitrides SAW devices, and their characterization, will be summarized in Sect. 3. Finally, Sect. 4 is devoted to applications of nitride SAW devices; among them, two novel devices will be described: a SAW-assisted photodetector, based on the

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Section: Integration Of Saw With 2degmentioning

confidence: 99%

Nitride‐based surface acoustic wave devices and applications

Calle

Pedrós

Palacios

et al. 2005

phys. stat. sol. (c)

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“…For this purpose, one can place between IDTs a semiconductor film with low voltage-controlled sheet conductivity. 17…”

Section: Resultsmentioning

confidence: 99%

The power flow angle of acoustic waves in thin piezoelectric plates

Kuznetsova

Зайцев

Teplykh

et al. 2008

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Abstract:The curves of slowness and power flow angle (PFA) of quasi-antisymmetric (A0) and quasi-symmetric (S0) Lamb waves as well as quasi-shear-horizontal (SH0) acoustic waves in thin plates of lithium niobate and potassium niobate of X-,Y-, and Z-cuts for various propagation directions and the influence of electrical shorting of one plate surface on these curves and PFA have been theoretically investigated. It has been found that the group velocity of such waves does not coincide with the phase velocity for the most directions of propagation. It has been also shown that S0 and SH0 wave are characterized by record high values of PFA and its change due to electrical shorting of the plate surface in comparison with surface and bulk acoustic waves in the same material. The most interesting results have been verified by experiment. As a whole, the results obtained may be useful for development of various devices for signal processing, for example, electrically controlled acoustic switchers.

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“…A few studies have reported on SAW devices using two-dimensional electron gas (2DEG) heterostructures, mainly AlGaAs/ GaAs on top of a strong piezoelectric substrate like LiNbO 3 (hybrid systems) [6,7] or MgZnO/ZnO quantum wells grown on sapphire substrates [8].…”

Section: Introductionmentioning

confidence: 99%

“…In [6], a more general model of left-handed transmission line metamaterials, composite right/left-handed (CRLH) transmission line, was proposed. Various types of applications based on left-handed TLs and CRLH TLs have been proposed, such as some couplers [7,8], leaky wave antennas [9,10], and filters [11].…”

Section: Introductionmentioning

confidence: 99%

AlGaN/GaN‐based SAW delay‐line oscillators

Grajal

Calle

Pedrós

et al. 2008

Micro & Optical Tech Letters

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used to tune the applicable bandgap frequency without compromising the bandgap bandwidth. CONCLUSIONSThe bandgap characteristics of EBG structures with and without shorting vias were compared, and parametric study results on a wideband UC-PBG structure were presented. For the EBG structures without shorting vias, it was found that the bandgap bandwidth increases when the substrate thickness is reduced. This behavior is different from that of the bandgap bandwidth of the EBG structure with shorting vias. This could be an advantage in MMIC applications, since a wide bandgap bandwidth could be obtained even for thin substrates.

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Novel concepts for GaAs/LiNbO/sub 3/ layered systems and their device applications

Cited by 17 publications

References 14 publications

Nitride‐based surface acoustic wave devices and applications

Nitride‐based surface acoustic wave devices and applications

The power flow angle of acoustic waves in thin piezoelectric plates

AlGaN/GaN‐based SAW delay‐line oscillators

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