ZnO thin films for high frequency SAW devices

Ieki, Hideharu; Kadota, Michio

doi:10.1109/ultsym.1999.849403

Cited by 18 publications

(11 citation statements)

References 12 publications

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“…Kadota and Minakata [1] have also obtained a maximum K 2 of 0.16% with a 0.5-λ-thick RF-magnetron-sputtered ZnO film on the glass substrate. In recent years, the use of electron cyclotron resonance (ECR) sputtering technique for ZnO film deposition alone has yielded high K 2 values in close agreement with the theoretical calculations [19].…”

Section: A Saw Propagation Characteristics: Experimental Studiessupporting

confidence: 67%

“…The observed variation in the coupling coefficient can be attributed to the fine changes in the quality of ZnO films, and can be linked to the deposition conditions that strongly influence the microstructure of the film. A survey of K 2 values reported in literature on diode and magnetron-sputtered ZnO films show lower values of experimentally obtained K 2 in comparison to the corresponding theoretical values [1], [4], [19]. Mitsuyu et al [4] have found K 2 ∼ 0.6% for ZnO thickness in the range 0.015-0.025 λ for the ZnO/IDT/fused-quartz structure.…”

Section: A Saw Propagation Characteristics: Experimental Studiesmentioning

confidence: 89%

“…Mitsuyu et al [4] have found K 2 ∼ 0.6% for ZnO thickness in the range 0.015-0.025 λ for the ZnO/IDT/fused-quartz structure. Ieki and Kadota [19] have obtained a K 2 = 0.075% with ZnO = 0.4 λ for the RFmagnetron-sputtered ZnO films on the 29 • 45 rotated Y -cut 35 • X propagating quartz substrate with a TCD of −5 ppm · • C −1 . Kadota and Minakata [1] have also obtained a maximum K 2 of 0.16% with a 0.5-λ-thick RF-magnetron-sputtered ZnO film on the glass substrate.…”

Section: A Saw Propagation Characteristics: Experimental Studiesmentioning

confidence: 99%

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Temperature stability of ZnO thin film SAW device on fused quartz

Tomar

Sreenivas

Mansingh

2005

IEEE Trans. Device Mater. Relib.

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Surface acoustic wave (SAW) filters for lowfrequency (38-65 MHz) applications have been developed using a radio frequency (RF)-magnetron-sputtered ZnO film on fusedquartz substrates. SAW propagation characteristics such as electromechanical coupling coefficient (K 2 ), SAW phase velocity (v), insertion loss, and temperature coefficient of delay (TCD) have been measured. The intergidital transducer (IDT)/ZnO/fusedquartz device structure yields almost zero TCD (1 ppm · • C −1 ) with 0.316 λ thick ZnO layer (for the device operating at 60 MHz). Alternately, an overlayer of positive TCD material (ZnO itself) has also been deposited on the IDT/ZnO(< 0.316 λ)/fused-quartz device at a low substrate temperature to reduce the TCD. A modified layered structure consisting of ZnO/IDT/ZnO/fused quartz yields almost zero TCD (−3 ppm · • C −1 ) with a 5.3-µm-thick ZnO overlayer and a 8.1-µm-thick (0.183 λ) ZnO bottom layer. Experimentally obtained SAW propagation characteristics have been compared with the theoretical results. Index Terms-Deposition by sputtering (81.15.Cd), filters (84.30.Vn), surface acoustic waves (SAWs) in piezoelectrics (77.65.Dq), thermal stability (68.60.Dv).

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Section: A Saw Propagation Characteristics: Experimental Studiessupporting

confidence: 67%

Section: A Saw Propagation Characteristics: Experimental Studiesmentioning

confidence: 89%

Section: A Saw Propagation Characteristics: Experimental Studiesmentioning

confidence: 99%

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Temperature stability of ZnO thin film SAW device on fused quartz

Tomar

Sreenivas

Mansingh

2005

IEEE Trans. Device Mater. Relib.

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“…Ni-doped ZnO film has high resistivity of over 10 8  cm [149], which is preferable for fabricating high frequency SAW filters with low insertion loss and high stability. It is reported that the preferable Ni content is between 1 and 2 wt%.…”

Section: Other Metal-doped Zno Based Piezoelectric Devicesmentioning

confidence: 99%

Giant piezoresponse and promising application of environmental friendly small-ion-doped ZnO

Pan

Luo

Yang

et al. 2011

Sci. China Technol. Sci.

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In recent years, with the growing concerns on environmental protection and human health, new materials, such as lead-free piezoelectric materials, have received increasing attention. So far, three types of lead-free piezoelectric systems have been widely researched, i.e., perovskites, bismuth layer-structured ferroelectrics, and tungsten-bronze type ferroelectrics. This article presents a new type of environmental friendly piezoelectric material with simple structure, the transition-metal(TM)-doped ZnO. Through substituting Zn 2+ site with small size ion, we obtained a series of TM-doped ZnO with giant piezoresponse, such as Zn 0.975 V 0.025 O of 170 pC/N, Zn 0.94 Cr 0.06 O of 120 pC/N, Zn 0.913 Mn 0.087 O of 86 pC/N and Zn 0.988 Fe 0.012 O of 127 pC/N. The tremendous piezoresponses are ascribed to the introduction of switchable spontaneous polarization and high permittivity in TM-doped ZnO.The microscopic origin of giant piezoresponse is also discussed. Substitution of TM ion with small ionic size for Zn 2+ results in the easier rotation of noncollinear TM-O1 bonds along the c axis under the applied field, which produces large piezoelectric displacement and corresponding piezoresponse enhancement. Furthermore, it proposes a general rule to guide the design of new wurtzite semiconductors with enhanced piezoresponses. That is, TM-dopant with ionic size smaller than Zn 2+ substitutes for Zn 2+ site will increase the piezoresponse of ZnO significantly. Finally, we discuss the improved performances of some TM-doped ZnO based piezoelectric devices.

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“…Piezoelectric ZnO is promising for fabrication of high frequency and low-loss surface acoustic wave (SAW) devices, bulk acoustic wave (BAW) devices, and microelectronic mechanical systems (MEMS). [1][2][3] Semiconducting ZnO has a direct bandgap that can be increased from 3.3 eV at room temperature to ;4.0 eV by alloying it with MgO to form a ternary Mg x Zn 1ÿ x O (0 x 0.3), while still maintaining the wurtzite crystal structure. It has been discovered that Mg x Zn 1ÿ x O can be used as a new piezoelectric material.…”

Section: Introductionmentioning

confidence: 99%

Hybrid deposition of piezoelectric $$(11\bar 20)$$ MgxZn1−xO (0≤x≤0.3) on $$(01\bar 12)$$ R-sapphire substrates using RF sputtering and MOCVDR-sapphire substrates using RF sputtering and MOCVD

Saraf

Chen

Siegrist

et al. 2006

Journal of Elec Materi

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Mg x Zn 1ÿ x O (0 x 0.3) films are deposited on R-plane ð0112Þ sapphire substrates using a hybrid deposition technique: metalorganic chemical vapor deposition and radiofrequency (RF) sputtering. Thick piezoelectric Mg x Zn 1ÿ x O films are deposited by RF sputtering on MOCVD grown thin ZnO buffers on Rsapphire substrate. Molar ratio of ZnO and MgO powders are mixed to form Mg x Zn 1ÿ x O (0 x 0.3) sputtering targets with NiO (2-3 wt.%) added for compensation doping to achieve piezoelectricity. Field emission scanning electron microscopy shows that the deposited films are dense and uniform. X-ray diffraction indicates that the sputter-deposited Mg x Zn 1ÿ x O (0 x 0.3) films retain the wurtzite crystal structure. The crystallinity of the deposited films is further improved by postannealing at 700°C in oxygen. Compositional analysis of the films is carried out using Rutherford back-scattering. High-frequency and low-loss surface acoustic wave (SAW) testing devices fabricated on these films are demonstrated. The SAW properties are tailored to changing Mg compositions. In the ZnO/R-Al 2 O 3 system, two types of wave modes, the Rayleigh-type and the Love-type wave modes, are investigated.

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ZnO thin films for high frequency SAW devices

Cited by 18 publications

References 12 publications

Temperature stability of ZnO thin film SAW device on fused quartz

Temperature stability of ZnO thin film SAW device on fused quartz

Giant piezoresponse and promising application of environmental friendly small-ion-doped ZnO

Hybrid deposition of piezoelectric $$(11\bar 20)$$ MgxZn1−xO (0≤x≤0.3) on $$(01\bar 12)$$ R-sapphire substrates using RF sputtering and MOCVDR-sapphire substrates using RF sputtering and MOCVD

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