The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Aluminum nitride (AlN) Lamb wave resonators (LWRs) utilizing the lowest symmetric (S0) mode have attracted much interests since they have high frequencies, low motional impedances, and capability of multiple frequencies on a single chip. However, the transverse spurious modes are often strong in AlN LWR, and largely degrade the performance in application, so suppression the transverse mode is highly...
Waveguiding layer acoustic waves (WLAW) technology is considered as a packageless solution for extreme miniaturization of acoustic wave devices. WLAW solution is also original and suitable for high-temperature applications. Indeed, the achievement of a stable high-temperature packaging still constitutes a technological lock, in particular regarding sealing performance. In this context, we consider...
To prevent unauthorized access to ICs, encryption can be enabled via extremely small and practically invisible microscale chips that are embedded inside the packaging of ICs. The authors lately demonstrated an acoustic power link based on AlN HBAR-like structures operating at 500 MHz [1]. Enormous acoustic losses introduced by air at such large frequencies necessitate tight coupling between the transducers...
In this paper, we fabricated a hybrid on-chip acoustic and field-effect device to investigate the acoustic carrier transportation in graphene. The device fabrication exploited aluminum nitride (AlN)-based surface micromachining process on a silicon wafer, facilitating an integration of a surface acoustic wave (SAW) delay line and a graphene field-effect transistor (GFET). The SAW device induced an...
Performance of AlN-based electroacoustic devices directly tie with piezoelectric and metal electrode film quality. In this paper, sputter techniques for the reactive sputtering of AlN and ScAlN thin films, for the deposition of highly textured metal electrodes, and for the deposition of multilayer Bragg acoustic reflectors for SMR devices using dual-target S-gun magnetrons are described and some film...
Partial substitution of Al by Sc in AlN wurtzite films leads to a strong enhancement of the piezoelectric properties as long as the wurtzite phase is maintained. This is very promising for improving piezoelectric MEMS devices and enlarging their application range. Nucleation of (0001)-AlScN works particularly well on Pt (111) thin films. However, in some applications, the growth on insulating substrates...
Acoustic wave characteristics are numerically investigated and compared in AlN/ZnO/diamond and Al2O3/GaN/sapphire with Pt electrodes. These structures have been previously reported as candidates for application in packageless sensors. They include a low-velocity guiding piezoelectric layer sandwiched between two high-velocity materials. The anisotropy of the combined materials, their symmetry and...
This paper reports on the investigation of 1 μm thick films of 20% Scandium-doped Aluminum Nitride (ScAlN) for the making of piezoelectric MEMS laterally vibrating resonators (LVRs). The ScAlN films, which can be sputter-deposited such as undoped Aluminum Nitride (AlN) films, were used to demonstrate high performance resonators. These devices showed quality factor (Qs) in excess of 1000 in air centered...
This paper introduces the use of artificial neural networks (ANNs) as a method to guide the design of high-performance MEMS resonators and applies it to the prediction of spurious modes (SMs) in the proximity of the series resonance of aluminum nitride (AlN) contour-mode MEMS resonators (CMRs). ANN enables both fast and accurate prediction of spurious modes, hence facilitating the MEMS designer in...
Aluminium scandium nitride (ASN) exhibits a largely enhanced piezoelectric response as compared to aluminium nitride (AlN), which makes it an upcoming piezoelectric material for next generation RF filters, sensors, actuators and energy harvesting devices. In this work, process-microstructure-property relationships of such ASN films containing up to 40 at% Sc were investigated. Hereby, the influence...
The production and the characterization of high-quality ScAlN films, whose electromechanical coupling and bandwidth are larger than those of traditional AlN films, is attracting interest to develop the next generation of bulk acoustic wave resonators for telecommunication devices operating above 5 GHz.
AlN MEMS CMRs offer high Q and kt2, and a center frequency (f0) that can be primarily set by lithography. They also have direct 50 Ω matching capability. These properties make AlN CMRs an ideal candidate to synthesize multi-frequency bandpass filters on a single chip with low insertion loss (IL). However, their practical implementation is hindered by fabrication induced variations. To address this...
Temperature stability is critical for commercial oscillators and many methods have been explored such as: a) constant-resistance-based control methods; b) DTCMs with look-up tables; c) phase-lock-loop based control methods. Whereas exemplary results have been attained with these techniques, to be effective they require: a) accurate knowledge of the source of temperature fluctuations; (b) the use of...
It is more difficult to nucleate AlN-ScN alloy thin films (AlScN) in pure (0001)-texture than it is with pure AlN thin films. AlN thus can serve as seed layer for AlScN. Equipment limitations may lead to the problem of a vacuum break between AlN and AlScN deposition, as it leads to oxidation of the AlN surface. This issue was studied with high resolution TEM and electron diffraction. The formed oxide...
We demonstrated the statistical element selection (SES) technique with an array of 1.15 GHz AlN MEMS subfilters fabricated in an 8” Si fabrication facility by A∗STAR, Institute of Microelectronics (IME), Singapore. The chip integration is achieved through a split-fab process where the hermetically thin-film-encapsulated (TFE) MEMS resonators are solder-bump bonded to a CMOS chip fabricated in a Samsung...
Recently, it was shown that heavily doped AlN film possess the high piezoelectricity by Akiyama et al [1]. On the other hand, SAW devices were widely used as filters and sensors. Among them, SAW in ScAlN film is attracting a lot of attention because this SAW devices have high electromechanical coupling coefficient K2. We analyzed the K2 value in Sc0.4Al0.6N was increased by c-axis tilted angle θ becoming...
Type I Lamb wave modes exhibit a strong affinity toward multimode behavior, especially the high-transduction-efficiency modes: S0 and S1 mode. Apodization, the standard technique to suppress the transverse modes for IDT-excited resonators, suffers from drawbacks such as additional loss and reduction of the effective coupling coefficient (k2eff). Most Lamb wave modes in AlN show a positive slope in...
RF filtering technologies based on piezoelectric MEMS resonators have been successfully developed and commercialized in the past decade thanks to their size and outstanding performance. The challenge to enhance filter's performance in terms of lower insertion losses and wider bandwidth still makes for an active research topic, especially spurring the interest for new classes of materials such as doped-AlN...
Multilayered structures with LT plates bonded to silicon or glass substrates via AlN, isotropic SiO2 or their combinations, were theoretically investigated as potential materials for resonators with high Q-factors required for the 5th generation of mobile communication systems. Characteristics of SH-waves propagating under Al grating in such structures, including electromechanical coupling and propagation...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.