S.J. Martin

Surface acoustic wave resonators on a ZnO‐on‐Si layered medium

The adaptation of surface acoustic wave resonator technology to a ZnO‐on‐Si layered medium is presented. Several distributed reflector schemes are considered, including shorted and isolated metallic strips, as well as grooves etched in the ZnO layer. In the case of etched groove reflectors, a first‐order velocity perturbation arises due to the dispersive nature of the layered medium. Unique resonator design considerations result from the reflector array velocity and reflectivity characteristics. Transverse mode resonances are characterized and their effect on resonator response eliminated by a novel transducer design. A technique for temperature compensating the devices by use of a thermal SiO2 layer is discussed.

Zinc‐oxide–on–silicon surface acoustic wave resonators

The first surface acoustic wave resonators fabricated using a ZnO‐on‐Si layered structure are described and characterized. The optimum location of the transducers in the resonant cavity and the general performance are first cited for devices containing isoloated aluminum, isolated Cr/Au, and shorted Cr/Au reflector strips. The transmission characteristics and reflecting properties of the shorted Cr/Au configuration are then examined in more detail. An unloaded Q of 3100 has been obtained with the shorted Cr/Au configuration at a resonant frequency of 105.4 MHz.

Vapor Sensing by Means of a ZnO-on-Si Surface Acoustic Wave Resonator

bient gas phase. Previous work employing SAW delay lines fabricated on quartz or Surface Acoustic Wave (SAW) devices can LiNb03 in conjunction with a chemically function as sensitive detectors of vapors. sensitive overlay have demonstrated gas The high surface acoustic energy density OK vapor sensitivity [l-31. of the device makes it extremely sensitive to the presence of molecules adsorbed from In this paper we discuss the first use of the gas phase. Mass loading by the adsora ZnO-on-Si SAW resonator as a gas sensor. bate is the primary mechanism €OK the SUK- In particular, the sensitivity of the face wave velocity perturbation. If the device to organic vapors is examined. The

High Q, Temperature Stable ZnO-On-SILICON SAW RESONATORS

A monolithic SAW ZnO/Si02/Si resonator device is reported and several configurations for reflector structures are described. The tuo-port resonators are found to exhibit Q-values in the 2,000 to 10,000 range depending upon the use of m etallic or etched reflector arrays. Temperature compensation through the use of thick thermal oxide layers is also demonstrated. strips, as uell as grooves etched in the ZnO layer, to form efficient distributed r eflectors and to realize Lou values of i nsertion loss at the resonant frequency. In section I1 we discuss the results obtained with aluminum and chrome/gold ref lector strips, w hile s ection 111 consider chemically etched groove devices. The results o f temperature compensation experiments are discussed in section IV.

Surface acoustic wave mode conversion resonator

It is well known that a ZnO‐on‐Si structure supports two distinct surface waves, called the Rayleigh and the Sezawa modes, if the ZnO layer is sufficiently thick. Herein we report a unique surface wave resonator that operates by efficiently converting between the two modes at the resonant frequency. The mode conversion resonator promises enhanced out‐of‐band signal rejection since input and output coupling is effected through different modes.

Coherent mode conversion by grooved arrays in layered media

Recent experiments have shown that a periodic array of grooves and strips on a layered medium provides efficient conversion between Rayleigh and Sezawa modes supported by the medium; these novel mode converting reflectors have been used to construct surface wave resonators. This paper presents a theoretical analysis of the mode conversion process starting from material parameters. A first‐order perturbation theory is used to construct a four‐port scattering matrix for each strip in the array. The scattering matrices are then converted to transmission matrices and cascaded to provide the overall scattering characteristics of the array. The predicted characteristics are in close agreement with experimentally measured values.

SAW Resonators Insensitive to IDT Position

A theoretical analysis of the ZnO-on-Si surface acoustic wave mode conversion resonator indicates that optimum performance can be attained irrespective of transducer location between reflector arrays. That is, a single transducer of Rayleigh or Sezawa periodicity can be placed anywhere between properly spaced mode conversion gratings and it will couple optimally to a standing wave of the same periodicity. An extension of the theory allows one to fabricate both one-port and two-port resonators with non-critical spacing between the transducers and the gratings. Experimental verification of the position independent behavior is presented for oneport and two-port devices.

Surface Wave Resonators on Silicon

Abstract : In this paper two topics new to the ZnO-on-Si resonator development are discussed: The use of SAW resonators to determine the effect of a laser anneal on layered medium propagation loss; and A conceptually new device, called the mode conversion resonator, which utilizes two propagating normal modes of the layered medium in order to gain enhanced out-of-band signal rejection.