High rejection Rx filters for GSM handsets with wafer level packaging

Wang, K.; Mueller, W. F.; Ruby, R.; Gat, Moshe; Bradley, P.; Barfknecht, A.T.; Geefay, F.; Han, Cheng-Nan; Gan, Gongwen; Chien, A.; Ly, B.

doi:10.1109/ultsym.2002.1193547

Cited by 16 publications

(4 citation statements)

References 5 publications

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“…The fabrication equipment available to date allows sputtering of highly c-orientated thin aluminium nitride (AlN) films with extremely good thickness and functional uniformity. Initially, research was focused around thickness-excited modes in view of resonator and filter applications [1][2][3]. To further extend the variety of thin film electroacoustic components, significant efforts have recently been directed towards the utilization of the fundamental symmetric Lamb (plate) waves [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…For plate wave devices the major limiting factors are the restricted membrane area and the relative susceptibility to acousto-and electro-migration effects in the electrodes, thus limiting the power handling capabilities. Figures 1(b) and (c) represent a thin film bulk acoustic wave resonator's exploiting membrane [1] and Bragg reflector [2] topologies, respectively. In both types of devices the major limitation stems from the AlN structural defects, namely cracks, formed at the edges of the patterned bottom electrode, thus limiting both device performance and reliability.…”

Section: Introductionmentioning

confidence: 99%

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Buried electrode electroacoustic technology for the fabrication of thin film based resonant components

Martin

Yantchev

Katardjiev

2006

J. Micromech. Microeng.

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A fabrication process for thin film electroacoustic devices utilizing buried electrodes is presented. A one-step lithography process has been developed to bury electrodes resulting in a planarized surface. The proposed technology is expected to bring about a number of benefits concerning the performance of a variety of thin film electroacoustic devices. With respect to thin film plate acoustic resonators (FPAR), burying the reflector electrodes results in improved reflectivity and potentially lower susceptibility to acousto-migration effects. It is also shown that employing the proposed technology for the fabrication of both thin film bulk acoustic resonators (FBAR) and thin film solidity mounted bulk acoustic resonators (SBAR) eliminates certain macro-structural defects in the piezoelectric film which is a prerequisite for substantially improved device performance and higher power handling capability. The buried electrode electroacoustic (EA) technology is demonstrated for a thin aluminium nitride (AlN) piezoelectric film with electrodes of both molybdenum (Mo) and tungsten (W). The latter have been primarily chosen because of their high electroacoustic material quality. Thin film resonant structures produced by this technology are characterized and their features are discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Buried electrode electroacoustic technology for the fabrication of thin film based resonant components

Martin

Yantchev

Katardjiev

2006

J. Micromech. Microeng.

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show abstract

“…The research is mainly focused around thickness-excited modes in view of resonator and filter applications. [1][2][3][4][5]. Currently two different device designs are independently and simultaneously being developed.…”

Section: Introductionmentioning

confidence: 99%

“…Currently two different device designs are independently and simultaneously being developed. The first based on the membrane topology has been extensively studied in the last 20 years and currently demonstrates a device quality factor (Q) approaching 2000 at around 2 GHz [1]. The drawbacks of the membrane approach are related to the relatively limited power handling capabilities [6] and the reduced sustainability to stresses in the thin films.…”

Section: Introductionmentioning

confidence: 99%