El gran impacto de la tecnología FBAR tanto en sistemas de radio frecuencia como más recientemente en sensores han motivado el desarrollo de aplicaciones integradas. Esto implica que los procesos de fabricación deberían lograr producir dispositivos resonadores con un alto factor de calidad, al tiempo que permitir la integración de los FBAR con tecnologías CMOS estándar. De tal manera, esta tesis doctoral aborda dichos requerimientos, contribuyendo con el diseño, fabricación y caracterización de resonadores FBAR; su integración con tecnologías CMOS estándar; y su aplicación a sistemas de sensores. El desarrollo de la tecnología de fabricación de los FBAR ha involucrado la puesta a punto de las técnicas de depósito y micro-mecanización de la estructura en capas del resonador, la cual está comprendida por una película de material acústico hecha de nitruro de aluminio (AlN). Se realizaron diversas pruebas para analizar la calidad del AlN depositado. También se probaron y pusieron a punto diferentes tecnologías de micro¬mecanización para liberar la estructura del FBAR, destacando entre ellas la técnica de ataque en seco por la cara de componentes, dados los altos factores de calidad obtenidos (superiores a 2.000 a 2,4 GHz). Sobre los dispositivos fabricados se realizaron caracterizaciones estructurales, modelos utilizando análisis de elementos finitos y la extracción de parámetros de circuito equivalente. Una variación del proceso que involucraba el diseño, modelado y fabricación de un dispositivo FBAR con compensación de temperatura fue igualmente desarrollada. En este ámbito vale la pena resaltar la concepción y realización de una novedosa técnica post-fabricación para el ajuste fino de la frecuencia de resonancia de los FBAR por medio de un haz de iones focalizados (FIB). Basado en la tecnología arriba mencionada, se desarrolló un método de integración heterogénea a nivel de oblea de los dispositivos FBAR en sustratos CMOS estándar. De acuerdo con este método, se logró fabricar por primera vez dispositivos FBAR flotando sobre sustratos CMOS estándar. Este método ha sido exitosamente demostrado por medio de la integración de los FBAR tanto con la tecnología comercial AMS035 como con la CNM25, desarrollada en el CNM-IMB (CSIC). En el terreno de las aplicaciones, se diseñaron y realizaron diferentes aplicaciones de sensores basadas en FBAR, siendo el detector de masas localizadas la más relevante de entre ellas. Es de anotar que esta aplicación fue demostrada por primera vez utilizando FBARs de alta frecuencia como elemento sensor. De tal forma, se contrastaron los resultados experimentales y de modelado del sensor. Por otra parte, se presenta también el concepto de sensores mecánicos basados en FBAR. Para ello se han desarrollado dos ejemplos: el acelerómetro basado en FBAR y el sensor de fuerza para aplicaciones de puntas de AFM. Se reporta también en esta tesis la fabricación y caracterización de un nuevo tipo de resonadores acústicos de AlN sin contacto entre electrodos. / The high impact of FBAR on radio-frequency and, most recently, on sensing systems has motivated the development of integrated applications. This means that the fabrication process should succeed in producing high-quality-factor resonators and, at the same time, in integrating FBARs with standard CMOS technologies. Hence, this Ph.D. thesis addresses these requirements by contributing with the design, fabrication and characterization of thin-film bulk acoustic wave resonators (FBAR); their integration with standard complementary-metal-oxide-semiconductor (CMOS) technologies; and their application to sensing systems. The development of the FBAR's fabrication technology has involved the set up of the deposition and micromachining techniques of the layered structure of the resonator, which comprises an acoustic layer made of aluminum nitride (AlN). Several tests on the deposition and characterization of the AlN quality were carried out. Also, different micro-machining technologies for FBAR releasing were tested, the front-side micro-machining technique having obtained the best quality-factor results (over 2,000 at 2.4 GHz). Structural and device experimental characterization; and equivalent-circuit parameter and finite-element modeling of the FBAR were carried out. A process variation involving the design, modeling and fabrication of a temperature-compensated (TC) FBAR device was also implemented. Another remarkable result is the implementation of a post-fabrication, focused-ion-beam assisted technique for tuning of the resonance frequency of the FBAR. Based on the foregoing-mentioned FBAR technology, a method for performing wafer-level heterogeneous integration of the FBAR with a CMOS substrate was developed. According to this method, the fabrication of a floating FBAR above standard CMOS substrates has been achieved for the first time. The method was demonstrated by integrating FBARs on the commercial AMS035 and the in-house CNM25 CMOS technologies. On the application side, different FBAR-based sensor applications were implemented, the localized-mass detector being the most relevant, which has been demonstrated for the first time for high-frequency bulk-acoustic resonators. Experimental and modeling results have been contrasted. Also, the concept of FBAR-based mechanical sensor has been introduced. Two examples are the embedded-FBAR accelerometer and the force sensor for AFM-cantilever applications. The fabrication and characterization results of an AlN-based contactless acoustic resonator are also reported in this thesis.

The background to this thesis is Australia’s Oceans Policy, which aims to develop an integrated and ecosystem-based approach to planning and management. An important part of this approach is the identification of natural regions in regional marine planning, for example by establishing marine protected areas for biodiversity conservation. These natural regions will need to be identified on a range of scales for different planning and management actions. The scale of the investigation reported in this thesis is applicable to spatial management at 1 km to 10 km scale and monitoring impacts at the 10s of m to 1 km biotope scale. Seabed biotopes represent a combination of seabed physical attributes and related organisms. To map seabed biotopes in deep water, remote sensing using a combination of acoustic, optical and physical sensors is investigated. The hypothesis tested in this thesis is that acoustic bathymetry and backscatter data from a Simrad EM1002 multi-beam sonar (MBS) can be used to infer (act as a surrogate of) seabed biotopes. To establish a link between the acoustic data and seabed biotopes the acoustic metrics are compared to the physical attributes of the seabed in terms of its substrate and geomorphology at the 10s m to 1 km scale using optical and physical sensors. At this scale the relationship between the dominant faunal functional groups and both the physical attributes of the seabed and the acoustic data is also tested. These tests use data collected from 14 regions and 2 biomes to the south of Australia during a voyage in 2000. Based on 62 reference sites of acoustic, video and physical samples, a significant relationship between ecological seabed terrain types and acoustic backscatter and bathymetry was observed. / These ecological terrain types of soft-smooth, soft-rough, hard-smooth and hard-rough were chosen as they were the most relevant to the biota in their ability to attach on or burrow into the seabed. A seabed scattering model supported this empirical relationship and the overall shape of backscatter to incidence angle relationship for soft and hard seabed types. The correlation between acoustic data (backscatter mean and standard deviation) and the visual and physical samples was most consistent between soft-smooth and hard-rough terrain types for a large range of incidence angles (16o to 70o). Using phenomenological backscatter features segmented into 10 common incidence angle bins from -70o to 70o the length resolution of the data decreased to 0.55 times depth. The decreased resolution was offset by improved near normal incidence (0o to 30o) seabed type discrimination with cross validation error reducing from 32% to 4%. A significant relationship was also established between the acoustic data and the dominant functional groups of fauna. Faunal functional groups were based on the ecological function, feeding mode and substrate preference, with 8 out of the 10 groups predicted with 70% correctness by the four acoustically derived ecological terrain types. Restricting the terrain classification to simple soft and hard using the acoustic backscatter data improved the prediction of three faunal functional groups to greater than 80%. Combining the acoustic bathymetry and backscatter data an example region, Everard Canyon, was interpreted at a range of spatial scales and the ability to predict the preferred habitat of a stalked crinoid demonstrated. / Seabed terrain of soft and hard was predicted from the acoustic backscatter data referenced to a common seabed incidence angle of 40o. This method of analysis was selected due to its combined properties of high spatial resolution, consistent between terrain discrimination at the widest range of incidence angles and consistent data quality checking at varying ranges. Based in part on the research reported in this thesis a mid-depth Simrad EM300 multibeam sonar was purchased for use in Australian waters. A sampling strategy is outlined to map all offshore waters with priority within the 100 m to 1500 m depths.