京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19723号 / 工博第4178号 / 新制||工||1644(附属図書館) / 32759 / 京都大学大学院工学研究科電子工学専攻 / (主査)教授 野田 進, 教授 木本 恒暢, 教授 川上 養一 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

This thesis describes a theoretical and experimental investigation of wireless energy transfer between high-Q resonant radiofrequency (RF) oscillators. A model used by Kurs \emph{et al} \cite{Kurs_original} was recast in a form which enabled expression of the results in terms of measurable electrical quantities. This model was tested using circular resonant copper loop antennas at a frequency near 10 MHz. Accurate calculation of the mutual inductance between loops was required in order to predict the loop coupling parameters, and was carried out using a custom-written computer code. Two resonant loop antenna RF oscillators were first used to check that the model predictions were accurate in the two-oscillator case. Based on the success of these tests, the model was extended to the case of three oscillators in two different configurations, the first having two receiving oscillators, and the second having two transmitting oscillators. Model predictions for both configurations were experimentally tested over a range of coil separations and angular inclinations. These experimental tests confirmed the model's applicability in the three-oscillator regime, with significant deviations from the model only being observed when any pair of loops was in very close proximity (i.e. when the separation of loop centers was comparable to the loop diameter). This may have been be due to either nonlinear dielectric losses (due to large amplitude RF electric fields) spoiling the Quality factors Q of the loop antenna resonators, or to increased capacitive coupling between loops at short distances (not included in the current model), or both. Further investigation would be required to definitively establish the origin of the deviation from the model at short distances, but from an engineering point of view accurate modelling of the performance in the "close loop" regime is not critical since the primary purpose of wireless power transfer is to transmit power over a reasonable distance.

This thesis reports on a new implementation of high quality factor (Q) copper (Cu) inductors on CMOS-grade (10-20ohm.cm) silicon (Si) substrates using a fully CMOS-compatible process. A low-temperature (less than300C) fabrication sequence is employed to reduce the loss of Si wafers at RF frequencies by trenching the Si substrate. The high aspect-ratio (30:1) trenches are subsequently bridged over or refilled with a low-loss material to close the open areas and to create a rigid low-loss island (Trenched Si Island) on which the inductors can be fabricated. The method reported here does not require air suspension of the inductors, resulting in mechanically-robust structures that are compatible with any packaging technology. The metal loss of inductors is reduced by electroplating thick (~20m) Cu layer. Fabricated inductors are characterized and modeled from S-parameter measurement. Measurement results are in good agreement with SONNET electromagnetic simulations. A one-turn 0.8nH Cu inductor fabricated on a Trenched Silicon Island (TSI) exhibits high Q of 71 at 8.75 GHz. Whereas, the identical inductor fabricated on a 20um thick silicon dioxide (SiO2) coated standard Si substrate has a maximum Q of 41 at 1.95GHz. Comparing the Q of inductors on TSI with that of other micromachined Si substrates reveals the significant effect of trenching the Si in reduction of the substrate loss. This thesis outlines the design, fabrication, characterization and modeling of spiral type Cu inductors on the TSIs.

This dissertation reports, for the first time, on the design and implementation of tunable micromachined bandpass filters in the ultra high frequency (UHF) range that are fully integrated on CMOS-grade (resistivity=10-20 ohm.cm) silicon. Filters, which are designed in the Elliptic and coupled-resonator configuration, are electrostatically tuned using tunable microelectromechanical (MEM) capacitors with laterally movable interdigitated fingers. Tunable filters and high-quality factor (Q) integrated passives are made in silver (Ag), which has the highest conductivity of all materials in nature, to reduce the ohmic loss. The loss of the silicon substrate is eliminated by using micromachining techniques. The combination of the highest-conductivity metal and a low-loss substrate significantly improves the performance of lumped components at radio frequencies (RF), resulting in an insertion loss of 6 dB for a tunable lumped bandpass filter at 1075 MHz with a 3 dB-bandwidth of 63 MHz and tuning range of 123 MHz. The bandpass filters are encapsulated at the wafer level using a low-temperature, thermally released, polymer packaging process. This thesis details the design, fabrication, and measurement results of the filters and provides strategies to improve their performance. The performance of filter components, including the tunable capacitors and inductors, is characterized and compared to the state-of-the-art micromachined passive components. The silver inductors reported in this thesis exhibit the record high Q, and the silver bandpass filters show the minimum insertion loss that has been achieved on a CMOS-grade silicon substrate, to the best of our knowledge. Alternatively, tunable capacitors can be made in the bulk of silicon using a modified version of the high-aspect-ratio polysilicon and single crystal silicon (HARPSS) fabrication technique to obtain a larger capacitance density at the expense of a higher conductive loss. Using this process, a 15 pF two-port tunable capacitor is fabricated and tuned by 240% with the application of 3.5 V to the isolated actuator. Silver inductors can be post integrated with HARPSS tunable capacitors to obtain tunable filters in the very high frequency (VHF) range. The reported bandpass filters can be monolithically integrated with CMOS and have the potential to replace several transmit and receive acoustic filters currently used in cellular phones.

Several fabrication techniques for surface micromachined 3-D structures have been developed for RF components. The fabrication techniques all have in common the use of epoxy patterning and subsequent metallization. Techniques and structures such as embedded conductors, epoxy-core conductors, a reverse-side exposure technique, a multi-exposure scheme, and inclined patterning are presented. The epoxy-core conductor technique makes it easy to fabricate high-aspect-ratio (10-20:1), tall (~1mm) RF subelements as well as potentially very complex structures by taking advantage of advanced epoxy processes. To demonstrate feasibility and usefulness of the developed fabrication techniques for RF applications, two test vehicles are employed. One is a solenoid type RF inductor, and the other is a millimeter wave radiating structure such as a W-band quarter-wavelength monopole antenna. The embedded inductor approach provides mechanical robustness and package compatibility as well as good electrical performance. An inductor with a peak Q-factor of 21 and an inductance of 2.6nH at 4.5GHz has been fabricated on a silicon substrate. In addition, successful integration with a CMOS power amplifier has been demonstrated. A high-aspect-ratio inductor fabricated using epoxy core conductors shows a maximum Q-factor of 84 and an inductance of 1.17nH at 2.6GHz on a glass substrate with a height of 900um and a single turn. Successful W-band monopole antenna fabrication is demonstrated. A monopole with a height of 800um shows its radiating resonance at 85GHz with a return loss of 16dB. In addition to the epoxy-based devices, an advanced tunable ferroelectric device architecture is introduced. This architecture enables a low-loss conductor device; a reduced intermodulation distortion (IMD) device; and a compact tunable LC module. A single-finger capacitor having a low-loss conductor with an electrode gap of 1.2um and an electrode thickness of 2.2um has been fabricated using a reverse-side exposure technique, showing a tunability of 33% at 10V. It shows an improved Q-factor of 21.5. Reduced IMD capacitors consist of wide RF gaps and narrowly spaced high resistivity electrodes with a gap of 2um and a width of 2um within the wide gap. A 14um gap and a 20um gap capacitor show improved IMD performance compared to a 4um gap capacitor by 6dB and 15dB, respectively, while the tunability is approximately 21% at 30V for all three devices due to the narrowly spaced multi-pair high resistivity DC electrodes within the gap. Finally, a compact tunable LC module is implemented by forming the narrow gap capacitor in an inductor shape. The resonance frequency of this device is variable as a function of DC bias and a frequency tunability of 1.1%/V is achieved. The RF components developed in this thesis illustrate the usefulness of the application of micromachining technology to this application area, especially as frequencies of operation of RF systems continue to increase (and therefore wavelengths continue to shrink).

De tous les circuits qui constituent un système radiofréquence complet, la partie radiofréquence apparaît comme un maillon délicat du système. Parmi les nombreuses fonctions radiofréquences, l'amplificateur de puissance (PA) représente un bloc particulièrement critique de la chaîne d'émission, du fait de sa consommation élevée et des forts niveaux des signaux qu'il doit gérer. Il résulte de ces contraintes que les techniques d'intégration utilisées sont généralement complexes et onéreuses, particulièrement pour la réalisation des éléments inductifs des réseaux de pré-adaptation des transistors de puissance, à partir de fils micro-soudés. Les travaux décrits dans ce manuscrit visent ainsi le développement d'une technologie permettant l'intégration faible coût d'inductances planaires de puissance en mesure de remplacer les fils micro-soudés. Ces travaux ont été réalisés en collaboration avec la société Freescale. Les démonstrateurs présentés mettent donc en œuvre la filière LDMOS sur substrat silicium faiblement résistif. Le mémoire est articulé autour de quatre chapitres. Le premier présente un état de l'art de l'intégration des amplificateurs de puissance RF à partir duquel nous définissons la problématique de cette intégration. Dans le deuxième chapitre, nous traitons des différents mécanismes de pertes présents dans les inductances planaires sur silicium ainsi que de leurs origines. Puis, nous posons les bases de leur modélisation électrique et des simulations électromagnétiques 3D qui seront conduites pour leur optimisation. Le troisième chapitre est ensuite consacré à la description et à l'optimisation de la technologie mise en place au sein du LAAS. Elle met en œuvre, sur un plan métallique qui écrante le silicium sur lequel sont intégrés les transistors, une couche de 65 µm de résine époxy SU8 sur laquelle est implémenté un niveau métallique en cuivre de 35 µm d'épaisseur. Des trous métallisés sont aussi réalisés à travers le niveau SU8 pour les contacts élec triques entre les transistors et le niveau Cu supérieur. Enfin, le quatrième et dernier chapitre traite des caractérisations expérimentales des inductances de test réalisées ainsi que des démonstrateurs intégrant ces inductances directement sur la puce de puissance LDMOS. Dans ce dernier cas, des mesures en forts signaux sont aussi présentées. L'intégration "Above-IC" d'un réseau d'inductances parallèles présentant une valeur finale de 0.2nH pour un facteur de qualité de 40 à 2 GHz et de 58 à 5 Ghz, tout en supportant une densité de courant de 1A/mm², permet d'aboutir à une valeur du rendement de 60% pour un amplificateur RF LDMOS de puissance 50W.

K-Band (18 to 26 GHz) dielectric resonator oscillators are typically used as a local oscillator in most K-Band digital transmitter/receiver topologies. Traditionally, the oscillator itself is made up of an active device, a dielectric resonator termination network, and a passive load matching network. The termination network embodies a cylindrical high permittivity dielectric resonator that is coupled on the same plane as a current carrying transmission line. This configuration provides an adequate resonance needed for oscillation but has some limitations. In order to provide a high Q resonance the entire oscillator is placed in a metal box to prevent radiation losses. This increases the overall size of the device and makes it difficult to integrate in smaller transceiver topologies. Secondly, a tuning screw is required to help excite the dominant mode of the resonator to achieve the high Q response. This can cause problems in precision due to the mechanical jitter of the screw inherent in mobile devices. By embedding this resonator inside the substrate it is possible to realize a very high Q resonance at a desired frequency and remove the need for a metal cavity and tuning screw. An additional advantage can be seen in terms of overall size reduction of the oscillator circuit. To demonstrate the feasibility of utilizing a dielectric resonator embedded within a substrate, a K-Band oscillator proof of concept has been designed, fabricated, and tested. The oscillator is comprised of a low noise active transistor device, an embedded k-band dielectric resonator and a passive transmission line load network. All elements within the oscillator are optimized to produce a steady oscillation near 20 GHz. Preliminary investigations of a microstrip resonator S-band (2-3 GHz) oscillator are first discussed. Secondly, various challenges in design and fabrication are discussed. Thereafter, simulated and measured results of the embedded DRO structure are presented. Emphasis is placed on output oscillation power and low phase noise. With further development, the entire oscillator can be embedded within the substrate leaving only the active device on the surface. This allows for a considerable reduction in material cost and simple integration with miniaturized digital transmitter/receiver devices.

The objective of this research is to apply micromachined silicon-based resonant gravimetric sensors to the detection of gas-phase volatile organic compounds (VOCs). This is done in two primary tasks: 1) the optimization and application of silicon disk resonators to the detection of gas-phase VOCs, and 2) the development and application of a novel gravimetric-capacitive multisensor platform for the detection of gas-phase VOCs. In the rst task, the design and fabrication of a silicon-based disk resonator structure utilizing an in-plane resonance mode is undertaken. The resonance characteristics of the disk resonator are characterized and optimized. The optimized characteristics include the resonator Q-factor as a function of geometric parameters, and the dynamic displacement of the in-plane resonance mode. The Q-factors of the disk resonators range from 2600 to 4360 at atmosphere for disk silicon thicknesses from 7 µm to 18 µm, respectively. The resonance frequency of the in-plane resonance mode ranges from 260 kHz up to 750 kHz. The disk resonators are applied to the sensing of gas-phase VOCs using (poly)isobutylene as a sensitive layer. Limits of detection for benzene, toluene and m-xylene vapors of 5.3 ppm, 1.2 ppm, and 0.6 ppm are respectively obtained. Finally, models for the limits of detection and chemical sensitivity of the resonator structures are developed for the case of the polymer layers used. In the second task, a silicon-based resonator is combined with a capacitive structure to produce a multisensor structure for the sensing of gas-phase VOCs. Fabrication of the multisensor structure is undertaken, and the sensor is theoretically modeled. The baseline capacitance of the capacitor component of the multisensor is estimated to be 170 fF. Finally, initial VOC detection results for the capacitive aspect of the sensor are obtained.

The light-matter interaction in the near-field of high-Q resonators in SOI and SiN platforms is studied. The interactions of high-Q traveling-wave resonators with both resonant and non-resonant nanoparticles are studied and different applications based on this enhanced interactions in near-field such as high-resolution imaging of mode profile of high-Q resonators, label-free sensing, optical trapping, and SERS sensing are investigated. A near-field imaging system for the investigation of the near-field phenomena in the near-field of high-Q resonators is realized. A new technique for high-resolution imaging of the optical modes in high-Q resonators based on the near-field perturbation is developed that enables to achieve a very high resolution (< 10 nm) near-field image. The prospect of the high Q resonators on SOI platform for highly multiplexed label-free sensing and the effect of different phenomena such as the analyte drift and diffusion and the binding kinetics are studied. Also, the possibility of enhancing nanoparticle binding to the sensor surface using optical trapping is investigated and the dynamic of a nanoparticle in the high-Q resonator optical trap is studied. Furthermore, the interaction between a resonant nanoparticle with a high-Q microdisk resonator and its application for SERS sensing is studied. A model for interaction of resonant nanoparticles with high-Q resonators is developed and the optimal parameters for the design of coupled microdisk resonator and a plasmonic nanoparticle are calculated. The possible of resonant plasmonic nanoparticle trapping and alignment in an SiN microdisk resonator optical trap is also shown.

De nouveaux besoins dans le domaine des télécommunications par satellite ont amené les industriels du secteur à se pencher sur l’optimisation des ressources en créant des systèmes reconfigurables, capables d’adapter leur fonctionnement fréquentiel en cours de mission. Cette thèse s’intéresse plus particulièrement aux multiplexeurs et à la manière de les rendre agiles à travers les filtres qui les composent ainsi qu’une adaptation de leur architecture.Dans un premier temps, le présent manuscrit dresse l’état de l’art des dispositifs accordables réalisés par les équipes de recherche du monde entier, avant de proposer des solutions mettant en œuvre une topologie de multiplexage à coupleurs hybrides. Dans un second temps, des études sont présentées portant sur une pluralité de concepts de cavités ou d’éléments de couplage accordables. Certains de ces concepts sont ensuite sélectionnés et assemblés afin de former des fonctions de filtrage et de multiplexage accordables. La dernière partie présente ainsi deux multiplexeurs accordables, l’un permettant une reconfiguration en bande étroite, l’autre en bande large, le premier ayant donné lieu à une réalisation expérimentale. / New needs in the field of satellite telecommunications have led manufacturers in the sector to focus on optimizing resources by creating reconfigurable systems able to adapt their operating frequencyplan during the mission. This thesis focuses on multiplexers and how to make them agile through their architecture and the filters that compose them.This manuscript starts by realizing the state of the art oftunable filtering devices through analysis of contributions made by research teams around the world. Based on this state of art,solutions to the problematic are proposed using a hybrid coupler multiplexing topology. Then studies are presented on various tunable cavities or coupling elements concepts. Some of these concepts have been selected and assembled to form tunable filtering and multiplexing functions. The last part thus presents two tunable multiplexers, allowing narrowband or broadband reconfiguration. An experimental realization has also been conducted on the narrowband version.