Nonlinear and chaotic behavior in CMOS- MEMS resonators
[eng] Microelectromechanical Systems (MEMS) are relevant components for the diversi cation and integration of functionalities into a single heterogeneous chip or package in the known More than Moore approach. This thesis contributes to this eld by exploiting the possibilities of mature CMOS technolo...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/666675 |
| Acceso en línea: | http://hdl.handle.net/10803/666675 |
| Access Level: | acceso abierto |
| Palabra clave: | CMOS-MEMS Ressonadors Dinàmica no lineal Caos Biestabilitat Dispositius Semiconductors i Microsistemes 53 621.3 |
| Sumario: | [eng] Microelectromechanical Systems (MEMS) are relevant components for the diversi cation and integration of functionalities into a single heterogeneous chip or package in the known More than Moore approach. This thesis contributes to this eld by exploiting the possibilities of mature CMOS technologies to develop chaotic CMOS-MEMS resonators with higher performance than obtained until now and supporting its potential application in compact chaos-based secure communication systems. Speci cally, this work deals with the analysis, design and experimental demonstration of chaotic electrical signal generation using simple MEMS structures with a high degree of integration and scalability in CMOS technologies and others. The work analyzes from a practical perspective the geometric and electrical conditions for sustained chaotic motion in electrostatically actuated beam-shaped resonators. Practical applications require reasonable and wide enough range of system parameters to assure a feasible functionality in current technologies. An exhaustive analysis and numerical study of the system features indicates the need for cross-well chaotic motion that implies a bistable performance of the MEMS device. Such conditions involve, in contrast to typical MEMS resonators applications (sensors or RF oscillators), a relatively large gap between the resonator and electrodes making the readout method a key issue. The on-chip CMOS capacitive readout circuit allows the detection of the resonator motion with a high signal-to-noise ratio. A nonlinear electromechanical model for capacitive clamped-clamped beam (cc-beam) resonators have been developed and implemented in an analog hardware description language (AHDL) enabling system level electrical simulations. The model accounts for nonlinearities from variable resonator-electrode gap, thermal effect, residual fabrication stress, fringing eld effect as well as an accurate resonator de ection pro le in contrast to pari allel plate approximations. Accurate analytical expressions of the design conditions for bistability have been derived from the model and validated through FEM simulations and experimental data. The results reached in this thesis goes beyond the merely numerical or analytical approaches stated up to now for beam-shaped resonators. Experimental measurements of extensive homoclinic chaotic motion have been reported for the rst time in a straight and non-axially forced bistable cc-beam resonator operating, in addition, in the MHz range. The pioneer results on such simple and highly scalable structures represents a breakthrough for the development of a compact and low-cost platform for the study of potential applications of bistability and chaotic signal generation with added values beyond the use of purely electronic circuits. |
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