The construction of mathematical models of micromechanical RF switches, taking into account their design features, the influence of technological factors, as well as the correct choice of materials, contributes to the most accurate design and creation of a switch with specified characteristics. The earlier analysis and study of the technological process of creating a MEMS switch made it possible to determine the groups of factors that have a significant impact on the electrophysical and frequency characteristics. Within the framework of assessing the influence of technological factors on their electrophysical and frequency properties, the influence of such technological parameters as the etching time of various layers and the processing temperature was established. The thickness of the dielectric layer and the membrane and the thickness of the gap between the membrane and the dielectric layer were set as design parameters. Also, a model of a MEMS switch was built, taking into account the influence of design and technological parameters on the characteristics of the switch in the on and off state. Aluminum was used as materials for conducting lines and electrodes, and silicon oxide was used as a dielectric layer. Measurements of the characteristics of the manufactured switches showed a low capacity ratio of the MEMS switch. As a result, it was decided to research and select the most suitable materials for this switch. This paper proposes a methodology for the selection of materials used in the design of an RF MEMS switch. The switches have been redesigned with new materials. Significantly better results were obtained by measuring the switches.
Effective design of micromechanical switches for operation in various frequency ranges is impossible without mathematical models including the correlation of electrophysical parameters with the design and technological parameters of their fabrication. This task is complicated by the fact that different technologies and materials are used to create RF MEMS switch. An earlier analysis of the creation of the MEMS switch allowed us to identify groups of factors that have a significant impact on the electrophysical and frequency characteristics. To assess the influence of technological factors on the electrophysical and frequency properties, technological parameters such as the etching time of various layers, the processing temperature, and material properties such as electrical conductivity, Young's modulus, permittivity, and electrical resistivity were selected. And as design parameters, changes in thickness during the formation of the dielectric layer and the membrane, the thickness of the gap between the membrane and the dielectric layer were considered. In this paper, we construct a MEMS switch model including the influence of design and technological parameters on the characteristics of the switch in the on and off state. Another task is to assess the impact of technological uncontrolled effects that occur under certain conditions in the fabrication of a switch. Electrodynamic modeling of the switch was performed by the finite element method using the mathematical model that includes design and technological parameters. The operation voltage, switching time, the frequency of natural vibrations of the membrane, and the voltage characteristic of the switch were studied. The mathematical model of a micromechanical switch, including the technological parameters of its fabrication, will allow developing technological processes for the fabrication of MEMS switches that match the requirements in the specified frequency ranges and have low losses.
The creation of effective procedures for the design and fabrication of RF MEMS switches with specified electrophysical properties for operation in different frequency ranges is an urgent task. This is due to the widespread use of RF MEMS in various fields of microelectronics. The task is complicated by the fact that, based on the areas of application, different variants of technologies, materials, topological and structural solutions are used to create RF MEMS switches. The article proposes a method of design and fabrication of RF MEMS switch with specified properties based on creating a model of micromechanical switch, taking into account significant technological parameters, properties of materials and options for structural and topological solutions. For the selected three groups of factors, the analysis of the main characteristics and parameters affecting the electrophysical and frequency properties of RF MEMS switch is carried out. The analysis of technological processes of fabrication allowed determining the influence of the non-etched photoresist layer on such electrophysical characteristics as the capacity of the switch in the up- and down-state. The analysis of the properties of materials, the influence of thickness changes in the formation of the dielectric layer and membrane, as well as the thickness of the gap between the membrane and the dielectric layer on the electrophysical and frequency properties of RF MEMS switch. It is established that the most significant parameters affecting the formation of the frequency characteristics of the switch is the change in its geometric dimensions. The developed model RF-MEMS switch, which takes into account the interaction highlighted important properties and relations with the electrical and frequency characteristics of RF MEMS switch. Modeling and analysis of the following characteristics (consequences of the model) RF MEMS switch.
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