Material selection methodology for RF MEMS switch design

Abstract

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.