Study and analysis of thin film contact behaviours in micro/nano devices

Abstract

Today’s nano scale technologies in wireless communication, microwave communication and other high value applications depend on RF MEMS technology to solve many intriguing problems. The competitive and inspiring developments of miniaturized communication devices strained the market to acquire efficient devices, this made possible only by advancing through RF MEMS technology.

In this project, the objectives are inquiring and examine into RF MEMS switch. It is used as a switching device which switches between on and off state through the mechanical displacement of a vertical movable structure. During the experiment, switching from off to on state via the actuator is the key point of the experiment. As the experiment simulates the switching state of a device, the actuator is supplied with ~100mV to study the reason behind the fluctuation of the voltage once the tip of the actuator made a contact with the wafer. The contact material in this study is on gold-gold contact, because the main factors for failure in RF MEMS switch were metal–metal adhesion and contact surface degradation, resulting in unacceptably high contact resistance, selecting gold in this study are due to its lowest resistivity and chemical reactivity as well as the reasonably hardness of gold. The failure in switching and the eventual result in reducing the lifespan of the switch mainly are caused by changes in contact resistance. The method of cleaning the gold contact, presence of contaminants, and the cleanliness of the testing station and so on, all these factors would affect the changes in contact resistance in various way.