The Electromechanical Responses of Suspended Graphene Ribbons for Electrostatic Discharge Applications.

摘要

This dissertation presents a novel suspended graphene ribbon device for electrostatic discharge (ESD) applications. The device structure is proposed and fabricated after careful design considerations. Compared to the conventional ESD devices such as diodes, bipolar junction transistors (BJTs), and metal-oxide-semiconductor field-effect transistors (MOSFETs), the proposed device structure is believed to render several advantages including zero leakage, low parasitic effects, fast response, and high current carrying capability, etc. A process flow is developed for higher yield and reliability of the suspended graphene ribbon device which is very delicate in nature. Direct current (DC) and transmission-line pulse test (TLP) measurements are carried out to investigate the switch-on behavior of the device which is crucial for ESD protection. DC measurement with a different configuration is used to characterize the mechanical shape evolution of the graphene ribbon upon biasing. Finite Element Simulations are also conducted to verify the experimental results, which are in good agreements. Furthermore, the breakdown properties of graphene ribbons are tested using TLP. It is found that graphene has a better current drivability compared to copper wires which is widely used as interconnects in integrated circuits (ICs). Also, bi-layer graphene has a higher breakdown current than monolayer graphene which indicates that multilayer graphene should be superior in current discharging. Last, Ab inito calculations are carried out to study the growth mechanism of multilayer graphene which is needed for graphene homo-epitaxy with precise control. It is found that a carbon cluster with six carbon atoms has the smallest kinetic barrier thus largest surface diffusivity during surface diffusion. So it is believed to be the most favorable diffusing species for graphene homo-epitaxy.