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Title:Stochastic Characterization of Gold-to-Gold Contacts in MEMS Based on a Gaussian Model for Surface Roughness
Author(s):Park, Kyeong Hyun
Contributor(s):Ravaioli, Umberto
Subject(s):micro-electro-mechanical systems
device characterization
Gaussian modeling
contact resistance
electron transport
Abstract:In electronic devices such as relays and switches, the problem of contact surfaces is of tremendous importance for the understanding of transport of information in integrated circuits. When an electric current flows through the contact boundary surface between two conducting bodies, the real contact area where the current can pass is far smaller than the nominal or apparent contact area, and the current constricts to real contact conducting spots. The resistance resulting from these constrictions is called the contact resistance. The contact resistance of conducting spots in a randomly rough contact surface at the atomistic scale is one of the most fundamental problems of conduction of a steady current. Although an equation for the contact resistance of a conducting spot exists, it is based on a simplistic assumption and statistcal properties, and there is neither a simulated version of a contact surface nor a relationship between the contact force and simulated contact resistance. This paper presents the relationship between the electronic transport in gold-to-gold contacts and a statistical description of the electrodes surface roughness based on a Gaussian model. Gold film has been widely used among candidate materials for electrodes in RF (radio frequency) contacting MEMS (micro-electromechanical systems) switches, because of its low resistivity and high resistance against oxidation. In this scope the contact resistance for Au-to-Au contact is theoretically computed based on an experimentally fit Gaussian model. The Au-to-Au contact resistance found in this paper were 0.0669 omega with the minimum contact force, 0.392 mN and 0.0420 omega with 0.985 mN of the contact force. These results are within an error margin of 5% compared to the recently published experimental data. Based on the theoretical contact resistances that fit to the actual contact, stochastic contact regions corresponding to different applied contact force are simulated. The main factors that this paper deals with are asperities on the surface based on roughness of the gold and changing contact areas depending on truncated heights of the Gaussian model.
Issue Date:2009-05
Publication Status:unpublished
Peer Reviewed:not peer reviewed
Date Available in IDEALS:2014-01-23

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