Gold Coated Multi-Walled Carbon Nanotube Surfaces As Low Force Electrical Contacts for MEMS Devices: Part 1

Abstract

An experimental investigation of gold coated, multi- walled carbon nanotube (CNT) surfaces was conducted, to determine the limits of these surfaces as electrical contacts. The multi-walled CNT's (MWCNT's) were synthesized on a silicon planar and sputter coated with a gold film. The planar surfaces were mounted on the tip of a piezo-electric actuator and mated with a coated Au hemispherical probe. The load conditions were typical of MEMS relay applications; (4V, 1-10mA) with an applied force of 1mN. For these conditions the surfaces were shown to maintain a stable contact resistance over 10 6 switching cycles. To determine the limits, the contact force was increased to 3mN under dry circuit conditions and the current increased to 20mA-50mA for the 1mN contact force. The contact resistance and surface degradation were compared to a reference Au-Au contact surface. For the coated MWCNT surfaces investigated the current loading limit was determined to be 20mA with the contacts failing with increased contact resistance after 50x10 6 cycles.