The Wear Processes of Gold Coated Multi-Walled Carbon Nanotube Surfaces Used as Electrical Contacts for Micro-Electro-Mechanical Switching

Abstract

An experimental investigation of gold coated, multi-walled carbon nanotube (CNT) surfaces was previously conducted, to determine the limits as electrical contacts. The results are summarized. The multi-walled CNT's (MWCNT's) were synthesized on a silicon planar and sputter coated with a gold film. The planar surfaces mounted on the tip of a piezo-electric actuator and mated with a coated Au hemispherical probe. The conditions typical of MEMS relay applications; (4 V, 1-10 mA) with an applied force of 1 mN. No failures were observed below, 10 × 106 cycles; to determine the limits, the current level was increased in stages to 50 mA. At 20 mA, the contacts were deemed to have failed due to an increased contact resistance at 70 × 106 cycles. In this paper the failure mechanism is described as a fine transfer mechanism linked to the thermodynamic processes at the contact interface as the contacts open, known as molten metal bridge transfer.