RF-MEMS switch using carbon nanotube composite gold electroplating

Multi-wall carbon nanotubes (CNT) were successfully composited in gold electroplated film. Aggregation of CNT in electroplated film was observed using a surfactant, since electrolyte ion such as SO32- surrounds the colloids and weakens coulomb repulsive force between colloids. Chemical modification of the CNT was effective to disperse in the electrolyte. The amount of the CNT in the electrolyte was estimated around 0.02wt%. The CNT co-deposited gold film (CNT-Au) has some excellent properties for radio frequency micro-electro-mechanical systems (RF-MEMS) switch, compared with Au and platinum containing Au film (AuPt). The hardness of the CNT-Au film is larger than the Au film, as almost same as the AuPt film. Meanwhile, the electrical resistivity of CNT-Au is much smaller than the AuPt film, as same as Au film. In tribology test, the CNT-Au film has superior property than the Au film The CNT-Au film was applied to the contact points of the RF-MEMS switch. In terms of high power handling capability, the CNT-Au contact is superior to the Au film contacts. © 2010 The Institute of Electrical Engineers of Japan.