Micromachined Pt-Rh and stainless steel relays for high power DC applications

摘要

This paper explores the viability of bulk metal foils, in particular platinum-rhodium (Pt-Rh), for use in high power micromechanical relays. The electrical and thermal response of electrostatically actuated three-terminal micro-relays is evaluated. The micro-relays have a footprint of 6.5 mm ~2 and an actuation area of 1.32 mm ~2. A stacked double cantilever structure isolates the actuation electrode from the current path. A micromachined heat sink is located on the upper cantilever. The devices are fabricated by micro-electrodischarge machining and directly assembled on power rated printed circuit boards. The impact of contact materials, and forced cooling is addressed. Preliminary results suggest that the Pt-Rh devices have total on-state resistances of 1.25 Ω and can handle currents substantially in excess of 1 A, and potentially in excess of 2.6 A.