A fast switching surface micromachined electrostatic relay

A MEMS relay with electrostatic actuation and novel spring and contact design was developed and tested. This four terminal, single-pole, single-throw normally-open device with bridge contacts (SPST-NO-Bridge) is fabricated by means of a three layer polysilicon surface micromachining process. The total chip-area, including bondpads, is only 700/spl times/700 /spl mu/m/sup 2/. Minimum switching voltage is under 30 V and operating voltage is 35 V. High forces along with gold to gold contacts lead to a stable switching behaviour. Contact resistance is 1.3 /spl Omega/ (+-10%) and off-resistance is up to 100 G/spl Omega/. The microrelay has been tested in ambient air under normal pressure. Results indicate a small change in electrical properties and no change in the mechanical performance when the device is cycled more than 10/sup 7/ (1 V, 10 /spl mu/A) and 10/sup 4/ (5 V, 1 mA) times. Switching time under normal pressure is below 100 /spl mu/s (on) and 50 /spl mu/s (off). This low-power electrostatic relay is very suitable for portable or self-energizing devices, such as Automated Test Equipment (ATE) or reset-switches in charge-amplifiers for piezoelectric sensors.