Ulrich Prechtel

High temperature stable RF MEMS switch based on tungsten-titanium

In this paper we present a high temperature stable, capacitive RF MEMS switch based on a tungsten-titanium alloy. The evaluation of the temperature stability was done by annealing experiments up to 500°C. Due to an intrinsic residual stress the switch features a large out of plane deflection. This allows the combination of high open-state isolation with a moderate pull-in voltage and with high restoring forces. Measurements of the high frequency performance in the 20 to 36 GHz range provided good results for insertion loss and isolation.

Broadband Single-Pole Multithrow RF-MEMS Switches for Ka-Band

This paper presents the design, fabrication and RF-characterization of SP3T, SP4T and SP6T RF-MEMS switches. All devices are fabricated on a 200 ¿m thin silicon substrate. The insertion loss of the SP3T is almost constant from 18 - 40 GHz with a value better than -0.5 dB. The SP4T and SP6T show an insertion loss better than -0.9 dB from 18 - 40 GHz. The isolation is better than -17 dB for all switches in almost all switching states from 18-40GHz. Furthermore, an on-wafer absorbing structure, acting as a quasi 50 ¿ match is shown, exhibiting a return loss of better than -10 dB for frequencies above 20 GHz.

RF MEMS Switches Based on an Alloy of Aluminum-Silicon-Copper

In this work we report on the development of electrostatically actuated RF MEMS switches which are based on a one sided clamped cantilever made of two layers of the same alloy of aluminum-silicon-copper. The switches are based on a low-complexity design and are fabricated by conventional sputter deposition and wet etching techniques on oxidized silicon substrates. Due to a well defined intrinsic stress gradient the cantilevers bend away from the substrate surface after release. This deflection allows the combination of high open-state isolation with a moderate pull-in voltage and with high restoring forces, which help to reduce sticking effects. The temperature behavior of the residual stress of each single layer that are the basis for the switch is investigated up to 400°C. Thereby, the change in stress over temperature as well as stress level in the as-deposited state is strongly dependent on deposition parameters. Furthermore, the change of deflection is evaluated up to 400°C at cantilever-type test structures. Finally, the high frequency performance of the switches was measured in the 23 to 36 GHz range showing good results for isolation and insertion loss.