Theoretical calculations based on phenomenology of ferroelectrics have been previously reported for lead zirconium titanate (PZT) system. This paper offers an experimental comparison of the crystal orientation dependence of dielectric properties for PZT thin films grown using reactive RF-sputtering. Highly oriented PZT thin films with a rhombohedral composition have been grown in different orientations using selective rapid thermal annealing cycles. The PZT(100) oriented films showed larger dielectric constant and loss compared to PZT(111) films. The PZT(100) films possessed sharp square-like hysteresis loops indicating a instantaneous switching of domains at the coercive field whereas the PZT(111) films showed smooth hysteresis loops as expected from our phenomenological calculations.
This contribution deals with capacitively actuated Ohmic switches in series single pole single throw (SPST) configuration for DC up to 4 GHz signal frequency (<0.5 dB insertion loss, 35 dB isolation) and in shunt switch SPST configuration for a frequency range from DC up to 80 GHz (<1.2 dB insertion loss, 18 dB isolation at 60 GHz). A novel high aspect ratio MEMS fabrication sequence in combination with wafer level packaging is applied for fabrication of the samples and allows for a relatively large actuation electrode area, and for high actuation force resulting in fast onresponse time of 10 s and off-response time of 6 s at less than 5 V actuation voltage. Large actuation electrode area and a particular design feature for electrode over travel and dynamic contact separation lead to high contact force in the closed state and to high force for contact separation to overcome sticking. The switch contacts, which are consisting of noble metal, are made in one of the latest process steps. This minimizes contamination of the contact surfaces by fabrication sequence residuals. A life time of 1 Billion switch cycles has been achieved. This paper covers design for reliability issues and reliability test methods using accelerated life time test. Different test methods are combined to examine electric and mechanical motion parameters as well as RF performance
A novel mm-wave MEMS single pole single throw (SPST) switch has been developed, which is driven by 5.0 V in 10.3 µs. The insertion loss and the isolation at 60 GHz were 1.2 dB and 18 dB, respectively. A two metal layer silicon interposer technology was also developed. We designed single pole double throw (SPDT) switch module, in which two SPST switch are accommodated on the silicon interposer chip. It consists of 3 µm thick Al wires and 12 µm thick low-k benzocyclobutene (BCB) interlayer dielectrics. They enabled sufficient signal integrity for 60 GHz and higher frequencies
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