Electric field breakdown at micrometre separations in air and vacuum
ABSTRACT At large separations, the behaviour of electrodes has been widely studied and is reasonably well understood. However, some
fundamental problems have not been properly addressed such as maximum safe operating voltages and critical dimensions required
at small separations between different types of materials. A systematic study of electrical breakdown at sub-millimetre separations
using materials commonly used in the fabrication of microdevices has been undertaken. Specimens for examination at electrode
separations from 500 nm to 25 μm have been made with different electrode configurations, such as flat to flat, flat to point
and point to point. All the tests were made in air and at differing pressures.
- SourceAvailable from: berkeley.edu[show abstract] [hide abstract]
ABSTRACT: Microrelays with liquid metal wetted contacts have been demonstrated using bidirectional electrothermal electromagnetic actuators. These relays were fabricated with the Metal MUMPs foundry process, which has a 20-mum-thick nickel structural layer. The operating voltage is under 0.5 V. The measured breakdown voltage and off-state resistance are greater than 200 V and 100 MOmega, respectively, and the gold-to-gold contact resistance is around 0.3 Omega. When the contacts are wetted with liquid gallium alloy (melting point at -20degC), the measured contact resistance can be as low as 0.015 Omega. As such, these bidirectional relays could have potential applications in high-power switching systems with low contact resistance using liquid metal wetted contacts.Journal of Microelectromechanical Systems 07/2007; · 2.13 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Devices with micrometer and submicrometer gaps can face a serious challenge due to electrical breakdown during manufacturing, handling, and operation. Therefore, it is necessary to be aware of the breakdown voltage at different gaps. Since the Paschen's law is not valid for gaps smaller than several micrometers, modified Paschen curve should be used to predict breakdown voltage for microdevices. One of the possible mechanisms responsible for the reduction of the maximum operation voltage at small gaps is the field emission (FE). In this paper, particle-in-cell/Monte Carlo collision simulations, including the ejection of electrons from the cathode due to a high electric field, have been carried out to estimate the significance of the FE effect on the breakdown voltage in microgaps. [All rights reserved Elsevier].IEEE Transactions on Plasma Science 11/2007; · 0.87 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: In this paper, the failure of the breakdown voltage from the Paschen's law at extremely small electrode separations is studied. The electrical breakdown in microgaps occurs at the voltages far below the Paschen curve minimum breakdown limit and the modified Paschen curve should be used. Offered explanation for the departure from the Paschen's law at small gap spacings is based on the increasing of the yield of the secondary electrons. The high electric fields existing in small gaps may enhance the secondary electron yield and this would lead to a lowering of the breakdown voltage and to the departure from the Paschen's law. Particlein-cell/Monte-Carlo (PIC/MCC) simulations with a new secondary emission model have been performed to estimate the importance of this mechanism in the discharge breakdown. Obtained simulation results suggest that deviations from the Paschen curve across the micron and submicorn gap spacing can be attributed to the ion-enhanced field emissions. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)Beiträge aus der Plasmaphysik 04/2007; 47(3):165 - 172.