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Experimental Study on Electrical Breakdown for Devices with Micrometer Gaps 被引量:2
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作者 孟国栋 成永红 +1 位作者 董承业 吴锴 《Plasma Science and Technology》 SCIE EI CAS CSCD 2014年第12期1083-1089,共7页
The understanding of electrical breakdown in atmospheric air across micrometer gaps is critically important for the insulation design of micro & nano electronic devices. In this paper, planar aluminum electrodes with... The understanding of electrical breakdown in atmospheric air across micrometer gaps is critically important for the insulation design of micro & nano electronic devices. In this paper, planar aluminum electrodes with gaps ranging from 2μm to 40 #m were fabricated by microelectromechanical system technology. The influence factors including gap width and surface dielectric states were experimentally investigated using the home-built test and measurement system. Results showed that for SiO2 layers the current sustained at 2-3 nA during most of the pre-breakdown period, and then rose rapidly to 10-30 nA just before breakdown due to field electron emission, followed by the breakdown. The breakdown voltage curves demonstrated three stages: (1) a constantly decreasing region (the gap width d 〈5 μm), where the field emission effect played an important role just near breakdown, supplying enough initial electrons for the breakdown process; (2) a plateau region with a near constant breakdown potential (5 μm〈 d 〈10 μm); (3) a region for large gaps that adhered to Paschen's curve (d 〉10μm). And the surface dielectric states including the surface resistivity and secondary electron yield were verified to be related to the propagation of discharge due to the interaction between initial electrons and dielectrics. 展开更多
关键词 electrical breakdown micrometer gaps field emission surface dielectric states surface resistivity secondary electron yield
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The Use of Geophysical Methods to Discriminate between Brine Layers and Freshwater Taliks in Permafrost Regions
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作者 Kenji Yoshikawa Vladimir Romanovsky +2 位作者 Nataria Duxbury Jerry Brown Alexandre Tsapin 《冰川冻土》 CSCD 北大核心 2004年第S1期301-309,共9页
Direct current resistivity and ground penetrating radar surveys were employed to obtain the value of the resistivity and dielectric constant in the brine near the Barrow, Alaska. The geophysical surveys were undertake... Direct current resistivity and ground penetrating radar surveys were employed to obtain the value of the resistivity and dielectric constant in the brine near the Barrow, Alaska. The geophysical surveys were undertaken together with the permafrost drilling program for the measuring of the ground temperature regime and for the core sampling. The sampled cores were measured for their physical and chemical properties in the laboratory under different temperature conditions ((-60) to (20) ℃). Laboratory results support field observations and led to the development of a technique for distinguishing freshwater taliks and brine layers in permafrost. These methods were also employed in freshwater taliks near Council, Alaska. The electrical resistivity is a powerful and sensitive parameter for brine detection. However, the resistivity is a less sensitive indicator of the soil type or water content under highly saline conditions. High frequency dielectric constant is an ideal second parameter for the indication of the soil type, liquid water content and other physical properties. The imaginary part of the dielectric constant and resistivity have a significant dependence upon salinity, i.e. upon freezing temperature. The ground temperature regime and the freezing point of the brine layer are important parameters for studying the electric properties of permafrost terrain. 展开更多
关键词 geophysical method resistivity and dielectric constant talik Barrow Alaska
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