JVST 2008 Abstract

MEMS Microhotplates for Thin Film and Nanowire Characterization


Juan C. Aceros, Nicol McGruer, George G. Adams


Summary

MEMS microhotplates fabricated using Silicon-On-Insulator (SOI) wafers were employed to characterize the electrical behavior of thin films and nanowires. Rapid thermal cyclic loading at 1KHz and 500Hz pulse frequencies with a 10% duty cycle were employed to allow the complete heating and cooling of the hotplates during testing. Sputtered Cr/Ru/Au thin films on SiO2 displayed high electrical conductivity and long lifetime. Sputtered Cr/Ru thin films on SiO2 displayed similar lifetimes as Ru thin films on SiO2. Sputtered Ru and RuOx nanowires on SiO2 displayed a resistivity of 72x10^{-8}Ohm m and 320x10^{-8}Ohm m respectively. It was found that cycle frequency did not influence their lifetimes under atmospheric or Nitrogen ambient conditions. Ru nanowires tested under N2 ambient displayed the longest lifetimes followed by Ru nanowires under atmospheric ambient and finally by RuOx nanowires. This behavior is attributed to an increase in the surface diffusion by the addition of O2 to the Ru. An increase of almost four times the thickness of the RuOx nanowire was calculated in order to match the same lifetime of the Ru nanowires. An activation energy (Ea) of 0.29eV was observed for Ru nanowires under atmospheric conditions. Biased percolating behavior with critical exponents ranging from 0.5 to 0.7 was found to describe the electrical behavior for all the nanowires.

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