INVESTIGATION OF BORON AND NITROGEN ION BEAM IMPLANTATION IN GOLD THIN FILMS FOR OHMIC MEMS SWITCH CONTACT IMPROVEMENT
Abstract
Contact material and more precisely surface properties are a major issue for RF MEMS ohmic switch reliability. Shallow ion implantation of boron and nitrogen on gold thin film is investigated to increase surface hardness with a limited impact on Electrical Contact Resistance (ECR). The implantation energies were chosen to place the concentration peak of the implanted species at a depth of 100 nm. A microstructural analysis shows that the hardness increases with boron concentration due to a solid solution hardening mechanism, whereas in case of nitrogen, for concentration above 1%, the nitrogen precipitates into a nitride phase correlated to a hardness decrease. The ECR is measured using a Nanoindenter XP which experimental setup reproduces MEMS ohmic switch contact (from 100 μN to 1 mN applied loads under 1 mA). A notable result is obtained with a boron dose of 7.37 x 1016 ions/cm² at 90 keV into gold thin film: 50% hardness increase and 2.6 times higher ECR than pure gold.
Origin | Files produced by the author(s) |
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