The electrical and mechanical properties of Au–V and Au–V2O5 thin films for wear-resistant RF MEMS switches

Bannuru, Thirumalesh; Brown, W. L.; Narksitipan, Suparut; Vinci, Richard P.

doi:10.1063/1.2902954

Cited by 17 publications

(18 citation statements)

References 20 publications

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“…One of the popular methods is using hard particles to form composite coatings. [13][14][15] It is widely accepted that the highly dispersive nano-particles in composites can realize good strengthening effect. In order to achieve good dispersion of nano-particles, the electrolyte has be to maintained by special techniques, such as vigorous agitation, air injection, and/or adding surfactants.…”

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confidence: 99%

Au-Ni-TiO₂Nano-Composite Coatings Prepared by Sol-Enhanced Method

Wang

Wei

et al. 2014

J. Electrochem. Soc.

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Gold coatings are widely used in many fields for their shining color, excellent corrosion resistance, and electrical conductivity. However, they are not mechanically strong with low wear resistance. In this paper, we have prepared nano-composite Au-Ni-TiO 2 coatings by our newly developed sol-enhanced electroplating method. In order to obtain the optimal mechanical properties, a systematic study of Au-Ni-x TiO 2 coatings with different sol concentrations (x is the sol doping concentration from 0 to 25 mmol/L) has been conducted. It was found that nano-particles (3-12 nm) of TiO 2 were highly dispersed in the coating matrix. The mechanical properties of sol-enhanced nano-composite coating were significantly increased. The nano-hardness of the coatings was improved from 2.55 ± 0.13 GPa to 3.20 ± 0.15 GPa. Consequently, the scratch resistance and wear resistance of the sol-enhanced coating were also improved significantly. Meanwhile, the electrical resistivity of the sol-enhanced coatings keeps a same level as the pure Au-Ni coatings. Gold (Au) and gold alloy have been widely used in various applications for their unique properties such as beautiful/shining color, high chemical stability, good ductility, excellent conductivity, and good weldability.1-5 Au, Au alloy and Au based composite coatings have been synthesized by various technologies, such as E-Beam Evaporation, Magnetron Sputtering, Sol-gel deposition, Chemical Vapour Deposition (CVD), Electrochemical Over-potential Deposition (OPD), and Electroplating.6-9 Among these fabrication methods, electroplating method is a simple way to fabricate gold coatings because of its energy effectiveness, time efficiency, without using vacuum technology and the controllability of coating thickness and grain size. 10In order to improve the hardness of pure Au, alloy elements such as Co and Ni were co-deposited with Au, which is known as hard Au. Hard Au can be used on decoration surface and electrical components where shining color, chemical inertness and good wear resistance are combined. As expected, however, the electrical conductivity decreased with increasing mechanical strength. 11,12For the requirements mentioned above, the mechanical properties such as wear resistance and hardness of coatings are the most important factors which dominate the durability and service life of coated parts. In the past decades, many attempts were devoted to improve the mechanical properties of Au coatings. One of the popular methods is using hard particles to form composite coatings. [13][14][15] It is widely accepted that the highly dispersive nano-particles in composites can realize good strengthening effect. In order to achieve good dispersion of nano-particles, the electrolyte has be to maintained by special techniques, such as vigorous agitation, air injection, and/or adding surfactants. However, it is difficult to achieve good suspension because of the small particle size and large surface energy, which caused agglomeration of the nano-particles. The surface appearance of Au based ...

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confidence: 99%

Au-Ni-TiO₂Nano-Composite Coatings Prepared by Sol-Enhanced Method

Wang

Wei

et al. 2014

J. Electrochem. Soc.

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“…This is seen in both solid solution and precipitation strengthened metals. The study conducted by Bannuru et al on Au-V and Au-V 2 O 5 show that the solid-solution Au-V has an electrical resistivity four times that of the ODS film with the same V content, suggesting solid-solution atoms can cause more electron scattering than an ODS material with the same volume percentage [21]. Additional causes of increased resistivity include temperature, vacancies, and dislocations.…”

Section: Introductionmentioning

confidence: 97%

“…However, many materials with very fine grain sizes have shown evidence of stress-induced grain growth, which leads to a decrease in strength. Studies conducted on nanocrystalline materials [21][22][23][24] suggest this type of grain growth can be attributed to grain-boundary sliding, diffusion, and grain rotation; therefore, if these are reduced, grain growth should be slowed or even stopped. Impurities introduced into the system can stabilize nanocrystalline microstructures by reducing grain boundary mobility and thereby stopping grain growth [17,[25][26][27].…”

Section: Introductionmentioning

confidence: 98%

“…One aspect of the ODS technique that shows great promise is the ability to increase hardness without greatly affecting conductivity [21]. ODS Au with V, Au-V 2 O 5 , showed both a larger increase in hardness coupled with a smaller increase in resistivity as a function of V content when compared to a Au-V solid-solution.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, high currents passed through the switch can lead to micro-welding from Joule heating, followed by detrimental deformation when the contact is broken [9,10]. In order to increase the lifetime of these contacts, numerous different techniques are used to increase the wear resistance by increasing the hardness of Au: grain size reduction [11][12][13][14], addition of solid solution impurities [3,13,[15][16][17], deposition of nanolaminate structures [18][19][20], or the introduction of small oxide particles [15,21,22]. However, all of these strengthening techniques can substantially increase the resistivity of Au.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical and electrical performance of thermally stable Au–ZnO films

Schoeppner

Goeke²,

Moody

et al. 2015

Acta Materialia

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The mechanical properties, thermal stability, and electrical performance of Au-ZnO composite thin films are determined in this work. The co-deposition of ZnO with Au via physical vapor deposition leads to grain refinement over that of pure Au; the addition of 0.1 vol.% ZnO reduces the as-grown grain size by over 30%. The hardness of the as-grown films doubles with 2% ZnO, from 1.8 to 3.6 GPa as measured by nanoindentation. Films with ZnO additions greater than 0.5% show no significant grain growth after annealing at 350°C, while pure gold and smaller additions do exhibit grain growth and subsequent mechanical softening. Films with 1% and 2% ZnO show a decrease of approximately 50% in electrical resistivity and no change in hardness after annealing. A model accounting for both changes in the interface structure between dispersed ZnO particles and the Au matrix captures the changes in mechanical and electrical resistivity. The addition of 1-2% ZnO co-deposited with Au provides a method to create mechanically hard and thermally stable films with a resistivity less than 80 nO-m. These results complement previous studies of other alloying systems, suggesting oxide dispersion strengthened (ODS) gold shows a desirable hardness-resistivity relationship that is relatively independent of the particular ODS chemistry.

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