Reliability in Hot Switched Ruthenium on Ruthenium MEMS Contacts

Basu, Anirban; Hennessy, R. P.; Adams, George G.; McGruer, N.E.

doi:10.1109/holm.2013.6651422

Cited by 13 publications

(7 citation statements)

References 14 publications

(28 reference statements)

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“…The hot switching voltage that was applied across the contacts was 5 V. The currents were attributed to Fowler Nordheim tunneling. Similar currents were observed independently in the present work using a transimpedance amplifier (for higher bandwidth measurements) as well as a source-measure unit as reported in [36,37]. It was observed that, even at a hot switching voltage of 1 V (less than the work function of Ru), a pre-contact current was present, indicating that Fowler Nordheim tunneling alone is not responsible for this current.…”

Section: Observation and Investigation Of Pre-contact Current -supporting

confidence: 89%

Hot switching damage mechanisms in MEMS contacts—evidence and understanding

Basu¹,

Hennessy²,

Adams³

et al. 2014

J. Micromech. Microeng.

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Using an AFM-based test setup, experiments were performed on Ru microcontacts under a variety of leading and trailing edge hot switching conditions, including different voltages, different currents, different polarities (including bipolar and ac up to 20 MHz), and different approach and separation rates. It was found that hot switching damage is a complex phenomenon for microcontacts. It consists of a number of different mechanisms occurring simultaneously to different degrees depending on the hot switching conditions. It was determined through a combination of experiments and models that the mechanisms leading to contact erosion operate when the electrodes are separated by less than a few Å or are barely touching. For leading edge hot switching, i.e. hot switching when the contacts are closing, the main damage mechanism was found to be associated with currents less than 0.15 mA. Pre-contact currents were observed on uncleaned contacts and were not found to contribute to contact damage. Despite the damage caused by hot switching, it was found that unless the contact material is almost or completely eroded, hot switching does not lead to high contact resistance or high adhesion on Ru contacts. Under bipolar hot switching conditions, microcontacts with a 400 μN contact force maintained a contact resistance of less than 1 Ω and a pull-off force less than 60 μN for more than 100 million cycles.

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Section: Observation and Investigation Of Pre-contact Current -supporting

confidence: 89%

Hot switching damage mechanisms in MEMS contacts—evidence and understanding

Basu¹,

Hennessy²,

Adams³

et al. 2014

J. Micromech. Microeng.

Self Cite

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“…Ruthenium is a leading candidate for next-generation integrated circuit (IC) interconnection [1][2][3][4], as an ultra-thin layer of ruthenium has an electrical conductivity higher than other competing metals [5], does not require special barrier layers, and can be deposited in narrow trenches by atomic deposition (ALD) [6,7]. Ruthenium is also a promising candidate for the electrodes of the dynamic random-access memory (DRAM) capacitors [8], gate electrodes in metal oxide semiconductor transistors (MOSFETs) [9], and high conductive coating for MEMS devices [10,11]. It is also widely used in heterogeneous catalysis [12].…”

Section: Introductionmentioning

confidence: 99%

Plasma Enhanced Atomic Layer Deposition of Ruthenium Films Using Ru(EtCp)2 Precursor

et al. 2021

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Ruthenium thin films were deposited by plasma-enhanced atomic layer deposition (PEALD) technology using Ru(EtCp)2 and oxygen plasma on the modified surface of silicon and SiO2/Si substrates. The crystal structure, chemical composition, and morphology of films were characterized by grazing incidence XRD (GXRD), secondary ion mass spectrometry (SIMS), and atomic force microscopy (AFM) techniques, respectively. It was found that the mechanism of film growth depends crucially on the substrate temperature. The GXRD and SIMS analysis show that at substrate temperature T = 375 °C, an abrupt change in surface reaction mechanisms occurs, leading to the changing in film composition from RuO2 at low temperatures to pure Ru film at higher temperatures. It was confirmed by electrical resistivity measurements for Ru-based films. Mechanical stress in the films was also analyzed, and it was suggested that this factor increases the surface roughness of growing Ru films. The lowest surface roughness ~1.5 nm was achieved with a film thickness of 29 nm using SiO2/Si-substrate for deposition at 375 °C. The measured resistivity of Ru film is 18–19 µOhm·cm (as deposited).

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“…Sensors 2020, 20, x FOR PEER REVIEW 2 of 10 adhesion, micro welding, and oxidation, resulting in increasing the contact resistance dramatically [12,13]. By comparison, the microfluidics inertial switch is a typical representative of using microdroplet as sensing element, which can avoid the problems of signal bouncing and contact wear during the switching motion [14].…”

Section: Introductionmentioning

confidence: 99%

“…According to the contact mode, the MEMS inertial switches can be divided into solid-to-solid type and liquid-to-solid type. Generally, the solid-to-solid electrical contacts, which use solid proof masses and beams, are susceptible to arcing, contact erosion, adhesion, micro welding, and oxidation, resulting in increasing the contact resistance dramatically [ 12 , 13 ]. By comparison, the microfluidics inertial switch is a typical representative of using microdroplet as sensing element, which can avoid the problems of signal bouncing and contact wear during the switching motion [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Study on Electrical Performance of a U-Type Microfluidic Acceleration Switch Using Salt Solution as the Sensitive Electrode

Shen

Chen

Chang

et al. 2020

Sensors

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The threshold of microfluidic inertial switch is excessively dependent on the size of the passive valve structure and the gas–liquid surface energy of working liquid. How to achieve high threshold and anti-high overload using liquid with low viscosity and low surface tension is a challenging work. Based on the designed U-type microfluidic inertial switch, the electrical characteristic of salt solution at microscale as well as the threshold and dynamic electrical performance of switch were studied. The VOF and CSD modules in CFD software were employed to analyze the dynamic flow process, and then the air–liquid surface moving displacement curve was compared by the theoretical model. A self-designed acceleration test platform was utilized to measure the static threshold, dynamic threshold, and anti-high overload of the inertial switch. The results show that the U-type microfluidics inertial switch using salt solution as sensitive electrode has better performance in power connection and anti-high overload. In particular, it also has the ability to achieve a range of dynamic threshold by changing the placement of the contact electrode, which can achieve rapid power on and off.

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Reliability in Hot Switched Ruthenium on Ruthenium MEMS Contacts

Cited by 13 publications

References 14 publications

Hot switching damage mechanisms in MEMS contacts—evidence and understanding

Hot switching damage mechanisms in MEMS contacts—evidence and understanding

Plasma Enhanced Atomic Layer Deposition of Ruthenium Films Using Ru(EtCp)2 Precursor

Study on Electrical Performance of a U-Type Microfluidic Acceleration Switch Using Salt Solution as the Sensitive Electrode

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