Hermetic diamond capsules for biomedical implants enabled by gold active braze alloys

Lichter, Samantha G.; Escudie, Mathilde; Stacey, Alastair; Ganesan, Kumaravelu; Fox, Kate; Ahnood, Arman; Apollo, Nicholas V.; Kua, Dunstan C.; Lee, Aaron; McGowan, Ceara; Saunders, Alexia L.; Burns, Owen; Nayagam, David A. X.; Williams, Richard A.; Garrett, David J.; Meffin, Hamish; Prawer, S.

doi:10.1016/j.biomaterials.2015.02.103

Cited by 39 publications

(34 citation statements)

References 29 publications

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“…Moreover, diamond brazing has been used for the fabrication of modern diamond devices for medical applications [4]. Conventionally, brazing of diamond is mainly implemented by reacting diamond grits with filler alloys at relatively high temperatures (approximately 930-1100 o C, depending on the filler alloys used)…”

Section: Introductionmentioning

confidence: 99%

Formation of TiC via interface reaction between diamond grits and Sn-Ti alloys at relatively low temperatures

Liao

Wang

et al. 2017

International Journal of Refractory Metals and Hard Materials

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In this paper, interfacial reaction between diamond grit and Sn-6Ti alloy was systematically studied at brazing temperatures from 600 to 1030 o C. A thin and uniform layer of scallop-like nano-sized TiC grains was formed after brazing for 30 minutes at 600 o C, and interfacial TiC grains subsequently coarsened as brazing temperature increased to 740 and 880 o C. Strip-like columnar TiC grains in a bilayer structure was further grown as brazing temperature increased to 930 o C. After brazing at 1030 o C, a dense layer of columnar TiC grains were formed. Based on the TEM micrographs of interfacial TiC, the formation and evolution of the growth morphologies of interfacial TiC was believed to be controlled by the diffusion of C flux from diamond grits, which is dependent on the brazing temperatures.

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Section: Introductionmentioning

confidence: 99%

Formation of TiC via interface reaction between diamond grits and Sn-Ti alloys at relatively low temperatures

Liao

Wang

et al. 2017

International Journal of Refractory Metals and Hard Materials

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“…We demonstrated that our packaged devices can both harvest ultrasonic energy as well as communicate information via amplitude-modulated ultrasonic backscattering. While the package is not significantly more effective in protecting the electronics from a corrosive environment than traditional polymer encapsulations, this analysis and fabrication method provide guidelines for developing packaging for acoustically coupled implants and similar packaging strategies have been used to build hermetic capsules for IMDs [51,56].…”

Section: Discussionmentioning

confidence: 99%

“…The filler could be anything from glass frit to an active-braze alloy or a eutectic paste [50]. Previous work by Lichter et al showed that diamond capsules could be hermetically laser-brazed together using gold-ABA [51]. For pure ceramic-to-ceramic bonding, custom laser welding systems utilizing non-linear optics could also be employed.…”

Section: B Microcracks In the Package Weld Seam Compromise The Hermementioning

confidence: 99%

Design of Ceramic Packages for Acoustically Coupled Implantable Medical Devices

Shen

Maharbiz

2019

Preprint

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Objective: Ultrasonic acoustic power transfer is an efficient mechanism for coupling energy to millimeter and submillimeter implants in the body. To date, published ultrasonically powered implants have been encapsulated with thin film polymers that are susceptible to well-documented failure modes in vivo, including water penetration and attack by the body. As with all medical implants, packaging with ceramic or metallic materials can reduce water vapor transmission and improve biostability to provide decadal device lifetime.In this paper, we evaluate methods of coupling acoustic energy to the interior of ceramic packages. Methods: The classic wave approach and modal expansion are used to obtain analytical expressions for acoustic transmission through two different package designs and these approaches are validated experimentally. A candidate package design is demonstrated using alumina packages and titanium lids, designed to be acoustically transparent. Results: Bulk modes are shown to be more effective at coupling acoustic energy to a piezoelectric receiver than flexural modes. Using bulk modes, packaged motes have an overall link efficiency of roughly 10%, compared to 25% for unpackaged motes. Packaging does not have a significant effect on translational misalignment penalties, but does increase angular misalignment penalties. Passive amplitudemodulated backscatter communication is demonstrated. Conclusion: Thin lids enable the use of acoustically coupled devices even with package materials of very different acoustic impedance. Significance: This work provides an analysis and method for designing packages that enable acoustic coupling with implantable medical devices, which could facilitate clinical translation. Fig. 1. System overview for acoustically coupled implantable medical devices (IMDs) utilizing ultrasonic backscatter communication. Information from many different energy domains can be encoded in the amplitude of the backscatter (green/blue waves). For these devices to be clinically useful, packaging must be designed that both protects the devices and also allows for acoustic coupling.

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“…To create robust, low-resistance electrical contacts to the sub-surface layer a laser milling and back brazing process was developed 23 .…”

Section: Fabrication Processmentioning

confidence: 99%

Optical and electronic properties of sub-surface conducting layers in diamond created by MeV B-implantation at elevated temperatures

Beveren

Liu

Bowers

et al. 2016

Journal of Applied Physics

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Boron implantation with in-situ dynamic annealing is used to produce highly conductive sub-surface layers in type IIa (100) diamond plates for the search of a superconducting phase transition. Here we demonstrate that high-fluence MeV ionimplantation, at elevated temperatures avoids graphitization and can be used to achieve doping densities of 6 at.%. In order to quantify the diamond crystal damage associated with implantation Raman spectroscopy was performed, demonstrating high temperature annealing recovers the lattice. Additionally, low-temperature electronic transport measurements show evidence of charge carrier densities close to the metal-insulator-transition. After electronic characterization, secondary ion mass spectrometry was performed to map out the ion profile of the implanted plates. The analysis shows close agreement with the simulated ion-profile assuming scaling factors that take into account an average change in diamond density due to device fabrication. Finally, the data show that boron diffusion is negligible during the high temperature annealing process. a)

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Hermetic diamond capsules for biomedical implants enabled by gold active braze alloys

Cited by 39 publications

References 29 publications

Formation of TiC via interface reaction between diamond grits and Sn-Ti alloys at relatively low temperatures

Formation of TiC via interface reaction between diamond grits and Sn-Ti alloys at relatively low temperatures

Design of Ceramic Packages for Acoustically Coupled Implantable Medical Devices

Optical and electronic properties of sub-surface conducting layers in diamond created by MeV B-implantation at elevated temperatures

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