scholarly journals Ultra-Long-Term Reliable Encapsulation Using an Atomic Layer Deposited HfO2/Al2O3/HfO2 Triple-Interlayer for Biomedical Implants

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 579 ◽  
Author(s):  
Li ◽  
Cauwe ◽  
Yang ◽  
Schaubroeck ◽  
Mader ◽  
...  
Keyword(s):  
Medical Devices ◽  
Electrochemical Impedance ◽  
Copper Film ◽  
Atomic Layer ◽  
Polymer Materials ◽  
Implantable Medical Devices ◽  
Layer Deposition ◽  
Excellent Electrochemical Performance ◽  
Thin Copper Film

Long-term packaging of miniaturized, flexible implantable medical devices is essential for the next generation of medical devices. Polymer materials that are biocompatible and flexible have attracted extensive interest for the packaging of implantable medical devices, however realizing these devices with long-term hermeticity up to several years remains a great challenge. Here, polyimide (PI) based hermetic encapsulation was greatly improved by atomic layer deposition (ALD) of a nanoscale-thin, biocompatible sandwich stack of HfO2/Al2O3/HfO2 (ALD-3) between two polyimide layers. A thin copper film covered with a PI/ALD-3/PI barrier maintained excellent electrochemical performance over 1028 days (2.8 years) during acceleration tests at 60 °C in phosphate buffered saline solution (PBS). This stability is equivalent to approximately 14 years at 37 °C. The coatings were monitored in situ through electrochemical impedance spectroscopy (EIS), were inspected by microscope, and were further analyzed using equivalent circuit modeling. The failure mode of ALD Al2O3, ALD-3, and PI soaking in PBS is discussed. Encapsulation using ultrathin ALD-3 combined with PI for the packaging of implantable medical devices is robust at the acceleration temperature condition for more than 2.8 years, showing that it has great potential as reliable packaging for long-term implantable devices.

scholarly journals Accelerated Hermeticity Testing of Biocompatible Moisture Barriers Used for the Encapsulation of Implantable Medical Devices

Coatings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 19
Author(s):  
Changzheng Li ◽  
Maarten Cauwe ◽  
Lothar Mader ◽  
David Schaubroeck ◽  
Maaike Op de Beeck
Keyword(s):  
Medical Devices ◽  
Performance Test ◽  
Atomic Layer ◽  
Accelerated Testing ◽  
Implantable Medical Devices ◽  
Barrier Layers ◽  
Potential Applicability ◽  
Moisture Barriers ◽  
Microscopic Inspection

Barrier layers for the long-term encapsulation of implantable medical devices play a crucial role in the devices’ performance and reliability. Typically, to understand the stability and predict the lifetime of barriers (therefore, the implantable devices), the device is subjected to accelerated testing at higher temperatures compared to its service parameters. Nevertheless, at high temperatures, reaction and degradation mechanisms might be different, resulting in false accelerated test results. In this study, the maximum valid temperatures for the accelerated testing of two barrier layers were investigated: atomic layer deposited (ALD) Al2O3 and stacked ALD HfO2/Al2O3/HfO2, hereinafter referred to as ALD-3. The in-house developed standard barrier performance test is based on continuous electrical resistance monitoring and microscopic inspection of Cu patterns covered with the barrier and immersed in phosphate buffered saline (PBS) at temperatures up to 95 °C. The results demonstrate the valid temperature window to perform temperature acceleration tests. In addition, the optimized ALD layer in combination with polyimide (polyimide/ALD-3/polyimide) works as effective barrier at 60 °C for 1215 days, suggesting the potential applicability to the encapsulation of long-term implants.

Atomic Layer Deposition of a Nanometer-Thick Li3PO4 Protective Layer on LiNi0.5Mn1.5O4 Films: Dream or Reality for Long-Term Cycling?

2021 ◽  
Vol 13 (13) ◽  
pp. 15761-15773
Author(s):  
Maxime Hallot ◽  
Borja Caja-Munoz ◽  
Clement Leviel ◽  
Oleg I. Lebedev ◽  
Richard Retoux ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Protective Layer ◽  
Atomic Layer ◽  
Layer Deposition

scholarly journals Atomic Layer Deposition for Preparation of Highly Efficient Catalysts for Dry Reforming of Methane

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 266 ◽  
Author(s):  
Soong Kim ◽  
Byeong Cha ◽  
Shahid Saqlain ◽  
Hyun Seo ◽  
Young Kim
Keyword(s):  
Atomic Layer Deposition ◽  
Heterogeneous Catalysts ◽  
Chemical Properties ◽  
Atomic Layer ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
High Catalytic Activity ◽  
Term Operation ◽  
Layer Deposition

In this article, the structural and chemical properties of heterogeneous catalysts prepared by atomic layer deposition (ALD) are discussed. Oxide shells can be deposited on metal particles, forming shell/core type catalysts, while metal nanoparticles are incorporated into the deep inner parts of mesoporous supporting materials using ALD. Both structures were used as catalysts for the dry reforming of methane (DRM) reaction, which converts CO2 and CH4 into CO and H2. These ALD-prepared catalysts are not only highly initially active for the DRM reaction but are also stable for long-term operation. The origins of the high catalytic activity and stability of the ALD-prepared catalysts are thoroughly discussed.

scholarly journals Protective multilayer packaging for long-term implantable medical devices

2014 ◽  
Vol 255 ◽  
pp. 124-129 ◽  
Author(s):  
Andreas Hogg ◽  
Stefanie Uhl ◽  
François Feuvrier ◽  
Yann Girardet ◽  
Benjamin Graf ◽  
...  
Keyword(s):  
Medical Devices ◽  
Implantable Medical Devices

scholarly journals Capacitance Electrochemical pH Sensor Based on Different Hafnium Dioxide (HfO2) Thicknesses

Chemosensors ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Zina Fredj ◽  
Abdoullatif Baraket ◽  
Mounir Ben Ali ◽  
Nadia Zine ◽  
Miguel Zabala ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Ph Sensor ◽  
Atomic Layer ◽  
Hafnium Dioxide ◽  
Thin Layers ◽  
Sensitive Layer ◽  
Layer Deposition ◽  
Highly Sensitive ◽  
Na Ions ◽  
Interfering Ions

Over the past years, to achieve better sensing performance, hafnium dioxide (HfO2) has been studied as an ion-sensitive layer. In this work, thin layers of hafnium dioxide (HfO2) were used as pH-sensitive membranes and were deposited by atomic layer deposition (ALD) process onto an electrolytic-insulating-semiconductor structure Al/Si/SiO2/HfO2 for the realization of a pH sensor. The thicknesses of the layer of the HfO2 studied in this work was 15, 19.5 and 39.9 nm. HfO2 thickness was controlled by ALD during the fabrication process. The sensitivity toward H+ was clearly higher when compared to other interfering ions such as potassium K+, lithium Li+, and sodium Na+ ions. Mott−Schottky and electrochemical impedance spectroscopy (EIS) analyses were used to characterise and to investigate the pH sensitivity. This was recorded by Mott–Schottky at 54.5, 51.1 and 49.2 mV/pH and by EIS at 5.86 p[H−1], 10.63 p[H−1], 12.72 p[H−1] for 15, 19.5 and 30 nm thickness of HfO2 ions sensitive layer, respectively. The developed pH sensor was highly sensitive and selective for H+ ions for the three thicknesses, 15, 19.5 and 39.9 nm, of HfO2-sensitive layer when compared to the other previously mentioned interferences. However, the pH sensor performances were better with 15 nm HfO2 thickness for the Mott–Schottky technique, whilst for EIS analyses, the pH sensors were more sensitive at 39.9 nm HfO2 thickness.

Enhancing the Cycling Stability of Tin Sulfide Anodes for Lithium Ion Battery by Titanium Oxide Atomic Layer Deposition

2016 ◽  
Vol 13 (2) ◽  
Author(s):  
Dongsheng Guan ◽  
Chris Yuan
Keyword(s):  
Atomic Layer Deposition ◽  
Structural Integrity ◽  
Electrochemical Impedance ◽  
Protective Coatings ◽  
Lithium Ion ◽  
Atomic Layer ◽  
Cycling Stability ◽  
Tin Sulfide ◽  
Transfer Resistance ◽  
Layer Deposition

The poor cyclability problem of SnS2 anodes in Li-ion batteries (LIB) is tackled for the first time by surface coatings with TiO2 via atomic layer deposition (ALD). ALD is capable to achieve uniform, conformal nanoscale coatings onto entire SnS2 electrodes, and enhance their cycling stability and rate performance. From our study, we found that the bare electrode delivers capacities eventually down to 219.2 mA h g−1 over 50 cycles, while the ALD TiO2-coated gains a final capacity of 323.7 mA h g−1 (47.7% higher). Electrochemical impedance analyses reveal that the improvement is ascribed to the smaller charge transfer resistance and formation of thinner solid–electrolyte interfaces (SEI) in the coated electrode, thanks to its better structural integrity and less electrolyte decomposition in the presence of protective coatings.

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