Highly-impermeable Al2O3/HfO2 moisture barrier films grown by low-temperature plasma-enhanced atomic layer deposition

Kim, Lae Ho; Jang, Jin; Jeong, Yong Jin; Kim, Kyunghun; Baek, Yonghwa; Kwon, Hyeok jin; An, Tae Kyu; Nam, Sooji; Kim, Se Hyun; Jang, Jaeyoung; Park, Jin Young

doi:10.1016/j.orgel.2017.07.051

Cited by 34 publications

(27 citation statements)

References 48 publications

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“…Amorphous HfO 2 shows relatively low WVTR, which makes it an excellent candidate as moisture barrier layers for VO 2 films. 41,42 Meanwhile, HfO 2 is a material with high melting point, high dielectric constant, and excellent mechanical properties. In this case, the suitable refractive index of the HfO 2 layer can meet the requirement for the antireflection effect of VO 2 thermochromic coatings (a comparison of different coating materials is summarized in Table S1).…”

Section: Structure Designmentioning

confidence: 99%

Mitigating Deterioration of Vanadium Dioxide Thermochromic Films by Interfacial Encapsulation

Chang

Cao

et al. 2019

Matter

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Long-term stability is a great challenge for commercializing VO 2 film, but corresponding research is lacking. This work demonstrated that the cross-section of VO 2 films is important to the corresponding deterioration process. An encapsulation structure is designed to protect VO 2 films from deterioration by utilizing stable and naturally hydrophobic HfO 2 layers. The proposed structure shows greatly extended service life, which could be equal to 16 years in the real environment. It provides a new strategy for stable VO 2 films in commercialization of applications.

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Section: Structure Designmentioning

confidence: 99%

Mitigating Deterioration of Vanadium Dioxide Thermochromic Films by Interfacial Encapsulation

Chang

Cao

et al. 2019

Matter

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“…The most extensive research is performed on Al 2 O 3 layers thanks to its low moisture permeability as well as its excellent thermal and mechanical properties [13,[22][23][24]. For example, single-layered 20 nm ALD Al 2 O 3 possesses superior WVTR in the order of 10 −3 g•m −2 •day −1 in a few days [25]. However, Al 2 O 3 easily dissolves through hydrolysis when directly exposed to aqueous solutions [17,[25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

“…For example, single-layered 20 nm ALD Al 2 O 3 possesses superior WVTR in the order of 10 −3 g•m −2 •day −1 in a few days [25]. However, Al 2 O 3 easily dissolves through hydrolysis when directly exposed to aqueous solutions [17,[25][26][27][28]. Researchers show that the Al 2 O 3 is a good moisture barrier for up to 24 h at room temperature, however this layer later deteriorates as it starts to dissolve in solutions [25,27].…”

Section: Introductionmentioning

confidence: 99%

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

Cauwe

Yang

et al. 2019

Coatings

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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.

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Section: Introductionmentioning

confidence: 99%

“…Although ALD Al 2 O 3 is a good barrier against water vapor, ions, and other gases, direct contact with aqueous solutions results in degradation due to hydrolysis [23][24][25]. To avoid the hydrolysis of Al 2 O 3 in aqueous solutions, capping the Al 2 O 3 layer with more chemically stable oxides, such as SiO 2 or HfO 2 , has been reported [24,26]. In 2017, we showed that capping an Al 2 O 3 layer with HfO 2 on both sides (ALD-3) and sandwiching it between two biphenyltetracarboxylic dianhydride and paraphenylenediamine (BPDA-PPD) polyimides (hereinafter referred to as PI) layers results in thin films with a very low WVTR at 100% relative humidity (RH) (decrease with a factor of 8000 compared to the bare PI layer) [4].…”

Section: Introductionmentioning

confidence: 99%

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

Cauwe

Mader

et al. 2019

Coatings

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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.

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Highly-impermeable Al2O3/HfO2 moisture barrier films grown by low-temperature plasma-enhanced atomic layer deposition

Cited by 34 publications

References 48 publications

Mitigating Deterioration of Vanadium Dioxide Thermochromic Films by Interfacial Encapsulation

Mitigating Deterioration of Vanadium Dioxide Thermochromic Films by Interfacial Encapsulation

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

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

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