Haiwen Li, Zhiwen He, Wei Wu, Long Zheng, Qingfang Xu, Tenghua Gao, Song Zhang, Honglian Dai, Takashi Goto, Rong Tu
Titanium alloy and stainless steel implants have been widely applied in orthopedics. However, harmful ions released from implant corrosion caused by human body fluids and bacterial infections may inhibit patients’ recovery. In this work, a polytetrafluoroethylene-silver composite coating was prepared by RF unbalanced magnetron sputtering to improve the bacterial and corrosion resistance of the SS316L. The removal rates of the composite coatings for Escherichia coli and Staphylococcus aureus reached 97.27% and 99.99%, respectively. The contact angle of 131.5° and fluorescence staining experiments show that the composite coating has an antiadhesive effect on bacteria and less cytotoxicity against osteoblasts. The corrosion voltage of the composite coating was much higher than that of the control SS316L substrate, and the corrosion current density was reduced to 1/3, implying the enhancement of the corrosion resistance of the SS316L substrate.
{"title":"Bacterial and corrosion resistance of polytetrafluoroethylene-silver composite coatings by magnetron sputtering","authors":"Haiwen Li, Zhiwen He, Wei Wu, Long Zheng, Qingfang Xu, Tenghua Gao, Song Zhang, Honglian Dai, Takashi Goto, Rong Tu","doi":"10.1116/6.0003545","DOIUrl":"https://doi.org/10.1116/6.0003545","url":null,"abstract":"Titanium alloy and stainless steel implants have been widely applied in orthopedics. However, harmful ions released from implant corrosion caused by human body fluids and bacterial infections may inhibit patients’ recovery. In this work, a polytetrafluoroethylene-silver composite coating was prepared by RF unbalanced magnetron sputtering to improve the bacterial and corrosion resistance of the SS316L. The removal rates of the composite coatings for Escherichia coli and Staphylococcus aureus reached 97.27% and 99.99%, respectively. The contact angle of 131.5° and fluorescence staining experiments show that the composite coating has an antiadhesive effect on bacteria and less cytotoxicity against osteoblasts. The corrosion voltage of the composite coating was much higher than that of the control SS316L substrate, and the corrosion current density was reduced to 1/3, implying the enhancement of the corrosion resistance of the SS316L substrate.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"65 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141383369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of spraying power on the microstructure and wear resistance of Ni-10 wt. %Al coating plasma sprayed with a 500 Hz sound vibration has been investigated. With the application of sound vibration, the compactness, cohesive bonding strength, and wear resistance of the coatings are all much higher. Meanwhile, with the increase of spraying power, the enhancement degree of the compactness, cohesive bonding strength, and wear resistance of the coatings are all increased. The sound vibration effects, which contain sound pressure, acoustic streaming, and heat effect, on the molten droplets are increased for their increasing melting induced by increasing spraying power. The wetting, flowing, and solidification of the molten droplets are all affected. Better wetting and flowing of the molten droplets promote their bonding on the surface of substrates and the solidified molten droplets, and their filling in the gaps of the solidified droplets.
{"title":"Influence of spraying power on microstructure and wear resistance of plasma spray Ni-10 wt. %Al coatings with a sound vibration","authors":"Jichun Wang, Haibo Wang, Xunxun Mu, Xixi Ma, Jiaming Qian, Pengfei Gao","doi":"10.1116/6.0003604","DOIUrl":"https://doi.org/10.1116/6.0003604","url":null,"abstract":"The effect of spraying power on the microstructure and wear resistance of Ni-10 wt. %Al coating plasma sprayed with a 500 Hz sound vibration has been investigated. With the application of sound vibration, the compactness, cohesive bonding strength, and wear resistance of the coatings are all much higher. Meanwhile, with the increase of spraying power, the enhancement degree of the compactness, cohesive bonding strength, and wear resistance of the coatings are all increased. The sound vibration effects, which contain sound pressure, acoustic streaming, and heat effect, on the molten droplets are increased for their increasing melting induced by increasing spraying power. The wetting, flowing, and solidification of the molten droplets are all affected. Better wetting and flowing of the molten droplets promote their bonding on the surface of substrates and the solidified molten droplets, and their filling in the gaps of the solidified droplets.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"57 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140965019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We are investigating a novel enrichment process that could allow the use of industrial complementary metal–oxide–semiconductor implanters to manufacture “quantum grade” 28Si layers for use in quantum computers. Our implanted layer exchange enrichment process leverages conventional deposition-based layer exchange approaches but replaces a step of depositing a Si layer above an Al layer with a 28Si implant into the top of an Al layer. A subsequent anneal dissolves Si into Al beneath the implanted region where Si diffuses and either epitaxially grows onto the substrate or forms poly-crystals in the Al [Schneider and England, ACS Appl. Mater. Interfaces 15, 21609 (2023)]. We have developed a qualitative model using simple assumptions and boundary conditions to estimate characteristic times and rates of epitaxy or poly-crystallization for this novel layer exchange process. We have used the model to explain crystallization outcomes reported in this paper and previously. We find that the absence of an oxide boundary layer separating Si and Al allows Si diffusion to become established within the first second of all the anneals studied and that crystallization actually completes during the temperature ramp of most of the anneals. The rapid evolution of Si supersaturation in Al beneath the implanted layer explains the ratios of epitaxial growth to poly-crystallization observed after these anneals. We use this understanding to propose the implant layer exchange conditions that could produce the highest quality mono-crystalline quantum grade Si.
{"title":"Crystallization kinetics during layer exchange of 28Si implanted Al films for fabrication of quantum computers: A theoretical model","authors":"Ella Schneider, Jonathan England","doi":"10.1116/6.0003638","DOIUrl":"https://doi.org/10.1116/6.0003638","url":null,"abstract":"We are investigating a novel enrichment process that could allow the use of industrial complementary metal–oxide–semiconductor implanters to manufacture “quantum grade” 28Si layers for use in quantum computers. Our implanted layer exchange enrichment process leverages conventional deposition-based layer exchange approaches but replaces a step of depositing a Si layer above an Al layer with a 28Si implant into the top of an Al layer. A subsequent anneal dissolves Si into Al beneath the implanted region where Si diffuses and either epitaxially grows onto the substrate or forms poly-crystals in the Al [Schneider and England, ACS Appl. Mater. Interfaces 15, 21609 (2023)]. We have developed a qualitative model using simple assumptions and boundary conditions to estimate characteristic times and rates of epitaxy or poly-crystallization for this novel layer exchange process. We have used the model to explain crystallization outcomes reported in this paper and previously. We find that the absence of an oxide boundary layer separating Si and Al allows Si diffusion to become established within the first second of all the anneals studied and that crystallization actually completes during the temperature ramp of most of the anneals. The rapid evolution of Si supersaturation in Al beneath the implanted layer explains the ratios of epitaxial growth to poly-crystallization observed after these anneals. We use this understanding to propose the implant layer exchange conditions that could produce the highest quality mono-crystalline quantum grade Si.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"53 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140965660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Liffredo, Nan Xu, Silvan Stettler, Federico Peretti, Luis Guillermo Villanueva
Sc-doped aluminum nitride (AlScN) allows for piezoelectric devices with large electromechanical coupling and the benefits increase with larger Sc doping in the film. However, with a larger Sc concentration, the process window narrows, and it is necessary to fine-tune the deposition parameters to achieve a good film. In this paper, we investigate depositions of highly doped AlScN (40% Sc) on unpatterned and patterned metal layers, to show how it is possible to maintain a good film quality on a metal electrode. We find how high-temperature deposition of the metal improves the AlScN film quality, how the gas mixture allows to reduce defects, and how film quality changes with thickness. We show that extreme care must be taken in the apparently trivial step of photoresist cleaning. Finally, we extract the mechanical, electrical, and piezoelectric properties of our optimized layer from a batch of fabricated resonators, obtaining a 5× improvement of piezoelectric coupling compared to undoped AlN and a 1.5× improvement from 32% doped AlScN.
{"title":"Piezoelectric and elastic properties of Al0.60Sc0.40N thin films deposited on patterned metal electrodes","authors":"M. Liffredo, Nan Xu, Silvan Stettler, Federico Peretti, Luis Guillermo Villanueva","doi":"10.1116/6.0003497","DOIUrl":"https://doi.org/10.1116/6.0003497","url":null,"abstract":"Sc-doped aluminum nitride (AlScN) allows for piezoelectric devices with large electromechanical coupling and the benefits increase with larger Sc doping in the film. However, with a larger Sc concentration, the process window narrows, and it is necessary to fine-tune the deposition parameters to achieve a good film. In this paper, we investigate depositions of highly doped AlScN (40% Sc) on unpatterned and patterned metal layers, to show how it is possible to maintain a good film quality on a metal electrode. We find how high-temperature deposition of the metal improves the AlScN film quality, how the gas mixture allows to reduce defects, and how film quality changes with thickness. We show that extreme care must be taken in the apparently trivial step of photoresist cleaning. Finally, we extract the mechanical, electrical, and piezoelectric properties of our optimized layer from a batch of fabricated resonators, obtaining a 5× improvement of piezoelectric coupling compared to undoped AlN and a 1.5× improvement from 32% doped AlScN.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"67 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140971700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aleksei Almaev, V. Nikolaev, Nikita Yakovlev, Pavel Butenko, Alexander Tsymbalov, Michael Boiko, Viktor Kopyev, Vladimir Krymov, Bogdan Kushnarev, Sevastian Shapenkov, Michael Sharkov, Anton Zarichny
Pt/(100) β-Ga2O3 Schottky barrier diodes were fabricated using a plate cleaved from the crystal grown by Czochralski method. Their electroconductive and photoelectric characteristics were studied. The following values were obtained: the Schottky barrier height (1.69/1.62/1.74 eV), ideality coefficient (1.09/1.14), saturation current density (9.91 × 10–15 A/cm2), diode series resistance (7.98 kΩ), and net donor concentration [(1.8–2.4) × 1018 cm–3]. The diodes demonstrate a high rectification ratio of 1010 at an applied voltage of ± 1 V and a relatively low experimental value of the leakage current density ∼10–11 A/cm2. These structures are solar-blind and also capable of operating in self-powered mode. The diodes are highly sensitive to short-wave ultraviolet radiation with a wavelength λ ≤ 265 nm. The maximum values of responsivity (20.4 A/W), external quantum efficiency (1.2 × 104%), and detectivity (9.6 × 1015 Hz0.5 × cm × W–1) of diodes were registered under exposure to irradiation at λ = 210 nm and at applied voltage of −1 V. The responsivity and external quantum efficiency values in the self-powered operation mode were 12.3 A/W and 7.2 × 103%, respectively. The diodes showed low rise and decay times in self-powered operation mode for photodiode based on Ga2O3: 14 and 30 ms, respectively.
{"title":"Electroconductive and photoelectric properties of Pt/(100) β-Ga2O3 Schottky barrier diode based on Czochralski grown crystal","authors":"Aleksei Almaev, V. Nikolaev, Nikita Yakovlev, Pavel Butenko, Alexander Tsymbalov, Michael Boiko, Viktor Kopyev, Vladimir Krymov, Bogdan Kushnarev, Sevastian Shapenkov, Michael Sharkov, Anton Zarichny","doi":"10.1116/6.0003618","DOIUrl":"https://doi.org/10.1116/6.0003618","url":null,"abstract":"Pt/(100) β-Ga2O3 Schottky barrier diodes were fabricated using a plate cleaved from the crystal grown by Czochralski method. Their electroconductive and photoelectric characteristics were studied. The following values were obtained: the Schottky barrier height (1.69/1.62/1.74 eV), ideality coefficient (1.09/1.14), saturation current density (9.91 × 10–15 A/cm2), diode series resistance (7.98 kΩ), and net donor concentration [(1.8–2.4) × 1018 cm–3]. The diodes demonstrate a high rectification ratio of 1010 at an applied voltage of ± 1 V and a relatively low experimental value of the leakage current density ∼10–11 A/cm2. These structures are solar-blind and also capable of operating in self-powered mode. The diodes are highly sensitive to short-wave ultraviolet radiation with a wavelength λ ≤ 265 nm. The maximum values of responsivity (20.4 A/W), external quantum efficiency (1.2 × 104%), and detectivity (9.6 × 1015 Hz0.5 × cm × W–1) of diodes were registered under exposure to irradiation at λ = 210 nm and at applied voltage of −1 V. The responsivity and external quantum efficiency values in the self-powered operation mode were 12.3 A/W and 7.2 × 103%, respectively. The diodes showed low rise and decay times in self-powered operation mode for photodiode based on Ga2O3: 14 and 30 ms, respectively.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"127 44","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140977481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shadhin Hussain, David J. Lary, K. Hara, K. Bera, Shahid Rauf, M. Goeckner
Modeling and forecasting the dynamics of complex systems, such as moderate pressure capacitively coupled plasma (CCP) systems, remains a challenge due to the interactions of physical and chemical processes across multiple scales. Historically, optimization for a given application would be accomplished via a design of experiment (DOE) study across the various external control parameters. Machine learning (ML) techniques show the potential to “forecast” process conditions not tested in a traditional DOE study and thereby allow better optimization and control of a plasma tool. In this article, we have used standard DOE as well as ML predictions to analyze I-V data in a moderate-pressure CCP system. We have demonstrated that supervised regression ML techniques can be a useful tool for extrapolating data even when a plasma system is undergoing a transition in the heating mode, in this case from the alpha to gamma mode. Classification analysis of control parameters is another possible application of ML techniques that can be deployed for system control. Here, we show that given a large set of measured data, the models can identify the gas ratio in the feed gas as well as correctly identify the operating pressure and electrode gap in almost all the cases.
由于物理和化学过程在多个尺度上的相互作用，对中压电容耦合等离子体 (CCP) 系统等复杂系统的动态进行建模和预测仍然是一项挑战。一直以来，针对特定应用的优化都是通过对各种外部控制参数进行实验设计 (DOE) 研究来实现的。机器学习 (ML) 技术显示出 "预测 "传统 DOE 研究中未测试的工艺条件的潜力，从而更好地优化和控制等离子体工具。在本文中，我们使用标准 DOE 和 ML 预测来分析中压 CCP 系统中的 I-V 数据。我们证明了监督回归 ML 技术是推断数据的有用工具，即使等离子系统正在经历加热模式的转变，在本例中是从阿尔法模式到伽马模式的转变。控制参数的分类分析是 ML 技术的另一个可能应用，可用于系统控制。在这里，我们展示了在给定大量测量数据的情况下，模型可以识别原料气体中的气体比例，并在几乎所有情况下正确识别工作压力和电极间隙。
{"title":"Case study in machine learning for predicting moderate pressure plasma behavior","authors":"Shadhin Hussain, David J. Lary, K. Hara, K. Bera, Shahid Rauf, M. Goeckner","doi":"10.1116/6.0003434","DOIUrl":"https://doi.org/10.1116/6.0003434","url":null,"abstract":"Modeling and forecasting the dynamics of complex systems, such as moderate pressure capacitively coupled plasma (CCP) systems, remains a challenge due to the interactions of physical and chemical processes across multiple scales. Historically, optimization for a given application would be accomplished via a design of experiment (DOE) study across the various external control parameters. Machine learning (ML) techniques show the potential to “forecast” process conditions not tested in a traditional DOE study and thereby allow better optimization and control of a plasma tool. In this article, we have used standard DOE as well as ML predictions to analyze I-V data in a moderate-pressure CCP system. We have demonstrated that supervised regression ML techniques can be a useful tool for extrapolating data even when a plasma system is undergoing a transition in the heating mode, in this case from the alpha to gamma mode. Classification analysis of control parameters is another possible application of ML techniques that can be deployed for system control. Here, we show that given a large set of measured data, the models can identify the gas ratio in the feed gas as well as correctly identify the operating pressure and electrode gap in almost all the cases.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"106 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140977883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nassima Jaghar, Mohamed Lahouij, H. Larhlimi, O. Abegunde, Y. Samih, M. Makha, J. Alami
During reactive sputtering of CrxNy, precise regulation of nitrogen gas is crucial to control the properties of the deposited coating. In the present work, we investigate the influence of nitrogen content on CrxNy characteristics, including morphology, crystalline structure, hardness, corrosion protection, and wear protection performances. Our findings reveal that the hexagonal Cr2N coatings, although slightly lower in hardness (19 GPa) compared to stoichiometric CrN, exhibit superior corrosion resistance with a protection efficiency of 82%, and a reduced sliding wear behavior at 1.35E-09 mm3/N/m. Conversely, stoichiometric CrN shows the highest hardness at 22.8 GPa. Using high-power impulsed magnetron sputtering as a deposition technique, we were able to design CrxNy protective coatings with desired microstructure and phase composition, enabling the production of performance-tailored CrxNy coatings suitable for a diverse range of applications.
{"title":"Tailoring structure, morphology, and tribo-mechanical properties of HiPIMS-deposited CrxNy coatings for enhanced performance in wear and corrosion protection","authors":"Nassima Jaghar, Mohamed Lahouij, H. Larhlimi, O. Abegunde, Y. Samih, M. Makha, J. Alami","doi":"10.1116/6.0003517","DOIUrl":"https://doi.org/10.1116/6.0003517","url":null,"abstract":"During reactive sputtering of CrxNy, precise regulation of nitrogen gas is crucial to control the properties of the deposited coating. In the present work, we investigate the influence of nitrogen content on CrxNy characteristics, including morphology, crystalline structure, hardness, corrosion protection, and wear protection performances. Our findings reveal that the hexagonal Cr2N coatings, although slightly lower in hardness (19 GPa) compared to stoichiometric CrN, exhibit superior corrosion resistance with a protection efficiency of 82%, and a reduced sliding wear behavior at 1.35E-09 mm3/N/m. Conversely, stoichiometric CrN shows the highest hardness at 22.8 GPa. Using high-power impulsed magnetron sputtering as a deposition technique, we were able to design CrxNy protective coatings with desired microstructure and phase composition, enabling the production of performance-tailored CrxNy coatings suitable for a diverse range of applications.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":" 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140993256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Diamondlike carbon (DLC) thin films have attracted growing interest due to their extraordinary properties, which occur if the fraction of sp3 C-bonds in the amorphous carbon films is high. This high fraction of sp3 C-bonds requires a high ionization rate of the sputtered carbon and a high kinetic energy of the carbon species. The first part of this article provides a detailed overview of the possibilities to increase the ionized fraction of the sputtered carbon and a brief description of the DLC growth models. The overview will include previously unpublished calculations by our group that include the ionization rate of carbon compared to some metals, the mean ionization path length of carbon, and the carbon ion flux at the substrate. In addition, the problem of simultaneous deposition of sp2- and sp3-bonded carbon during a HiPIMS pulse is explained for the first time. In the second part, we will present the influence of different carbon-based target materials on ionization, arcing, and deposition rates. Therefore, three different carbon-based target materials were investigated for high-power impulse magnetron sputtering (HiPIMS) depositions of a-C films: (a) graphite target, (b) fine-grained graphite target, and (c) glassy carbon target. The acquired data were compared to dc magnetron sputtering (dcMS). For HiPIMS, the pulse parameters and the total argon gas pressure were varied. The deposition process was characterized by the acquisition of the target currents and voltages, the arcing rate, optical emission spectroscopy (OES), and monitoring the deposition rate using a quartz crystal microbalance. The studies revealed that with HiPIMS, arcing was increased strongly with the peak current density for the graphite target. With the glassy carbon target, arcing was low at the beginning but increased with the duration of the tests. This target had a polished surface in the as-delivered state, which became rougher during sputtering. Similar deposition rates have been measured for dcMS and HiPIMS. With OES, only a low ionization of carbon was identified. The deposition of a-C coatings produced films with a low hardness of about 1200 HV (about 12 GPa) for both sputtering methods (dcMS and HiPIMS), as no substrate bias was applied. It can be concluded that arcing was lowest with the glassy carbon target and that the ionization rate was not significantly influenced by the change in the target material.
{"title":"Investigating different carbon-based target materials: Can we improve ionization in HiPIMS for the deposition of diamondlike carbon films?","authors":"M. Fenker, Martin Balzer, Holger Kaßner","doi":"10.1116/6.0003333","DOIUrl":"https://doi.org/10.1116/6.0003333","url":null,"abstract":"Diamondlike carbon (DLC) thin films have attracted growing interest due to their extraordinary properties, which occur if the fraction of sp3 C-bonds in the amorphous carbon films is high. This high fraction of sp3 C-bonds requires a high ionization rate of the sputtered carbon and a high kinetic energy of the carbon species. The first part of this article provides a detailed overview of the possibilities to increase the ionized fraction of the sputtered carbon and a brief description of the DLC growth models. The overview will include previously unpublished calculations by our group that include the ionization rate of carbon compared to some metals, the mean ionization path length of carbon, and the carbon ion flux at the substrate. In addition, the problem of simultaneous deposition of sp2- and sp3-bonded carbon during a HiPIMS pulse is explained for the first time. In the second part, we will present the influence of different carbon-based target materials on ionization, arcing, and deposition rates. Therefore, three different carbon-based target materials were investigated for high-power impulse magnetron sputtering (HiPIMS) depositions of a-C films: (a) graphite target, (b) fine-grained graphite target, and (c) glassy carbon target. The acquired data were compared to dc magnetron sputtering (dcMS). For HiPIMS, the pulse parameters and the total argon gas pressure were varied. The deposition process was characterized by the acquisition of the target currents and voltages, the arcing rate, optical emission spectroscopy (OES), and monitoring the deposition rate using a quartz crystal microbalance. The studies revealed that with HiPIMS, arcing was increased strongly with the peak current density for the graphite target. With the glassy carbon target, arcing was low at the beginning but increased with the duration of the tests. This target had a polished surface in the as-delivered state, which became rougher during sputtering. Similar deposition rates have been measured for dcMS and HiPIMS. With OES, only a low ionization of carbon was identified. The deposition of a-C coatings produced films with a low hardness of about 1200 HV (about 12 GPa) for both sputtering methods (dcMS and HiPIMS), as no substrate bias was applied. It can be concluded that arcing was lowest with the glassy carbon target and that the ionization rate was not significantly influenced by the change in the target material.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"44 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141010382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Edward A. Supple, Christopher J. K. Richardson, Brian P. Gorman
Nanometer-scale crystallographic structure and orientation of a NbTiN/AlN/NbTiN device stack grown via plasma-assisted molecular beam epitaxy on c-plane sapphire are reported. Structure, orientation, interface roughness, and thickness are investigated using correlative four-dimensional scanning transmission electron microscopy and atom probe tomography (APT). This work finds NbTiN that is rock salt structured and highly oriented toward ⟨111⟩ with rotations about that axis corresponding to step edges in the c-plane sapphire with a myriad of twin boundaries that exhibit nanoscale spacing. The wurtzite (0001) AlN film grown on (111) NbTiN exhibits nm-scale changes in the thickness resulting in pinhole shorts across the barrier junction. The NbTiN overlayer grown on AlN is polycrystalline, randomly oriented, and highly strained. APT was also used to determine local changes in chemistry within the superconductor and dielectric. Deviation from both intended cation:cation and cation:anion ratios are observed. The results from conventional and nanoscale metrology highlight the challenges of engineering nitride trilayer heterostructures in material systems with complicated and understudied phase space.
报告了在 c 平面蓝宝石上通过等离子体辅助分子束外延生长的 NbTiN/AlN/NbTiN 器件堆栈的纳米级晶体结构和取向。利用相关的四维扫描透射电子显微镜和原子探针断层扫描（APT）对结构、取向、界面粗糙度和厚度进行了研究。这项研究发现，铌钛氮具有岩盐结构，并高度定向于⟨111⟩，围绕该轴的旋转与 c 平面蓝宝石中的阶梯边缘相对应，其孪晶边界具有无数的纳米级间距。在(111) NbTiN 上生长的(0001) 晶格氮化铝薄膜在厚度上呈现出纳米级的变化，从而在势垒结上形成针孔短路。生长在氮化铌上的氮化钛覆盖层是多晶、随机取向和高度应变的。APT 还用于确定超导体和电介质内部的局部化学变化。观察到阳离子：阳离子和阳离子：阴离子的比例均偏离预期。来自传统和纳米尺度计量学的结果凸显了在具有复杂和未充分研究的相空间的材料系统中设计氮化物三层异质结构所面临的挑战。
{"title":"Atomic structure of a NbTiN/AlN/NbTiN Josephson junction grown by molecular-beam epitaxy","authors":"Edward A. Supple, Christopher J. K. Richardson, Brian P. Gorman","doi":"10.1116/6.0003518","DOIUrl":"https://doi.org/10.1116/6.0003518","url":null,"abstract":"Nanometer-scale crystallographic structure and orientation of a NbTiN/AlN/NbTiN device stack grown via plasma-assisted molecular beam epitaxy on c-plane sapphire are reported. Structure, orientation, interface roughness, and thickness are investigated using correlative four-dimensional scanning transmission electron microscopy and atom probe tomography (APT). This work finds NbTiN that is rock salt structured and highly oriented toward ⟨111⟩ with rotations about that axis corresponding to step edges in the c-plane sapphire with a myriad of twin boundaries that exhibit nanoscale spacing. The wurtzite (0001) AlN film grown on (111) NbTiN exhibits nm-scale changes in the thickness resulting in pinhole shorts across the barrier junction. The NbTiN overlayer grown on AlN is polycrystalline, randomly oriented, and highly strained. APT was also used to determine local changes in chemistry within the superconductor and dielectric. Deviation from both intended cation:cation and cation:anion ratios are observed. The results from conventional and nanoscale metrology highlight the challenges of engineering nitride trilayer heterostructures in material systems with complicated and understudied phase space.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"73 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141008513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subhashis Das, Nirosh M. Eldose, H. Stanchu, Fernando Maia de Oliveira, M. Benamara, Yuriy I. Mazur, Zhong Chen, Alan Mantooth, Gregory J. Salamo
SiC is an indirect bandgap semiconductor with material properties ideal for power electronics but not so much as an optical emitter. Meanwhile, gallium arsenide (GaAs) is a material known for high-performance optical devices due to its direct bandgap and carrier lifetime. Integrating GaAs with silicon carbide (SiC) can result in the best of both materials. However, integrating the two presents a significant challenge due to the large lattice mismatch between the two materials. In this paper, we investigate the growth of high-quality GaAs directly on 4H-SiC and on AlAs/4H-SiC substrates. The thin films were characterized using key techniques for structural and optical analyses, such as x-ray diffraction, atomic force microscopy, and photoluminescence (PL) spectroscopy. The 3D-island nature of growth of GaAs directly on SiC results in weak in-plane correlation with the substrate but high photoluminescence. This was demonstrated with an observed PL intensity comparable to the PL observed from a GaAs substrate with a similar buffer layer. Introduction of a thin AlAs nucleation layer results in improved wetting of the substrate, better in-plane correlation with substrate, and overall improved crystalline quality and is now under further study.
碳化硅（SiC）是一种间接带隙半导体，其材料特性非常适合用于电力电子设备，但不太适合用作光学发射器。与此同时，砷化镓（GaAs）因其直接带隙和载流子寿命而成为高性能光学设备的理想材料。将砷化镓与碳化硅（SiC）集成在一起，可以获得两种材料的最佳效果。然而，由于这两种材料之间存在较大的晶格不匹配，因此将二者整合在一起是一项巨大的挑战。在本文中，我们研究了在 4H-SiC 和 AlAs/4H-SiC 衬底上直接生长高质量砷化镓的情况。我们使用 X 射线衍射、原子力显微镜和光致发光 (PL) 光谱等结构和光学分析的关键技术对薄膜进行了表征。砷化镓直接在碳化硅上生长的三维孤岛性质导致其与基底的面内相关性很弱，但光致发光却很高。观察到的 PL 强度与具有类似缓冲层的砷化镓基底观察到的 PL 强度相当，证明了这一点。引入薄薄的 AlAs 成核层可改善基底的润湿性，提高与基底的面内相关性，并全面提高结晶质量，目前正在进一步研究中。
{"title":"Epitaxial growth and characterization of GaAs (111) on 4H-SiC","authors":"Subhashis Das, Nirosh M. Eldose, H. Stanchu, Fernando Maia de Oliveira, M. Benamara, Yuriy I. Mazur, Zhong Chen, Alan Mantooth, Gregory J. Salamo","doi":"10.1116/6.0003454","DOIUrl":"https://doi.org/10.1116/6.0003454","url":null,"abstract":"SiC is an indirect bandgap semiconductor with material properties ideal for power electronics but not so much as an optical emitter. Meanwhile, gallium arsenide (GaAs) is a material known for high-performance optical devices due to its direct bandgap and carrier lifetime. Integrating GaAs with silicon carbide (SiC) can result in the best of both materials. However, integrating the two presents a significant challenge due to the large lattice mismatch between the two materials. In this paper, we investigate the growth of high-quality GaAs directly on 4H-SiC and on AlAs/4H-SiC substrates. The thin films were characterized using key techniques for structural and optical analyses, such as x-ray diffraction, atomic force microscopy, and photoluminescence (PL) spectroscopy. The 3D-island nature of growth of GaAs directly on SiC results in weak in-plane correlation with the substrate but high photoluminescence. This was demonstrated with an observed PL intensity comparable to the PL observed from a GaAs substrate with a similar buffer layer. Introduction of a thin AlAs nucleation layer results in improved wetting of the substrate, better in-plane correlation with substrate, and overall improved crystalline quality and is now under further study.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"6 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141006188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：