Yu Zheng, Peng Xu, Long Li, Qibin Liu, Shanzhu Guo
β-type TiNb biomedical alloys have received quite significant attention rooted in their excellent comprehensive performance. Nevertheless, their practical application is hampered by relatively poor performance and biological toxicity. Herein, TixNb alloy coatings were fabricated on the surface of Ti6Al4V (TC4) by laser cladding to evade the property-toxicity trade-off. Biocompatibility and mechanical properties, as well as the corrosion resistance of the TixNb alloy coatings, were discussed. The results show that the microstructure is composed of β grains and a small amount of the α″ martensite phase uniformly precipitated around them. The rapid melting process of laser cladding promotes the formation of the β phase, which improves the microhardness and wear resistance of the coating. However, the corrosion resistance was significantly improved due to the formation of the densification and stabilization of the passive films formed on the coating’s surface. Benefiting from the superior wettability and the biologically active sites of Ti and Nb on the alloy surface, MG-63 cells adhered to the coating’s surfaces in spindle shape and proliferated rapidly in cell experiments, denoting that the coatings have better biocompatibility than TC4. Hereby, the obtained TixNb laser cladding coatings with excellent mechanical properties and biocompatibility have extensive application prospects in the field of orthopedic biomaterials.
{"title":"Enhancing biocompatibility, mechanical properties, and corrosion resistance of laser cladding β-TiNb coatings","authors":"Yu Zheng, Peng Xu, Long Li, Qibin Liu, Shanzhu Guo","doi":"10.1116/6.0002885","DOIUrl":"https://doi.org/10.1116/6.0002885","url":null,"abstract":"β-type TiNb biomedical alloys have received quite significant attention rooted in their excellent comprehensive performance. Nevertheless, their practical application is hampered by relatively poor performance and biological toxicity. Herein, TixNb alloy coatings were fabricated on the surface of Ti6Al4V (TC4) by laser cladding to evade the property-toxicity trade-off. Biocompatibility and mechanical properties, as well as the corrosion resistance of the TixNb alloy coatings, were discussed. The results show that the microstructure is composed of β grains and a small amount of the α″ martensite phase uniformly precipitated around them. The rapid melting process of laser cladding promotes the formation of the β phase, which improves the microhardness and wear resistance of the coating. However, the corrosion resistance was significantly improved due to the formation of the densification and stabilization of the passive films formed on the coating’s surface. Benefiting from the superior wettability and the biologically active sites of Ti and Nb on the alloy surface, MG-63 cells adhered to the coating’s surfaces in spindle shape and proliferated rapidly in cell experiments, denoting that the coatings have better biocompatibility than TC4. Hereby, the obtained TixNb laser cladding coatings with excellent mechanical properties and biocompatibility have extensive application prospects in the field of orthopedic biomaterials.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135396696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The performance of current nuclear medicine imaging systems is largely limited by the performance of detectors, and high spatial resolution detectors require high optical yield scintillator arrays. In this work, we simulated and designed for the first time a distributed Bragg reflector (multilayer dielectric film) that covers the entire lutetium yttrium oxyorthosilicate emission spectral band and consists of three 1/4 wavelength (λ/4) primary film systems centered at 420, 500, and 575 nm. In order to achieve ultrahigh reflectivity at the full incidence angle of the scintillator emitting surface, we propose a master optical configuration combining the dielectric film with a metal film/diffuse reflection adhesive. To explain this mechanism, we also simulated the change in reflectivity of the actual inner surface light collection. Experimental results show that a combination of a highly reflective reflector can achieve full-angle high reflectance at the total angle of incidence. We find that the dielectric film does not change the total reflection structure inside the crystal, while the light-blocking layer changes and increases the angular reflection of the dielectric film about the angle. These findings provide important insights into surface treatment as well as the design of scintillation crystal arrays, with far-reaching implications for high spatial resolution optical imaging systems.
{"title":"Full-angle high-reflection ultrathin composite film realizing high spatial resolution of scintillation crystal array","authors":"Jing Yang, Linwei Wang, Zhang Chen, Zhongjun Xue, Shuwen Zhao, Dongzhou Ding","doi":"10.1116/6.0002875","DOIUrl":"https://doi.org/10.1116/6.0002875","url":null,"abstract":"The performance of current nuclear medicine imaging systems is largely limited by the performance of detectors, and high spatial resolution detectors require high optical yield scintillator arrays. In this work, we simulated and designed for the first time a distributed Bragg reflector (multilayer dielectric film) that covers the entire lutetium yttrium oxyorthosilicate emission spectral band and consists of three 1/4 wavelength (λ/4) primary film systems centered at 420, 500, and 575 nm. In order to achieve ultrahigh reflectivity at the full incidence angle of the scintillator emitting surface, we propose a master optical configuration combining the dielectric film with a metal film/diffuse reflection adhesive. To explain this mechanism, we also simulated the change in reflectivity of the actual inner surface light collection. Experimental results show that a combination of a highly reflective reflector can achieve full-angle high reflectance at the total angle of incidence. We find that the dielectric film does not change the total reflection structure inside the crystal, while the light-blocking layer changes and increases the angular reflection of the dielectric film about the angle. These findings provide important insights into surface treatment as well as the design of scintillation crystal arrays, with far-reaching implications for high spatial resolution optical imaging systems.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135741606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molybdenum carbide (MoC) and molybdenum carbonitride (MoCN) films were successfully deposited by plasma-enhanced atomic layer deposition (PEALD) using bis(isopropylcyclopentadienyl)molybdenum(IV) dihydride [(iPrCp)2MoH2] as the Mo precursor at temperatures of 200−400 °C. To obtain the MoC and MoCN films, 4%H2/96%Ar (H2/Ar) and 4%H2/96%N2 (H2/N2) plasmas were selectively used as co-reactants, respectively. PEALD MoC and MoCN exhibited atomic layer deposition temperature windows of 200−400 and 250−300 °C with growth per cycle of 0.012 and 0.047 nm/cycle, respectively. X-ray photoelectron spectroscopy revealed that the 300 °C-grown MoC film prepared using an H2/Ar plasma contained Mo–C bonds and an atomic composition of MoC0.77. In contrast, the 300 °C-grown MoCN film prepared using an H2/N2 plasma exhibited Mo–C and Mo–N bonds, with an atomic composition of MoC0.31N0.23. The atomic composition of the PEALD MoCN films varied depending on the deposition temperature; at 200 °C, the carbon-rich MoC0.52N0.16 film was obtained, whereas the MoC0.23N0.23 film with a carbon-to-nitrogen ratio of 1 was grown at a higher temperature of 400 °C. The 300 °C-grown MoC film was crystallized into a cubic δ-MoC phase, whereas the PEALD MoCN film showed diffraction peaks corresponding to the hexagonal MoC and molybdenum nitride (MoN) structures. The as-deposited PEALD MoC and MoCN films at 300 °C exhibited resistivities of 600 and 3038 μΩ cm, respectively, and post-deposition annealing at 700−800 °C resulted in significantly low resistivities of 37−203 μΩ cm due to the formation of metallic Mo films.
{"title":"Plasma-enhanced atomic layer deposition of molybdenum carbide and carbonitride films using bis(isopropylcyclopentadienyl)molybdenum(IV) dihydride and an H2/N2/Ar plasma","authors":"Wangu Kang, Ji Sang Ahn, Jeong Hwan Han","doi":"10.1116/6.0002970","DOIUrl":"https://doi.org/10.1116/6.0002970","url":null,"abstract":"Molybdenum carbide (MoC) and molybdenum carbonitride (MoCN) films were successfully deposited by plasma-enhanced atomic layer deposition (PEALD) using bis(isopropylcyclopentadienyl)molybdenum(IV) dihydride [(iPrCp)2MoH2] as the Mo precursor at temperatures of 200−400 °C. To obtain the MoC and MoCN films, 4%H2/96%Ar (H2/Ar) and 4%H2/96%N2 (H2/N2) plasmas were selectively used as co-reactants, respectively. PEALD MoC and MoCN exhibited atomic layer deposition temperature windows of 200−400 and 250−300 °C with growth per cycle of 0.012 and 0.047 nm/cycle, respectively. X-ray photoelectron spectroscopy revealed that the 300 °C-grown MoC film prepared using an H2/Ar plasma contained Mo–C bonds and an atomic composition of MoC0.77. In contrast, the 300 °C-grown MoCN film prepared using an H2/N2 plasma exhibited Mo–C and Mo–N bonds, with an atomic composition of MoC0.31N0.23. The atomic composition of the PEALD MoCN films varied depending on the deposition temperature; at 200 °C, the carbon-rich MoC0.52N0.16 film was obtained, whereas the MoC0.23N0.23 film with a carbon-to-nitrogen ratio of 1 was grown at a higher temperature of 400 °C. The 300 °C-grown MoC film was crystallized into a cubic δ-MoC phase, whereas the PEALD MoCN film showed diffraction peaks corresponding to the hexagonal MoC and molybdenum nitride (MoN) structures. The as-deposited PEALD MoC and MoCN films at 300 °C exhibited resistivities of 600 and 3038 μΩ cm, respectively, and post-deposition annealing at 700−800 °C resulted in significantly low resistivities of 37−203 μΩ cm due to the formation of metallic Mo films.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135826267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michael E. Liao, Kenny Huynh, Zhe Cheng, Jingjing Shi, Samuel Graham, Mark S. Goorsky
The impact of postbond annealing on the structural and thermal characteristics of 130 nm thick exfoliated (201) β-Ga2O3 (via H+ ion implantation) wafer bonded to (0001) 4H-SiC was studied. Thirty nanometer amorphous-Al2O3 was grown on the β-Ga2O3 substrates prior to bonding as an interlayer between β-Ga2O3 and 4H-SiC. The surface activated bonding technique was utilized for bonding, which induces a thin nanometer amorphous interfacial region at the bonded interface (Al2O3|4H-SiC). We demonstrate annealing the bonded structure at 800 °C up to 1 h is beneficial: (1) the removal of residual strain in the exfoliated β-Ga2O3 layer that was due to the exfoliation implant, (2) reduction of lattice mosaicity in the β-Ga2O3 layer, (3) nearly complete recrystallization of the amorphous bonded interfacial region, and (4) partial recrystallization of the initially amorphous-Al2O3 interlayer. The thermal characteristics correspondingly improve with the improvement in structural characteristics. The thermal conductivity of the as-bonded β-Ga2O3 layer was 2.9 W/m K, and the thermal boundary conductance of the bonded interface was 66 MW/m2 K. After annealing at 800 °C for 1 h, triple-axis x-ray diffraction ω:2θ measurements showed a reduction in strain for the β-Ga2O3 layer and the symmetric (201) rocking curve widths. We simultaneously observe a doubling of the β-Ga2O3 thermal conductivity to 6.0 W/m K and a 20% increase in the thermal boundary conductance. However, upon further annealing up to 10 h and fully recrystallizing both the Al2O3 interlayer and bonded interface, the thermal boundary conductance dropped by ∼30%. This preliminary result suggests that crystalline heterointerfaces may not necessarily be the most optimal interfacial structure for thermal transport.
{"title":"Thermal transport and structural improvements due to annealing of wafer bonded β-Ga2O3|4H-SiC","authors":"Michael E. Liao, Kenny Huynh, Zhe Cheng, Jingjing Shi, Samuel Graham, Mark S. Goorsky","doi":"10.1116/6.0002693","DOIUrl":"https://doi.org/10.1116/6.0002693","url":null,"abstract":"The impact of postbond annealing on the structural and thermal characteristics of 130 nm thick exfoliated (201) β-Ga2O3 (via H+ ion implantation) wafer bonded to (0001) 4H-SiC was studied. Thirty nanometer amorphous-Al2O3 was grown on the β-Ga2O3 substrates prior to bonding as an interlayer between β-Ga2O3 and 4H-SiC. The surface activated bonding technique was utilized for bonding, which induces a thin nanometer amorphous interfacial region at the bonded interface (Al2O3|4H-SiC). We demonstrate annealing the bonded structure at 800 °C up to 1 h is beneficial: (1) the removal of residual strain in the exfoliated β-Ga2O3 layer that was due to the exfoliation implant, (2) reduction of lattice mosaicity in the β-Ga2O3 layer, (3) nearly complete recrystallization of the amorphous bonded interfacial region, and (4) partial recrystallization of the initially amorphous-Al2O3 interlayer. The thermal characteristics correspondingly improve with the improvement in structural characteristics. The thermal conductivity of the as-bonded β-Ga2O3 layer was 2.9 W/m K, and the thermal boundary conductance of the bonded interface was 66 MW/m2 K. After annealing at 800 °C for 1 h, triple-axis x-ray diffraction ω:2θ measurements showed a reduction in strain for the β-Ga2O3 layer and the symmetric (201) rocking curve widths. We simultaneously observe a doubling of the β-Ga2O3 thermal conductivity to 6.0 W/m K and a 20% increase in the thermal boundary conductance. However, upon further annealing up to 10 h and fully recrystallizing both the Al2O3 interlayer and bonded interface, the thermal boundary conductance dropped by ∼30%. This preliminary result suggests that crystalline heterointerfaces may not necessarily be the most optimal interfacial structure for thermal transport.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135826266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-01Epub Date: 2023-07-18DOI: 10.1116/6.0002803
Ashley N Keobounnam, Chase Lenert-Mondou, Alexzandria Kubik, Morgan J Hawker
Silk fibroin is a naturally derived polymer with great potential for biomedical use due to its strength, lack of immune response, and ability to biodegrade. The relatively hydrophobic nature of silk, however, can cause challenges with cell adhesion in vivo. Therefore, modification must be performed to improve the surface hydrophilicity, enhancing silk utility in the biomedical space. Low-temperature plasma (LTP) treatment is an established method for polymer modification and has the benefits of being a solvent-free, adaptable process. N2 and H2O(g) LTP treatments are both well-documented as strategies to enhance polar functional groups on a polymer's surface. However, many polymers tend to revert to their original hydrophobic state upon aging, reversing the effects of LTP modification. The hydrophobic recovery of N2 and H2O(g) LTP-modified silk has not been previously studied but has important implications for the uses and longevity of silk substrates in biomedical contexts. The goal of this study was to systematically evaluate the hydrophobic recovery of N2 and H2O(g) LTP-treated silk films. Films were LTP-modified using optimized plasma parameters (applied power, pressure, treatment time) and aged under both ambient and elevated temperature conditions up to 6 weeks after the initial treatment. Silk film surface properties were evaluated immediately after treatment and throughout the aging process using both water contact angle goniometry and x-ray photoelectron spectroscopy. LTP-treated silk films demonstrated a significant decrease in hydrophobicity compared to the untreated controls. Remarkably, both N2 and H2O(g) LTP modifications resulted in surfaces that retained hydrophilic properties over the 6 week aging period. Our findings represent a departure from what has been previously demonstrated in most LTP-modified synthetic polymers, suggesting that the secondary structure of silk fibroin plays a critical role in resisting hydrophobic recovery.
{"title":"Evaluating hydrophobic recovery of N<sub>2</sub> and H<sub>2</sub>O(g) plasma modified silk fibroin films aged at ambient and elevated temperatures.","authors":"Ashley N Keobounnam, Chase Lenert-Mondou, Alexzandria Kubik, Morgan J Hawker","doi":"10.1116/6.0002803","DOIUrl":"10.1116/6.0002803","url":null,"abstract":"<p><p>Silk fibroin is a naturally derived polymer with great potential for biomedical use due to its strength, lack of immune response, and ability to biodegrade. The relatively hydrophobic nature of silk, however, can cause challenges with cell adhesion <i>in vivo</i>. Therefore, modification must be performed to improve the surface hydrophilicity, enhancing silk utility in the biomedical space. Low-temperature plasma (LTP) treatment is an established method for polymer modification and has the benefits of being a solvent-free, adaptable process. N<sub>2</sub> and H<sub>2</sub>O(g) LTP treatments are both well-documented as strategies to enhance polar functional groups on a polymer's surface. However, many polymers tend to revert to their original hydrophobic state upon aging, reversing the effects of LTP modification. The hydrophobic recovery of N<sub>2</sub> and H<sub>2</sub>O(g) LTP-modified silk has not been previously studied but has important implications for the uses and longevity of silk substrates in biomedical contexts. The goal of this study was to systematically evaluate the hydrophobic recovery of N<sub>2</sub> and H<sub>2</sub>O(g) LTP-treated silk films. Films were LTP-modified using optimized plasma parameters (applied power, pressure, treatment time) and aged under both ambient and elevated temperature conditions up to 6 weeks after the initial treatment. Silk film surface properties were evaluated immediately after treatment and throughout the aging process using both water contact angle goniometry and x-ray photoelectron spectroscopy. LTP-treated silk films demonstrated a significant decrease in hydrophobicity compared to the untreated controls. Remarkably, both N<sub>2</sub> and H<sub>2</sub>O(g) LTP modifications resulted in surfaces that retained hydrophilic properties over the 6 week aging period. Our findings represent a departure from what has been previously demonstrated in most LTP-modified synthetic polymers, suggesting that the secondary structure of silk fibroin plays a critical role in resisting hydrophobic recovery.</p>","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"41 5","pages":"050401"},"PeriodicalIF":2.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10356174/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9940426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polycrystalline hexagonal GaN films were deposited directly on amorphous quartz (fused glass) substrates at 250 °C by plasma-enhanced atomic layer deposition. An atomically sharp GaN/quartz interface is observed from transmission electron microscopy images, which is further demonstrated by x-ray reflectivity measurements. The atomic force microscopy image reveals a smooth surface of GaN. The concentrations of oxygen and carbon impurities in GaN are 6.3 and 0.64%, respectively, according to x-ray photoelectron spectroscopy analysis. The electron mobility measured by Hall is 1.33 cm2 V−1 s−1. The results show that high-quality GaN films are obtained on amorphous quartz substrates, and GaN/quartz can be used as a template for the fabrication of GaN-based devices.
{"title":"Plasma-enhanced atomic layer deposition of crystalline GaN thin films on quartz substrates with sharp interfaces","authors":"Sanjie Liu, Yangfeng Li, Qing Liu, Jiayou Tao, Xinhe Zheng","doi":"10.1116/6.0002639","DOIUrl":"https://doi.org/10.1116/6.0002639","url":null,"abstract":"Polycrystalline hexagonal GaN films were deposited directly on amorphous quartz (fused glass) substrates at 250 °C by plasma-enhanced atomic layer deposition. An atomically sharp GaN/quartz interface is observed from transmission electron microscopy images, which is further demonstrated by x-ray reflectivity measurements. The atomic force microscopy image reveals a smooth surface of GaN. The concentrations of oxygen and carbon impurities in GaN are 6.3 and 0.64%, respectively, according to x-ray photoelectron spectroscopy analysis. The electron mobility measured by Hall is 1.33 cm2 V−1 s−1. The results show that high-quality GaN films are obtained on amorphous quartz substrates, and GaN/quartz can be used as a template for the fabrication of GaN-based devices.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135891102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuo Huang, Prem Panneerchelvam, Chad M. Huard, Shyam Sridhar, Peter L. G. Ventzek, Mark D. Smith
The critical dimensions of advanced semiconductor manufacturing processes have decreased to a few tens of nanometers while the aspect ratios have increased beyond 100. The performance of plasma etch patterning processes as well as the cost and time of the development cycle are critical to the success of ramping a new technology node toward profitable high-volume manufacturing. In this paper, a computational patterning software, ProETCH®, has been developed with rigorous physics and advanced algorithms for modeling the etch patterning process, with the featured capabilities in calibrating the reaction mechanisms and optimizing the etch process. A shallow trench isolation etch process using self-aligned double patterning was investigated. A reaction mechanism of silicon etch by Ar/Cl2 plasma was developed to address the surface reactions, and a plasma hypermodel was introduced to correlate process operating conditions to plasma parameters at the wafer surface. The parameters of the reaction mechanism and the plasma hypermodel were calibrated with experimental data obtained from cross-sectional scanning electron microscope (XSEM) images. The calibrated model is used to identify the different fundamental pathways that contribute to the observed profile metrics in XSEMs. The model was then used for process development and optimization by solving the forward and inverse problems. In the forward problem, the model is used to predict the etching profile at different process conditions. Predictions for both interpolation conditions (process parameters within the range used for developing the model) and extrapolation conditions (process parameters outside of the range used for developing the model) agree well with the experimental data with the root mean square error less than 4 nm (1 nm resolution used for the mesh). In the inverse problem, the developed model is used to search for process conditions (e.g., values of bias power and pressure), which could result in desirable profiles. The solutions to the inverse problem demonstrate a degeneracy in process space of the etching process for a given target profile.
{"title":"Process optimization for shallow trench isolation etch using computational models","authors":"Shuo Huang, Prem Panneerchelvam, Chad M. Huard, Shyam Sridhar, Peter L. G. Ventzek, Mark D. Smith","doi":"10.1116/6.0002838","DOIUrl":"https://doi.org/10.1116/6.0002838","url":null,"abstract":"The critical dimensions of advanced semiconductor manufacturing processes have decreased to a few tens of nanometers while the aspect ratios have increased beyond 100. The performance of plasma etch patterning processes as well as the cost and time of the development cycle are critical to the success of ramping a new technology node toward profitable high-volume manufacturing. In this paper, a computational patterning software, ProETCH®, has been developed with rigorous physics and advanced algorithms for modeling the etch patterning process, with the featured capabilities in calibrating the reaction mechanisms and optimizing the etch process. A shallow trench isolation etch process using self-aligned double patterning was investigated. A reaction mechanism of silicon etch by Ar/Cl2 plasma was developed to address the surface reactions, and a plasma hypermodel was introduced to correlate process operating conditions to plasma parameters at the wafer surface. The parameters of the reaction mechanism and the plasma hypermodel were calibrated with experimental data obtained from cross-sectional scanning electron microscope (XSEM) images. The calibrated model is used to identify the different fundamental pathways that contribute to the observed profile metrics in XSEMs. The model was then used for process development and optimization by solving the forward and inverse problems. In the forward problem, the model is used to predict the etching profile at different process conditions. Predictions for both interpolation conditions (process parameters within the range used for developing the model) and extrapolation conditions (process parameters outside of the range used for developing the model) agree well with the experimental data with the root mean square error less than 4 nm (1 nm resolution used for the mesh). In the inverse problem, the developed model is used to search for process conditions (e.g., values of bias power and pressure), which could result in desirable profiles. The solutions to the inverse problem demonstrate a degeneracy in process space of the etching process for a given target profile.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"261 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136143955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grzegorz Sadowski, Rui Shu, Arnaud le Febvrier, Zhijia Han, Denis Music, Weishu Liu, Per Eklund
Mg3Bi2-based compounds are of great interest for thermoelectric applications near room temperature. Here, undoped p-type Mg3SbxBi2−x thin films were synthesized using magnetron sputtering (three elemental targets in Ar atmosphere) with a growth temperature of 200 °C on three different substrates, namely, Si as well as c- and r-sapphire. The elemental composition was measured with energy-dispersive x-ray spectroscopy and the structure by x-ray diffraction. The electrical resistivity and the Seebeck coefficient were determined under He atmosphere from room temperature to the growth temperature. All samples are crystalline exhibiting the La2O3-type crystal structure (space group P-3m1). The observed thermoelectric response is consistent with a semiconductive behavior. With increasing x, the samples become more electrically resistive due to the increasing bandgap. High Bi content (x < 1) is thus beneficial due to lower resistivity and a higher power factor near room temperature. Thermoelectric thin films synthesized at low temperatures may provide novel pathways to enable flexible devices on polymeric and other heat-sensitive substrates.
{"title":"Structural evolution and thermoelectric properties of Mg3SbxBi2<i>−</i>x thin films deposited by magnetron sputtering","authors":"Grzegorz Sadowski, Rui Shu, Arnaud le Febvrier, Zhijia Han, Denis Music, Weishu Liu, Per Eklund","doi":"10.1116/6.0002635","DOIUrl":"https://doi.org/10.1116/6.0002635","url":null,"abstract":"Mg3Bi2-based compounds are of great interest for thermoelectric applications near room temperature. Here, undoped p-type Mg3SbxBi2−x thin films were synthesized using magnetron sputtering (three elemental targets in Ar atmosphere) with a growth temperature of 200 °C on three different substrates, namely, Si as well as c- and r-sapphire. The elemental composition was measured with energy-dispersive x-ray spectroscopy and the structure by x-ray diffraction. The electrical resistivity and the Seebeck coefficient were determined under He atmosphere from room temperature to the growth temperature. All samples are crystalline exhibiting the La2O3-type crystal structure (space group P-3m1). The observed thermoelectric response is consistent with a semiconductive behavior. With increasing x, the samples become more electrically resistive due to the increasing bandgap. High Bi content (x &lt; 1) is thus beneficial due to lower resistivity and a higher power factor near room temperature. Thermoelectric thin films synthesized at low temperatures may provide novel pathways to enable flexible devices on polymeric and other heat-sensitive substrates.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136066216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We determined the surface structure of cleaved CaF2(111) via atomic force microscopy and low-energy atom scattering spectroscopy for surface analyses of insulators. A pulsed 3 keV-20Ne0 impinged on the sample. The backscattered particles were detected at a scattering angle of 180°. It was found that (1) fluorine atoms dominated the topmost surfaces of cleaved CaF2(111) and (2) the topmost layer of fluorine atoms was located at an inward shift of 0.2 Å with respect to the bulk lattice structure.
{"title":"Surface structural analysis of CaF2(111) using low-energy atom scattering spectroscopy","authors":"Hiroaki Fukuta, Goon Tan, Tomoaki Oga, Akifumi Matsuda, Mamoru Yoshimoto, Kenji Umezawa","doi":"10.1116/6.0002392","DOIUrl":"https://doi.org/10.1116/6.0002392","url":null,"abstract":"We determined the surface structure of cleaved CaF2(111) via atomic force microscopy and low-energy atom scattering spectroscopy for surface analyses of insulators. A pulsed 3 keV-20Ne0 impinged on the sample. The backscattered particles were detected at a scattering angle of 180°. It was found that (1) fluorine atoms dominated the topmost surfaces of cleaved CaF2(111) and (2) the topmost layer of fluorine atoms was located at an inward shift of 0.2 Å with respect to the bulk lattice structure.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135643424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Herrera-Gomez, M. O. Vazquez-Lepe, P. G. Mani-Gonzalez, P. Pianetta, F. S. Aguirre-Tostado, O. Ceballos-Sanchez
One doublet is usually employed to fit the Si0 substrate species in the Si 2p photoemission spectra from Si (001) H-terminated (after piranha treatment) and oxidized surfaces. However, there is a second substrate-top component (ST) with a binding energy of 0.3 eV higher than the bulk component; its intensity varies from ∼10% at normal emission (i.e., 90° from the surface) to ∼20% at 35°. It is present even for oxidized surfaces and does not correspond to any of the suboxide species. It corresponds to the first layers of the substrate and is responsible for the decrease in the signal dip between the two S–O branches of the Si 2p spectra for glancing electron takeoff angles. Although it is resolvable for monochromatized sources, the ST component is absent in the literature on Si 2p spectra.
{"title":"The <i>ST</i> component in the Si 2<i>p</i> photoemission spectrum from H-terminated and oxidized Si (001) surfaces","authors":"A. Herrera-Gomez, M. O. Vazquez-Lepe, P. G. Mani-Gonzalez, P. Pianetta, F. S. Aguirre-Tostado, O. Ceballos-Sanchez","doi":"10.1116/6.0002690","DOIUrl":"https://doi.org/10.1116/6.0002690","url":null,"abstract":"One doublet is usually employed to fit the Si0 substrate species in the Si 2p photoemission spectra from Si (001) H-terminated (after piranha treatment) and oxidized surfaces. However, there is a second substrate-top component (ST) with a binding energy of 0.3 eV higher than the bulk component; its intensity varies from ∼10% at normal emission (i.e., 90° from the surface) to ∼20% at 35°. It is present even for oxidized surfaces and does not correspond to any of the suboxide species. It corresponds to the first layers of the substrate and is responsible for the decrease in the signal dip between the two S–O branches of the Si 2p spectra for glancing electron takeoff angles. Although it is resolvable for monochromatized sources, the ST component is absent in the literature on Si 2p spectra.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135642793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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