Plasma processes are widely used in the fabrication of integrated circuits for the smaller, faster, more powerful circuits demanded by new technology. High-performance semiconductor equipment is required for dynamic random-access memory and three-dimensional NAND flash memory in semiconductor manufacturing. To enhance the speed of RF impedance matching, this paper proposes a method for calculating the load impedance of the plasma chamber. To calculate the target value of the variable components, we employ the input impedance of the impedance-matching unit and the complex impedances of the variable components. In addition, the internal parameters are automatically tuned through the gradient-descent method of machine learning, which improves the accuracy of impedance matching. The new matching method achieved a fast matching time and high efficiency of the matching trajectories. Moreover, it avoids the increase of the reflected power during the matching process, which causes plasma instability, and prohibits significant matching delay in a specific area, which disadvantages the conventional matching algorithm. These advantages are expected to significantly expand the development of new plasma processes from that of conventional impedance matching.
{"title":"Improved impedance matching speed with gradient descent for advanced RF plasma system","authors":"Dongwon Shin, Sang Jeen Hong","doi":"10.1116/6.0003034","DOIUrl":"https://doi.org/10.1116/6.0003034","url":null,"abstract":"Plasma processes are widely used in the fabrication of integrated circuits for the smaller, faster, more powerful circuits demanded by new technology. High-performance semiconductor equipment is required for dynamic random-access memory and three-dimensional NAND flash memory in semiconductor manufacturing. To enhance the speed of RF impedance matching, this paper proposes a method for calculating the load impedance of the plasma chamber. To calculate the target value of the variable components, we employ the input impedance of the impedance-matching unit and the complex impedances of the variable components. In addition, the internal parameters are automatically tuned through the gradient-descent method of machine learning, which improves the accuracy of impedance matching. The new matching method achieved a fast matching time and high efficiency of the matching trajectories. Moreover, it avoids the increase of the reflected power during the matching process, which causes plasma instability, and prohibits significant matching delay in a specific area, which disadvantages the conventional matching algorithm. These advantages are expected to significantly expand the development of new plasma processes from that of conventional impedance matching.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135095237","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}
Achim Nadzeyka, Torsten Richter, Paul Mazarov, Fabian Meyer, Alexander Ost, Lars Bruchhaus
In this work, we present an overview of nanopatterning and imaging applications using newly developed workflows with focused ion beams (FIBs) produced with a GaBiLi liquid metal alloy ion source. The primary beam of this source type contains gallium, bismuth, and lithium as well as cluster ions which can be separated quickly using a Wien filter. Lithium ion milling has been applied to generate heptamer-arranged nanohole arrays in gold films with high resolution. Workflows for two-step bowtie nanofabrication using lithium and bismuth ions from the same source have been established. Furthermore, we present ion beam imaging results that were obtained with lithium ions on various sample materials. Combining the large sputter yield and high depth resolution of heavy bismuth ions with the high lateral imaging resolution of light lithium ions enables 3D nanoscale tomography using different ion species generated from the same source. Sample tilt is not required due to the top-down geometry of the FIB.
{"title":"Focused ion beams from GaBiLi liquid metal alloy ion sources for nanofabrication and ion imaging","authors":"Achim Nadzeyka, Torsten Richter, Paul Mazarov, Fabian Meyer, Alexander Ost, Lars Bruchhaus","doi":"10.1116/6.0002918","DOIUrl":"https://doi.org/10.1116/6.0002918","url":null,"abstract":"In this work, we present an overview of nanopatterning and imaging applications using newly developed workflows with focused ion beams (FIBs) produced with a GaBiLi liquid metal alloy ion source. The primary beam of this source type contains gallium, bismuth, and lithium as well as cluster ions which can be separated quickly using a Wien filter. Lithium ion milling has been applied to generate heptamer-arranged nanohole arrays in gold films with high resolution. Workflows for two-step bowtie nanofabrication using lithium and bismuth ions from the same source have been established. Furthermore, we present ion beam imaging results that were obtained with lithium ions on various sample materials. Combining the large sputter yield and high depth resolution of heavy bismuth ions with the high lateral imaging resolution of light lithium ions enables 3D nanoscale tomography using different ion species generated from the same source. Sample tilt is not required due to the top-down geometry of the FIB.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135093837","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}
Kwon Sang Lee, Kun-Chieh Chien, Barbara Groh, I-Te Chen, Michael Cullinan, Chih-Hao Chang
Periodic nanostructures have important applications in nanophotonics and nanostructured materials as they provide various properties that are advantageous compared to conventional solid materials. However, there is a lack of metrology techniques that are suitable for large-scale manufacturing, as the traditional tools used in nanotechnology have limited throughput and depth resolution. In this work, we use spectroscopic scatterometry as a fast and low-cost alternative to characterize the porosity of three-dimensional (3D) periodic nanostructures. In this technique, the broadband reflectance of the structure is measured and fitted with physical models to predict the structure porosity. The process is demonstrated using 3D periodic nanostructures fabricated using colloidal phase lithography at various exposure dosages. The measured reflectance data are compared with an optical model based on finite-difference time-domain and transfer-matrix methods, which show qualitative agreement with the structure porosity. We found that this technique has the potential to further develop into an effective method to effectively predict the porosity of 3D nanostructures and can lead to real-time process control in roll-to-roll nanomanufacturing.
{"title":"Characterization of porosity in periodic 3D nanostructures using spectroscopic scatterometry","authors":"Kwon Sang Lee, Kun-Chieh Chien, Barbara Groh, I-Te Chen, Michael Cullinan, Chih-Hao Chang","doi":"10.1116/6.0003035","DOIUrl":"https://doi.org/10.1116/6.0003035","url":null,"abstract":"Periodic nanostructures have important applications in nanophotonics and nanostructured materials as they provide various properties that are advantageous compared to conventional solid materials. However, there is a lack of metrology techniques that are suitable for large-scale manufacturing, as the traditional tools used in nanotechnology have limited throughput and depth resolution. In this work, we use spectroscopic scatterometry as a fast and low-cost alternative to characterize the porosity of three-dimensional (3D) periodic nanostructures. In this technique, the broadband reflectance of the structure is measured and fitted with physical models to predict the structure porosity. The process is demonstrated using 3D periodic nanostructures fabricated using colloidal phase lithography at various exposure dosages. The measured reflectance data are compared with an optical model based on finite-difference time-domain and transfer-matrix methods, which show qualitative agreement with the structure porosity. We found that this technique has the potential to further develop into an effective method to effectively predict the porosity of 3D nanostructures and can lead to real-time process control in roll-to-roll nanomanufacturing.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135350928","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}
Titanium and titanium alloys are the most commonly used implant materials, but they are biologically inert. These materials lack rapid osseointegration and resistance to bacterial infections, problems that remain unsolved. The preparation of titanium dioxide coatings by microarc oxidation improves both the biocompatibility of titanium-based materials and their resistance to corrosion during long-term presence in the body. This paper discusses and summarizes the mechanisms of microarc oxidation and some classical models that need to be developed to provide a better understanding and guidance for future research. Subsequently, the effects of electrolyte type, additives, and surface modification of the microarc oxidized coating on the coating morphology were analyzed in detail. In addition, biological applications of microarc oxidation coatings are analyzed, including antimicrobial properties, osseointegration, hydrophilicity, corrosion resistance, and wear resistance.
{"title":"Review of microarc oxidation of titanium implant","authors":"Guang Yang, Yulu Meng, Chenghui Qian, Xiaohong Chen, Ping Liu, Honglei Zhou, Binbin Kang, Xiangpeng Tang, Lanjuan Diao, Fanfan Zhou","doi":"10.1116/6.0002941","DOIUrl":"https://doi.org/10.1116/6.0002941","url":null,"abstract":"Titanium and titanium alloys are the most commonly used implant materials, but they are biologically inert. These materials lack rapid osseointegration and resistance to bacterial infections, problems that remain unsolved. The preparation of titanium dioxide coatings by microarc oxidation improves both the biocompatibility of titanium-based materials and their resistance to corrosion during long-term presence in the body. This paper discusses and summarizes the mechanisms of microarc oxidation and some classical models that need to be developed to provide a better understanding and guidance for future research. Subsequently, the effects of electrolyte type, additives, and surface modification of the microarc oxidized coating on the coating morphology were analyzed in detail. In addition, biological applications of microarc oxidation coatings are analyzed, including antimicrobial properties, osseointegration, hydrophilicity, corrosion resistance, and wear resistance.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135697454","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}
Jihye Park, Minji Jeong, Young Joon Cho, Kyung Joong Kim, Truong Ba Tai, Hyeyoung Shin, Jong Chul Lim, Hyo Sik Chang
The continuous scaling down of dynamic random access memory devices has necessitated a comprehensive understanding of the initial growth mechanism in atomic layer deposition. In this study, HfO2 was deposited using tetrakis(ethylmethylamido)hafnium (TEMAHf)-H2O on H-/OH-terminated Si (100) surfaces. By analyzing the Hf-O peak in the FTIR spectra and medium-energy ion scattering measurements, it was determined that a monolayer was formed on the H-Si surface at a rate (10 cycles) lower than that for the OH-Si surface (4 cycles). The ligand variations during each cycle, as determined by FTIR measurements, enabled the suggestion of the initial precursor adsorption mechanism. An analysis of the infrared spectra and secondary ion mass spectrometry depth profiles revealed surface-dependent differences in interfacial bonding. This explained the variation in the rate of formation of 1 Ml. Additionally, theoretical investigations using density functional theory calculations identified the reaction pathway with the lowest energy barrier, thereby validating the experimentally proposed mechanism. This study to elucidate the Si surface and the TEMAHf-H2O reaction mechanism provided insights into the analysis of the initial precursor adsorption mechanism for other types of precursors.
{"title":"Investigation of tetrakis(ethylmethylamido)hafnium adsorption mechanism in initial growth of atomic layer deposited-HfO2 thin films on H-/OH-terminated Si (100) surfaces","authors":"Jihye Park, Minji Jeong, Young Joon Cho, Kyung Joong Kim, Truong Ba Tai, Hyeyoung Shin, Jong Chul Lim, Hyo Sik Chang","doi":"10.1116/6.0002920","DOIUrl":"https://doi.org/10.1116/6.0002920","url":null,"abstract":"The continuous scaling down of dynamic random access memory devices has necessitated a comprehensive understanding of the initial growth mechanism in atomic layer deposition. In this study, HfO2 was deposited using tetrakis(ethylmethylamido)hafnium (TEMAHf)-H2O on H-/OH-terminated Si (100) surfaces. By analyzing the Hf-O peak in the FTIR spectra and medium-energy ion scattering measurements, it was determined that a monolayer was formed on the H-Si surface at a rate (10 cycles) lower than that for the OH-Si surface (4 cycles). The ligand variations during each cycle, as determined by FTIR measurements, enabled the suggestion of the initial precursor adsorption mechanism. An analysis of the infrared spectra and secondary ion mass spectrometry depth profiles revealed surface-dependent differences in interfacial bonding. This explained the variation in the rate of formation of 1 Ml. Additionally, theoretical investigations using density functional theory calculations identified the reaction pathway with the lowest energy barrier, thereby validating the experimentally proposed mechanism. This study to elucidate the Si surface and the TEMAHf-H2O reaction mechanism provided insights into the analysis of the initial precursor adsorption mechanism for other types of precursors.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135388456","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. Serra González, M. Keil, R. Deshpande, S. Kadkhodazadeh, N. Okulova, R. J. Taboryski
Surface plasmon resonances have been exploited for many applications due to their tunability, which is directly related to the geometry of nanostructures. Based on their dimension and material stack, the resonances can be tailored to achieve high absorbing or reflecting nanopatterned surfaces designed for specific wavelengths. While the preferred lithographic printing techniques in the field allow high precision and control of the structures, they are limited in throughput, thus restricting possible large-scale applications. In this work, we present a full process flow, which can produce hundreds of square meters of nanopillar arrays by combining resolution enhancement techniques (RETs) on a deep-UV stepper for fabricating a silicon master and roll-to-roll extrusion coating (R2R-EC) for its replication. We demonstrate optimized exposures with the combination of dipole off-axis illumination, triple cross-exposure, and the addition of assisted features on the mask design. By simulating the RETs compared to a conventional setup, we show how lithographic parameters such as the normalized image log-slope (NILS) improve from 0.90 to 2.05 or the resist image contrast (RIC) increases from 0.429 to 0.813. We confirm these results by printing wafer-size hexagonal and rectangular arrays of nanopillars with 340, 350, and 360 nm pitches and diameters ranging from 100 to 200 nm. We show the successful replication of both designs by R2R-EC, an industrial process, which produces hundred-meter rolls of patterned polymer. We demonstrate that after metallization, the samples are suitable for solar absorption by measuring their absorptance (absorbed to incident intensity) and comparing it with the solar irradiance peak. We achieve a 70% efficiency for both hexagonal and rectangular arrays at resonant peaks of 550 and 600 nm, respectively, where the hexagonal array better matches the solar irradiance peak. Additionally, the plasmonic samples block 78% of the heat radiation when compared to a plain black polymer foil for reference, making them more efficient for solar harvesting applications.
{"title":"Design and large-scale nanofabrication of plasmonic solar light absorbers","authors":"M. Serra González, M. Keil, R. Deshpande, S. Kadkhodazadeh, N. Okulova, R. J. Taboryski","doi":"10.1116/6.0002998","DOIUrl":"https://doi.org/10.1116/6.0002998","url":null,"abstract":"Surface plasmon resonances have been exploited for many applications due to their tunability, which is directly related to the geometry of nanostructures. Based on their dimension and material stack, the resonances can be tailored to achieve high absorbing or reflecting nanopatterned surfaces designed for specific wavelengths. While the preferred lithographic printing techniques in the field allow high precision and control of the structures, they are limited in throughput, thus restricting possible large-scale applications. In this work, we present a full process flow, which can produce hundreds of square meters of nanopillar arrays by combining resolution enhancement techniques (RETs) on a deep-UV stepper for fabricating a silicon master and roll-to-roll extrusion coating (R2R-EC) for its replication. We demonstrate optimized exposures with the combination of dipole off-axis illumination, triple cross-exposure, and the addition of assisted features on the mask design. By simulating the RETs compared to a conventional setup, we show how lithographic parameters such as the normalized image log-slope (NILS) improve from 0.90 to 2.05 or the resist image contrast (RIC) increases from 0.429 to 0.813. We confirm these results by printing wafer-size hexagonal and rectangular arrays of nanopillars with 340, 350, and 360 nm pitches and diameters ranging from 100 to 200 nm. We show the successful replication of both designs by R2R-EC, an industrial process, which produces hundred-meter rolls of patterned polymer. We demonstrate that after metallization, the samples are suitable for solar absorption by measuring their absorptance (absorbed to incident intensity) and comparing it with the solar irradiance peak. We achieve a 70% efficiency for both hexagonal and rectangular arrays at resonant peaks of 550 and 600 nm, respectively, where the hexagonal array better matches the solar irradiance peak. Additionally, the plasmonic samples block 78% of the heat radiation when compared to a plain black polymer foil for reference, making them more efficient for solar harvesting applications.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135718697","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}
Henry I. Smith, Mark Mondol, Feng Zhang, Timothy Savas, Michael Walsh
To date, zone-plate-array lithography has employed an array of binary pi-phase zone plates, each 135 μm in diameter, operating at 405 nm wavelength, in conjunction with a spatial-light modulator and a moving stage, to expose large-area patterns in photoresist without a mask. Although the low focal efficiency (<34%) and high background (>66%) of such zone plates can be mitigated via proximity-effect correction, increased focal efficiency would enable higher quality patterning. To that end, we have designed flat, diffractive-optical “metalenses.” Each is first divided into Fresnel zones, across which the effective index-of-refraction is modulated by forming appropriate pillars or holes such that diffracted beams interfere constructively at the focal spot, located 100 μm in front of the lens plane. The diffraction efficiency of each zone is simulated using rigorous-coupled-wave analysis. A genetic algorithm is then used to determine if higher efficiency can be achieved by repositioning of the pillars or modifying their widths. MEEP software is used to predict focal efficiency of the completed metalens design. Scanning-electron-beam lithography was used to fabricate effective-index-modulated metalenses in CSAR-62 e-beam resist. In some cases, the focal properties and efficiencies of such structures were measured, yielding focal efficiencies up to 54%. In other cases, the e-beam-written pattern was transferred into a spin-on hard mask and then into an organic dielectric of 1.9 index of refraction using reactive ion etching. Focal efficiencies up to 69% are predicted for such structures, a significant improvement over the binary pi-phase zone plates used previously.
{"title":"High-efficiency metalenses for zone-plate-array lithography","authors":"Henry I. Smith, Mark Mondol, Feng Zhang, Timothy Savas, Michael Walsh","doi":"10.1116/6.0003024","DOIUrl":"https://doi.org/10.1116/6.0003024","url":null,"abstract":"To date, zone-plate-array lithography has employed an array of binary pi-phase zone plates, each 135 μm in diameter, operating at 405 nm wavelength, in conjunction with a spatial-light modulator and a moving stage, to expose large-area patterns in photoresist without a mask. Although the low focal efficiency (&lt;34%) and high background (&gt;66%) of such zone plates can be mitigated via proximity-effect correction, increased focal efficiency would enable higher quality patterning. To that end, we have designed flat, diffractive-optical “metalenses.” Each is first divided into Fresnel zones, across which the effective index-of-refraction is modulated by forming appropriate pillars or holes such that diffracted beams interfere constructively at the focal spot, located 100 μm in front of the lens plane. The diffraction efficiency of each zone is simulated using rigorous-coupled-wave analysis. A genetic algorithm is then used to determine if higher efficiency can be achieved by repositioning of the pillars or modifying their widths. MEEP software is used to predict focal efficiency of the completed metalens design. Scanning-electron-beam lithography was used to fabricate effective-index-modulated metalenses in CSAR-62 e-beam resist. In some cases, the focal properties and efficiencies of such structures were measured, yielding focal efficiencies up to 54%. In other cases, the e-beam-written pattern was transferred into a spin-on hard mask and then into an organic dielectric of 1.9 index of refraction using reactive ion etching. Focal efficiencies up to 69% are predicted for such structures, a significant improvement over the binary pi-phase zone plates used previously.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135718695","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}
Many of the device parameters measured in scientific research and engineering applications depend on the ambient temperature to varying degrees. A Schottky barrier diode (SBD) is in direct contact with the environment, namely, gas, pressure, and temperature; therefore, a change in the state of the Schottky contact (SC) immediately affects its parameters in contrast to the p-n junction and semiconductor transistors. The temperature sensitivity capability of the Au/n-GaAs SBDs has been analyzed by numerical simulation of its current–voltage characteristics using a thermionic emission relation. The obtained results from the simulation study have shown that the thermal sensitivity of the SBDs has increased with a decrease in the current level value at the same SC area size, and it has decreased with a decrease in the SC area size under the same current level. Moreover, it has been concluded from the fact that a SBD with a large SC area should be operated for the cryogenic temperature range under a low current level rather than high current levels. The results of this kind of study can help us to select the SC dimension suitable for many purposes in scientific research and engineering applications.
{"title":"Theoretical approach to thermal sensitivity capability of metal-semiconductor diodes with different Schottky contact area","authors":"Abdulmecit Turut","doi":"10.1116/6.0002976","DOIUrl":"https://doi.org/10.1116/6.0002976","url":null,"abstract":"Many of the device parameters measured in scientific research and engineering applications depend on the ambient temperature to varying degrees. A Schottky barrier diode (SBD) is in direct contact with the environment, namely, gas, pressure, and temperature; therefore, a change in the state of the Schottky contact (SC) immediately affects its parameters in contrast to the p-n junction and semiconductor transistors. The temperature sensitivity capability of the Au/n-GaAs SBDs has been analyzed by numerical simulation of its current–voltage characteristics using a thermionic emission relation. The obtained results from the simulation study have shown that the thermal sensitivity of the SBDs has increased with a decrease in the current level value at the same SC area size, and it has decreased with a decrease in the SC area size under the same current level. Moreover, it has been concluded from the fact that a SBD with a large SC area should be operated for the cryogenic temperature range under a low current level rather than high current levels. The results of this kind of study can help us to select the SC dimension suitable for many purposes in scientific research and engineering applications.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135718699","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}
Sang-Jin Chung, Pingshan Luan, Minjoon Park, Andrew Metz, Gottlieb S. Oehrlein
The scalloping of oxide-nitride-oxide (ONO) stacked layers on vertical sidewalls during high-aspect-ratio contact etch is commonly seen and characterized by the horizontal etching of oxide and nitride layers at different etch rates. To understand the mechanisms of ONO scalloping in complex plasma chemistry, it is crucial to examine the surface chemistry of silicon dioxide and silicon nitride processed with single fluorocarbon (FC) or hydrofluorocarbon (HFC) gases. To simulate the isotropic etching of SiO2 and Si3N4 sidewalls, we use a horizontal trench structure to study the effect of neutral radicals produced by FC (Ar/C4F8), HFC (Ar/CH3F, CH2F2, or CH3F), FC/HFC (Ar/C4F8/CH2F2), or FC/H2 (Ar/C4F8/H2), plasma for aspect-ratio (AR) up to 25. To eliminate the effect of ions, oxide and nitride trench structures were treated by inductively coupled plasma. The changes in the film thickness as a function of AR were probed by ellipsometry. Additionally, x-ray photoelectron spectroscopy (XPS) measurements on oxide and nitride substrates processed by Ar/C4F8 and Ar/CH2F2 plasma were performed at various locations: outside of the trench structure, near the trench entrance (AR = 4.3), and deeper in the trench (AR = 12.9). We find a variety of responses of the trench sidewalls including both FC deposition and spontaneous etching which reflect (1) the nature of the FC and HFC gases, (2) the nature of the surfaces being exposed, and (3) the position relative to the trench entrance. Overall, both the etching and deposition patterns varied systematically depending on the precursor gas. We found that the ONO scalloping at different ARs is plasma chemistry dependent. Oxide showed a binary sidewall profile, with either all deposition inside of the trench (with FC and FC/H2 processing) or etching (HFC and FC/HFC). Both profiles showed a steady attenuation of either the deposition or etching at higher AR. On the nitride substrate, etching was observed near the entrance for HFC precursors, and maximum net etching occurred at higher AR for high F:C ratio HFC precursors like CHF3. XPS measurements performed with Ar/C4F8 and Ar/CH2F2 treated surfaces showed that Ar/C4F8 overall deposited a fluorine-rich film outside and inside of the trench, while Ar/CH2F2 mostly deposited a cross-linked film (except near the trench entrance) with an especially thin graphitic-like film deep inside the trench.
{"title":"Exploring oxide-nitride-oxide scalloping behavior with small gap structure and chemical analysis after fluorocarbon or hydrofluorocarbon plasma processing","authors":"Sang-Jin Chung, Pingshan Luan, Minjoon Park, Andrew Metz, Gottlieb S. Oehrlein","doi":"10.1116/6.0002868","DOIUrl":"https://doi.org/10.1116/6.0002868","url":null,"abstract":"The scalloping of oxide-nitride-oxide (ONO) stacked layers on vertical sidewalls during high-aspect-ratio contact etch is commonly seen and characterized by the horizontal etching of oxide and nitride layers at different etch rates. To understand the mechanisms of ONO scalloping in complex plasma chemistry, it is crucial to examine the surface chemistry of silicon dioxide and silicon nitride processed with single fluorocarbon (FC) or hydrofluorocarbon (HFC) gases. To simulate the isotropic etching of SiO2 and Si3N4 sidewalls, we use a horizontal trench structure to study the effect of neutral radicals produced by FC (Ar/C4F8), HFC (Ar/CH3F, CH2F2, or CH3F), FC/HFC (Ar/C4F8/CH2F2), or FC/H2 (Ar/C4F8/H2), plasma for aspect-ratio (AR) up to 25. To eliminate the effect of ions, oxide and nitride trench structures were treated by inductively coupled plasma. The changes in the film thickness as a function of AR were probed by ellipsometry. Additionally, x-ray photoelectron spectroscopy (XPS) measurements on oxide and nitride substrates processed by Ar/C4F8 and Ar/CH2F2 plasma were performed at various locations: outside of the trench structure, near the trench entrance (AR = 4.3), and deeper in the trench (AR = 12.9). We find a variety of responses of the trench sidewalls including both FC deposition and spontaneous etching which reflect (1) the nature of the FC and HFC gases, (2) the nature of the surfaces being exposed, and (3) the position relative to the trench entrance. Overall, both the etching and deposition patterns varied systematically depending on the precursor gas. We found that the ONO scalloping at different ARs is plasma chemistry dependent. Oxide showed a binary sidewall profile, with either all deposition inside of the trench (with FC and FC/H2 processing) or etching (HFC and FC/HFC). Both profiles showed a steady attenuation of either the deposition or etching at higher AR. On the nitride substrate, etching was observed near the entrance for HFC precursors, and maximum net etching occurred at higher AR for high F:C ratio HFC precursors like CHF3. XPS measurements performed with Ar/C4F8 and Ar/CH2F2 treated surfaces showed that Ar/C4F8 overall deposited a fluorine-rich film outside and inside of the trench, while Ar/CH2F2 mostly deposited a cross-linked film (except near the trench entrance) with an especially thin graphitic-like film deep inside the trench.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135816221","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}
Hryhorii Stanchu, Abdulla Said, Oluwatobi Olorunsola, Sudip Acharya, Sylvester Amoah, Mohammad Zamani-Alavijeh, Fernando M. de Oliveira, Santosh Karki Chhetri, Jin Hu, Yuriy I. Mazur, Shui-Qing Yu, Gregory Salamo
A study of the mechanism of Sn out-diffusion was performed by annealing Ge0.905Sn0.095 layers at 300 °C. The changes in Sn composition and strain state were confirmed by x-ray diffraction and photoluminescence spectroscopy. Surface defects, appearing as Sn particles, with the highest density of 3.5 × 108 cm−2 were detected by atomic force microscopy after annealing for 2 h. The strain in the GeSn layer stabilized for more prolonged annealing, while the density of particles decreased and their size increased. Annealing results are discussed in terms of Sn segregation and subsequent diffusion along dislocation lines, enhanced out-diffusion by dislocations migration, and surface particle coalescence.
{"title":"Role of dislocations on Sn diffusion during low temperature annealing of GeSn layers","authors":"Hryhorii Stanchu, Abdulla Said, Oluwatobi Olorunsola, Sudip Acharya, Sylvester Amoah, Mohammad Zamani-Alavijeh, Fernando M. de Oliveira, Santosh Karki Chhetri, Jin Hu, Yuriy I. Mazur, Shui-Qing Yu, Gregory Salamo","doi":"10.1116/6.0002957","DOIUrl":"https://doi.org/10.1116/6.0002957","url":null,"abstract":"A study of the mechanism of Sn out-diffusion was performed by annealing Ge0.905Sn0.095 layers at 300 °C. The changes in Sn composition and strain state were confirmed by x-ray diffraction and photoluminescence spectroscopy. Surface defects, appearing as Sn particles, with the highest density of 3.5 × 108 cm−2 were detected by atomic force microscopy after annealing for 2 h. The strain in the GeSn layer stabilized for more prolonged annealing, while the density of particles decreased and their size increased. Annealing results are discussed in terms of Sn segregation and subsequent diffusion along dislocation lines, enhanced out-diffusion by dislocations migration, and surface particle coalescence.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135299086","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}
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