Z. Mei, H. Bi, Qing Cao, Yuqing Wang, Wenyu Lin, Junfeng Ye, Xudi Wang
The narrow structure within the vacuum system usually results in a slow evacuation process. Additionally, the high outgassing rate caused by the large surface-to-volume ratio can prevent the vacuum level from meeting the performance requirements of the device. In this paper, the evacuation of the stainless steel parallel plates is established based on a two-dimensional equation combined with the outgassing theory of the recombination–dissociation-limited model. The relationship between the measured and intrinsic outgassing rates was investigated by varying the gap size, pump-out port size, and temperature. The results show that the internal pressure is nonuniformly distributed during the pump-down process, even reaching a quasiequilibrium state. This indicates that the widely used throughput method can make a difference in measuring outgassing rates. This provides a theoretical basis for testing intrinsic outgassing rates, calculating pressure distribution, and configuring pumps or getters in complex vacuum systems.
{"title":"Investigation of the intrinsic outgassing rates for narrow structured vacuum devices under readsorption effect","authors":"Z. Mei, H. Bi, Qing Cao, Yuqing Wang, Wenyu Lin, Junfeng Ye, Xudi Wang","doi":"10.1116/6.0002906","DOIUrl":"https://doi.org/10.1116/6.0002906","url":null,"abstract":"The narrow structure within the vacuum system usually results in a slow evacuation process. Additionally, the high outgassing rate caused by the large surface-to-volume ratio can prevent the vacuum level from meeting the performance requirements of the device. In this paper, the evacuation of the stainless steel parallel plates is established based on a two-dimensional equation combined with the outgassing theory of the recombination–dissociation-limited model. The relationship between the measured and intrinsic outgassing rates was investigated by varying the gap size, pump-out port size, and temperature. The results show that the internal pressure is nonuniformly distributed during the pump-down process, even reaching a quasiequilibrium state. This indicates that the widely used throughput method can make a difference in measuring outgassing rates. This provides a theoretical basis for testing intrinsic outgassing rates, calculating pressure distribution, and configuring pumps or getters in complex vacuum systems.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"32 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":"114534062","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}
fac-Tris(2-phenylpyridine) iridium [Ir(ppy)3] has been investigated by means of soft desorption/ionization induced by neutral SO2 clusters in combination with mass spectrometry. Desorption of intact Ir(ppy)3 was observed. Further analysis of the isotopic pattern revealed two forms of ionization, either by uptake of a proton or by electron abstraction. The relative contribution of the two processes depends on measurement time and H2O partial pressure, as well as preparation scheme and surface morphology of the samples.
{"title":"Cluster-induced desorption/ionization mass spectrometry of Ir(ppy)3","authors":"P. Keller, S. Aoyagi, Michael Dürr","doi":"10.1116/6.0002556","DOIUrl":"https://doi.org/10.1116/6.0002556","url":null,"abstract":"fac-Tris(2-phenylpyridine) iridium [Ir(ppy)3] has been investigated by means of soft desorption/ionization induced by neutral SO2 clusters in combination with mass spectrometry. Desorption of intact Ir(ppy)3 was observed. Further analysis of the isotopic pattern revealed two forms of ionization, either by uptake of a proton or by electron abstraction. The relative contribution of the two processes depends on measurement time and H2O partial pressure, as well as preparation scheme and surface morphology of the samples.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"18 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":"115665990","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}
Manish Ojha, Y. Mohammed, D. S. Stone, A. Elmustafa
This paper investigates the surface morphology, mechanical properties, and electrical resistivity of 96.5Sn–3.0Ag–0.5Cu (SAC305) thin films deposited on Si and SiO2 substrates through RF magnetron sputtering. Various deposition parameters were tested using both DC and RF power sources at different pressures and powers to produce robust continuous films. The most optimal surface morphology, with an average grain size of ∼1 μm and a thickness of ∼2.2 μm, was accomplished at a pressure of 2.4 mTorr and 200 W power. After polishing, a uniform thickness of 1800 nm with a mean roughness (Ra) of 14.9 nm was obtained. The samples contained polycrystalline β-Sn grains at (200) diffraction planes with a preferred orientation 2θ of 30.70°. Although the XRD pattern did not indicate any Ag peaks, weak peaks of Ag3Sn were observed at 2θ of 37.60° and 39.59°, corresponding to diffraction planes (020) and (211), respectively. The electrical resistivity of the SAC305 thin film deposited on the SiO2 substrate and of the bulk SAC305 samples were measured as 19.6 and 13.7 μΩ cm, respectively. It was noted that changes in hold time at peak loads or the rate of loading in the creep experiments did not significantly influence the creep properties of the SAC305 bulk or thin film material.
{"title":"Microstructure, creep properties, and electrical resistivity of magnetron sputtering deposited SAC305 thin films","authors":"Manish Ojha, Y. Mohammed, D. S. Stone, A. Elmustafa","doi":"10.1116/6.0002949","DOIUrl":"https://doi.org/10.1116/6.0002949","url":null,"abstract":"This paper investigates the surface morphology, mechanical properties, and electrical resistivity of 96.5Sn–3.0Ag–0.5Cu (SAC305) thin films deposited on Si and SiO2 substrates through RF magnetron sputtering. Various deposition parameters were tested using both DC and RF power sources at different pressures and powers to produce robust continuous films. The most optimal surface morphology, with an average grain size of ∼1 μm and a thickness of ∼2.2 μm, was accomplished at a pressure of 2.4 mTorr and 200 W power. After polishing, a uniform thickness of 1800 nm with a mean roughness (Ra) of 14.9 nm was obtained. The samples contained polycrystalline β-Sn grains at (200) diffraction planes with a preferred orientation 2θ of 30.70°. Although the XRD pattern did not indicate any Ag peaks, weak peaks of Ag3Sn were observed at 2θ of 37.60° and 39.59°, corresponding to diffraction planes (020) and (211), respectively. The electrical resistivity of the SAC305 thin film deposited on the SiO2 substrate and of the bulk SAC305 samples were measured as 19.6 and 13.7 μΩ cm, respectively. It was noted that changes in hold time at peak loads or the rate of loading in the creep experiments did not significantly influence the creep properties of the SAC305 bulk or thin film material.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"20 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":"122730417","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}
Se-Jin Oh, Chang-Gil Son, Min-kyu Sohn, Doug-Yong Sung, Min-Sung Kim, Ji-Soo Im, Sang Ki Nam
This study proposes an optical emission spectroscopy (OES) analysis methodology to improve the ability to detect etching endpoints during high-level semiconductor plasma etching processes. Representative etching endpoint detection methods using single wavelength intensity or multiple wavelength intensity ratio changes include a low signal-to-noise ratio, high plasma instability, a small etching open area, and weak by-product emission signal problems due to deep etching under high-level process conditions such as high aspect ratio contact etching (HARC). As a result, it is difficult to detect the etching endpoint due to the very small or noisy change in the intensity over time due to the process progress of the wavelength selected by OES to detect the etching endpoint. In this study, a method of deriving an accumulative time correlation value according to process progress between selected wavelengths was developed by selecting all wavelengths observed in a specific wavelength region such as ultraviolet region in a spectrum emitted from plasma during a plasma etching process. After classifying the entire correlation signal groups derived as a pair of two intensity peak wavelengths into a dynamic time wrapping algorithm, the intensity change rate of the signal according to the process time was observed by selecting the signal with the most sensitive time change rate during the process. During the vertical nand flash memory manufacturing process, a test wafer for the purpose of detecting the etching endpoint was manufactured and evaluated under the conditions of the cell metal contact etching process, which is a high-level HARC etching process. As a result, it was confirmed that the signal selected by deriving the time accumulative correlation method had a high intensity change rate and a signal-to-noise ratio over time compared to a single wavelength or a plurality of wavelength ratio signals. The method proposed in this study is expected to contribute to process optimization by contributing to improving the ability to detect etching endpoints in high-level plasma etching processes in the future.
{"title":"Method for improving dry etching end point detection based on change in time accumulation correlation of plasma emitting wavelengths","authors":"Se-Jin Oh, Chang-Gil Son, Min-kyu Sohn, Doug-Yong Sung, Min-Sung Kim, Ji-Soo Im, Sang Ki Nam","doi":"10.1116/6.0002890","DOIUrl":"https://doi.org/10.1116/6.0002890","url":null,"abstract":"This study proposes an optical emission spectroscopy (OES) analysis methodology to improve the ability to detect etching endpoints during high-level semiconductor plasma etching processes. Representative etching endpoint detection methods using single wavelength intensity or multiple wavelength intensity ratio changes include a low signal-to-noise ratio, high plasma instability, a small etching open area, and weak by-product emission signal problems due to deep etching under high-level process conditions such as high aspect ratio contact etching (HARC). As a result, it is difficult to detect the etching endpoint due to the very small or noisy change in the intensity over time due to the process progress of the wavelength selected by OES to detect the etching endpoint. In this study, a method of deriving an accumulative time correlation value according to process progress between selected wavelengths was developed by selecting all wavelengths observed in a specific wavelength region such as ultraviolet region in a spectrum emitted from plasma during a plasma etching process. After classifying the entire correlation signal groups derived as a pair of two intensity peak wavelengths into a dynamic time wrapping algorithm, the intensity change rate of the signal according to the process time was observed by selecting the signal with the most sensitive time change rate during the process. During the vertical nand flash memory manufacturing process, a test wafer for the purpose of detecting the etching endpoint was manufactured and evaluated under the conditions of the cell metal contact etching process, which is a high-level HARC etching process. As a result, it was confirmed that the signal selected by deriving the time accumulative correlation method had a high intensity change rate and a signal-to-noise ratio over time compared to a single wavelength or a plurality of wavelength ratio signals. The method proposed in this study is expected to contribute to process optimization by contributing to improving the ability to detect etching endpoints in high-level plasma etching processes in the future.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"8 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":"133898680","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}
In this study, the operation of npn-type GaN-based heterojunction bipolar transistors with different net acceptor concentrations in p-base regions was simulated. It was confirmed that there is a critical net acceptor concentration (NA-ND) depending on the thickness of the base region and that if the NA-ND is lower than the critical value, the collector current may anomalously increase, regardless of base current injection. This phenomenon is caused by the punch-through process via the depletion layer extending from the collector–base junction. The effect of the valence band energy offset at the emitter-base heterojunction (ΔEV) on the current gain (β) was also investigated, and the results showed that β peaks when ΔEV is 0.22–0.30 eV. This is determined by the balance between the hot-electron injection and thermal diffusion processes in the electron transport from the emitter to the base.
{"title":"Simulation analyses of carrier dynamics in npn-type GaN-heterojunction bipolar transistors with different hole-concentration p-base layers","authors":"Akira Mase, Yusuke Iida, Masaya Takimoto, Yutaka Nikai, Takashi Egawa, Makoto Miyoshi","doi":"10.1116/6.0002577","DOIUrl":"https://doi.org/10.1116/6.0002577","url":null,"abstract":"In this study, the operation of npn-type GaN-based heterojunction bipolar transistors with different net acceptor concentrations in p-base regions was simulated. It was confirmed that there is a critical net acceptor concentration (NA-ND) depending on the thickness of the base region and that if the NA-ND is lower than the critical value, the collector current may anomalously increase, regardless of base current injection. This phenomenon is caused by the punch-through process via the depletion layer extending from the collector–base junction. The effect of the valence band energy offset at the emitter-base heterojunction (ΔEV) on the current gain (β) was also investigated, and the results showed that β peaks when ΔEV is 0.22–0.30 eV. This is determined by the balance between the hot-electron injection and thermal diffusion processes in the electron transport from the emitter to the base.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"131 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":"130480274","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}
F. M. de Oliveira, Chen Li, Pijush K. Ghosh, A. Kuchuk, M. Ware, Y. Mazur, G. Salamo
In this work, we study the thermal evolution of the optical and electrical features of an InN thin film. By correlating photoluminescence (PL) and Hall effect results, we determine the appropriate values of the correlation parameter to be used in the empirical power law that associates the electron concentration with the linewidth of the PL spectrum, in the scope of the Burstein–Moss effect across a wide range of temperatures. Additionally, by associating Raman and PL results, we observe the thermally induced compressive strain widening of the bandgap of the InN film. Our findings demonstrate the reliability of optical methods in providing contactless measurements of electrical and structural features of semiconductors.
{"title":"Temperature dependent correlation of Hall effect and optical measurements of electron concentration in degenerate InN thin film","authors":"F. M. de Oliveira, Chen Li, Pijush K. Ghosh, A. Kuchuk, M. Ware, Y. Mazur, G. Salamo","doi":"10.1116/6.0002866","DOIUrl":"https://doi.org/10.1116/6.0002866","url":null,"abstract":"In this work, we study the thermal evolution of the optical and electrical features of an InN thin film. By correlating photoluminescence (PL) and Hall effect results, we determine the appropriate values of the correlation parameter to be used in the empirical power law that associates the electron concentration with the linewidth of the PL spectrum, in the scope of the Burstein–Moss effect across a wide range of temperatures. Additionally, by associating Raman and PL results, we observe the thermally induced compressive strain widening of the bandgap of the InN film. Our findings demonstrate the reliability of optical methods in providing contactless measurements of electrical and structural features of semiconductors.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"16 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":"133822520","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}
A novel interpolation and difference optimized (IDO) machine learning model to predict the depth of silicon etching is proposed, which is particularly well-suited to addressing small sample problems. Our approach involves dividing both experimental and simulation data obtained from the Technology Computer-Aided Design (TCAD) software into training and testing sets. Both experimental data and TCAD simulation data are used as inputs to machine learning module 1 (ML1), while ML2 takes the actual experimental data as inputs and then learns the difference between the experimental data and the TCAD simulation data, outputting the difference. The outputs generated by ML1 and ML2 serve as input parameters to machine learning module 3 (ML3), and the weights of ML3 are updated through its own learning process to produce the final prediction results. We demonstrate that our IDO model, which contains three basic ML algorithms, achieves higher prediction accuracy compared to the basic ML algorithm alone. Moreover, through ablation studies, we establish that the three components of the IDO prediction model are inseparable. The IDO model exhibits improved generalization performance, making it particularly suitable for small sample datasets in the semiconductor processing domain.
{"title":"Interpolation and difference optimized machine learning model for accurate prediction of silicon etching depth with small sample dataset","authors":"Ye Yang, Yang Xu","doi":"10.1116/6.0002823","DOIUrl":"https://doi.org/10.1116/6.0002823","url":null,"abstract":"A novel interpolation and difference optimized (IDO) machine learning model to predict the depth of silicon etching is proposed, which is particularly well-suited to addressing small sample problems. Our approach involves dividing both experimental and simulation data obtained from the Technology Computer-Aided Design (TCAD) software into training and testing sets. Both experimental data and TCAD simulation data are used as inputs to machine learning module 1 (ML1), while ML2 takes the actual experimental data as inputs and then learns the difference between the experimental data and the TCAD simulation data, outputting the difference. The outputs generated by ML1 and ML2 serve as input parameters to machine learning module 3 (ML3), and the weights of ML3 are updated through its own learning process to produce the final prediction results. We demonstrate that our IDO model, which contains three basic ML algorithms, achieves higher prediction accuracy compared to the basic ML algorithm alone. Moreover, through ablation studies, we establish that the three components of the IDO prediction model are inseparable. The IDO model exhibits improved generalization performance, making it particularly suitable for small sample datasets in the semiconductor processing domain.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130952507","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}
Simran Shahi, Asma Ahmed, Ruizhe Yang, Anthony Cabanillas, Anindita Chakravarty, Maomao Liu, H. N. Jaiswal, Yu Fu, Yutong Guo, Satyajeetsinh Shaileshsin Jadeja, Hariharan Murugesan, Anthony Butler, Chu Te Chen, Joel Muhigirwa, Mohamed Enaitalla, Jun Liu, Fei Yao, Huamin Li
With the rise of two-dimensional (2D) materials and nanoelectronics, compatible processes based on existing Si technologies are highly demanded to enable new and superior device functions. In this study, we utilized an O2 plasma treatment as a compatible and tunable method for anionic substitution doping in 2D WSe2. With an introduced WOx layer, moderate or even degenerate doping was realized to enhance hole transport in WSe2. By combining with 2D MoS2, an evolution of the 2D heterogeneous junction, in terms of the energy band structure and charge transport, was comprehensively investigated as a function of applied electric fields. The heterogeneous WSe2/MoS2 junction can function as an antiambipolar transistor and exhibit exceptional and well-balanced performance, including a superior peak-valley ratio of 2.4 × 105 and a high current density of 55 nA/μm. This work highlights the immense potential of 2D materials and their engineering to seamlessly integrate with existing semiconductor technology and enhance the efficiency of future nanoelectronics.
{"title":"Plasma-induced energy band evolution for two-dimensional heterogeneous anti-ambipolar transistors","authors":"Simran Shahi, Asma Ahmed, Ruizhe Yang, Anthony Cabanillas, Anindita Chakravarty, Maomao Liu, H. N. Jaiswal, Yu Fu, Yutong Guo, Satyajeetsinh Shaileshsin Jadeja, Hariharan Murugesan, Anthony Butler, Chu Te Chen, Joel Muhigirwa, Mohamed Enaitalla, Jun Liu, Fei Yao, Huamin Li","doi":"10.1116/6.0002888","DOIUrl":"https://doi.org/10.1116/6.0002888","url":null,"abstract":"With the rise of two-dimensional (2D) materials and nanoelectronics, compatible processes based on existing Si technologies are highly demanded to enable new and superior device functions. In this study, we utilized an O2 plasma treatment as a compatible and tunable method for anionic substitution doping in 2D WSe2. With an introduced WOx layer, moderate or even degenerate doping was realized to enhance hole transport in WSe2. By combining with 2D MoS2, an evolution of the 2D heterogeneous junction, in terms of the energy band structure and charge transport, was comprehensively investigated as a function of applied electric fields. The heterogeneous WSe2/MoS2 junction can function as an antiambipolar transistor and exhibit exceptional and well-balanced performance, including a superior peak-valley ratio of 2.4 × 105 and a high current density of 55 nA/μm. This work highlights the immense potential of 2D materials and their engineering to seamlessly integrate with existing semiconductor technology and enhance the efficiency of future nanoelectronics.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115092061","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}
A. Midouni, A. Chaouachi, Sami Barkaoui, Nejib Abassi, Samir Chakhari, A. Mahjoubi, D. Ghernaout, A. Hamzaoui, Muhammad Imran Khan, N. Elboughdiri
The present work described the enhanced photodegradation of the Congo Red (CR) dye under visible light irradiation. The co-doped ceria (Ce0.7La0.15Ca0.15O2−δ) was prepared by the colloidal solution combustion synthesis way using colloidal silica as a template. The characterization of the as-synthesized cerium oxide (CeO2, known as ceria) nanoparticles was assessed by diffraction, scanning electron microscopy, Raman spectroscopy, differential thermal analysis, thermοgravimetric analysis, ultraviolet (UV)–visible spectroscopy, and photoluminescence measurements. It revealed the cubic spinel structure with space group Fd-3 m (JCPDS card No. 34-0394), average size between 23 and 92 nm, and bandgap energy from 2.69 to 2.73 eV. The photodegradation of the CR dye under solar irradiation allowed studying the photocatalytic activities of the prepared ceria. After 180 min of light irradiation with the ceria 2 catalyst, CR absorbance was almost nil. The highest degradation rate ∼13.7 × 10−4 min−1 was recorded using co-doped ceria prepared with adding 1.0 ml of colloidal silica. This exciting activity can be attributed to the smallest particle size ∼23 nm, the smallest lattice parameter a = 5.4511 Å, and the catalyst’s highest bandgap ∼2.73 eV. Based on the investigation, ceria 2 nanoparticles have many possible uses in wastewater cleaning agent. Ceria 2 catalysts might be ideal for photocatalyst materials, UV filters, and photoelectric devices.
{"title":"Ce0.7La0.15Ca0.15O2−δ nanoparticles synthesis via colloidal solution combustion method: Studying structural and physicochemical properties and Congo Red dye photodegradation","authors":"A. Midouni, A. Chaouachi, Sami Barkaoui, Nejib Abassi, Samir Chakhari, A. Mahjoubi, D. Ghernaout, A. Hamzaoui, Muhammad Imran Khan, N. Elboughdiri","doi":"10.1116/6.0002825","DOIUrl":"https://doi.org/10.1116/6.0002825","url":null,"abstract":"The present work described the enhanced photodegradation of the Congo Red (CR) dye under visible light irradiation. The co-doped ceria (Ce0.7La0.15Ca0.15O2−δ) was prepared by the colloidal solution combustion synthesis way using colloidal silica as a template. The characterization of the as-synthesized cerium oxide (CeO2, known as ceria) nanoparticles was assessed by diffraction, scanning electron microscopy, Raman spectroscopy, differential thermal analysis, thermοgravimetric analysis, ultraviolet (UV)–visible spectroscopy, and photoluminescence measurements. It revealed the cubic spinel structure with space group Fd-3 m (JCPDS card No. 34-0394), average size between 23 and 92 nm, and bandgap energy from 2.69 to 2.73 eV. The photodegradation of the CR dye under solar irradiation allowed studying the photocatalytic activities of the prepared ceria. After 180 min of light irradiation with the ceria 2 catalyst, CR absorbance was almost nil. The highest degradation rate ∼13.7 × 10−4 min−1 was recorded using co-doped ceria prepared with adding 1.0 ml of colloidal silica. This exciting activity can be attributed to the smallest particle size ∼23 nm, the smallest lattice parameter a = 5.4511 Å, and the catalyst’s highest bandgap ∼2.73 eV. Based on the investigation, ceria 2 nanoparticles have many possible uses in wastewater cleaning agent. Ceria 2 catalysts might be ideal for photocatalyst materials, UV filters, and photoelectric devices.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116357599","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}
Sumit Choudhary, Midathala Yogesh, D. Schwarz, H. Funk, Subrata Ghosh, S. Sharma, J. Schulze, K. Gonsalves
Germanium channel FinFET transistors process integration on a silicon substrate is a promising candidate to extend the complementary metal–oxide–semiconductor semiconductor roadmap. This process has utilized the legacy of state-of-art silicon fabrication process technology and can be an immediate solution to integrate beyond Si channel materials over standard Si wafers. The fabrication of such devices involves several complicated technological steps, such as strain-free epi layers over the Si substrate to limit the substrate leakage and patterning of narrow and sharp fins over germanium (Ge). To overcome these issues, the active p-type germanium layers were grown over n-type germanium and virtual substrates. The poly ((4-(methacryloyloxy) phenyl) dimethyl sulfoniumtriflate) was utilized as a polymeric negative tone e-beam resist for sub-20 nm critical dimensions with low line edge roughness, line width roughness, and high etch resistance to pattern p-Ge fins to meet these concerns. Here, the devices use the mesa architecture that will allow low bandgap materials only at the active regions and raised fins to reduce the active area interaction with the substrate to suppress leakage currents. This paper discusses the simple five-layer process flow to fabricate FinFET devices with critical optimizations like resist prerequisite optimization conditions before exposure, alignment of various layers by electron beam alignment, pattern transfer optimizations using reactive ion etching, and bilayer resist for desired lift-off. The Ge-on-Si FinFET devices are fabricated with a width and gate length of 15/90 nm, respectively. The devices exhibit the improved ION/IOFF in order of ∼105, transconductance Gm ∼86 μS/μm, and subthreshold slope close to ∼90 mV/dec.
{"title":"Novel process integration flow of germanium-on-silicon FinFETs for low-power technologies","authors":"Sumit Choudhary, Midathala Yogesh, D. Schwarz, H. Funk, Subrata Ghosh, S. Sharma, J. Schulze, K. Gonsalves","doi":"10.1116/6.0002767","DOIUrl":"https://doi.org/10.1116/6.0002767","url":null,"abstract":"Germanium channel FinFET transistors process integration on a silicon substrate is a promising candidate to extend the complementary metal–oxide–semiconductor semiconductor roadmap. This process has utilized the legacy of state-of-art silicon fabrication process technology and can be an immediate solution to integrate beyond Si channel materials over standard Si wafers. The fabrication of such devices involves several complicated technological steps, such as strain-free epi layers over the Si substrate to limit the substrate leakage and patterning of narrow and sharp fins over germanium (Ge). To overcome these issues, the active p-type germanium layers were grown over n-type germanium and virtual substrates. The poly ((4-(methacryloyloxy) phenyl) dimethyl sulfoniumtriflate) was utilized as a polymeric negative tone e-beam resist for sub-20 nm critical dimensions with low line edge roughness, line width roughness, and high etch resistance to pattern p-Ge fins to meet these concerns. Here, the devices use the mesa architecture that will allow low bandgap materials only at the active regions and raised fins to reduce the active area interaction with the substrate to suppress leakage currents. This paper discusses the simple five-layer process flow to fabricate FinFET devices with critical optimizations like resist prerequisite optimization conditions before exposure, alignment of various layers by electron beam alignment, pattern transfer optimizations using reactive ion etching, and bilayer resist for desired lift-off. The Ge-on-Si FinFET devices are fabricated with a width and gate length of 15/90 nm, respectively. The devices exhibit the improved ION/IOFF in order of ∼105, transconductance Gm ∼86 μS/μm, and subthreshold slope close to ∼90 mV/dec.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121070154","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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