The electrical characteristics and stability of rectangular nanobar interconnects are investigated owing to their importance and reliability concern in electronic devices. One dimensional gold and copper nanobars (cross section 150–180 × 80–150 nm2 and length 3.0–5.0 μm), fabricated by milling of respective thin films with a 30 keV Ga+ ion probe (size 10–20 nm) at a current of ∼1 nA, are studied for their current bearing capacity and temperature profile caused by Joule heating. The temperature attained is shown to depend on the length with a maximum lying at the bar center. The electromigration of species (drift velocity for gold being ∼0.92 nm/s) forms void and induces breakage in the bar at a current density of ∼1011 A m−2. The phenomenon is governed by the bar length, prevailing temperature gradient, crystal defects, and grain boundaries. The thermo-migration process facilitates or impedes the electromigration effects depending upon the direction of the thermal gradient and electric field. The I–V characteristics of a gold bar with a gap of ∼44 nm under a vacuum of ∼10−6 mbar follow a classical Child–Langmuir V3/2 law in the voltage range of 10–45 V, but the copper electrodes with a large gap of ∼250 nm (created by ion milling) demonstrate V0.05-dependence up to 32 V, V1/2-law at 39–58 V, and Fowler–Nordheim emission [with an effective area of 1600 nm2 and a field enhancement factor of 8.1] above 66 V.
{"title":"Electrical characteristics, stability, electromigration, Joule heating, and reliability aspect of focused ion beam fabricated gold and copper nanobar interconnects on SiO2 and glass substrates","authors":"A. Singh, J. Kumar","doi":"10.1116/6.0000514","DOIUrl":"https://doi.org/10.1116/6.0000514","url":null,"abstract":"The electrical characteristics and stability of rectangular nanobar interconnects are investigated owing to their importance and reliability concern in electronic devices. One dimensional gold and copper nanobars (cross section 150–180 × 80–150 nm2 and length 3.0–5.0 μm), fabricated by milling of respective thin films with a 30 keV Ga+ ion probe (size 10–20 nm) at a current of ∼1 nA, are studied for their current bearing capacity and temperature profile caused by Joule heating. The temperature attained is shown to depend on the length with a maximum lying at the bar center. The electromigration of species (drift velocity for gold being ∼0.92 nm/s) forms void and induces breakage in the bar at a current density of ∼1011 A m−2. The phenomenon is governed by the bar length, prevailing temperature gradient, crystal defects, and grain boundaries. The thermo-migration process facilitates or impedes the electromigration effects depending upon the direction of the thermal gradient and electric field. The I–V characteristics of a gold bar with a gap of ∼44 nm under a vacuum of ∼10−6 mbar follow a classical Child–Langmuir V3/2 law in the voltage range of 10–45 V, but the copper electrodes with a large gap of ∼250 nm (created by ion milling) demonstrate V0.05-dependence up to 32 V, V1/2-law at 39–58 V, and Fowler–Nordheim emission [with an effective area of 1600 nm2 and a field enhancement factor of 8.1] above 66 V.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80072116","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. G. Kolosko, S. Filippov, E. O. Popov, S. Ponyaev, A. Shchegolkov
This work represents a new approach for analyzing emission characteristics of multitip field cathodes. The approach is based on using a computerized field emission projector to investigate the behavior of the microscopic emission sites of the field cathode surface. Adsorption-desorption processes on the surface—which influence the emission current level—were investigated by tracking the individual emission sites under conditions of a sharp decrease and increase in the voltage level. An analysis of the transient process showed that emission sites with highest local currents almost do not participate in changing the overall level of emission current, but they became smaller with a decrease in the step voltage contribution of the dimmest sites. Similar dependences were obtained for rising voltage levels but with much faster transitions.
{"title":"Investigation of the current level instability of the multitip field emitters with computerized field emission projector","authors":"A. G. Kolosko, S. Filippov, E. O. Popov, S. Ponyaev, A. Shchegolkov","doi":"10.1116/6.0000622","DOIUrl":"https://doi.org/10.1116/6.0000622","url":null,"abstract":"This work represents a new approach for analyzing emission characteristics of multitip field cathodes. The approach is based on using a computerized field emission projector to investigate the behavior of the microscopic emission sites of the field cathode surface. Adsorption-desorption processes on the surface—which influence the emission current level—were investigated by tracking the individual emission sites under conditions of a sharp decrease and increase in the voltage level. An analysis of the transient process showed that emission sites with highest local currents almost do not participate in changing the overall level of emission current, but they became smaller with a decrease in the step voltage contribution of the dimmest sites. Similar dependences were obtained for rising voltage levels but with much faster transitions.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78911019","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}
S. Schlipf, A. Clausner, J. Paul, S. Capecchi, L. Wambera, K. Meier, E. Zschech
Chip-package interaction-caused mobility degradation in CMOS transistors is a critical degradation mechanism for microelectronic devices. An approach based on nondestructive indentation is applied to induce highly localized stress fields. Strain-sensitive ring oscillator circuits are integrated to monitor parametric deviations during mechanical loading. In this study, the indentation technique is used to investigate the impact of the chip layout and geometry of a flip chip-packaged test chip. Complementary FE simulation provides a better understanding of the relevant stress-strain fields and enables a comparison of the parametric circuit deviations within a dedicated stress tensor. The results demonstrate the capability to study the stress-strain distribution in microelectronic devices during external loading with indentation and to determine its impact on transistor degradation.
{"title":"Chip layout impact on stress-induced mobility degradation studied with indentation","authors":"S. Schlipf, A. Clausner, J. Paul, S. Capecchi, L. Wambera, K. Meier, E. Zschech","doi":"10.1116/6.0000581","DOIUrl":"https://doi.org/10.1116/6.0000581","url":null,"abstract":"Chip-package interaction-caused mobility degradation in CMOS transistors is a critical degradation mechanism for microelectronic devices. An approach based on nondestructive indentation is applied to induce highly localized stress fields. Strain-sensitive ring oscillator circuits are integrated to monitor parametric deviations during mechanical loading. In this study, the indentation technique is used to investigate the impact of the chip layout and geometry of a flip chip-packaged test chip. Complementary FE simulation provides a better understanding of the relevant stress-strain fields and enables a comparison of the parametric circuit deviations within a dedicated stress tensor. The results demonstrate the capability to study the stress-strain distribution in microelectronic devices during external loading with indentation and to determine its impact on transistor degradation.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83522466","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}
As ultraviolet (UV) sensors are often employed in external environments, they should be able to function efficiently outdoors while remaining unaffected by liquids or changes in humidity. In this study, we developed a tin (IV) oxide nanowire (SnO2 NW)/graphene heterostructure-based UV detector that can accurately detect UV light without being affected by exposure to liquids. A (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl) phosphonic acid (HDF–PA) passivation layer was self-assembled on an SnO2 NW/graphene heterostructure sensing channel to make its surface superhydrophobic (contact angle of ∼154°). This configuration prevents UV sensing distortion due to current leakage in case the sensor is exposed to various liquids. HDF–PA, which is less than 1.5 nm thick, slightly reduces UV transmission, rendering it a suitable passivation material to repel external liquids. In addition, the heterostructure of SnO2 NWs and graphene, as a UV sensing channel, can provide higher UV sensitivity than that of pristine graphene. The proposed method can be applied to fabricate stable, sensitive, and robust optical sensors that can withstand various environmental conditions.
{"title":"Superhydrophobic SnO2 nanowire/graphene heterostructure-based ultraviolet detectors","authors":"Y. Kang, Sanghyun Ju","doi":"10.1116/6.0000565","DOIUrl":"https://doi.org/10.1116/6.0000565","url":null,"abstract":"As ultraviolet (UV) sensors are often employed in external environments, they should be able to function efficiently outdoors while remaining unaffected by liquids or changes in humidity. In this study, we developed a tin (IV) oxide nanowire (SnO2 NW)/graphene heterostructure-based UV detector that can accurately detect UV light without being affected by exposure to liquids. A (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl) phosphonic acid (HDF–PA) passivation layer was self-assembled on an SnO2 NW/graphene heterostructure sensing channel to make its surface superhydrophobic (contact angle of ∼154°). This configuration prevents UV sensing distortion due to current leakage in case the sensor is exposed to various liquids. HDF–PA, which is less than 1.5 nm thick, slightly reduces UV transmission, rendering it a suitable passivation material to repel external liquids. In addition, the heterostructure of SnO2 NWs and graphene, as a UV sensing channel, can provide higher UV sensitivity than that of pristine graphene. The proposed method can be applied to fabricate stable, sensitive, and robust optical sensors that can withstand various environmental conditions.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78535126","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}
E. Hieckmann, U. Mühle, P. Chekhonin, E. Zschech, J. Gambino
Deep trenches, as essential elements of silicon chips used in electronic high-power and high-frequency devices, are known as starting points for dislocation generation under the influence of internal mechanical stresses resulting mainly from the difference in the thermal expansion coefficients between silicon and silicon dioxide. Since the electrical insulation of the devices requires a sequence of mechanical, chemical, and high-temperature processes during the preparation of the deep trenches, including the formation of an amorphous SiO2 edge layer, the emergence of the internal stresses is hardly avoidable. The method of cross correlation backscattered electron diffraction in the scanning electron microscope is used here to quantitatively determine the magnitude and local distribution of internal stresses in silicon around the deep trenches after four different process steps. For this purpose, Kikuchi diffraction images are recorded of the wafer cross section areas along lines perpendicular and parallel to the deep trenches. After Fourier transformation, these images are cross correlated with the Fourier transform of the diffraction image from a stressfree reference sample site. The well-established numerical evaluation of cross correlation functions provides the complete distortion tensor for each measuring point of the line scan, from which the stress tensor can be calculated using Hooke's law. It is found that the in-plane normal stress component σ11 perpendicular to the long edges of the deep trench is larger than the other stress components. That means it essentially determines the magnitude of the von-Mises stress, which was determined as a general stress indicator for all measuring points, too. A characteristic feature is the local distribution of the stress component σ11 with maximum tensile stresses of some hundred megapascals at transition between Si and amorphous SiO2 on the long edges of the deep trench, and with even higher maximum compressive stresses immediately below the bottom of the deep trench. At a distance of about 2 μm from the edges of a single deep trench, all stress components decrease to negligibly small values so that steep stress gradients occur. The range and distribution of tensile and compressive stresses are in accordance with finite element simulations; however, the measured stresses are higher than expected for all investigated states so that dislocation formation seems to be possible. The influence of the electron acceleration voltage on the determination of the internal stresses is discussed as well.
{"title":"Investigations of internal stresses in high-voltage devices with deep trenches","authors":"E. Hieckmann, U. Mühle, P. Chekhonin, E. Zschech, J. Gambino","doi":"10.1116/6.0000515","DOIUrl":"https://doi.org/10.1116/6.0000515","url":null,"abstract":"Deep trenches, as essential elements of silicon chips used in electronic high-power and high-frequency devices, are known as starting points for dislocation generation under the influence of internal mechanical stresses resulting mainly from the difference in the thermal expansion coefficients between silicon and silicon dioxide. Since the electrical insulation of the devices requires a sequence of mechanical, chemical, and high-temperature processes during the preparation of the deep trenches, including the formation of an amorphous SiO2 edge layer, the emergence of the internal stresses is hardly avoidable. The method of cross correlation backscattered electron diffraction in the scanning electron microscope is used here to quantitatively determine the magnitude and local distribution of internal stresses in silicon around the deep trenches after four different process steps. For this purpose, Kikuchi diffraction images are recorded of the wafer cross section areas along lines perpendicular and parallel to the deep trenches. After Fourier transformation, these images are cross correlated with the Fourier transform of the diffraction image from a stressfree reference sample site. The well-established numerical evaluation of cross correlation functions provides the complete distortion tensor for each measuring point of the line scan, from which the stress tensor can be calculated using Hooke's law. It is found that the in-plane normal stress component σ11 perpendicular to the long edges of the deep trench is larger than the other stress components. That means it essentially determines the magnitude of the von-Mises stress, which was determined as a general stress indicator for all measuring points, too. A characteristic feature is the local distribution of the stress component σ11 with maximum tensile stresses of some hundred megapascals at transition between Si and amorphous SiO2 on the long edges of the deep trench, and with even higher maximum compressive stresses immediately below the bottom of the deep trench. At a distance of about 2 μm from the edges of a single deep trench, all stress components decrease to negligibly small values so that steep stress gradients occur. The range and distribution of tensile and compressive stresses are in accordance with finite element simulations; however, the measured stresses are higher than expected for all investigated states so that dislocation formation seems to be possible. The influence of the electron acceleration voltage on the determination of the internal stresses is discussed as well.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73343839","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}
Over the past several decades, atomic force microscopy (AFM) has advanced from a technique used primarily for surface topography imaging to one capable of characterizing a range of chemical, mechanical, electrical, and magnetic material properties with subnanometer resolution. In this review, we focus on AFM as a nanoscale mechanical property characterization tool and examine various AFM contact and intermittent contact modes that add mechanical contrast to an imaged surface. Through detailed analysis of the tip-sample contact mechanics, this contrast can be converted into quantitative measurements of various nanomechanical properties including elastic modulus, shear modulus, wear rate, adhesion, and viscoelasticity. Different AFM modes that provide such measurements are compared and contrasted in this work on a wide range of materials including ceramics, metals, semiconductors, polymers, and biomaterials. In the last few years, considerable improvements have been made in terms of fast imaging capabilities, tip preservation, and quantitative mechanics for multifrequency measurements as well as well-known AFM modes like amplitude modulation and peak-force tapping. In line with these developments, a major highlight of this review is the discussion of the operation and capabilities of one such mode, namely, intermittent contact resonance AFM (ICR-AFM). The applications of ICR-AFM to nanoscale surface and subsurface quantitative mechanical characterizations are reviewed with specific examples provided for thin polymeric films and patterned nanostructures of organosilicate dielectric materials. The combination of AFM-based mechanical characterization with AFM-based chemical spectroscopy to allow nanoscale structure-property characterization is also discussed and demonstrated for the analysis of low-k dielectric/copper nanoelectronic interconnect structures and further highlights synergistic advances in the AFM field.
{"title":"Atomic force microscopy for nanoscale mechanical property characterization","authors":"G. Stan, S. King","doi":"10.1116/6.0000544","DOIUrl":"https://doi.org/10.1116/6.0000544","url":null,"abstract":"Over the past several decades, atomic force microscopy (AFM) has advanced from a technique used primarily for surface topography imaging to one capable of characterizing a range of chemical, mechanical, electrical, and magnetic material properties with subnanometer resolution. In this review, we focus on AFM as a nanoscale mechanical property characterization tool and examine various AFM contact and intermittent contact modes that add mechanical contrast to an imaged surface. Through detailed analysis of the tip-sample contact mechanics, this contrast can be converted into quantitative measurements of various nanomechanical properties including elastic modulus, shear modulus, wear rate, adhesion, and viscoelasticity. Different AFM modes that provide such measurements are compared and contrasted in this work on a wide range of materials including ceramics, metals, semiconductors, polymers, and biomaterials. In the last few years, considerable improvements have been made in terms of fast imaging capabilities, tip preservation, and quantitative mechanics for multifrequency measurements as well as well-known AFM modes like amplitude modulation and peak-force tapping. In line with these developments, a major highlight of this review is the discussion of the operation and capabilities of one such mode, namely, intermittent contact resonance AFM (ICR-AFM). The applications of ICR-AFM to nanoscale surface and subsurface quantitative mechanical characterizations are reviewed with specific examples provided for thin polymeric films and patterned nanostructures of organosilicate dielectric materials. The combination of AFM-based mechanical characterization with AFM-based chemical spectroscopy to allow nanoscale structure-property characterization is also discussed and demonstrated for the analysis of low-k dielectric/copper nanoelectronic interconnect structures and further highlights synergistic advances in the AFM field.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90758659","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}
Haoqing Zhang, J. Pekárek, Jianguo Feng, Xiaocheng Liu, Huanan Li, Hanliang Zhu, V. Svatos, I. Gablech, P. Podešva, Sheng Ni, L. Yobas, P. Neužil
Microfluidic devices typically require complex shapes such as funnels, spirals, splitters, channels with different widths, or customized objects of arbitrary complexity with a smooth transition between these elements. Device layouts are generally designed by software developed for the design of integrated circuits or by general computer-aided design drawing tools. Both methods have their limitations, making these tasks time consuming. Here, a script-based, time-effective method to generate the layout of various microfluidic chips with complex geometries is presented. The present work uses the nanolithography toolbox (NT), a platform-independent software package, which employs parameterized fundamental blocks (cells) to create microscale and nanoscale structures. In order to demonstrate the functionality and efficiency of the NT, a few classical microfluidic devices were designed using the NT and then fabricated in glass/silicon using standard microfabrication techniques and in poly(dimethylsiloxane) using soft lithography as well as more complex techniques used for flow-through calorimetry. In addition, the functionality of a few of the fabricated devices was tested. The powerful method proposed allows the creation of microfluidic devices with complex layouts in an easy way, simplifying the design process and improving design efficiency. Thus, it holds great potential for broad applications in microfluidic device design.
{"title":"nanolithography toolbox—Simplifying the design complexity of microfluidic chips","authors":"Haoqing Zhang, J. Pekárek, Jianguo Feng, Xiaocheng Liu, Huanan Li, Hanliang Zhu, V. Svatos, I. Gablech, P. Podešva, Sheng Ni, L. Yobas, P. Neužil","doi":"10.1116/6.0000562","DOIUrl":"https://doi.org/10.1116/6.0000562","url":null,"abstract":"Microfluidic devices typically require complex shapes such as funnels, spirals, splitters, channels with different widths, or customized objects of arbitrary complexity with a smooth transition between these elements. Device layouts are generally designed by software developed for the design of integrated circuits or by general computer-aided design drawing tools. Both methods have their limitations, making these tasks time consuming. Here, a script-based, time-effective method to generate the layout of various microfluidic chips with complex geometries is presented. The present work uses the nanolithography toolbox (NT), a platform-independent software package, which employs parameterized fundamental blocks (cells) to create microscale and nanoscale structures. In order to demonstrate the functionality and efficiency of the NT, a few classical microfluidic devices were designed using the NT and then fabricated in glass/silicon using standard microfabrication techniques and in poly(dimethylsiloxane) using soft lithography as well as more complex techniques used for flow-through calorimetry. In addition, the functionality of a few of the fabricated devices was tested. The powerful method proposed allows the creation of microfluidic devices with complex layouts in an easy way, simplifying the design process and improving design efficiency. Thus, it holds great potential for broad applications in microfluidic device design.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83330921","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}
K. N. Rathod, Keval Gadani, Davit Dhruv, V. G. Shrimali, S. Solanki, A. D. Joshi, J. Singh, K. Chae, K. Asokan, P. Solanki, N. Shah
In this study, we investigate the effect of ion irradiation on Y0.95Ca0.05MnO3 (YCMO) thin films. X-ray diffraction and Raman spectroscopy measurements show single-phase and strain/stress modifications with ion irradiation. Rutherford backscattering spectrometry confirms the variation in oxygen vacancies. The near-edge x-ray absorption fine structure shows valence state reduction of Mn ions, which is attributed to oxygen vacancies. The optimal resistive switching ratio is observed at the lowest fluence (1 × 1011 ions/cm2) of ion irradiation. At higher fluences (1 × 1012 and 1 × 1013 ions/cm2), the strain relaxation and oxygen vacancy annihilation are ascribed to the local annealing effect. The double logarithmic curve and modified Langmuir–Child's law satisfy the space charge limited conduction mechanism in all thin films. These results suggest the crucial role of irradiation-induced oxygen vacancies in modifying the electronic structure and electrical properties of YCMO thin films.
{"title":"Effect of oxygen vacancy gradient on ion-irradiated Ca-doped YMnO3 thin films","authors":"K. N. Rathod, Keval Gadani, Davit Dhruv, V. G. Shrimali, S. Solanki, A. D. Joshi, J. Singh, K. Chae, K. Asokan, P. Solanki, N. Shah","doi":"10.1116/6.0000507","DOIUrl":"https://doi.org/10.1116/6.0000507","url":null,"abstract":"In this study, we investigate the effect of ion irradiation on Y0.95Ca0.05MnO3 (YCMO) thin films. X-ray diffraction and Raman spectroscopy measurements show single-phase and strain/stress modifications with ion irradiation. Rutherford backscattering spectrometry confirms the variation in oxygen vacancies. The near-edge x-ray absorption fine structure shows valence state reduction of Mn ions, which is attributed to oxygen vacancies. The optimal resistive switching ratio is observed at the lowest fluence (1 × 1011 ions/cm2) of ion irradiation. At higher fluences (1 × 1012 and 1 × 1013 ions/cm2), the strain relaxation and oxygen vacancy annihilation are ascribed to the local annealing effect. The double logarithmic curve and modified Langmuir–Child's law satisfy the space charge limited conduction mechanism in all thin films. These results suggest the crucial role of irradiation-induced oxygen vacancies in modifying the electronic structure and electrical properties of YCMO thin films.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89380268","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}
Group-IV alloys of Ge and/or Si with Sn are challenging to prepare due to the low solubility of Sn in both of these elements. Herein, we describe a remote plasma-enhanced chemical vapor deposition (RPECVD) system designed to synthesize such group-IV alloys. Thin films of Ge, Ge1−ySiy, Ge1−xSnx, and Ge1−x−ySiySnx were deposited in the range of 280−410 °C on Si (001) substrates utilizing a remote He plasma with downstream injected mixtures of SnCl4, SiH4, and/or GeH4 precursors. The composition and structural properties of these RPECVD films were characterized with x-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy. They were found to be crystalline, oriented with the substrate, and nearly relaxed due to the formation of an ∼5 nm thick interface layer with a high density of edge dislocations and stacking faults.
{"title":"Design of a remote plasma-enhanced chemical vapor deposition system for growth of tin containing group-IV alloys","authors":"G. Grzybowski, M. Ware, A. Kiefer, B. Claflin","doi":"10.1116/6.0000406","DOIUrl":"https://doi.org/10.1116/6.0000406","url":null,"abstract":"Group-IV alloys of Ge and/or Si with Sn are challenging to prepare due to the low solubility of Sn in both of these elements. Herein, we describe a remote plasma-enhanced chemical vapor deposition (RPECVD) system designed to synthesize such group-IV alloys. Thin films of Ge, Ge1−ySiy, Ge1−xSnx, and Ge1−x−ySiySnx were deposited in the range of 280−410 °C on Si (001) substrates utilizing a remote He plasma with downstream injected mixtures of SnCl4, SiH4, and/or GeH4 precursors. The composition and structural properties of these RPECVD films were characterized with x-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy. They were found to be crystalline, oriented with the substrate, and nearly relaxed due to the formation of an ∼5 nm thick interface layer with a high density of edge dislocations and stacking faults.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89564192","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 paper, we demonstrate the fabrication of TiO2 patterns on both planar and various highly curved substrates via nanoimprint lithography followed by thermal treatment. First, a photocurable Ti-containing monomer is synthesized by reacting titanium (IV) ethoxide with 2-(methacryloyloxy)ethyl acetoacetate. The monomer is formulated with a visible light photoinitiator system to prepare a photocurable nanoimprint resin (TiO2-resin). Afterward, the resin is able to be patterned onto highly curved substrates using a soft mold via the double transfer technique. Resin patterns can be simply transformed to TiO2 patterns after thermal treatment. Refractive index of TiO2 can also be tuned by changing the calcination condition.
{"title":"Direct imprinting of TiO2 patterns on highly curved substrates","authors":"Ming Luo, Xin Hu","doi":"10.1116/6.0000554","DOIUrl":"https://doi.org/10.1116/6.0000554","url":null,"abstract":"In this paper, we demonstrate the fabrication of TiO2 patterns on both planar and various highly curved substrates via nanoimprint lithography followed by thermal treatment. First, a photocurable Ti-containing monomer is synthesized by reacting titanium (IV) ethoxide with 2-(methacryloyloxy)ethyl acetoacetate. The monomer is formulated with a visible light photoinitiator system to prepare a photocurable nanoimprint resin (TiO2-resin). Afterward, the resin is able to be patterned onto highly curved substrates using a soft mold via the double transfer technique. Resin patterns can be simply transformed to TiO2 patterns after thermal treatment. Refractive index of TiO2 can also be tuned by changing the calcination condition.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88957913","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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