Mo/Si muitilayer mirrors(30 periods,doublelayer thickness 7nm)with the AZ-PF514 resist pattern whose smallest lines and spaces structure was 0.5pm were etched by reactive ion etching(RIE)in a fluorinated plasma.The et...Mo/Si muitilayer mirrors(30 periods,doublelayer thickness 7nm)with the AZ-PF514 resist pattern whose smallest lines and spaces structure was 0.5pm were etched by reactive ion etching(RIE)in a fluorinated plasma.The etch rate,selectivity and etch profile were investigated as a function of the gas mixture,pressure,and plasma rf power.The groove depth and the etch proHle were investigated by an atomic force microscope before RIE,after RIE and after resist removal.展开更多
The thermal and chemical stabilities of Mo/Si multilayer structure used in Bragg-Fresnel optics were studied to get optimal technological parameters of pattern generation.Mo/Si multilayers were annealed at temperature...The thermal and chemical stabilities of Mo/Si multilayer structure used in Bragg-Fresnel optics were studied to get optimal technological parameters of pattern generation.Mo/Si multilayers were annealed at temperature ranging from 360 to 770 K,treated with acetone and 5‰NaOH solution,and characterized by small-angle x-ray diffraction technique as well as x-ray photoelectron spectroscopy and Olympus microscopy.展开更多
Efficient thermal management is critical to the reliability and performance of nanoscale electronic and photonic devices,particularly those incorporating multilayer structures.In this study,non-equilibrium molecular d...Efficient thermal management is critical to the reliability and performance of nanoscale electronic and photonic devices,particularly those incorporating multilayer structures.In this study,non-equilibrium molecular dynamics simulations were conducted to systematically investigate the effects of temperature,penetration depth,and Si layer thickness on the interfacial thermal resistance(ITR)in nanometer-scale Mo/Si multilayers,widely employed in extreme ultraviolet lithography.The results indicate that:(i)temperature variations exert a negligible influence on the ITR of amorphous Mo/Si interfaces,which remains stable across the range of 200-900 K;(ii)increasing penetration depth enhances the overlap of phonon density of states,thereby significantly reducing ITR;(iii)the ITR decreases with increasing Si thickness up to4.2 nm due to quasi-ballistic phonon transport,but rises again as phonon scattering becomes more pronounced at larger thicknesses.This study provides quantitative insights into heat transfer mechanisms at amorphous interfaces and also offers a feasible strategy for tailoring interfacial thermal transport through structural design.展开更多
Mo/Si multilayers were fabricated by using magnetron sputtering method at different background pressures:6×10-5 Torr,3×10-5 Torr,and 3×10-6 Torr.The reflectivity of the Mo/Si multilayers increased from ...Mo/Si multilayers were fabricated by using magnetron sputtering method at different background pressures:6×10-5 Torr,3×10-5 Torr,and 3×10-6 Torr.The reflectivity of the Mo/Si multilayers increased from 1.93% to 16.63%,and the center wavelength revealed a blue shift to 0.12 nm with the decrease of background pressure.Grazing incident X-ray diffraction(GIXRD) indicated that multilayers fabricated at high background pressure possessed better periodic structure and thinner Mo-on-Si interlayers.Low crystallization degree in(110) preferred the orientation of Mo layers and serious interdiffusion in the Mo/Si multilayers fabricated at low background pressure were observed by transmission electron microscopy(TEM).According to quantitative analysis of microstructural parameters,the Mo layers thickness and thickness ratio of Mo/Si multilayers both decreased and approached the design value gradually by the decrease of background pressure.In addition,the thicknesses of Mo-on-Si and Si-on-Mo interlayers were 1.17 nm and 0.85 nm respectively.It is suggested that the influence of background pressures on the microstructure has a critical role in determining the optical properties of Mo/Si multilayers.展开更多
By direct observations of transmission electron microscopy (TEM), irreversible morphological transformations of as-deposited amorphous Au/Si multilayer (a-Au/a-Si) were observed on heating. The well arrayed sequence o...By direct observations of transmission electron microscopy (TEM), irreversible morphological transformations of as-deposited amorphous Au/Si multilayer (a-Au/a-Si) were observed on heating. The well arrayed sequence of the multilayer changed to zigzag layered structure at 478 K (=Tzig). Finally, the zigzag structure transformed to Au nanoparticles at 508 K. The distribution of the Au nanoparticles was random within the thin film. In situ X-ray diffraction during heating can clarify partial crystallization Si (c-Si) in the multilayer at 450 K (= ), which corresponds to metal induced crystallization (MIC) from amorphous Si (a-Si) accompanying by Au diffusion. On further heating, a-Au started to crystallize at around 480 K (=Tc) and gradually grew up to 3.2 nm in radius, although the volume of c-Si was almost constant. Continuous heating caused crystal Au (c-Au) melting into liquid AuSi (l-AuSi) at 600 K (= ), which was lower than bulk eutectic temperature ( ). Due to the AuSi eutectic effect, reversible phase transition between liquid and solid occurred once temperature is larger than . Proportionally to the maximum temperatures at each cycles (673, 873 and 1073 K), both and Au crystallization temperature approaches to . Using a thermodynamic theory of the nanoparticle formation in the eutectic system, the relationship between and the nanoparticle size is explained.展开更多
Si/a-C:H(Ag)multilayer films with different modulation periods are prepared to test their potential applications in human body.The composition,microstructure,mechanical and tribological properties in the simulated bod...Si/a-C:H(Ag)multilayer films with different modulation periods are prepared to test their potential applications in human body.The composition,microstructure,mechanical and tribological properties in the simulated body fluid are investigated.The results show the concentration of Ag first decreases and then increases with the modulation period decreasing from 984 nm to 250 nm.Whereas the C content has an opposite variation trend.Notably,the concentration of Ag plays a more important role than the modulation period in the properties of the multilayer film.The a-C:H sublayer of the film with an appropriate Ag concentration(8.97 at.%)(modulation period of 512 nm)maintains the highest sp3/sp2 ratio,surface roughness and hardness,and excellent tribological property in the stimulated body fluid.An appropriate number of Ag atoms and size of Ag atom allow the Ag atoms to easily enter into the contact interface for load bearing and lubricating.This work proves that the Ag nanoparticles in the a-C:H sublayer plays a more important role in the tribological properties of the composite-multilayer film in stimulated body fluid condition.展开更多
Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size,strong anti-interference ability,high current-driven mobility,and compatibility ...Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size,strong anti-interference ability,high current-driven mobility,and compatibility with existing spintronic technology.In this work,we present a tunable room temperature skyrmion platform based on multilayer stacks of MgO/FeNiB/Mo.We systematically studied the creation of magnetic skyrmions in MgO/FeNiB/Mo multilayer structures with perpendicular magnetic anisotropy(PMA).In these structures,the magnetic anisotropy changes from PMA to in-plane magnetic anisotropy(IMA)as the thickness of FeNiB layer increases.By adjusting the applied magnetic field and electric current,stable and high-density skyrmions can be obtained in the material system.The discovery of this material broadens the exploration of new materials for skyrmion and promotes the development of spintronic devices based on skyrmions.展开更多
We investigated the effects of Si-layer-thickness ratios on ultraviolet (UV) peak intensities of Si/ SiO2 multilayered films produced by alternately stacking several-nanometer-thick Si and SiO2 layers using radio-freq...We investigated the effects of Si-layer-thickness ratios on ultraviolet (UV) peak intensities of Si/ SiO2 multilayered films produced by alternately stacking several-nanometer-thick Si and SiO2 layers using radio-frequency sputtering for the first time. The Si-layer-thickness ratio of the Si/SiO2 film is a very important parameter for enhancing the peak intensity because the ratio is concerned with the size of Si nanocrystals in the film, which might affect the intensity of the UV light emission from the film. We prepared seven samples with various estimated Si-layer-thickness ratios, and measured the photoluminescence spectra of the samples after annealing at 1150°C, 1200°C, or 1250°C for 25 min. From our experiments, we estimate that the proper Si-layer-thickness ratio to obtain the strongest UV peaks from the Si/SiO2 multilayered films is around 0.29. Such a UV-lightemitting thin film is expected to be used in future higher-density optical-disk systems.展开更多
基金the German Research Society Deutsche Forschungsgesellschaft(Forschergruppe Nanometerschichtsysteme).
文摘Mo/Si muitilayer mirrors(30 periods,doublelayer thickness 7nm)with the AZ-PF514 resist pattern whose smallest lines and spaces structure was 0.5pm were etched by reactive ion etching(RIE)in a fluorinated plasma.The etch rate,selectivity and etch profile were investigated as a function of the gas mixture,pressure,and plasma rf power.The groove depth and the etch proHle were investigated by an atomic force microscope before RIE,after RIE and after resist removal.
基金Supported by the National Natural Science Foundation of China under Grant No.69578023。
文摘The thermal and chemical stabilities of Mo/Si multilayer structure used in Bragg-Fresnel optics were studied to get optimal technological parameters of pattern generation.Mo/Si multilayers were annealed at temperature ranging from 360 to 770 K,treated with acetone and 5‰NaOH solution,and characterized by small-angle x-ray diffraction technique as well as x-ray photoelectron spectroscopy and Olympus microscopy.
基金supported by the National Natural Science Foundation of China(Grant No.52206092)the National Key R&D Program of China(Grant No.2024YFF0508900)+1 种基金the Big Data Computing Center of Southeast Universitythe Center for Fundamental and Interdisciplinary Sciences of Southeast University。
文摘Efficient thermal management is critical to the reliability and performance of nanoscale electronic and photonic devices,particularly those incorporating multilayer structures.In this study,non-equilibrium molecular dynamics simulations were conducted to systematically investigate the effects of temperature,penetration depth,and Si layer thickness on the interfacial thermal resistance(ITR)in nanometer-scale Mo/Si multilayers,widely employed in extreme ultraviolet lithography.The results indicate that:(i)temperature variations exert a negligible influence on the ITR of amorphous Mo/Si interfaces,which remains stable across the range of 200-900 K;(ii)increasing penetration depth enhances the overlap of phonon density of states,thereby significantly reducing ITR;(iii)the ITR decreases with increasing Si thickness up to4.2 nm due to quasi-ballistic phonon transport,but rises again as phonon scattering becomes more pronounced at larger thicknesses.This study provides quantitative insights into heat transfer mechanisms at amorphous interfaces and also offers a feasible strategy for tailoring interfacial thermal transport through structural design.
基金supported by the National Natural Sciences Foundation of China (Grant No.50671042)the Open Project of State Key Laboratory of Applied Optics (Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences) (Grant No.201004)the Ph.D.Innovation Programs Foundation of Jiangsu Province (Grant No.CXZZ12_0671)
文摘Mo/Si multilayers were fabricated by using magnetron sputtering method at different background pressures:6×10-5 Torr,3×10-5 Torr,and 3×10-6 Torr.The reflectivity of the Mo/Si multilayers increased from 1.93% to 16.63%,and the center wavelength revealed a blue shift to 0.12 nm with the decrease of background pressure.Grazing incident X-ray diffraction(GIXRD) indicated that multilayers fabricated at high background pressure possessed better periodic structure and thinner Mo-on-Si interlayers.Low crystallization degree in(110) preferred the orientation of Mo layers and serious interdiffusion in the Mo/Si multilayers fabricated at low background pressure were observed by transmission electron microscopy(TEM).According to quantitative analysis of microstructural parameters,the Mo layers thickness and thickness ratio of Mo/Si multilayers both decreased and approached the design value gradually by the decrease of background pressure.In addition,the thicknesses of Mo-on-Si and Si-on-Mo interlayers were 1.17 nm and 0.85 nm respectively.It is suggested that the influence of background pressures on the microstructure has a critical role in determining the optical properties of Mo/Si multilayers.
文摘By direct observations of transmission electron microscopy (TEM), irreversible morphological transformations of as-deposited amorphous Au/Si multilayer (a-Au/a-Si) were observed on heating. The well arrayed sequence of the multilayer changed to zigzag layered structure at 478 K (=Tzig). Finally, the zigzag structure transformed to Au nanoparticles at 508 K. The distribution of the Au nanoparticles was random within the thin film. In situ X-ray diffraction during heating can clarify partial crystallization Si (c-Si) in the multilayer at 450 K (= ), which corresponds to metal induced crystallization (MIC) from amorphous Si (a-Si) accompanying by Au diffusion. On further heating, a-Au started to crystallize at around 480 K (=Tc) and gradually grew up to 3.2 nm in radius, although the volume of c-Si was almost constant. Continuous heating caused crystal Au (c-Au) melting into liquid AuSi (l-AuSi) at 600 K (= ), which was lower than bulk eutectic temperature ( ). Due to the AuSi eutectic effect, reversible phase transition between liquid and solid occurred once temperature is larger than . Proportionally to the maximum temperatures at each cycles (673, 873 and 1073 K), both and Au crystallization temperature approaches to . Using a thermodynamic theory of the nanoparticle formation in the eutectic system, the relationship between and the nanoparticle size is explained.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51801133,51505318,and 51671140)the Science and Technology Major Project of Shanxi Province,China(Grant No.20181102013)+1 种基金the Shanxi Provincial Youth Fund,China(Grant No.201801D221135)the“1331 Project”Engineering Research Center of Shanxi Province,China(Grant No.PT201801).
文摘Si/a-C:H(Ag)multilayer films with different modulation periods are prepared to test their potential applications in human body.The composition,microstructure,mechanical and tribological properties in the simulated body fluid are investigated.The results show the concentration of Ag first decreases and then increases with the modulation period decreasing from 984 nm to 250 nm.Whereas the C content has an opposite variation trend.Notably,the concentration of Ag plays a more important role than the modulation period in the properties of the multilayer film.The a-C:H sublayer of the film with an appropriate Ag concentration(8.97 at.%)(modulation period of 512 nm)maintains the highest sp3/sp2 ratio,surface roughness and hardness,and excellent tribological property in the stimulated body fluid.An appropriate number of Ag atoms and size of Ag atom allow the Ag atoms to easily enter into the contact interface for load bearing and lubricating.This work proves that the Ag nanoparticles in the a-C:H sublayer plays a more important role in the tribological properties of the composite-multilayer film in stimulated body fluid condition.
基金Project supported by the National Basic Research Program of China (Grant No.2015CB921403)the National Key Research and Development Program of China (Grant No.2016YFA0300804)+2 种基金the National Natural Science Foundation of China (Grant Nos.51871236,11874408,51431009,92263202,and 51971240)the Science Center of the National Science Foundation of China (Grant No.52088101)the Strategic Priority Research Program (B,Grant No.XDB33030200)of the Chinese Academy of Sciences (CAS)。
文摘Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size,strong anti-interference ability,high current-driven mobility,and compatibility with existing spintronic technology.In this work,we present a tunable room temperature skyrmion platform based on multilayer stacks of MgO/FeNiB/Mo.We systematically studied the creation of magnetic skyrmions in MgO/FeNiB/Mo multilayer structures with perpendicular magnetic anisotropy(PMA).In these structures,the magnetic anisotropy changes from PMA to in-plane magnetic anisotropy(IMA)as the thickness of FeNiB layer increases.By adjusting the applied magnetic field and electric current,stable and high-density skyrmions can be obtained in the material system.The discovery of this material broadens the exploration of new materials for skyrmion and promotes the development of spintronic devices based on skyrmions.
文摘We investigated the effects of Si-layer-thickness ratios on ultraviolet (UV) peak intensities of Si/ SiO2 multilayered films produced by alternately stacking several-nanometer-thick Si and SiO2 layers using radio-frequency sputtering for the first time. The Si-layer-thickness ratio of the Si/SiO2 film is a very important parameter for enhancing the peak intensity because the ratio is concerned with the size of Si nanocrystals in the film, which might affect the intensity of the UV light emission from the film. We prepared seven samples with various estimated Si-layer-thickness ratios, and measured the photoluminescence spectra of the samples after annealing at 1150°C, 1200°C, or 1250°C for 25 min. From our experiments, we estimate that the proper Si-layer-thickness ratio to obtain the strongest UV peaks from the Si/SiO2 multilayered films is around 0.29. Such a UV-lightemitting thin film is expected to be used in future higher-density optical-disk systems.
