The configurations of stacking faults and morphologies of strain induced ε martensite plates in an FeMnSiCrNi alloy were investigated through electron microscopy analysis. The Shockley partial dislocation structures....The configurations of stacking faults and morphologies of strain induced ε martensite plates in an FeMnSiCrNi alloy were investigated through electron microscopy analysis. The Shockley partial dislocation structures. sensitive to external stress. determine the configurations of stacking faults in γphase Partial dislocations at the front sides of stacking faults are usetul for the nucleation of εmartensite plates. The growth of ε martensite plates is accompanied with the disappearance of local pre-existing stacking faults, The ε martensite vanants behave in three morphologies of respective stopping. continuous penetrating and intersections with the formation of secondary ε martensite plates展开更多
Growth and ordering of coherently strained Ge-rich islands in Ge/Si single layer and multilayer systems and the influence of island arrangements on the evolutio n of the surface morphology of Si cap layers during depo...Growth and ordering of coherently strained Ge-rich islands in Ge/Si single layer and multilayer systems and the influence of island arrangements on the evolutio n of the surface morphology of Si cap layers during deposition by low-pressure c hemical vapour deposition(LPCVD) on Si(001) substrates at 700℃ have been invest igated by TEM of cross-section and plan-view specimens. At distances between the Ge layers of 35-50nm, vertical order of GeSi islands is observed for Ge-Si bila yer systems and for Ge-Si multilayer systems consisting of 5 layer pairs whereas lateral ordering parallel to <100> substrate directions is observed for the lat ter case only. In agreement with earlier results the vertical ordering in the mu ltilayer system can be understood as result of the elastic interaction between i sland nuclei forming in the layers with close islands in a buried layer below. T he lateral ordering along <100> may be attributed to the anisotropy of the elast ic interaction. Characteristic for all Si surfaces are the spatial correlation b etween the presence of island-induced lattice strain and the appearance of array s of larger square-shaped pyramids with distinct faceting and facet edges along <110>. The results reflect the importance of the control of growth parameters an d of the island-induced strain state for the evolution of the Si top layer surfa ce morphology during LPCVD growth.展开更多
Shapes, dimensions, arrangements and the microstructure of self-assembled island s fabricated by low-pressure chemical vapour deposition (LPCVD) of Ge at 700℃ o nto Si(110) substrates have been investigated for diffe...Shapes, dimensions, arrangements and the microstructure of self-assembled island s fabricated by low-pressure chemical vapour deposition (LPCVD) of Ge at 700℃ o nto Si(110) substrates have been investigated for different nominal Ge coverage by transmission electron microscopy (TEM) of plan-view and cross-section specime ns and have been compared with photoluminescence (PL) measurements of Si-capped layer samples. The transition from the 2-dimensional layer to the 3-dimensional island growth mode takes place for a Ge deposition of nominally less than 2 mono layers. Upon this transition, many coherent islands and few larger islands with extended defects are observed. The coherent islands possess a dome-like shape an d lateral sizes up to 130nm. Photoluminescence spectra show island-related peaks whose energy positions are shifted towards lower energy with higher Ge coverage .展开更多
Developing highly accurate critical dimension standards is a significant task for nanoscale metrology. In this paper, we put forward an alternative approach to fabricate amorphous Si critical dimension structures with...Developing highly accurate critical dimension standards is a significant task for nanoscale metrology. In this paper, we put forward an alternative approach to fabricate amorphous Si critical dimension structures with direct Si lattice calibration in the same frame scanning transmission electron microscopy image. Based on the traceable measurement analysis, the optimized method can provide the same calibration accuracy and increase the fabrication throughput and lower the cost simultaneously, which benefits the application needs in atomic force microscopy(AFM) tip geometry characterization,benchmarking measurement tools, and conducting comparison measurements between different approaches.展开更多
Lattice-strained Si thin films grown onto SiGe(110)/Si(110) are attracting because of their potential to realize high-speed transistors. In this study we observe surface morphology of Si/SiGe/Si(110) using scanning el...Lattice-strained Si thin films grown onto SiGe(110)/Si(110) are attracting because of their potential to realize high-speed transistors. In this study we observe surface morphology of Si/SiGe/Si(110) using scanning electron microscopy and we also observe microstructure of the identical position using cross-sectional transmission electron microscopy. These results reveal that crossing of stress-induced twins causes remarkable surface roughness. We propose using vicinal substrate to avoid this phenomenon and our successive experimental results are shown in this paper.展开更多
Joining is a crucial process for the production of complex-shaped advanced engineering materials.Deep understanding of ceramic–metal interfaces during joining or following heat-treatment steps is therefore of importa...Joining is a crucial process for the production of complex-shaped advanced engineering materials.Deep understanding of ceramic–metal interfaces during joining or following heat-treatment steps is therefore of important concern in designing the new systems.Capacitor discharge joining(CDJ)method was firstly carried out to compose the ceramic–metal joint material by silicon nitride(Si3N4)–titanium(Ti)constituents.Afterwards,heat treatment was performed on the Si3N4-Ti joints in air atmosphere at 1000℃temperature to reveal the interface reactions and phases.Reaction layer that occurred between the Si3N4 and Ti interfaces and new phase formations were examined by transmission electron microscopy(TEM)-based various imaging and chemical analysis techniques.Electron transparent samples for TEM characterization were prepared by focused ion beam(FIB)milling and lifting method.Based on the detailed TEM results,Si and N diffusion arising from the Si3N4 ceramic was observed towards Ti metal foil side and further interacted with Ti atoms.The upshot of current diffusion was that Ti3N2 reaction layer with 50 nm thickness was formed at the interface while titanium silicon nitride(Ti6Si3N)matrix phase including dendritic-shaped Ti2 N grains occurred in the Ti interlayer.It is believed that our TEM-based microscopy results not only provide the knowledge on ceramic–metal joint materials by CDJ method,but also contribute new insights on the development of various new joint systems.展开更多
Three-dimensional stacked transistors based on Si/SiGe heterojunction are a potential candidate for future low-power and high-performance computing in integrated circuits.Observing and accurately measuring strain in S...Three-dimensional stacked transistors based on Si/SiGe heterojunction are a potential candidate for future low-power and high-performance computing in integrated circuits.Observing and accurately measuring strain in Si/SiGe heterojunctions is critical to increasing carrier mobility and improving device performance.Transmission electron microscopy(TEM)with high spatial resolution and analytical capabilities provides technical support for atomic-scale strain measurement and promotes significant progress in strain mapping technology.This paper reviews atomic-scale strain analysis for advanced Si/SiGe heterostructure based on TEM techniques.Convergent-beam electron diffraction,nano-beam electron diffraction,dark-field electron holography,and high-resolution TEM with geometrical phase analysis,are comprehensively discussed in terms of spatial resolution,strain precision,field of view,reference position,and data processing.Also,the advantages and critical issues of these strain analysis methods based on the TEM technique are sum-marized,and the future direction of TEM techniques in the related areas is prospected.展开更多
文摘The configurations of stacking faults and morphologies of strain induced ε martensite plates in an FeMnSiCrNi alloy were investigated through electron microscopy analysis. The Shockley partial dislocation structures. sensitive to external stress. determine the configurations of stacking faults in γphase Partial dislocations at the front sides of stacking faults are usetul for the nucleation of εmartensite plates. The growth of ε martensite plates is accompanied with the disappearance of local pre-existing stacking faults, The ε martensite vanants behave in three morphologies of respective stopping. continuous penetrating and intersections with the formation of secondary ε martensite plates
文摘Growth and ordering of coherently strained Ge-rich islands in Ge/Si single layer and multilayer systems and the influence of island arrangements on the evolutio n of the surface morphology of Si cap layers during deposition by low-pressure c hemical vapour deposition(LPCVD) on Si(001) substrates at 700℃ have been invest igated by TEM of cross-section and plan-view specimens. At distances between the Ge layers of 35-50nm, vertical order of GeSi islands is observed for Ge-Si bila yer systems and for Ge-Si multilayer systems consisting of 5 layer pairs whereas lateral ordering parallel to <100> substrate directions is observed for the lat ter case only. In agreement with earlier results the vertical ordering in the mu ltilayer system can be understood as result of the elastic interaction between i sland nuclei forming in the layers with close islands in a buried layer below. T he lateral ordering along <100> may be attributed to the anisotropy of the elast ic interaction. Characteristic for all Si surfaces are the spatial correlation b etween the presence of island-induced lattice strain and the appearance of array s of larger square-shaped pyramids with distinct faceting and facet edges along <110>. The results reflect the importance of the control of growth parameters an d of the island-induced strain state for the evolution of the Si top layer surfa ce morphology during LPCVD growth.
文摘Shapes, dimensions, arrangements and the microstructure of self-assembled island s fabricated by low-pressure chemical vapour deposition (LPCVD) of Ge at 700℃ o nto Si(110) substrates have been investigated for different nominal Ge coverage by transmission electron microscopy (TEM) of plan-view and cross-section specime ns and have been compared with photoluminescence (PL) measurements of Si-capped layer samples. The transition from the 2-dimensional layer to the 3-dimensional island growth mode takes place for a Ge deposition of nominally less than 2 mono layers. Upon this transition, many coherent islands and few larger islands with extended defects are observed. The coherent islands possess a dome-like shape an d lateral sizes up to 130nm. Photoluminescence spectra show island-related peaks whose energy positions are shifted towards lower energy with higher Ge coverage .
基金supported by the National Key Scientific Instrument and Equipment Development Projects of China(Grant No.2014YQ090709)the National Key Research and Development Program of China(Grant No.2016YFA0200902)Major Projects of Science and Technology Commission of Shanghai,China(Grant No.17JC1400800)
文摘Developing highly accurate critical dimension standards is a significant task for nanoscale metrology. In this paper, we put forward an alternative approach to fabricate amorphous Si critical dimension structures with direct Si lattice calibration in the same frame scanning transmission electron microscopy image. Based on the traceable measurement analysis, the optimized method can provide the same calibration accuracy and increase the fabrication throughput and lower the cost simultaneously, which benefits the application needs in atomic force microscopy(AFM) tip geometry characterization,benchmarking measurement tools, and conducting comparison measurements between different approaches.
文摘Lattice-strained Si thin films grown onto SiGe(110)/Si(110) are attracting because of their potential to realize high-speed transistors. In this study we observe surface morphology of Si/SiGe/Si(110) using scanning electron microscopy and we also observe microstructure of the identical position using cross-sectional transmission electron microscopy. These results reveal that crossing of stress-induced twins causes remarkable surface roughness. We propose using vicinal substrate to avoid this phenomenon and our successive experimental results are shown in this paper.
基金Anadolu University(Eskisehir,Turkey)for financial support by BAP-030217 project.
文摘Joining is a crucial process for the production of complex-shaped advanced engineering materials.Deep understanding of ceramic–metal interfaces during joining or following heat-treatment steps is therefore of important concern in designing the new systems.Capacitor discharge joining(CDJ)method was firstly carried out to compose the ceramic–metal joint material by silicon nitride(Si3N4)–titanium(Ti)constituents.Afterwards,heat treatment was performed on the Si3N4-Ti joints in air atmosphere at 1000℃temperature to reveal the interface reactions and phases.Reaction layer that occurred between the Si3N4 and Ti interfaces and new phase formations were examined by transmission electron microscopy(TEM)-based various imaging and chemical analysis techniques.Electron transparent samples for TEM characterization were prepared by focused ion beam(FIB)milling and lifting method.Based on the detailed TEM results,Si and N diffusion arising from the Si3N4 ceramic was observed towards Ti metal foil side and further interacted with Ti atoms.The upshot of current diffusion was that Ti3N2 reaction layer with 50 nm thickness was formed at the interface while titanium silicon nitride(Ti6Si3N)matrix phase including dendritic-shaped Ti2 N grains occurred in the Ti interlayer.It is believed that our TEM-based microscopy results not only provide the knowledge on ceramic–metal joint materials by CDJ method,but also contribute new insights on the development of various new joint systems.
基金supported by National Natural Science Foundation of China (12234005)the Fundamental Research Funds for the Central Universities。
文摘Three-dimensional stacked transistors based on Si/SiGe heterojunction are a potential candidate for future low-power and high-performance computing in integrated circuits.Observing and accurately measuring strain in Si/SiGe heterojunctions is critical to increasing carrier mobility and improving device performance.Transmission electron microscopy(TEM)with high spatial resolution and analytical capabilities provides technical support for atomic-scale strain measurement and promotes significant progress in strain mapping technology.This paper reviews atomic-scale strain analysis for advanced Si/SiGe heterostructure based on TEM techniques.Convergent-beam electron diffraction,nano-beam electron diffraction,dark-field electron holography,and high-resolution TEM with geometrical phase analysis,are comprehensively discussed in terms of spatial resolution,strain precision,field of view,reference position,and data processing.Also,the advantages and critical issues of these strain analysis methods based on the TEM technique are sum-marized,and the future direction of TEM techniques in the related areas is prospected.
