The principles and practice of electron microscopy

Transcription

1 The principles and practice of electron microscopy Second Edition Ian M. Watt CAMBRIDGE UNIVERSITY PRESS

2 Contents Preface tofirstedition page ix Preface to second edition xi 1 Microscopy with light and electrons Microscope systems using light 1 the simple microscope: the compound microscope 1.2 The diffraction barrier 7 resolving power of microscopes 1.3 The confocal microscope Beating the wavelength restriction 11 electronic illumination 1.5 Microscopy with electrons 14 electron lenses: aberrations and defects of electron lenses: manipulating electron beams: scanned beam microscopy: electron microscopes in practice 1.6 High resolution by electron microscopy the proof of the pudding 25 bonus points in electron microscopy 1.7 Summary Suggested further reading 29 2 Electron-specimen interactions: processes and detectors Beam-specimen interactions. 30 secondary electrons: reflected or backscattered electrons: x-ray photons: Auger electrons: cathodoluminescence: absorbed (specimen) current: transmitted electrons 2.2 Crystalline specimens 49 crystalline structures: diffraction by crystal planes: the electron diffraction camera: convergent beam electron diffraction: electron channelling patterns 2.3 Effect of variation of electron energy 54 microscopic performance: beam-specimen interactions 2.4 Electron interference effects 56 Fresnel fringes 2.5 Suggested further reading 57 3 The electron microscope family Introduction The transmission electron microscope (TEM) 60 the two-lens TEM: higher-resolution microscopes: the high-resolution TEM in

3 vi Contents practice: the commercial TEM: the analytical TEM: the high-voltage electron microscope (HVEM): the atomic resolution microscope (ARM) 3.3 The scanning electron microscope (SEM) 89 basic principles: the SEM in practice: signal generation, display and image recording: high-resolution SEMs: commercial SEMs: specialised SEMs 3.4 Scanning transmission electron microscopy (STEM and FESTEM) 124 transmission microscopy on a dedicated SEM: scanning microscopy on a dedicated TEM: the field emission STEM (FESTEM) 3.5 Combined light and electron microscopes Digital image recording Suggested further reading 135 Specimen preparation for electron microscopy Introduction Specimen requirements for the TEM 136 specimen support grids: specimen support films 4.3 Basic preparatory methods for TEM specimens 140 particulate samples: surface replication: shadowcasting: thinned specimens: thin foils and films 4.4 Specimen requirements for the SEM 160 specimen size 4.5 Preparatory methods for SEM specimens 162 mounting: coating: replication: ultra-microtomed cross-sectioning: freezing 4.6 Preparation of moist specimens 169 drying biological specimens: freeze substitution: freeze-fracturing and freezeetching: cryo-microscopy: freezing processes 4.7 Cytochemical preparations 185 immunocytochemistry and colloidal gold 4.8 Other preparatory techniques 186 microwaves in specimen preparation: conductive fixation 4.9 Specimen storage Suggested further reading 187 The interpretation and analysis of micrographs Interpretation of transmission micrographs 189 amorphous and crystalline materials: shadowcasting: making measurements from micrographs: instrumental effects: specimen preparation artefacts 5.2 Interpretation of scanning micrographs 205 effects of tilt: depth of field effects and dynamic focusing: electron energy effects: making measurements from scanning micrographs: other modes of operation of the SEM: instrumental effects to be seen in micrographs: more instrumental effects: specimen preparation artefacts 5.3 Recording and printing electron micrographs 232

4 Contents vii 5.4 Stereoscopic microscopy 238 viewing the micrographs 5.5 Image processing and analysis 255 quantitative electron microscopy: image processing: determination of mass thickness by image analysis: stereology 5.6 Suggested further reading Analysis in the electron microscope Electron diffraction 263 electron diffraction in the TEM: electron diffraction in the SEM: electron diffraction in STEM 6.2 X-ray microanalysis on electron microscopes 274 x-ray spectrometers on electron microscopes: practical use of x-ray spectrometers on electron microscopes: the dedicated electron probe x-ray microanalyser (EPMA) 6.3 Electron energy loss spectrometry (ELS or EELS) 294 parallel EELS (PEELS) 6.4 Auger electron spectroscopy Cathodoluminescence (CL) imaging Suggested further reading Specialised EM- and other microscopical and analytical techniques Dark-field electron microscopy 303 displaced objective aperture: tilted-beam illumination: strioscopy: dark-field STEM imaging 7.2 Spot scan Microradiography Voltage contrast in the SEM EBIC, OBIC and SOM-SEM Scanning electron acoustic microscopy (SEAM) Spin-polarised SEM (Spin SEM) In-situ microscopy Electron beam lithography and nano-lithography Reflection electron microscopy (REM) Other microscopical and analytical techniques 316 alternative forms of microscopy: alternative methods for analysis: analysis of crystalline surfaces: methods for bulk analysis 7.12 Suggested further reading Examples of the use of electron microscopy Introduction Particulate specimens 334 industrial particles: biological particles

5 viii Contents 8.3 Surfaces 338 direct examination of surfaces: replicas: biological specimens 8.4 Thin films, foils and sections 341 thin films: thin foils: thin sections 8.5 Suggested further reading " 344 Case studies 346 photographic emulsions: pigments and colours: virus identification: electroless nickel films: food processing: paper fibres: opal structure: glass polishing: xerographic copying: pathology: plant sciences: environmental SEM: HRTEM of synthetic diamond films: car exhaust catalyst development: microfossils Appendixes Production and measurement of high vacua 379 vacuum pumps: vacuum gauges: practical vacuum systems: suggested further reading 2 Vacuum deposition of thin metallic and carbon films for electron microscopy 400 evaporation and condensation processes: evaporation sources for metallic films: deposition of carbon films: deposition of thin films by sputtering: suggested further reading 3 X-ray spectrometry 413 wavelength-dispersive x-ray spectroscopy (WDS or WDX): energy-dispersive x-ray spectroscopy (EDS or EDX): comparison of WDS and EDS: light-element analysis: suggested further reading 4 Electron sources for electron microscopes 432 thermionic emission: the triode electron gun: high-voltage electron guns: field emission: suggested further reading Bibliography 448 References 448 Additional literature on electron microscopy 462 laboratory handbooks: proceedings of international conferences: other books on EM and its applications: periodicals Names and addresses of EM manufacturers and their agents 472 Name index 474 Subject index 479