An Introduction to Electron Microscopy by FEI Company2. PART 1:
A BRIEF OVERVIEW
OF MICROSCOPY
• Origins of microscopy
• Historical figures in microscopy
• Three basic classifications of microscopes
• Comparing light microscopy to electron microscopy
© 2011 FEI Company
3. History of Microscopy
Human eye cells Paint on concrete Trace elements in quartz
Mikros (small) + Skopeo (look at)
Greek Origin
© 2011 FEI Company
4. Historic Figures in Microscopy
Antony van Leeuwenhoek Robert Hooke Ernst Abbe Ernst Ruska Richard Feynman
(1632-1723) (1635-1703) (1840-1905) (1906-1988) (1918-1988)
© 2011 FEI Company
5. Basic Microscope Classifications
laser diode
electron source
first condenser lens
multiple segmentphotodiode X, Y piezoelectric
second condenser lens
(position sensitive detector) scanner
condenser aperture mirror
objective condenser lens
microcondenser lens
Scanning
OpticalCharged
(light)
objective aperture
specimen (thin) probe
particle
microscope
selected area objective lens
aperture
light beam
objective imaging piezoelectric
Z lens
scanner microscope
specimen diffraction lens
intermediate lens
first projector lens
light source second projector lens cantilever
Optical (light) microscope
sample Scanning projector chamber
probe microscope Charged particle microscope
(stationary)
(Illustration of a TEM shown) fluorescent screen
© 2011 FEI Company
6. Comparing Microscopes
LIGHT MICROSCOPE ELECTRON MICROSCOPE
Electrons are used to “see” –
The source of The ambient light source is
light is replaced by an electron
illumination light for the microscope
gun built into the column
The lens type Glass lenses Electromagnetic lenses
Focal length is charged by
Magnification Magnification is changed by
changing the current through
method moving the lens
the lens coil
Viewing the Fluorescent screen or
Eyepiece (ocular)
sample digital camera
Entire electron path from
Use of vacuum No vacuum gun to camera must be
under vacuum
© 2011 FEI Company
7. PART 2:
UNDERSTANDING KEY CONCEPTS
& CORE TECHNOLOGIES
IN MICROSCOPY
• What is resolution and resolving power?
• What is an electron?
• The electron gun
• Electromagnetic lenses
• The importance of vacuum technology
© 2011 FEI Company
8. KEY CONCEPT: Resolution
Resolution
is defined as the act, process, or capability of
distinguishing between two separate, but adjacent
objects or sources of light, or between two nearly
equal wavelengths.
Resolving Power
is the ability to make points or lines which are
closely adjacent in an object distinguishable in
an image.
© 2011 FEI Company
12. KEY CONCEPT: The Electron
An atom is made up of:
Protons
Neutrons
Electron
© 2011 FEI Company
13. CORE TECHNOLOGY: The Electron Gun
• Three main sources
of electrons:
• Tungsten
• LaB6 (lanthanum hexaboride)
• Field Emission Gun (FEG)
• Different costs and
benefits of each
• Each selected primarily
for their brightness
© 2011 FEI Company
15. CORE TECHNOLOGY: The Vacuum
• A vacuum is a region
of reduced gas pressure.
• Electron microscopes
use a vacuum to make
electrons behave
like light.
© 2011 FEI Company
16. PART 3:
UNDERSTANDING
ADVANCED
MICROSCOPES
• Transmission Electron Microscopes (TEM)
• Scanning Electron Microscopes (SEM)
• Focused Ion Beam Microscopes (FIB)
• FEI DualBeam™ Systems (FIB/SEM)
© 2011 FEI Company
17. What is a Transmission Electron Microscope?
electron source
condenser system
specimen (thin)
objective lens
projector lens
© 2011 FEI Company
18. TEM Aberration Correction
Spherical Aberration Chromatic Aberration
• Chromatic aberration is distortion that occurs when there is a failure of a lens to
focus all colors (wavelengths) to the same convergence point.
• Correcting the aberration is necessary, otherwise the resulting image would
be blurry and delocalized, a form of aberration where periodic structures
appear to extend beyond their physical boundaries.
• Recent improvements in aberration correction have resulted in significantly-
improved image quality and sample information.
• Spherical aberration occurs when parallel light rays that pass through the central
region of the lens focus farther away than the light rays that pass through the
edges of the lens.
• Result is multiple focal points and a blurred image.
© 2011 FEI Company
20. Environmental Microscopy with TEM
Nickel catalyst film on silica membrane
FEI Titan ETEM
Nickel oxide particles in nitrogen gas
© 2011 FEI Company
21. What is Scanning Transmission Electron Microscopy?
Elemental map of a 45 nm PMOS
transistor structure
STEM image of a 32nm semiconductor device EDX map of semiconductor device
© 2011 FEI Company
22. What is a Scanning Electron Microscope?
electron source
electron beam
impact area
vacuum
© 2011 FEI Company
23. Comparing SEM and TEM
TEM SEM
Beam focused to fine point;
Electron Beam Broad, static beams
sample is scanned line by line
Accelerating voltage much lower; not SEM voltage ranges from
Voltages Needed
necessary to penetrate the specimen 60-300,000 volts
Wide range of specimens
Interaction of the
Specimen must be very thin allowed; simplifies
beam electrons
sample preparation
Information needed is
Electrons must pass through and be
Imaging collected near the surface
transmitted by the specimen
of the specimen
Transmitted electrons are collectively Beam is scanned along the
Image Rendering focused by the objective lens and surface of the sample to
magnified to create a real image build up the image
© 2011 FEI Company
24. What is a Focused Ion Beam? (FIB)
Platinum Nano-Wire
FIB-cut in steel v2a EE by 1nA to
Cross-section of a semiconductor wafer imagedsteel a plasma FIB
1B milling-002 with
FEI V400ACE Focused Ion Beam
Physical Failure Analysis
© 2011 FEI Company
25. What is a DualBeam™ System?
Bidens Ferulifolia Pollen on plant structures
© 2011 FEI Company
26. PART 4:
HOW ARE ELECTRON
AND ION MICROSCOPES
USED TODAY?
• Industrial applications
• Life sciences
• Natural resources and energy
• Scientific research
© 2011 FEI Company
32. PART 5:
THE FUTURE OF
MICROSCOPY AND
NANOTECHNOLOGY
• Nanotechnology: the future of science
• What is nanotechnology?
• Nanotechnology applications
• Student and teacher resources
© 2011 FEI Company
34. What is Nanotechnology?
na·no·tech·no·lo·gy noun na-nō-tek-nä-lə-jē:
the science of manipulating materials on an atomic or molecular scale
especially to build microscopic devices (as robots)
Electrospun polymethyl methacrylate(PMMA) fibres
Sildenafil Crystals ALU bumps on integrated circuit
Contamination on polymer Polystyrene nanospheres on optical photoresist
Alveoli (glandular secretions)
Artery with red blood cells CuInSe2 Mesentericum Spores mosquito
Tuber thin film
Water mite parasiting on a
© 2011 FEI Company
36. Student and Teacher Resources
Learn more about FEI, our products, technologies,
and innovations at fei.com
A glossary of useful terms can be found at:
fei.com/resources/glossary-of-terms.aspx
Download or read online the complete “Introduction to
Electron Microscopy” booklet at fei.com/introtoem
© 2011 FEI Company
37. FEI Company
FEI is the world leader in transmission, scanning electron,
and ion beam microscopy. FEI is responsible for numerous
innovations in technology and the integration of electron
and ion optics, fine mechanics, microelectronics,
computer sciences, and vacuum engineering.
FEI is at the forefront of electron
and ion beam microscopy, the
innovation leader since 1935.
Learn more about us
at fei.com
© 2011 FEI Company