Introduction to ESEM

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Introduction to ESEM

• Ed Griffith
• ESEM Product Support
• FEI Boston

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Introduction to ESEM

• Why ESEM?
• Firstly, because its an SEM
• What can it do?

3
Regular samples polished metalBse
Sec
lowkV
4
Look at biological samples
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Shoot resolution
at 6 torr?HiVac - yes!
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Introduction to ESEM

• Why have a poor vacuum?

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Flexibility with uncoated samples
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Samples that are not prepared for
vacuum
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Look at outgasing samples
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Introduction to ESEM

• Thats why ESEM
• Brief ESEM history
• What is ESEM?
• Overview of Applications and Accessories

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Introduction to ESEM

• ESEM launched in 1989
• Progression of ESEM in the market
• new concept in SEM market
• in-situ sample inspection segment
• Philips and FEI

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Introduction to ESEM

• What is ESEM?

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ESEM Vacuum System - XL30 ESEM FEG
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ESEM Dual PLA Pumping System
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ESEM Beam Gas Path Length BGPL
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ESEM Gas Ionization Detectors
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Gaseous Secondary Electron Detector
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ESEM Large Field of View Detector
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Introduction to ESEM Applications

• Regular SEM samples prepared the regular way
• imaging
• EDS
• Uncoated and Unprepared samples
• Dynamic experiments with samples
• the environment in the specimen chamber
• accessories for dynamic experiments in ESEM

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Survey a sample
BSe of rustlow mag
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Imaging and EDS
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Low kV in HiVac
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Introduction to ESEM Applications

• Regular SEM samples prepared the regular way
• imaging
• EDS
• Uncoated and Unprepared samples
• Dynamic experiments with samples
• the environment in the specimen chamber
• accessories for dynamic experiments in ESEM

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Uncoated Bse vs. Sec little difference
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Uncoated Bse vs. Sec difference
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Same material can look different
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Preparation alters the results
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Coating covers details
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HiVac or Cryo is not an option
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Introduction to ESEM Applications

• Regular SEM samples prepared the regular way
• imaging
• EDS
• Uncoated and Unprepared samples
• Dynamic experiments with samples
• the environment in the specimen chamber
• accessories for dynamic experiments in ESEM

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Wetting of fibers
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Wet algae mat
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Wet biological samples
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In-situ hydration/dehydration
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Watching paint dry
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Water films
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Wet Samples
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Peltier Cooling Stage
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Heat samples to lower temperatures
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Heat samples and collect EDS data
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Heat to higher temperatures
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1000oC Hot Stage
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Microinjector-Micromanipulator
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Heating and mechanical testing
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Mechanical Testing Stage
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Residual Gas Analysis
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Cryo microscopy in ESEM

• Conventional HiVac cryo
• preservation of sample surface
• bulk analysis - sample fracturing
• low kV
• Cryo in ESEM mode
• no coating
• imaging and EDS
• faster rates of sublimation
• stabilizes very beam sensitive samples
• specific gas environments, including water vapor
• studying time resolved rapid reactions
• polymerization

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Cryo sample Ice cream

• Components of material
• ice crystals
• air pockets
• frozen sugar/cream
• Texture depends upon distribution of the phases
• Storage temperature of -20C
• Study what happens with change in handling
  conditions

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Ice cream Conventional Cryo microscopy

• Advantages
• Ice can be maintained in the structure
• Disadvantage
• Matrix phase is glassy below glass transition
  temp
• Temperature is too low
• Metal coating needed

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Ice cream Conventional ESEM

• Disadvantages
• Cant use pure water vapor to image
• frosting on the surface
• Ice sublimes at desired use temperature
• Cant distinguish air pockets from former ice
  cavities
• Without ice crystals, air pockets coalesce
  because the matrix will move

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Ice cream Distorted structure
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Ice cream nonConventional Cryo ESEM

• Specimen temperature
• held at -20C
• Image with gas mixture
• of 0.5 torr of water vapor
• and 1.7 torr of N2O

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Ice cream

• Etching ice

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At the edges with ESEM - defining new contrast
mechanisms - defining what new information can
be collected

• Charge Contrast Imaging
• internal structure information
• Contrast mechanisms in liquids and low Z
  materials
• Sec- emission and escape depth
• energy loss and band gaps
• Spectroscopy

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Charge Contrast Imaging - CCI
Aluminum Hydroxide
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Charge Contrast Imaging - CCI

• hydroxides
• carbonates
• sulfides
• spinals
• Zircon
• diamond
• biominerals
• dopants
• surface contamination

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Polymers
p
p
p
6.0 eV
7.1 eV
8.3 eV
4.6 eV
p
p
p
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Polymers

• Sec- image
  Intensity Histogram

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Polymers

• Sec- image - false color Intensity
  Histogram

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Contrast in liquids

• oil in water
  water in oil

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