scanning electron microscopy. what is an sem? a scanning electron microscope is an instrument that...
TRANSCRIPT
Scanning Electron Microscopy
What is an SEM?
• A Scanning Electron Microscope is an instrument that investigates the surfaces of solid samples by using a beam of electrons in a vacuum.
What is an SEM?
• A Scanning Electron Microscope is an instrument that investigates the surfaces of solid samples by using a beam of electrons in a vacuum.
• The image is generated by the secondary emissions from the sample.
What is an SEM?
Advantages of using an SEMinstead of a light microscope
• Imaging
– high resolution (because of short wavelength) - >1.4nm
Advantages of using an SEM instead of a light microscope
• Imaging
– high resolution (because of short wavelength) - >1.4nm
– Secondary electron imaging for topology
Advantages of using an SEM instead of a light microscope
• Imaging
– high resolution (because of short wavelength) - >1.4nm
– Secondary electron imaging for topology
– Backscatter electron imaging for chemistry
Advantages of using an SEM instead of a light microscope
• Imaging
– high resolution (because of short wavelength) - >1.4nm
– Secondary electron imaging for topology
– Backscatter electron imaging for chemistry
– High depth of field
Advantages of using an SEM instead of a light microscope
• Imaging
– high resolution (because of short wavelength) - >1.4nm
– Secondary electron imaging for topology
– Backscatter electron imaging for chemistry
– High depth of field
• Elemental Analysis – EDXS (Energy-dispersive X-ray analysis)
Advantages of using an SEM instead of a light microscope
• Imaging
– high resolution (because of short wavelength) - >1.4nm
– Secondary electron imaging for topology
– Backscatter electron imaging for chemistry
– High depth of field
• Elemental Analysis – EDXS (Energy-dispersive X-ray analysis)
• Structural Analysis – EBSD (Electron Back-scatter Diffraction analysis)
Advantages of using an SEM instead of a light microscope
• Imaging
– high resolution (because of short wavelength) - >1.4nm
– Secondary electron imaging for topology
– Backscatter electron imaging for chemistry
– High depth of field
• Elemental Analysis – EDXS (Energy-dispersive X-ray analysis)
• Structural Analysis – EBSD (Electron Back-scatter Diffraction analysis)
• Ease of sample preparation since most SEMs only require the sample to be conductive.
Advantages of using an SEM instead of a light microscope
Sample Constraints
Sample Constraints
•Must fit in chamber (!)
Sample Constraints
•Must fit in chamber
•Must be compatible with vacuum (even for ESEM samples)
Sample Constraints
•Must fit in chamber
•Must be compatible with vacuum (even for ESEM samples)
•Must have conductive surface (not necessary for ESEM samples)
JEOL 5910 General-Purpose SEM
FEI XL30 FEG-ESEM
JEOL 6320 High-resolution SEM
Secondary Electron ImagesGive information about sample's topography
BSE Images
Give information about sample's chemistry
EDS SpectraGive information about sample's composition
SE Cu
Pb Sn
Give information about elemental distribution in the sample
X-Ray Maps
Backscatter patterns composed of intersecting bands
Electron beam strikes a crystalline material tilted at 70°
Indexable patterns
Center for Materials Science and Engineering
Electron Microscopy SEF
Location: 13-1012Normal Working Hours: 8:30 am – 4:45 pm on M-F24 hr accessible for evening/weekend users (not for undergraduates)
Staff:Dr. Anthony (Tony) Garratt-Reed (TEM, SEM, STEM)Dr. Yong Zhang (TEM, SEM, STEM)Mr. Patrick Boisvert (SEM, Microtome)