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)