Scanning Electron Microscopy (SEM)

When performing Scanning Electron Microscopy (SEM) Analysis, a high-energy electron beam is projected onto the surface of a solid sample (composed of conductive materials such as metals or composites), ejecting electrons, X-rays and photons used to produce high-resolution images and other detailed information about the specimen.

Capable of achieving a magnification range as high as 100,000x, SEM analysis offers remarkable insights into a material’s chemistry and structure,  combining both morphology and elemental composition data. Insights from SEM Analysis are paramount to advanced materials research across industries ranging from aerospace to personal electronics.

Strengths

  • High-resolution imaging
  • Precise compositional analysis
  • Versatility among various scientific industries
  • Non-destructive analysis (allows repeated analysis of the same sample)
  • Provides topographical and crystallographic information about material structure
  • Indispensable aid in gaining an in-depth understanding of material properties

Limitations

  • Cannot deliver information about the internal structure of samples
  • Operating in a vacuum chamber hinders the analysis of gases or liquids
  • May introduce image distortions due to charging effects on non-conductive samples

Learn More

Example Output 0

SEM Analysis Process

Sample Preparation

Samples are mounted properly for SEM analysis. Non-conductive samples may be coated with platinum or gold (sputter coating) to improve image quality.

SEM Imaging Modes

Secondary Electron (SE) Imaging

SE images provide high-resolution information about the sample’s topography, revealing details about the sample’s surface texture, roughness, and morphology. It is the most commonly used SEM imaging mode.

Backscattered Electron (BSE) Imaging

BSE images show average atomic numbers in sample regions. Brighter areas indicate higher nuclear numbers that can help distinguish phases with varied chemical elements.

Energy-Dispersive X-ray Spectroscopy (EDS)

Used in conjunction with SEM, EDS detects the X-rays emitted from atoms when stimulated by the primary electron beam, providing elemental composition and distribution information.

Cathodoluminescence (CL) Imaging

Different materials emit light at specific wavelengths, allowing for Cl imaging to identify and map luminescent areas.

In-Lens Secondary Electron (InLens SE) Imaging

In-Lens SE offers superior resolution compared to standard SE imaging, particularly for capturing topographic details on rough or tilted surfaces.

Learn more about the Signals in SEM Imaging Modes

Sample Requirements

SEM Example Outputs

A Full SEM Imaging Report will usually contain the following:

  • Summary of the project objectives and goals at a high level, including a description of the sample(s) and what will be measured or investigated
  • Identification and description of the SEM instrument used for imaging
  • Outline of sample preparation methods, including the instrument(s) used as well as any charge mediation or specialty sample mounts (if needed)
  • Images and callouts of key observations and takeaways
  • All images will specify what type of electrons were collected to produce the micrograph, as well as where (approximately) on the sample the image was collected.
  • Discussion and interpretation of findings
  • Overview of possible next steps for testing

Top-down image of spherical nanoparticles and aggregates grown on silicon substrate

From: Center for Advanced Materials Analysis in Oregon

SEM-EDS Map of elemental distribution across a battery electrode cross-section.

SEM Instruments Used

ThermoFisher Scientific Helios 5 UC (x3)

ThermoFisher Scientific Helios 5 UC (x3)

A specific model of an SEM manufactured by Thermo Fisher Scientific, the ThermoFisher Scientific Helios 5 UC (x3), incorporates DualBeam technology, advanced electron optics, and high current abilities using a Gallium (GA) source.

  • Maximum Horizontal Field Width: 2.3 mm at 4 mm WD
  • Electron Beam:
    • Resolution Limit: 0.7 nm at 1 kV
    • Current Range: 0.8 pA to 100 nA
    • Accelerating Voltage Range: 350 V to 30 kV
  • Ion Beam
    • Resolution Limit: 4.0 nm at 30 kV using preferred statistical method
    • Current Range: 1 pA to 100 nA
    • Accelerating Voltage Range: 500 V to 30kV
View Instrument Brochure
Thermo Scientific Scios

Thermo Scientific Scios

An advanced scientific instrument essential for medical and pharmaceutical research, the Thermo Scientific Scios utilizes high-powered microscopy to analyze materials and biological samples at an ultra-high resolution.

  • Powerful charge neutralization
  • Enables analysis on magnetic samples
  • Able to operate above vacuum pressure
JEOL JSM-IT800 SHL - Schottky Field Emission Microscope

JEOL JSM-IT800 SHL - Schottky Field Emission Microscope

Equipped with a Schottky Field Emission Gun, this SEM is designed for higher resolution needs and offers magnification capabilities up to 2,000,000x. With this microscope, researchers involved in nanotechnology, semiconductors, materials, and life sciences can view surface features as small as 50 nanometers.

  • Versatile electromagnetic/electrostatic hybrid lens design for outstanding imaging and analysis performance
  • NEO ENGINE – intelligent automated electron beam control
  • Advanced auto functions including beam alignment, focus, and stigmation
  • In-lens field emission gun
  • Aperture Angle Control Lens (ACL) for superb resolution at any kV or probe current
  • Beam Deceleration (BD) mode reduces effects of lens aberrations at the sample
  • Large specimen chamber with multiple ports
  • Montage images and elemental maps
  • Smile View Lab for data management and report generation
  • Live Analysis with integrated JEOL EDS elemental screening
  • High spatial resolution imaging and analysis of nanostructures
View Instrument Brochure

What is Scanning Electron Microscopy (SEM)?

A Scanning Electron Microscope (SEM) scans the surface of solid samples living and nonliving by rastering a high-energy electron beam. Because of the high accelerating voltage used to power the electron beam, SEMs yield resolution limits orders-of-magnitude improved over conventional light-based microscopes.

Why Use SEM Analysis?

SEM analysis significantly reduces the need for excessive preparation and processing times. As a result, SEM can quickly provide valuable materials insights involved in manufacturing quality control, forensic investigations, and other fields demanding time-sensitive decisions.

 

Applications of SEM

Materials Science

SEM magnifies the finest surface features of material samples, enabling analysis of nanoscale structures smaller than optical wavelengths. This is particularly useful when examining nanoscale defects invisible to the naked eye, including craters, fissures, or delaminations. Industries benefiting from SEM include:

Semiconductors and Electronics

SEM is invaluable to the semiconductor and electronics industries. It is intrinsic to failure analysis, and to efforts to optimize product performance and manufacturing processes.  SEM further supports R&D in semiconductors and electronics by providing essential information about new materials, fabrication methods, and structure-property relationships.

 

How Does SEM Work?

In scanning electron microscopy analysis, high-energy electrons are directed in a focused beam at a solid sample, resulting in subatomic interactions that emit different signal particles used to analyze the material.

Backscattered and secondary electrons are used to create visual maps of the surface, enabling measurement and analysis of exposed features. X-rays provide additional information about the elemental make-up of the material, and are positionally mapped to specific regions of the surface.

 

SEM vs. STEM

Scanning Electron Microscopy vs. (Scanning) Transmission Electron Microscopy

Both scanning electron microscopes and scanning transmission electron microscopes involve a highly-focused, high-energy electron beam rastering over a sample; the two techniques differ in what signals are collected.

In SEMs, the instrument picks up only secondary and back-scattered electrons that are reflected from the sample surface, and produces an image based on the intensity of that reflected beam.

On the other hand, in STEM imaging, the specimens are actually so thin that the probe/primary electron beam is actually able to pass through the sample. These electrons transmit through the sample comprise the detected signal used to produce the STEM micrograph. Because STEM uses a higher accelerating voltage to drive electrons fully through the sample, it has an enhanced resolution limit (approximately 0.1 nm; as compared with the 1-5 nm limit for SEM).

Scanning electron microscopy (SEM) analysis is widely used in life and material sciences, as well as for failure analysis concerning compositional and morphological defects. Alternatively, STEM is the industry standard for nanomaterials and nanoscale device research, supplying the atomic-scale resolution required for evaluating crystal structures and identifying crystalline defects.

 

Why Choose Covalent Metrology for SEM Analysis?

Our clients trust Covalent Metrology for SEM analysis results that exceed their expectations. We provide industry-leading, high-resolution scanning electron microscopy capabilities that offer superior data essential for understanding and optimizing the quality of your materials.

  1. Enhanced R&D Capabilities: Our SEM analysis provides critical insights that can accelerate your research and development processes.
  2. Quality Control Improvement: High-resolution imaging helps identify and resolve material issues, potentially leading to improved product quality.
  3. Rapid Turnaround: For time-sensitive projects, Covalent offers expedited processing to deliver your data in as little as 24 hours.
  4. Comprehensive Reporting: We provide detailed analysis and full documentation of measurement conditions and results, offering you actionable insights.
  5. Support for Informed Decision-Making: Our data and analysis can help guide strategic decisions in product development and manufacturing processes.

Contact Covalent Metrology today to learn how SEM analysis will enhance your company’s reputation and success.

Learn more about using Scanning Electron Microscopy services today!