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Raman-SEM Correlative Microscopy
Complement electron microscopy with Raman spectroscopy
Increase your sample knowledge when you quickly overlay scanning electron microscope images (SEM) with Raman spectral data. No need to be a Raman expert to create stunning chemical images using the Thermo Scientific DXR3xi Raman Imaging Microscope that can:
- Reveal unique information from micro to nano scale features
- Effortlessly combine Raman and SEM data using MAPs software
- Provide depth profiling with little to no sample preparation
Why adopt Raman
Collect Raman chemical images to complement your electron microscopy and expand your sample knowledge to accelerate your product development, root cause investigation, thesis, patent or publication.
Use Raman spectroscopy in your lab to…
 | Enhance SEM data with Raman microscopy |
 | Characterize chemistry, including morphology and polymorphism |
 | Elucidate organic materials |
 | Save time and preserve your sample |
Easily characterize and compare unknown features using the DXR3xi Raman Imaging Microscope.
Raman-SEM Applications
Graphene electrode defects
Difficulties in transferring 2D graphene electrodes from a copper substrate to the final semiconductor surface can be seen with this Raman image overlaid on the electron micrograph. A good quality image would show the graphene (red) as solid lines between the gold (green) contacts. The data show that the graphene is not continuous, indicating a need to improve the sample handling procedure. Raman spectroscopy can also quantify the number of layers of graphene transferred as well as differentiate between various carbon materials such as graphene and graphite.
Semiconductor stress
Strain in semiconductors has been shown to push the limits of electronic device performance and thermal properties. This Raman-EM correlated image shows a mismatch of lattice constants between the SiGe and the top silicon epi-layer, causing stress on the semiconductor chip. The transition from red to blue color represents a shift in the Raman spectra, indicating more stress in the silicon.
Geological polymorphism
Information on spatial relationships, mineral content, polymorphism, and chemical details can be generated by correlating SEM-EDS images with Raman microscopy images. The EDS shows the presence of titanium, aluminum, and silicon. The Raman image provides additional information and shows the location of quartz (blue), orthoclase (green), amphibole (yellow), and albite (red). Raman has identified the silica polymorph present in this sample to be quartz. It also has identified the K-feldspar polymorph to be orthoclase.
Background
Scanning electron microscopy (SEM) offers exquisite, high-resolution imaging of samples in order to study their morphology, grain size, grain shape, and microstructural features. Despite these valuable insights, SEM alone cannot provide compositional data for a sample. For this reason, a technique such as energy dispersive x-ray spectroscopy (EDS) is often paired with SEM in the study of geological samples in order to provide “color” to greyscale SEM images. EDS is a microanalysis tool that uses the electron beam to inspire the emission of characteristic x-rays that can be used to identify the elemental composition of the sample. By scanning the electron beam across a region, compositional maps can be correlated with the electron microscopy image of the sample region. The correlation of the SEM and EDS data affords the ability to correlate microstructure to elemental composition.
The challenge
Unfortunately, SEM and EDS have difficulty in sample speciation and morphology characterization. Polymorphic minerals with identical elemental compositions, but differing crystal structures, are critical to understand because their formation is dependent on temperature and pressure, and understanding these parameters helps to elucidate a geological sample’s origins and formation conditions.
The solution
Raman spectroscopy is a non-destructive, chemically-selective, optical technique that is used to characterize chemical backbone, polymorph structure, and degree of crystallinity. Additionally, Raman polarization measurements enable the elucidation of crystal orientation, making Raman spectral analysis perfect for understanding a material’s structure-function relationship.
MAPS software protocol
This procedure can be used to correlate Raman and scanning electron microscopy (SEM) images using Thermo Scientific MAPS software. The Raman images were acquired using the Thermo Scientific OMNICxi Software with a DXR3xi Raman Imaging Microscope. The SEM images were acquired on a Thermo Scientific ESEM Quanta600 Scanning Electron Microscope outfitted with a tungsten hairpin thermionic electron gun.
- Open the OMNICxi software (version 1.4 or greater) and MAPS software (version 3.5 or greater).
- Open a .MAPX data file in the OMNICxi software.
- Process results as normal in the OMNICxi (Chemigram, peak area, MCR, etc.) software. Then adjust the intensity sliders as desired.
- Save region as a TIFF file as shown below. RGB or 16-bit gray scale can be selected.
- Open a new project in the MAPS software.
- Right click on Layer and load an SEM image TIFF file.
- Click on Next arrow to complete the multi-point alignment and finish the image import (no alignment is necessary).
- Create a new Raman layer by clicking on Add layer button.
- Import Raman images to layer by right clicking and selecting Import Images from dropdown menu.
- Multiple Raman images can be selected. In this example three are loaded into MAPS software.
- Select all Raman images, then right click and select Align.
- Right click on SEM image to place 2 or 3 points on image. The example shown below has three points (green, blue and purple). Then right click on Raman image and place the same three points.
- Click on the Next button to complete the alignment.
- Set color and transparent background by checking Fluorescence box.
- Color remaining channels and optimize as desired.
Why adopt Raman
Collect Raman chemical images to complement your electron microscopy and expand your sample knowledge to accelerate your product development, root cause investigation, thesis, patent or publication.
Use Raman spectroscopy in your lab to…
| Enhance SEM data with Raman microscopy |
| Characterize chemistry, including morphology and polymorphism |
| Elucidate organic materials |
| Save time and preserve your sample |
Easily characterize and compare unknown features using the DXR3xi Raman Imaging Microscope.
Raman-SEM Applications
Graphene electrode defects
Difficulties in transferring 2D graphene electrodes from a copper substrate to the final semiconductor surface can be seen with this Raman image overlaid on the electron micrograph. A good quality image would show the graphene (red) as solid lines between the gold (green) contacts. The data show that the graphene is not continuous, indicating a need to improve the sample handling procedure. Raman spectroscopy can also quantify the number of layers of graphene transferred as well as differentiate between various carbon materials such as graphene and graphite.
Semiconductor stress
Strain in semiconductors has been shown to push the limits of electronic device performance and thermal properties. This Raman-EM correlated image shows a mismatch of lattice constants between the SiGe and the top silicon epi-layer, causing stress on the semiconductor chip. The transition from red to blue color represents a shift in the Raman spectra, indicating more stress in the silicon.
Geological polymorphism
Information on spatial relationships, mineral content, polymorphism, and chemical details can be generated by correlating SEM-EDS images with Raman microscopy images. The EDS shows the presence of titanium, aluminum, and silicon. The Raman image provides additional information and shows the location of quartz (blue), orthoclase (green), amphibole (yellow), and albite (red). Raman has identified the silica polymorph present in this sample to be quartz. It also has identified the K-feldspar polymorph to be orthoclase.
Background
Scanning electron microscopy (SEM) offers exquisite, high-resolution imaging of samples in order to study their morphology, grain size, grain shape, and microstructural features. Despite these valuable insights, SEM alone cannot provide compositional data for a sample. For this reason, a technique such as energy dispersive x-ray spectroscopy (EDS) is often paired with SEM in the study of geological samples in order to provide “color” to greyscale SEM images. EDS is a microanalysis tool that uses the electron beam to inspire the emission of characteristic x-rays that can be used to identify the elemental composition of the sample. By scanning the electron beam across a region, compositional maps can be correlated with the electron microscopy image of the sample region. The correlation of the SEM and EDS data affords the ability to correlate microstructure to elemental composition.
The challenge
Unfortunately, SEM and EDS have difficulty in sample speciation and morphology characterization. Polymorphic minerals with identical elemental compositions, but differing crystal structures, are critical to understand because their formation is dependent on temperature and pressure, and understanding these parameters helps to elucidate a geological sample’s origins and formation conditions.
The solution
Raman spectroscopy is a non-destructive, chemically-selective, optical technique that is used to characterize chemical backbone, polymorph structure, and degree of crystallinity. Additionally, Raman polarization measurements enable the elucidation of crystal orientation, making Raman spectral analysis perfect for understanding a material’s structure-function relationship.
MAPS software protocol
This procedure can be used to correlate Raman and scanning electron microscopy (SEM) images using Thermo Scientific MAPS software. The Raman images were acquired using the Thermo Scientific OMNICxi Software with a DXR3xi Raman Imaging Microscope. The SEM images were acquired on a Thermo Scientific ESEM Quanta600 Scanning Electron Microscope outfitted with a tungsten hairpin thermionic electron gun.
- Open the OMNICxi software (version 1.4 or greater) and MAPS software (version 3.5 or greater).
- Open a .MAPX data file in the OMNICxi software.
- Process results as normal in the OMNICxi (Chemigram, peak area, MCR, etc.) software. Then adjust the intensity sliders as desired.
- Save region as a TIFF file as shown below. RGB or 16-bit gray scale can be selected.
- Open a new project in the MAPS software.
- Right click on Layer and load an SEM image TIFF file.
- Click on Next arrow to complete the multi-point alignment and finish the image import (no alignment is necessary).
- Create a new Raman layer by clicking on Add layer button.
- Import Raman images to layer by right clicking and selecting Import Images from dropdown menu.
- Multiple Raman images can be selected. In this example three are loaded into MAPS software.
- Select all Raman images, then right click and select Align.
- Right click on SEM image to place 2 or 3 points on image. The example shown below has three points (green, blue and purple). Then right click on Raman image and place the same three points.
- Click on the Next button to complete the alignment.
- Set color and transparent background by checking Fluorescence box.
- Color remaining channels and optimize as desired.