Transmission Electron Microscopy - Crystal Structure

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SUMMARY

The discussion centers on the use of Transmission Electron Microscopy (TEM) for analyzing a layered semiconductor structure consisting of AlGaAs and GaAs. The primary objectives include confirming identical crystallographic orientation, verifying the correct thickness of the device, and ensuring no secondary phases exist between layers. The challenge arises from the sample's thickness of approximately 5µm, which exceeds the typical 100nm limit for TEM. Participants suggest exploring cross-section sample preparation techniques to facilitate TEM analysis.

PREREQUISITES
  • Understanding of Transmission Electron Microscopy (TEM) principles
  • Knowledge of semiconductor materials, specifically AlGaAs and GaAs
  • Familiarity with crystallographic orientation concepts
  • Experience with sample preparation techniques for electron microscopy
NEXT STEPS
  • Research cross-section sample preparation techniques for TEM analysis
  • Learn about the limitations of TEM regarding sample thickness
  • Investigate alternative microscopy methods for thicker samples, such as Scanning Electron Microscopy (SEM)
  • Explore the implications of crystallographic orientation on semiconductor performance
USEFUL FOR

Researchers, materials scientists, and semiconductor engineers involved in the characterization of layered semiconductor structures and those seeking to optimize methods for analyzing material properties using electron microscopy.

happycamper
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Hi

I have a tutorial problem involving determining the ideal methods for identifying material properties of a layered semiconductor structure. The problem states to use either scanning or transmission electron microscopy. THe structure consists of several monolayers (around 5nm) of AlGaAs grown epitaxially on a GaAs substrate. After that, a thicker layer (around 5um) of GaAs is grown on top of the AlGaAs.

I need to a) confirm the materials have identical crystallographic orientation, b) ensure the device has the correct thickness, and c) confirm there is no presence of secondary phases between the layers.

It seems obvious that the TEM has to be used, but from what i have found, the samples need to be no more than about 100nm thick (this sample would be over 5000nm thick). Any help or pushes-in-the-right-direction would be appreciated.

Thanks
 
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Hi,
your sample is called as tandem sample (useful for solar cells i guess!).
yes for TEM samples transparent to electron beam.
Do you know the cross-section sample preparation technique for TEM ?
 

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