Optimized procedure for conventional TEM sample preparation using birefringence

Area of Science:

• Materials Science
• Analytical Chemistry
• Microscopy

Background:

• High-precision specimen preparation is crucial for quality transmission electron microscopy (TEM) analyses.
• Conventional methods for TEM specimen preparation can be time-consuming and prone to sample damage.
• Accurate thickness estimation is vital during mechanical thinning processes.

Purpose of the Study:

• To present an optimized procedure for conventional TEM specimen preparation.
• To utilize the thickness-dependence of interference colors in birefringent materials for accurate thickness estimation.
• To reduce ion-milling times and prevent damage during mechanical thinning.

Main Methods:

• Exploited thickness-dependence of interference colors in birefringent materials.
• Applied the method to sapphire and silicon carbide cross-section samples.
• Demonstrated suitability for dimpling and wedge-polishing techniques.

Main Results:

• Achieved accurate visual thickness estimation, especially for thicknesses below 20 µm.
• Reduced ion-milling times to below 30 minutes.
• Prevented specimen damage or breakage during mechanical thinning.

Conclusions:

• The presented method offers a precise and efficient approach for TEM specimen thickness estimation.
• This technique is particularly beneficial for thin specimens where mechanical methods lack accuracy.
• Optimized visual estimation can be further enhanced by RGB spectrum analysis of interference colors.