Article

Strategies for Reducing Charging of Insulating Samples in Auger Electron Spectroscopy

Surface Analysis Spotlight: AES

by Juergen Scherer Sr. Staff Scientist

 

Auger electron spectroscopy (AES) provides surface-sensitive elemental and chemical analysis with high spatial resolution, making it valuable for applications ranging from microelectronics and thin films to failure analysis and advanced materials. However, insulating materials and electrically isolated features can present significant analytical challenges. Charge accumulation during electron-beam irradiation can lead to spectral distortion, peak shifting, signal loss, and, in severe cases, an inability to obtain meaningful data.

Key Takeaways

Practical approaches for reducing and managing charging during AES analysis include:

• Optimizing experimental conditions for bulk insulators and insulating thin films: Selecting appropriate measurement conditions can reduce charge accumulation and improve the quality and stability of AES measurements on bulk insulating materials and insulating thin films.
• Charge neutralization using an ion beam neutralizer: An ion beam neutralizer can be particularly useful when the analysis area is grounded but is surrounded by insulating material, helping to control charging of the surrounding region.
• Grounding samples at the sample holder: A sample-holder-mounted grounding probe can provide electrical contact to otherwise poorly grounded samples.
• Using an in-situ grounding probe: A remotely controlled grounding probe provides another option for establishing electrical contact to a sample or specific region of interest inside the analysis chamber.
• Grounding isolated features using a focused ion beam (FIB): Electrically isolated features, such as semiconductor bond pads that are not connected to ground, can present a particular challenge for AES analysis. An in-situ FIB can be used to modify the sample locally to establish an electrical path to ground.

Experimental conditions, ion beam charge neutralization, sample grounding, and in situ FIB modification provide complementary approaches for addressing different charging scenarios. Applying the appropriate strategy can improve data quality and reliability and extend AES analysis to insulating and heterogeneous samples that might otherwise be difficult to characterize.

Join Dr. Juergen Scherer at AVS 72 in Pittsburgh on Tuesday, November 10, 2026, for his presentation, “Strategies for Reducing Charging of Insulating Samples in Auger Electron Spectroscopy,” to learn more about practical approaches for managing charging during AES analysis of insulating and electrically isolated samples.

Figure 1: Charging of surrounding polyimide was neutralized using the Ar ion neutralize

Figure 2: Charging of polyimide and electrically floating solder bump eliminated by using high tilt and low beam voltage

Figure 3: Bondpad grounded using the in-situ FIB