Exploration of atom probe tomography at sub-10K

Area of Science:

• Materials Science
• Analytical Chemistry
• Physics

Background:

• Operating temperature critically influences atom probe tomography (APT) performance, affecting spatial precision and mass resolving power.
• Commercial APT systems typically operate at temperatures around 25 K.
• Lowering specimen temperature is a key parameter for enhancing APT capabilities.

Purpose of the Study:

• To modify CAMECA LEAP® and EIKOS™ atom probe systems to achieve sub-10 K specimen temperatures.
• To investigate the impact of sub-10 K operation on APT performance metrics.
• To analyze various material systems under these cryogenic conditions.

Main Methods:

• Mechanical redesign of LEAP® and EIKOS™ APT systems to enable sub-10 K operation.
• Analysis of pure Al, pure W, doped Si, and GaN using modified APT instruments.
• Quantitative assessment of spatial precision, mass resolving power, stoichiometry, and charge-state ratio.

Main Results:

• Sub-10 K operation significantly improves spatial precision in APT.
• Mass resolving power shows a minor improvement at lower temperatures.
• Enhanced spatial precision allows for the resolution of lattice planes in doped Si.
• Improved mass spectral analysis and reduced noise floors lead to more accurate GaN composition measurements.

Conclusions:

• Operating APT at sub-10 K offers substantial benefits for spatial resolution and compositional accuracy.
• This advancement is particularly valuable for analyzing semiconductors and metallurgical materials.
• Further exploration of sub-10 K parameter space holds potential for new discoveries in materials analysis.