Atom Probe Tomography (APT) is a microscopy technique that provides 3D atom-by-atom imaging of materials with a uniquely powerful combination of spatial and chemical resolution. A wide range of materials can be analyzed including metals, alloys, intermetallics, semi-conductors, thin films and oxide scales. Features that are typically studied are for example phase compositions, phase separation, concentration gradients, clustering and segregation to grain boundaries, phase boundaries and dislocations. The sensitivity is the same for all element (except for hydrogen), including the light elements like C, O and N. The technique is based on field evaporation of ions from a very sharp needle-shaped sample. Electropolishing or FIB/SEM is applied to fabricate suitable samples.
The instrument at Chalmers Materials Analysis Laboratory, which is the only one in the Nordic countries, is a LEAP 3000X HR. The volume of material that is analyzed is about 60x60x200 nm3, meaning that several million atoms are detected, positioned and chemically identified. The analysis time is a few hours.
For more information, please contact Research Engineer Katarina Logg.
IMAGO LEAP 3000X HR, instrument data:
• Max. pulse frequency: 250 kHz
• Mass resolving power (typical): 1000 FWHM
• Min. temperature: 18 K
• Detection efficiency: 37%
• Pressure (typical): 10-11 torr
• Laser wavelength: 532 nm
• Laser pulse energy: 0.02 - 2 nJ
• Max voltage pulse: 1732 V
• Max DC voltage: 15 kV
• Max detection rate: 10%
• Acceptance angle: ca. 70°
• Lateral resolution: ca. 0.2 nm
• Depth resolution: ca. 0.1 nm