FEI Strata 235 Dual Beam FIB
The dual-beam FIB system combines multiple experimental systems within the same chamber so that combinations of different techniques can be accommodated by unique sample preparation, manipulation and analysis methods. The system contains both a focused Ga+ ion beam and a field emission scanning electron column. The ion column can be used for selective removal of material by ion beam milling. In addition, the ion beam can be used for ion-enhanced imaging of fine texture analysis in crystalline materials. The high resolution field emission electron beam can be used for chemical analysis through either electron dispersive spectroscopy or z-contrast imaging using a scanning transmission electron microscope (STEM) detector, or can be combined with an electron backscatter detector for orientation imaging analysis.
The utility of the ion and electron columns is enhanced by the ability to selectively deposit either Pt or SiO2 with either of the two beams. With selective deposition, nanoscale electrical contacts can be made for rapid prototyping and analysis of novel electronic structures and materials. Multiple micro-manipulators within the chamber can measure electrical characteristics or position samples with nanoscale precision. Most notably, the dual-beam system combines all of these techniques so that the user can selectively section, image, manipulate and analyze the chemical and crystallographic nature of a material without ever removing it from the chamber. (Instrument schedule and requirements: 12- 8am, 8-1pm, 1-6pm, 6-12pm; 2 sessions at a time, regardless of which session.)
Capabilities of the NCEM FIB:
Imaging: Secondary electrons or ions produced by the incoming electron or Ga+ beams are collected to form an image of the sample. Eight different detectors (including a STEM detector) give users tremendous flexibility in achieving the proper imaging conditions for their samples.
Milling/Etching: The FIB can locally etch the sample surface with submicron precision. Many variables and material properties affect the sputtering rate of a sample. These include beam current, sample density, sample atomic mass, and incoming ion mass. The ion species used at NCEM is Ga+. Additionally, iodine gas-assisted etching is available. When a gas is introduced near the surface of the sample during milling, the sputtering yield can increase depending on the chemistry between the gas and the sample. This results in less redeposition and more efficient milling.
Deposition: Conductive or insulator material can also be deposited with the aid of a gas in close proximity to the sample surface. Our system is equipped to deposit either metal (Pt) or insulator (SiO2). These materials can be deposited with either the ion or electron beam.
Microchemical analysis: Element mapping and energy dispersive X-ray spectrometry (EDS) are available on the NCEM FIB system.
Orientation imaging: Advanced diffraction and crystallographic analysis capabilities, based on electron backscatter diffraction (EBSD), are an integral part of our FIB system.
Nanoscale manipulation of TEM membranes or other samples with either a Omniprobe microneedle or 2 Kleindiek micromanipulators is possible. All of these probes can also be used for localized electronic measurements.
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Ion column |
Electron column |
Accel. voltage |
10-30 kV |
0.2 – 30 kV |
Beam current range |
1 pA – 20 nA |
0.7 pA - 36.9 nA |
Resolution |
7 nm |
3 nm |
For updates or questions, contact Andrew Minor.
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At left, an electron-transparent membrane was milled with the FIB from a single-crystal LiNbO3 sample that had been processed with a focused femtosecond laser. The microstructural changes that result from the laser pulse were then analyzed (right) with electron microdiffraction, showing both amorphous (b) and crystalline (c) regions beneath the ablation. |
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Pt deposited selectively at the ends of a Y-junction carbon nanotube to provide contacts for electrical measurements. The Pt was deposited with the electron beam from an organic precursor within the chamber. |
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STEM image of hole drilled in a Au- coated Silicon Nitride membrane with the Ga ion beam. |
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Ion enhanced imaging and analysis of transgranular crack propagation in a Ni-Co-Cr disk alloy designed for extended high-temperature durability. Shown at left is an ion-enhanced electron image. At right is an orientation-imaging electron backscattered image from the same location, color-coded to reveal the crystallographic orientation of each grain. |
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