Dual-Beam Sample Preparation
NREL uses a dual-beam focused ion-beam (FIB) workstation for ion milling, metal deposition, ion imaging, and electron imaging on the micrometer and nanometer scale of advanced photovoltaic materials and devices.
![Materials characterization is an essential strength of the focused-ion beam (FIB) platform. Material can be removed or added while observing the evolution of the surface topography features of the specimen with ion beam stimulated secondary electrons](/materials-science/assets/images/photo_14514.jpg)
NREL's dual-beam focused-ion beam workstation for fabricating microscopy samples and nanostructures.
The dual-beam FIB supports other analytical tools such as transmission electron microscopy (TEM), and precise, site-specific sample preparation for TEM, SEM, and local electrode atom probe (LEAP). See below examples.
Acquiring chemical spectra and elemental maps is another feature of this system with energy-dispersive spectroscopy (EDS). Three-dimensional chemical reconstructions can be obtained by combining controlled ion milling with chemical mapping. The FIB is equipped with a gas injection system (GIS) platinum metal deposition capability that can be used with either ion-beam-assisted or electron-beam-assisted chemical vapor deposition. Using a digital patterning generator also allows for complete FIB milling or deposition of complex structures with software-supplied parameters or by direct input of bitmap files (or both). See below examples.
Examples of Dual-Beam Focused-Ion-Beam Sample Fabrication Capabilities
![SEM microphoto of contacts attached to a nanowire.](/materials-science/assets/images/photo_vapor_deposition.jpg)
![Third of three TEM images showing cutting of trenches to remove a wafer section and transferring that section to a grid post. Here the wafer section is lifted out and seen from the side.](/materials-science/assets/images/photo_tem_sample_prep_3.jpg)
FIB: TEM sample preparation — FIB prepared TEM cross-section (from A to C). Opposing trenches are milled out with the Ga+ ion source and a 1-2 µm thin section is left free standing in the wafer. A side view shows the depth of the trenches. The section is then welded to the micro-manipulator, extracted from the wafer then transferred and welded to a TEM grid post. Final thinning down to a thickness of < 100nm is achieved using low incident angles and low Ga ion current.
![SEM image of sharpened probe sample tip.](/materials-science/assets/images/photo_electrode_tip.jpg)
![Scanning electron image of cross-section of a multijunction solar cell followed by EDS elemental maps of the indium, gallium, phosphorus, and arsenic in the cross-section.](/materials-science/assets/images/se_image.jpg)
![Scanning electron image of cross-section of a multijunction solar cell followed by EDS elemental maps of the indium in the cross-section.](/materials-science/assets/images/elemental_map_in.jpg)
![Scanning electron image of cross-section of a multijunction solar cell followed by EDS elemental maps of the gallium in the cross-section.](/materials-science/assets/images/elemental_map_ga.jpg)
![Scanning electron image of cross-section of a multijunction solar cell followed by EDS elemental maps of the phosphorus in the cross-section.](/materials-science/assets/images/elemental_map_p.jpg)
![Scanning electron image of cross-section of a multijunction solar cell followed by EDS elemental maps of the arsenic in the cross-section.](/materials-science/assets/images/elemental_map_as.jpg)
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