New MSE Core Characterization Facility Established

FACILITIES DESCRIPTIONS

FOCUSED ION BEAM/SCANNING ELECTRON MICROSCOPY

For the nanoscale analysis, UT Dallas is well equipped in state-of-the-art electron microscopy as well. A focused ion beam system available in the Advanced Microscopy Laboratory is a FEI Nova 200 NanoLab, which is a dual column SEM/FIB. It combines ultra-high resolution field emission scanning electron microscopy (SEM) and focused ion beam (FIB) etch and deposition for nanoscale prototyping, machining, 2-D and 3-D characterization and analysis. Five gas injection systems are available for deposition ( Pt, C, SiO2) and etching ( iodine for metals and a dielectric etch). The FIB will be critical for transmission electron microscopy  sample preparation of III-V compounds. Nanoscale chemical analysis is performed with energy dispersive X-ray spectroscopy (EDS). The secondary electron image resolution at the dual beam coincidence point is 1.5 nanometers at 15 kilovolts. The FIB optics have better than 7 nm resolution at 30 kilovolts. A high-resolution digital patterning system controlled from the user interface is also available. Predefined device structures in bitmap format can be directly imported to the patterning system for nanoscale fabrication. The FEI Nova 200 is also equipped with an Oxford OmniProbe 400 nano-manipulator stage, which includes four manipulators with 10 nanometer  positioning resolution. Students are trained to operate this instrument routinely by a dedicated full time staff member.

HIGH-RESOLUTION TRANSMISSION ELECTRON MICROCOPY

High Resolution Transmission Electron Microscopy (HRTEM) provides powerful and essential tools for investigators in nanoscale science and engineering and will also serve as a powerful vehicle to bring state-of-the art nanoscale materials research into the classroom. The facility operates and maintains two transmission electron microscopes (TEM), and a host of sample preparation equipment.  It also provides microscopy computing and visualization capabilities. Techniques and equipment include high resolution structural analysis; the high-resolution imaging TEM/STEM is a JEOL 2100 F which is a 200 kilovolt field emission TEM. Its capability includes atomic scale structural imaging with a resolution of better than 0.22 nanometers.  The HRTEM is also equipped for high resolution chemical and electronic structure analysis. High-resolution analytical TEM/STEM is an atomic resolution TEM/STEM (JEOL 200ARM) equipped with an energy dispersive x-ray spectrometer (EDS), an electron energy loss spectrometer (EELS) and a high angle Z-contrast imaging detector. This instrument performs chemical and electronic structure analysis with a spatial resolution of better than 0.1 nanometers in EELS mode and is also capable of spectrum imaging and mapping. The image resolution in the chemically sensitive Z-contrast scanning TEM (STEM) mode will be about 78 pm. Our in-situ capability also includes in-situ cryogenic cooling and heating, electrothermal biasing, STM-TEM, AFM-TEM, nanoindentation, liquid-cell, tomography and a computer control system for remote microscopy operation.

X-RAY DIFFRACTION SUITE

A new X-ray diffraction suite has been acquired. A Rigaku SmartLab high resolution XRD system funded by National Science Foundation  MRI Award No. 1531811 is capable of out-of-plane 2-Theta/omega, asymmetric 2-Theta measurements and in-plane measurements. The in-plane arm also facilitates the acquisition of a complete pole figure from 0-90° with respect to the surface normal. The high resolution optics will allow for a range of optics on the incident side including conventional slits, 2-bounce monochromators or 4-bounce monochromators. An additional 2-bounce monochromator is also installed on the receiving (detector) side to obtain maximum resolution. The ability to easily switch between a selection of monochromator options is vital for a multi-user system where each project will have different objectives and requirements for the trade-off between high intensity and high resolution data. The high-speed detector has expanded functionality to materials with low diffraction intensities as well as provide for faster data acquisition during time-consuming measurements such as pole-figures. The system comes with a full and educational version of the International Centre for Diffraction Data (ICDD) database that will allow for phase identification.  Also included is data acquisition software and a suite of analysis software packages that will provide for: 1) crystal structure determination; 2) phase identification; 3) reference intensity ratio (RIR) quantitative analysis; 4) crystal size determination; 5) residual stress analysis; 6) reciprocal space map and pole figure generation; 7) rocking curve analysis and simulation; and 8) XRR fitting for density, thickness, and roughness extraction (Parrat’s equation).

A Rigaku Ultima III X-ray Diffractometer system is also available. The system is equipped with a cross beam optics system to permit either high-resolution parallel beam with a motor controlled multilayer mirror, or a Bragg-Brentano Para-Focusing beam (without the multilayer mirror) which are permanently mounted, pre-aligned and user selectable with no need for any interchange between components. Curved graphite crystal or Ge monochromator are also available. An integrated annealing attachment permits the in-situ examination of film structure up to 1500°C. The instrument enables a variety of applications including in-plane and normal geometry phase identification, quantitative analysis, lattice parameter refinement, crystallite size, structure refinement, residual stress, density, roughness (from reflectivity geometries), and depth-controlled phase identification. The advanced thin film attachments enable precise sample alignment for x-ray reflectivity, grazing-incidence x-ray diffraction, epitaxial film concentration and structure analysis using reciprocal space mapping and rocking curve measurements. Detection consists of a computer-controlled scintillation counter. Sample sizes up to 100 millimeters in diameter can be accommodated on this system. A complete set of control, database and analysis workstations and software is associated with these new systems.