Electron Backscatter Diffraction Detector Research Articles

Polytypism Study in SiC Epilayers Using Electron Backscatter Diffraction

The electron backscatter diffraction (EBSD) detector placed inside a commercial scanning electron microscope (SEM) has been used to study of different SiC polytypes. Different growth conditions in chemical vapor deposition (CVD) method were applied to obtain the 3C- and 4H-SiC polytypes epitaxial layers. Growth processes were conducted on the Si-face on-axis 4H-SiC substrates. The growth temperature was in the range of 1300-1620°C and the reactor pressure was 75mbar. The initial C/Si ratio was varied from 0.075 reaching final value of 1.8. It was observed that intentional ramping of the C/Si ratio at the first stage of the growth clearly influences the 4H/3C factor. The growth temperature and ramping of the C/Si ratio were the main parameters to achieve a homogeneous 3C and 4H-SiC epitaxial layers.

Analysis of micro void formation at grain boundary triple points in monotonically strained AA6022-T43 sheet metal

This study reports on the micro voids formed in a 1 mm thick sheet of rolled aluminum alloy AA6022 subjected to monotonic tensile loading. In this research micro voids were found to occur at certain grain boundary triple point (GBTP) junctions. The orientations of the grains at various GBTP junctions were determined using an electron backscatter diffraction detector mounted in a field-emission scanning electron microscope. Because damage evolution and eventual final failure are driven by local tensile hydrostatic stresses arising from microhetereogenities, the hydrostatic stress state surrounding the GBTP junction was evaluated using a crystal plasticity material model implemented in a finite element analysis code. Grain orientations that result in a local hydrostatic state of tension surrounding the GBTP junction were found to have a tendency to form micro voids.

Spatial Resolution of Electron Backscatter Diffraction in a FEG-SEM

Crystallographic information can be determined for bulk specimens in a SEM by utilizing electron backscatter diffraction (EBSD), which is also referred to as backscatter electron Kikuchi diffraction. This technique provides similar information to that provided by selected area electron channeling (SAEC). However, the spatial resolutions of the two techniques are limited by different processes. In SAEC patterns, the spatial resolution is limited to ˜2 μm by the motion of the beam on the specimen, which results from the angular rocking of the beam and the aberration of the probe forming lens. Therefore, smaller incident probe sizes provide no improvement in spatial resolution of SAEC patterns. In contrast, the spatial resolution for EBSD, which uses a stationary beam and an area detector, is determined by 1) the incident probe size and 2) the size of the interaction volume from which significant backscattered electrons are produced in the direction of the EBSD detector. The second factor is influenced by the accelerating voltage, the specimen tilt, and the relative orientation of scattering direction and the specimen tilt axis.