Dislocation Strain Field Mapping Using Dark-Field Electron Holography

Abstract Strain fields of dislocation on SiGe/Si structures were measured by dark-field electron holography. Compared with regular TEM imaging of dislocation and precession electron diffraction (PED), dark-field electron holography has high spatial resolution with a relatively large field-of-view without the need to acquire atomic-resolution images. This technique can be used to resolve the dislocation core at atomic scale. As a demonstration, two edge dislocation cores of 2.9nm apart were resolved by dark-field electron holography. It is also demonstrated that, like regular dark-field imaging methods, dark-field electron holography can be used to determine Burgers vector orientation with additional information of strain distribution around the dislocation core and improved spatial resolution.