Towards 3D strain mapping of nanostructures and nanoparticles
FacultiesFakultät für Naturwissenschaften
In this work I was developing the methods of 3D strain mapping of nanostructures. The experiments in my work were performed by TEM. All together these techniques enable to reconstruct 8 components of 9-element infinitesimal 3D strain tensor with high precision and accuracy. The first technique (chapter 2) is based on inline dark-field holography and it enables to measure 4 components of the lateral strain tensor. In this chapter it is shown that using this technique one can calculate reliable strain maps from off-the-shelf 32-nm node CMOS device structures. The presented technique has the great advantage of high throughput because the important and precise information can be derived from a simple measurement. The results of the strain mapping are compared with geometric phase analysis of high-resolution TEM images. The second technique (chapter 3) is based on analysis of dark-field images acquired at different specimen tilts so that the tilt range will cover just a few degrees of the tilt. In chapter 1.4 it is shown that the change in crystal lattice orientation is nothing else as additional components of the 9-element strain tensor. The practical application of this technique is demonstrated on a commercial semiconductor device, containing multiple 22 nm technology transistor structures. The third technique (chapter 4) represents the extension of the previous technique because by using the sophisticated algorithms precise two-dimensional maps of crystal orientation with high spatial resolution and large field of view can be computed from multiple Bragg reflections. With the approach the local change in crystal orientation can be mapped with the precision of < 0.1 degrees and high spatial resolution which is limited by the size of the crystal unit cell. The practical application of this approach is demonstrated on the specimen prepared from a Ni-based super-alloy CMSX-4.
Subject HeadingsDurchstrahlungselektronenmikroskopie [GND]
Transmission electron microscopy [LCSH]