TY - THES

T1 - Towards Atom Probe Crystallography of Thin Films

AU - Rainer, Daniel

N1 - no embargo

PY - 2023

Y1 - 2023

N2 - Atom probe tomography is a materials characterization technique which provides 3D compositional maps on the near atomic scale. Processing the gathered information of the atomic spatial distribution is frequently referred to as atom probe crystallography. This technique can be used for example to analyze ordering processes in metal alloys. Another promising application might be the investigation of the atomic arrangement within thin film materials. The latter could deepen the understanding on the relations between structure and properties of the thin film. Combining the extracted crystallographic and chemical information can be a powerful tool to further improve and develop thin film material systems. The present work aims to investigate the retrievable crystallographic information of thin films using the atom probe. Due to its versatility and broad application, TiN was selected as model thin film material. Electron backscatter diffraction experiments were performed to prepare single crystalline atom probe specimens along the primary crystallographic directions <100>, <110>, and <111>. Transmission Kikuchi diffraction measurements were carried out to confirm the crystallographic orientation of the atom probe specimens along the intended desorption axis. Simulations were conducted to determine the theoretical results of the field evaporation process. Field ion microscopy investigations were performed to study the surface structure and to compare the results with the field desorption maps of the atom probe experiments. Finally, atom probe tomography experiments were carried out and various data filtering techniques were applied to analyze the retrievable crystallographic information. The results of the electron backscatter and transmission Kikuchi diffraction experiments reveal the desired <100>, <110> and <111> orientations of the TiN atom probe specimens. The simulations show that the crystallographic patterns within the field desorption maps correspond to the cubic primitive crystal structure, despite the NaCl structure of TiN. Conventional field ion microscopy does not provide any information about the crystallography of TiN. The field desorption images of the atom probe experiments (voltage as well as laser mode) show no clear crystallographic patterns. In general, the multiple hit ratios are rather high (>50%) and might deteriorate the retrievable crystallographic information. Displaying only single or multiple detector hits can slightly improve the visibility of poles and zone lines. Excluding atoms which require a higher number of pulses to field evaporate and illustrating the data after the latter does not provide any crystallographic information regarding TiN. In both cases, voltage and laser mode experiments, it is possible to resolve individual lattice planes within spatial distribution maps.

AB - Atom probe tomography is a materials characterization technique which provides 3D compositional maps on the near atomic scale. Processing the gathered information of the atomic spatial distribution is frequently referred to as atom probe crystallography. This technique can be used for example to analyze ordering processes in metal alloys. Another promising application might be the investigation of the atomic arrangement within thin film materials. The latter could deepen the understanding on the relations between structure and properties of the thin film. Combining the extracted crystallographic and chemical information can be a powerful tool to further improve and develop thin film material systems. The present work aims to investigate the retrievable crystallographic information of thin films using the atom probe. Due to its versatility and broad application, TiN was selected as model thin film material. Electron backscatter diffraction experiments were performed to prepare single crystalline atom probe specimens along the primary crystallographic directions <100>, <110>, and <111>. Transmission Kikuchi diffraction measurements were carried out to confirm the crystallographic orientation of the atom probe specimens along the intended desorption axis. Simulations were conducted to determine the theoretical results of the field evaporation process. Field ion microscopy investigations were performed to study the surface structure and to compare the results with the field desorption maps of the atom probe experiments. Finally, atom probe tomography experiments were carried out and various data filtering techniques were applied to analyze the retrievable crystallographic information. The results of the electron backscatter and transmission Kikuchi diffraction experiments reveal the desired <100>, <110> and <111> orientations of the TiN atom probe specimens. The simulations show that the crystallographic patterns within the field desorption maps correspond to the cubic primitive crystal structure, despite the NaCl structure of TiN. Conventional field ion microscopy does not provide any information about the crystallography of TiN. The field desorption images of the atom probe experiments (voltage as well as laser mode) show no clear crystallographic patterns. In general, the multiple hit ratios are rather high (>50%) and might deteriorate the retrievable crystallographic information. Displaying only single or multiple detector hits can slightly improve the visibility of poles and zone lines. Excluding atoms which require a higher number of pulses to field evaporate and illustrating the data after the latter does not provide any crystallographic information regarding TiN. In both cases, voltage and laser mode experiments, it is possible to resolve individual lattice planes within spatial distribution maps.

KW - Atomsondentomographie

KW - Atomsondenkristallografie

KW - Dünne Schichten

KW - Kristallografie

KW - TiN

KW - Titannitrid

KW - Atom probe tomography

KW - Atom probe crystallography

KW - Thin films

KW - Crystallography

KW - TiN

KW - Titanium nitride

M3 - Master's Thesis

ER -