Focused Ion Beam (FIB) is an important analytical and sample modification technique in the field of electron and ion microscopy. It has been widely used in different kinds of applications including semiconductor device failure analysis, material science research, nanoscale 3D tomography, as well as microstructure prototyping and surface modification. Recent developments from the rapid growing industry and our frontier research have posted new challenges on the FIB technology itself. Higher resolution has been realized by state-of-the-art hardware infrastructures and less sample destruction has been achieved by efficient operation recipes.
In this doctoral thesis, a study of advanced Focused Ion Beam sample preparation is presented, with the goal to prepare samples with low or no damage. The study is divided into two aspects according to various aspects in the FIB applications: sample damage and in-situ preparation. In the first aspect, sample damage, namely amorphization, ion implantation and FIB milling rate are investigated on crystalline silicon specimens with a gallium FIB tool. To study the ion-beam induced amorphous layer thickness under certain conditions, silicon specimens were prepared by FIB into specific geometry, so that the induced amorphous layer can be imaged and the thickness can be determined quantitatively using Transmission Electron Microscopy (TEM). Atom Probe Tomography (APT) was carried out to study the implanted ion concentration of gallium FIB prepared silicon specimens. In addition, the gallium FIB milling rate was also studied for a silicon substrate using Scanning Electron Microscopy (SEM). These experimental results provide detailed information of beam-sample interactions from the FIB sample preparation. In order to gain a systematic understanding of the processes, as well as to be able to predict the outcome of a specific FIB recipe, a physics model and an adapted algorithm (TRIDYN) based on Binary Collision Approximation (BCA) were used for the simulation of FIB processes. The predicted results based on simulations were compared with experiments. The proposed model was successfully validated by the experimental results, i.e., the TRIDYN algorithm has the capability to provide predictions for the multi- step FIB sample preparation process and the respective recipes.
The other aspect involves a novel design of a hardware configuration of a SEM/FIB system add-on to perform in-situ surface modification tasks such as argon ion polishing of specimens. This Beam Induced Polishing System (BIPS) overcomes the disadvantages that some of the ex-situ methods have, and it completes some of the advanced FIB recipes for extremely thin and pristine specimens. In the thesis, the functionality of a BIPS system is explained in detail, and first experimental results are shown to demonstrate the proof of concept of the system.
To summarize, this doctoral thesis presents an adapted algorithm, which is validated by experiments, to simulate the multi-step Focused Ion Beam process for recipes of low- damage sample preparation; A novel in-situ experiment system BIPS is also introduced, providing an option to complement SEM/FIB systems for advanced FIB sample preparation recipes.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:33727 |
| Date | 10 April 2019 |
| Creators | Huang, Jin |
| Contributors | Zschech, Ehrenfried, Boit, Christian, Möller, Wolfhard, Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/acceptedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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