Analysis of the growth kinetics during high temperature crystal growth of large area SiC using gamma-computed-laminography for the in-situ 3D imaging of the growth interface

该项目提案解决了单晶碳化硅在约2200°C下生长的动力学问题，并利用了通过3D计算机断层扫描和伽玛计算机层析成像系统获得的生长界面的原位测量数据。在第一期项目成果的基础上，重点研究大直径碳化硅微球结晶过程中的生长现象。为此，将分析不同晶种取向下生长岛的多面初始生长和随后的聚并。该项目的目标是扩展和量化第一个项目阶段的生长模型，该模型已经包括了晶体缺陷横向过度生长的基本方面以及单晶面积的扩大。作为预期项目任务的前期工作，实验室已经安装了一台新的PVT生长机（生长直径为150 mm和200 mm的SiC球体）。为了可视化大直径SiC晶体生长界面的生长过程，计划安装原位伽玛计算机层析成像系统。由于晶体直径大，能量为125 keV甚至160 keV的x射线在碳化硅孔中完全衰减。因此，应用对角x射线成像系统是必要的。后一项任务从第一个项目阶段的结果中获益良多，在第一个项目阶段，通过一个小尺寸的75毫米碳化硅孔对成像的分析已经考虑到了x射线阴影伪影。最后，使用考虑公平数据原则（可查找、可访问、可互操作和可重用）的电子数据库对实验数据进行分析，并对SiC结晶过程中的相关生长现象进行系统调查。在SiC结晶过程中的所有过程数据以及所有原位CT成像结果和SiC表征测量将收集在数据库中，允许系统和部分自动化分析。

The project proposal addresses the kinetics of the growth of single crystalline silicon carbide at ca. 2200 °C and makes use of in-situ measurement data of the growth interface acquired by 3D computed tomography as well as gamma-computed-laminography imaging systems. Based on the results of the first project phase, the scientific study focuses on growth phenomena during the crystallization of SiC boules with a large diameter. For this purpose, the multi-facetted initial growth as well as subsequent coalescence of the growth islands will be analyzed for various crystal seed orientations. The goal of the project is to extend and quantify the growth model of the first project phase that already included basic aspects of the lateral overgrowth of crystal defects as well as the enlargement of the single crystalline area. As preliminary work of the anticipated project tasks, a new PVT growth machine (growth of SiC boules with a diameter of 150 mm and 200 mm) has been installed in the lab. In order to visualize the growth processes at the growth interface of SiC crystals with a large diameter, the installation of an in-situ gamma-computed laminography imaging system is planned. Because of the large crystal diameter, X-rays of an energy of 125 keV and even of 160 keV are completely attenuated in the SiC boule. Therefore, the application of a diagonal X-ray imaging system is necessary. The latter task profits significantly from the results of the first project phase in which the analysis of the imaging through a small size 75 mm SiC boule already accounted for X-ray shadowing artefacts.Finally, the analysis of the experimental data and the systematic investigation of the related growth phenomena during the crystallization of SiC will be carried out using an electronic data base that considers the FAIR-data-principle (Findable, Accessible, Interoperable, and Re-usable). All process data during crystallization of SiC as well as all in-situ CT imaging results and SiC characterization measurements will be collected in the data base that allows a systematic and partially automated analysis.