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

该项目建议书涉及单晶碳化硅在约100 ℃下生长的动力学。2200 °C，并利用通过3D计算机断层扫描以及伽马计算机断层成像系统获得的生长界面的原位测量数据。基于项目第一阶段的结果，科学研究的重点是大直径SiC晶锭结晶过程中的生长现象。为此，将针对各种晶种取向分析多面初始生长以及随后的生长岛的合并。该项目的目标是扩展和量化第一项目阶段的生长模型，该模型已经包括晶体缺陷的横向过度生长以及单晶区域的扩大的基本方面。作为预期项目任务的前期工作，在实验室安装了一台新的PVT生长机（生长直径为150 mm和200 mm的SiC梨晶）。为了观察大直径SiC晶体生长界面处的生长过程，计划安装一个原位γ计算断层成像系统。由于大的晶体直径，能量为125keV甚至160keV的X射线在SiC晶锭中完全衰减。因此，对角线X射线成像系统的应用是必要的。后一项任务从第一项目阶段的结果中获益匪浅，在第一项目阶段中，通过小尺寸75 mm SiC晶锭的成像分析已经考虑了X射线阴影伪影。最后，将使用考虑FAIR数据原理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研究（可查找、可扩展、可互操作和可重用）。SiC结晶过程中的所有工艺数据以及所有原位CT成像结果和SiC表征测量结果都将收集在数据库中，从而可以进行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.