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

该项目提案涉及在约2200°C下单晶碳化硅的生长动力学，并利用3D计算机层析成像和伽马计算机层析成像系统获得的生长界面的现场测量数据。在第一阶段研究成果的基础上，重点研究了大直径碳化硅微球结晶过程中的生长现象。为此，将针对不同的晶种取向，分析生长岛的多面初始生长以及随后的融合。该项目的目标是扩展和量化第一个项目阶段的生长模型，该模型已经包括晶体缺陷横向过度生长以及单晶区扩大的基本方面。作为预期项目任务的前期工作，已经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的碳化硅微球)。为了可视化大直径碳化硅晶体生长界面的生长过程，计划安装一套原位伽马计算层析成像系统。由于晶体直径较大，能量为125keV甚至160keV的X射线在碳化硅球泡中完全衰减。因此，对角线X射线成像系统的应用是必要的。后一项任务得益于第一个项目阶段的结果，在该项目阶段，通过小尺寸75 mm碳化硅团块的成像分析已经考虑了X射线阴影伪影。最后，将使用一个考虑公平数据原则(可发现、可访问、可互操作和可重复使用)的电子数据库来分析实验数据和系统地研究碳化硅结晶过程中的相关生长现象。碳化硅结晶过程中的所有工艺数据以及所有现场CT成像结果和碳化硅特性测量将被收集在数据库中，以便进行系统和部分自动化的分析。

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.