Dislocation Strain Mapping in SiC Power Semiconductors: A Correlative ECCI, HR-EBSD, and Modeling Approach

As part of the DISMAP project, Prof. Friedrich is working on the systematic mapping of elastic strain fields in 4H-SiC power semiconductors. The goal is to achieve a non-destructive and quantitative characterization of the strain fields of individual defects - including basal plane dislocations, screw dislocations, step dislocations, and stacking faults - in SiC wafers, which has not been possible until now. Silicon carbide is a key material for the next generation of power semiconductors in electric vehicles, photovoltaic systems, and industrial inverters. The electrical properties and long-term reliability of these devices are largely determined by crystalline defects.

To this end, the project utilizes correlative scanning electron microscopy: Electron Channeling Contrast Imaging is used to image relevant defect types, which are then identified through systematic contrast analysis. In addition, high-resolution electron backscatter diffraction is used to measure and reconstruct elastic strain tensors with a sensitivity of approximately 10⁻⁴. The strain fields are interpreted at the atomic level and integrated into a theoretical framework to establish a consistent reference database. This database serves as the foundation for strain-sensitive metrology methods and offers significant potential for transfer to industrial applications.