TEM Investigation on High Dose Al Implanted 4H-SiC Epitaxial Layer

Abstract

Within this work, the effect of high dose Al ion implantation on 4H-SiC epitaxial layer is displayed. Through TEM investigation it is demonstrated that the implanted surface is suitable as seed for subsequent epitaxial regrowth generating a crystal free of extended defects. In order to assess the defects within the projected range of the ion implanted area, High Angle Annular Dark Field STEM (HAADF-STEM) analyses were performed demonstrating the atomic arrangement of the lattice in correspondence of the dislocation loop and the deviation of the crystallographic planes of 4H-SiC, driven by stress relaxation, that determine the staircase configuration of the implant pattern. Further emphasis is given to the detailed analysis of the precipitates atomic structure, whose preferential localization is ascertained. Using Energy-Dispersive X-ray spectroscopy (EDS) analysis, the precipitate is finally established as Al crystal with an FCC structure.