Origin and Generation Process of a Triangular Single Shockley Stacking Fault Expanding from the Surface Side in 4H-SiC PIN Diodes

• Published in: Journal of electronic materials Vol. 50; no. 11; pp. 6504 - 6511
• Main Authors: Ota, Chiharu, Nishio, Johji, Okada, Aoi, Iijima, Ryosuke
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.11.2021; Springer Nature B.V
• Subjects: Basal plane; Burgers vector; Characterization and Evaluation of Materials; Chemistry and Materials Science; Edge dislocations; Electroluminescence; Electron microscopes; Electronics and Microelectronics; Epitaxial growth; Instrumentation; Materials Science; Optical and Electronic Materials; Original Research Article; Photoluminescence; PIN diodes; Solid State Physics; Stacking faults; Substrates; Synchrotron radiation; Synchrotrons; Threshold currents; X ray imagery; X ray topography; partial dislocation; TED-BPD-TED; 4H-SiC; forward degradation; single Shockley stacking fault
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-021-09186-y

A triangular single Shockley stacking fault (1SSF) in 4H-SiC, expanding from the surface to the substrate/epilayer interface, was investigated. The triangular 1SSF was observed during electroluminescence examination of PIN diodes that had line-and-space anodes with open windows. The threshold current density of the 1SSF expansion was comparatively intermediate, and differed from that of a 1SSF that expanded from a basal plane dislocation (BPD) that had penetrated from the substrate into the epilayer, and from that of a 1SSF that expanded from a BPD that had converted into threading edge dislocations (TEDs) at the substrate/epilayer interface. No BPDs or surface damage such as cracks were observed by photoluminescence imaging, synchrotron x-ray topography imaging, or scanning electron microscope imaging near the origin of the expansion region. High-resolution observation using cross-sectional transmission electron microscopy showed that a partial dislocation (PD) was present on the basal plane and two inclined TEDs were present on both sides of the PD. A g · b analysis showed that this dislocation had a Burgers vector of ± (1/3) [11 2 ¯ 0], and it was estimated to be a combination of a TED-BPD-TED structure with a short BPD before expansion. Therefore, the triangular 1SSF from the surface side can be explained to have expanded from this BPD. Furthermore, considering the possibility of the BPD-TED conversion at the epitaxial growth process, the TED-BPD-TED dislocation was speculated to have formed after epitaxial growth. The perfect control of the forward voltage degradation of 4H-SiC device is thought to be realized by focusing on this type of BPD.