3D Imaging and Characterization of Threading Screw Dislocations in 4H-SiC n+ Using Confocal Photoluminescence Microscopy

Irwan Saleh Kurniawan^1,2*, Russel Cruz Sevilla^1,2, Hsiu-Ming Hsu^1,2, Chi-Tsu Yuan^1,2

¹Department of Physiscs, Chung Yuan Christian University, Taoyuan, Taiwan
²Center for Semiconductor Materials and Advanced Optics, Taoyuan, Taiwan

* Presenter:Irwan Saleh Kurniawan, email:ikurniawan90@gmail.com

The demand for high-efficiency power devices has increased interest in wide-bandgap semiconductors like 4H-SiC due to its superior electrical and thermal properties. However, defects such as threading screw dislocations (TSDs) can degrade device performance by affecting carrier lifetime and leakage currents. This study utilizes confocal photoluminescence (PL) microscopy to inspect and characterize TSDs in 4H-SiC n+ bulk wafer. KOH etching reveals TSDs as hexagonal pits on the wafer surface. PL microscopy illuminates the defects and analyses the emitted light along the dislocation lines, capturing their spatial distribution and density. The bright core dislocation line is visible at the bottom of the etch pit in cross-sectional views. Spectral analysis reveals dislocation energy peaks around 2.1 eV, with an average photoluminescence lifetime of 0.47 ns. 3D imaging visualizes the dislocations behavior below the surface. These findings provide valuable insights into the optical and electronic properties of TSDs, contributing to the development of non-destructive inspection methods for 4H-SiC.

Keywords: 4H-SiC, Threading Screw Dislocations (TSDs), Confocal Photoluminescence Microscopy, Non-Destructive Inspection, 3D Imaging