Nanoscale Infrared Spectroscopic Characterization of Extended Defects in 4H-Silicon Carbide

Scott G. Criswell, Nadeemullah A. Mahadik, James C. Gallagher, Julian Barnett, Luke Kim, Morvarid Ghorbani, Bhaveshkumar Kamaliya, Nabil D. Bassim, Thomas Taubner and Joshua D. Caldwell

Nano Letters 24, 114 (2024)

Extended defects in wide-bandgap semiconductors have been widely investigated using techniques providing either spectroscopic or microscopic information. Nano-Fourier transform infrared spectroscopy (nano-FTIR) is a nondestructive characterization method combining FTIR with nanoscale spatial resolution (∼20 nm) and topographic information. Here, we demonstrate the capability of nano-FTIR for the characterization of extended defects in semiconductors by investigating an in-grown stacking fault (IGSF) present in a 4H-SiC epitaxial layer. We observe a local spectral shift of the mid-infrared near-field response, consistent with the identification of the defect stacking order as 3C-SiC (cubic) from comparative simulations based on the finite dipole model (FDM). This 3C-SiC IGSF contrasts with the more typical 8H-SiC IGSFs reported previously and is exemplary in showing that nanoscale spectroscopy with nano-FTIR can provide new insights into the properties of extended defects, the understanding of which is crucial for mitigating deleterious effects of such defects in alternative semiconductor materials and devices.