Nondestructive Spectroscopic Investigation of N-Type 4H-SiC Defects Irradiated With Low Fluence 16.5 MeV/u Ta Ions

SiC-based devices are extensively used in environments subject to radiation, where high-fluence irradiation causes amorphization and chemical reordering in 4H-SiC. In this article, we examine the evolution of defects in the nitrogen-doped, n-type surface region of 4H-SiC at room temperature by exposing it to 16.5 MeV/u Ta ion irradiation at low fluences (108~1010 cm−2). Atomic force microscopy (AFM) imaging reveals elongated protrusions on the surface of the 4H-SiC resulting from irradiation, and the root mean square (rms) increases to 1.3, 2.7, and 2.9 nm with increasing irradiation fluence. In the X-ray photoelectron spectroscopy (XPS) spectra, the Si-C bond decreases, while the Si-O-C bond, C-O bond, and
$\text{O}^{\prime }$
increase with increasing irradiation fluence. Based on photoluminescence (PL) spectra and Raman spectra, we suggest that the defects present in the irradiated SiC with low fluence Ta ion mainly consist of C vacancies and their complexes and a small amount of disordered Si-Si bond. In summary, the C atoms of SiC are more likely to collide away from their original positions, leading to Si-C bond breaks. As the irradiation fluence increases, Si and O atoms will occupy these vacancies and form relevant defects.