Emission Defects Induced by Focused Ga Ion Implantation under High-Dose Window in Silicon Carbide

Focused ion beam (FIB) implantation provides a versatile method for engineering defects. In this work, we report a previously unobserved defect-related zero-phonon line (ZPL)─termed ZPL Spot ─induced by high-dose focused gallium (Ga) ion implantation (30 kV, 600 pA) into a 4H-SiC substrate. Under cryogenic conditions (1.6 K), the ZPL Spot emission is centered around 750 nm with a narrow line width, fwhm < 0.4 nm. Depth-resolved photoluminescence measurements, performed via both vertical line scanning and depth-specific 2D lateral mapping, indicate that the location of the ZPL Spot emission is at the base of microvias fabricated by the high-dose implantation. This distinct localization clearly differentiates the ZPL Spot emission from conventional defect emissions originating within bulk 4H-SiC, which is further confirmed by emission polarization measurements. Based on a comprehensive analysis of the formation conditions of the ZPL Spot emission, and correlative high-resolution transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) measurements, we propose that the emission center is associated with high-dose implanted Ga ions and forms within the damaged layer of the 4H-SiC substrate.