Defects distribution and evolution in selected-area helium ion implanted 4H-SiC

Color centers in silicon carbide has been widely studied in view of the promising near-infrared emission near the low-loss telecom wavelengths as well as the maturity of semiconductor technology of silicon carbide material. Recently, there is an urgent need to generate color centers in predetermined location so as to integrate with photonic cavities of waveguides. In this paper, we report an experimentally demonstration of the generation of VSi, CSiVC, and NCVSi color centers in 4H-SiC using helium ion microscope in 5×5 µm areas with subsequent annealing treatment. Combined with transmission electron microscopy (TEM), photoluminescence (PL) and cathodoluminescence (CL) spectroscopy and Raman stress analysis, the evolution and distribution of color centers were thoroughly investigated. Cross-sectional TEM revealed the presence of helium bubbles in center of the implanted region with high doses which account for the observed quench of PL emission in center of the implanted regions in both PL and CL measurements. PL spectra from the virgin, implanted and annealed samples proved the appearance of VSi after implantation and the transformation from VSi to CSiVC and NCVSi centers after annealing at 1000 ℃. Moreover, as the increase of the implantation dose, the area of NCVSi centers increases whereas that of CSiVC decreases, which implied a competitive relationship between the formation of CSiVC and NCVSi defects. The comparison between stress distribution and CSiVC defect distribution illustrated that CSiVC centers predominantly distributed around the surface rupture region after thermal annealing where significant stress repair occurred. The results suggest that focused helium ion implantation holds promise for the precise coupling of VSi, CSiVC and NCVSi centers in predefined location in integrated photonics applications.