Influence of the Al-ion implantation temperature in 4H-SiC on the activation rate and the quality of the subsequent thermal oxide

To optimize the channel doping process and gate oxide reliability of planar 4H-SiC MOSFETs, this study systematically investigates the influence of aluminum ion implantation temperature (25 °C vs. 500 °C) on dopant distribution and the quality of the subsequently thermally grown oxide layer. Through comparative analysis of the electrical characteristics and material properties of samples implanted at different temperatures, it is found that under low-concentration aluminum doping, the activation rates for both 25 °C and 500 °C implants are nearly identical, approaching 100%. However, implantation at 500 °C exhibits a higher activation rate under high-concentration doping conditions. In contrast, implantation at 25 °C introduces a higher density of dislocations, leading to an increase in interface state density at the interface between the subsequently thermally grown SiO₂ layer and the 4H-SiC substrate, as well as a rise in leakage current. The results demonstrate that the implantation temperature directly affects the integrity of the gate dielectric oxide layer by modulating the processes of damage formation and repair, providing critical insights for optimizing the doping process in high-performance SiC power devices. • Damage Differentiation in 4H-SiC Induced by Aluminum Ion Implantation at 25°C versus 500°C. • Activation concentration difference in 4H-SiC with aluminum ion implantation at 25°C versus 500°C. • Impact of Aluminum Ion Implantation at 25°C and 500°C on the Quality of Thermally Grown SiO₂ Layers on 4H-SiC.