Process Sensitivity of 355 nm-Laser-Induced High-Concentration Aluminum Doping for P-Type Layer in Semi-Insulating 4H-SiC

The advancement of high-power 4H-SiC devices demands innovative solutions to address doping challenges. This study introduces a 355 nm DPSS Nd:YAG laser scanning doping as a method for aluminum doping and surface modification in semi-insulating 4H-SiC, addressing the limitations of conventional ion-implantation techniques. Through a systematic investigation of laser fluence, we identify process windows that balance carrier activation and material properties. At a fluence threshold of 2.588 J/cm2, effective Al activation was achieved, while higher fluences induce polysilicon formation, as verified by Raman, GIXRD, SIMS, and Hall measurements. Remarkably, laser processing generates a multilayer surface structure– graphite, polysilicon, poly-SiC, and 4H-SiC–potentially reducing the barrier height. This method demonstrates significant potential for fabricating high-performance ptype contacts on 4H-SiC. These findings highlight the sensitivity and versatility of laser doping, offering critical insights into next-generation SiC fabrication strategies.