Structural and electrical characteristics of oxygen-implanted 6H-SiC

Silicon carbide is an important wide band gap semiconductor for high-temperature, high-voltage, high-power and high-frequency devices. Ion implantation is an important aspect for both fundamental research and device applications. In this report, oxygen ions, 70 keV with dose ranging from 5 × 10¹³ to 5 × 10¹⁵ cm^-2, have been implanted into n-type 6H-SiC. The damage behavior and internal stress were checked by Rutherford backscattering spectroscopy and channeling and X-rays rocking curve, respectively. Atomic force microscope observations revealed that the surface morphology is quite sensitive to the implantation even at a dose of 1 × 10¹⁴/cm^-2. After annealing in nitrogen at 1200°C, no remarkable damage recovery could be seen if the deposit damage energy is above the critical value. Schottky structures of Au/SiC have been fabricated and I-V curves of metal/SiC/InGeNi were measured at room temperature at both forward and reverse bias, electrical isolation effect was observed at proper implantation dose. The results indicated that there exists a dose window for electrical isolations. X-ray photoelectron spectroscopy (XPS) confirmed the formation of silicon oxide and CO due to oxygen implantation. In case of high-dose ion implantation, graphite phase was detected.