Al+ and B+ implantations into 6H-SiC epilayers and application to pn junction diodes

Aluminum (Al) and boron (B) ion implantations at room temperature into n-type 6H-SiC epilayers have been investigated. Rutherford backscattering spectroscopy (RBS) channeling measurements revealed larger lattice damage in Al+ implantation at a given total implantation dose. A nearly perfect electrical activation ratio (>90%) could be attained by high-temperature annealing at 1600 degrees C for Al+ and 1700 degrees C for B+ implantations. Mesa pn junction diodes formed by either Al+ or B+ implantation with a 1 x 10(14) cm(-2) dose exhibited high blocking voltages of 950 similar to 1070 V, which are 80 similar to 90% of the ideal value predicted for the diode structure. The forward current can clearly be divided into two components of diffusion and recombination currents. B+-implanted diodes showed higher breakdown voltage on average but poor forward conduction. Comparison of the performance of Al+ and B+-implanted diodes is discussed.