Al+ and B+ Implantations into 6H-SiC Epilayers and Application to pn Junction Diodes

摘要

Aluminum (Al) and boron (B) ion implantations at room temperature into n-type 6H-SiC epilayers have been investigated. Rutherford backscattering spectros- copy (RBS) channeling measurements revealed larger lattice damage in Al+ implantation at a given total implantation dose. A nearly perfect electrical activation ratio (>90/100) could be attained by high-temperature annealing at 1600℃ for Al+ and 1700℃ for B+ implantations. Mesa pn junction diodes formed by either Al+ or B+ implantation with a 1 × 10~14 cm~-2 dose exhibited high blocking voltages of 950～1070 V, which are 80～90/100 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.