The annealing behavior of B or N dual implants in 1-SiC thin films has been studied using cross-sectional transmission electron microscopy (XTEM), secondary ion mass spectroscopy (SIMS), and four point probe electrical measurements. A high resistivity layer was produced after annealing the B implanted-amorphous layer in the temperature range from 1000°C to 1500°C for 300 a; however, the resistivity rapidly decreased as a result of annealing at higher temperatures. The reasons for these changes in resistivity and the lack of p-type conduction at all annealing temperatures in these B implants include: (1) possible compensation of the native n-type carriers, (2) reduction in the B concentration via formation of B-containing precipitates between 1300°C and 1600°C and out diffusion of this species at and above 1600°C, and (3) creation of additional n-type carriers.
No precipitates or defect structure was observed in N implanted-annealed samples. The resistivity of this non amorphous n-type layer decreased with increasing annealing temperatures from 700°C to 1800°C. Furthermore n-p junction diodes were fabricated for the first time in β-SiC via N implantation into samples previously in situ doped with 8 × 1018/cm3 Al coupled with rapid thermal annealing at 1200°C for 300 a. A typical diode ideality constant and a saturation current for these diodes was 3.4 and 9 × 10-10 A/cm2, respectively.