Doping of silicon carbide by ion implantation

A brief survey is given of some recent results on doping of 4H- and 6H-SiC by ion implantation. The doses and energies used are between 10⁹ and 10¹⁵ cm^-2 and 100 keV and 5 MeV, respectively, and B and Al ions (p-type dopants) are predominantly studied. After low dose implantation (≤10¹⁰ cm^-2) a strong compensation is observed in n-type samples and this holds irrespective of implantation temperature up to 600°C. However, at higher doses (10¹⁴-10¹⁵ Al/cm²) the rate of defect recombination (annihilation) increases substantially during hot implants (>200°C), and in these samples one type of structural defect dominates after post-implant annealing at 1700-2000°C. The defect is identified as a dislocation loop composed of clustered interstitial atoms inserted on the basal plane in the hexagonal crystal structure. Finally, transient enhanced diffusion (TED) of ion-implanted boron in 4H-samples is discussed.