High temperature high-dose implantation of aluminum in 4H-SiC

Heavily doped p-type layers obtained by implanting aluminum near its solubility limit (∼2×1020Al∕cm3) in 4H-SiC are characterized as a function of the implant and anneal temperatures. For a typical implant temperature of 650°C, Al activation rates of ∼6%–35% are obtained for anneals from 1600 to 1750°C, respectively. For higher temperature implants at 1000°C, the Al activation rates are significantly improved, approaching ∼100% for the same anneal temperatures, with a best p-type resistivity of ∼0.20Ωcm. For SiC device fabrication, these results demonstrate that by using higher Al implant temperatures, lower anneal temperatures can be used while obtaining close to 100% Al activation.