Shuttle Activation Annealing of Implanted Al in 4H-SiC

A shuttle-type annealing process as a new high-temperature activation annealing technique for SiC has been investigated. Wide-range annealing time (1 s to 3 h) and temperature (1300 to 2000 °C) dependences of electrical properties for Al-ion-implanted 4H-SiC are examined using capacitance–voltage (C–V) and Hall measurement. When the annealing temperature is between 1700 and 1900 °C, the acceptor activation ratio of 80% shows no dependence on the annealing time from 1 s to 30 min, while the Hall measurement reveals that both the hole density and the mobility increase with an increase in the annealing time and/or annealing temperature. This indicates that the activation of Al acceptors is a fast process compared with the implantation-damage annealing-out processes. The surface morphology of rapidly annealed samples is fairly smooth. An appropriate annealing condition should be determined with due consideration of the trade-off between electrical quality, surface morphology, and throughput.