Often the cap annealing of Al ion implanted SiC is done at high temperature (1900°C and more). However, the roughening of the SiC surface reduces the performance of the device.
Using amorphous carbon thin film deposited with ECR plasma as a cap prior to annealing helps alleviate this problem. The a-C that has been grown with ECR plasma is hard as diamond and heat resistant and therefore prevents the roughening of the underlying substrate during the annealing.
The ECR deposition allows for pinhole-free thickness-precise deposition of a-C on any substrate and annealing at 2000°C has been demonstrated.
After annealing, a plasma process is applied to completely remove the a-C layer.