Influence of annealing parameters on surface roughness, mobility, and contact resistance of aluminium implanted 4H SiC

The impact of implantation temperature and dose as well as the annealing process with and without a graphite capping layer on surface roughness, carrier mobility and specific contact resistance are investigated and compared. The use of the capping layer is proven to be particularly advantageous: (1) a deterioration of surface roughness can be avoided even for high dose implantations and (2) the specific contact resistance is reduced. Furthermore, it is shown that a capping layer prevents surface contamination during annealing.