Energy order effect of aluminum multiple implantation in 6H-SiC

A fivefold aluminum implantation was performed at room temperature in two n-type epitaxial 6H-SiC. The energies went from 25 keV to 300 keV, aiming at forming a 0.5 mu m depth p(+)-n junction, with a box profile p(+)-region at a concentration of 4*10(19) cm(-3). The two samples wen: implanted with two different energy orders. First, differences were observed between the aluminum chemical profiles (SIMS) of each sample For example, the channeling tail is reduced for the one which was implanted with an increasing energy order. This phenomenon leads to a more abrupt electrical junction, and favors the reproducibility of the process. The SIMS profiles are compared with a specific Monte Carlo simulator recently developed, taking into account the implantation angles and the channeling effect. RBS/C spectra show then for the same sample a larger amorphized layer, and a steeper transition between the amorphous and crystalline layers. Both samples were finally annealed in the same conditions, and their post-annealed characteristics are also described.