Detailed analysis and precise modeling of multiple-energy Al implantations through SiO2 layers into 4H-SiC

This paper presents a detailed analysis and precise modeling of multiple-energy Al implantations necessary for boxlike profiles in the p(+)-region of 4H-SiC power devices To demonstrate the balance between "scatter-in channeling" and "amorphization-suppressed channeling," a thin-surface SiO(2) layer is formed on 4H-SiC substrates misoriented by 8 degrees from (0001) toward [11 (2) over bar0]. Experimental, as well as Monte-Carlo-simulated, as-implanted concentration profiles of Al normally incident to the surface suggest that the least ion channeling is realized for implantations Without SiO(2) in a decreasing energy order. To understand this mechanism, concentration profiles of Al implantations at a single energy with and without SiO(2) are modeled using the dual-Pearson approach. Based on the developed model, the At ion channeling in 4H-SiC is discussed in terms of effects of surface SiO(2) layers and the sequence of multiple-energy implantations.