Detailed Analysis and Precise Modeling of Multiple-Energy Al Implantations Through $\hbox {SiO}_{2}$ 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 SiO₂ layer is formed on 4H-SiC substrates misoriented by 8deg from (0001) toward [112 macr0]. 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 SiO₂ in a decreasing energy order. To understand this mechanism, concentration profiles of Al implantations at a single energy with and without SiO₂ are modeled using the dual-Pearson approach. Based on the developed model, the Al ion channeling in 4H-SiC is discussed in terms of effects of surface SiO₂ layers and the sequence of multiple-energy implantations.