Theoretical study on the improvement of the doping efficiency of Al in 4H-SiC by co-doping group-IVB elements |
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| Affiliation: | 1.State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China;2.Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311200, China;3.School of Materials Science and Engineering&Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450001, China |
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| Abstract: | The p-type doping efficiency of 4H silicon carbide (4H-SiC) is rather low due to the large ionization energies of p-type dopants. Such an issue impedes the exploration of the full advantage of 4H-SiC for semiconductor devices. In this study, we show that co-doping group-IVB elements effectively decreases the ionization energy of the most widely used p-type dopant, i.e., aluminum (Al), through the defect-level repulsion between the energy levels of group-IVB elements and that of Al in 4H-SiC. Among group-IVB elements Ti has the most prominent effectiveness. Ti decreases the ionization energy of Al by nearly 50%, leading to a value as low as ~0.13 eV. As a result, the ionization rate of Al with Ti co-doping is up to ~5 times larger than that without co-doping at room temperature when the doping concentration is up to 1018 cm-3. This work may encourage the experimental co-doping of group-IVB elements such as Ti and Al to significantly improve the p-type doping efficiency of 4H-SiC. |
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| Keywords: | 4H-SiC p-type co-doping ab initio study |
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