Influence of the Metallization Composition and Annealing Process Parameters on the Resistance of Ohmic Contacts to n-type 6H-SiC
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For silicon carbide, the problem of obtaining low-resistance ohmic contacts with improved service characteristics remains topical despite a significant body of experimental data. The influence exerted by the composition of Ni and TiAl metallization, alloying parameters, additional doping of the contact layer of silicon carbide (SiC) with N+ nitrogen ions, and the crystallographic Si- or C-face on the resistance of ohmic contacts to n-6H-SiC is examined. It is found that the greatest influence on how ohmic contacts to n-6H-SiC are formed is exerted by the alloying process resulting in a decrease in the contact resistance by approximately six times. The process of additional doping with N+ also reduces the contact resistance by nearly a factor of four. It is found that low-resistance contacts can be obtained on both faces with approximately the same low resistance. TiAl metallization is optimal for the C-face, and Ni metallization, for the Si-face. This choice of metallization makes it possible to obtain ohmic contacts on both polar faces with approximately the same resistances on the order of 2.5 × 10–4 Ω cm2.
Keywords:silicon carbide ohmic contact ion implantation
This work was financially supported by the Ministry of Education and Science of the Russian Federation (agreement no. 14.581.21.0021, unique identifier RFMEFI58117X0021).
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