We investigated parameters of nickel contacts to 21R-SiC doped with nitrogen (carrier concentration of 3x10(18) cm(-3)) after rapid thermal annealing (RTA) at different conditions. It was found that significant modifications of the contact structure occur in the temperature range of 400-750 degreesC. During annealing a thin film of NiSi is formed which prevents carbon atom penetration to a surface of the contact. A measured specific contact resistance was about 5x10(-3) Ohm(.)cm(2).