In this work, we present the effect of nitrogen etching by hydrogen during the CVD growth of SiC. This effect could play a major role in many phenomena involved in doping. We show that not only silicon and carbon but also nitrogen can be etched and further redeposited. Even though the atomic concentration of nitrogen is very small compared to the main species, etching experiments show that the deposited layer can be significantly doped, typically 10 % of the etched layer doping. An etching reaction between nitrogen and hydrogen has been added to the simulation model. We show that the model fits the experimental observations on a large part of the susceptor.