The present invention relates to a crack-free monocrystalline nitride layer having the composition AlxGa1−xN, where 0≦x≦0.3, and a substrate that is likely to generate tensile stress in the nitride layer. The structure successively includes the substrate; a nucleation layer; a monocrystalline intermediate layer having a selected thickness on the nucleation layer; a monocrystalline seed layer of an AlBN compound in which the boron content is between 0 and 10% having a selected thickness on the intermediate layer and a relaxation rate, at ambient temperature, of less than 80%; and the monocrystalline nitride layer.