Electrical and structural properties of MgB₂ films prepared by sequential deposition of B and Mg on the NbN-buffered Si(100) substrate

NbN-buffered Si(100) substrates were used for the preparation of the MgB₂ films grown by a sequential evaporation of the B and Mg. It was shown that the application of the NbN buffer layer deposited at room temperature and preannealed in the in-situ step before the process of the MgB₂ film preparation results in improved superconductivity and transport properties of the final films. The observation was confirmed by the magneto-optic and microwave measurements. The results show that the maximum zero resistance critical temperature 36 K is the highest value for the in-situ prepared polycrystalline MgB₂ films on the Si substrate.