A new preparation method for MgB2 films, involving chemical vapour deposition from B2H6 was reported. This was a 2-step ex situ approach, with the precursor B films grown by CVD from B2H6 at 460C, followed by post-annealing in Mg vapour at 830C. The prepared MgB2 thin films on Al2O3 polycrystalline substrates had an onset transition temperature of 35K and a zero-resistance temperature of about 24K. Well-crystallized MgB2 grains were clearly observed in scanning electron microscopy images and were confirmed by X-ray diffraction analysis. The advantages of the proposed method included the possibility of preparing large-area superconducting films.

A New Method for Preparing Superconducting MgB2 Films from Diborane. D.S.Wang, X.H.Fu, Z.P.Zhang, J.Yang: Chinese Physics Letters, 2002, 19, 1179-80