It was recalled that thin-film deposition technology was the first critical step in the development of the 39K superconductor. It had been found to be a challenging task due to the volatility of Mg, the phase stability of MgB2, the low sticking coefficients of Mg at high temperatures and the reactivity of Mg with O. A brief overview of then-current deposition techniques was provided here from the thermodynamic perspective, with an emphasis on a very successful technique for producing high-quality in situ epitaxial MgB2 films: hybrid physical–chemical vapour deposition.

Progress in the Deposition of MgB2 Thin Films. X.X.Xi, A.V.Pogrebnyakov, X.H.Zeng, J.M.Redwing, S.Y.Xu, Q.Li, Z.K.Liu, J.Lettieri, V.Vaithyanathan, D.G.Schlom, H.M.Christen, H.Y.Zhai, A.Goyal: Superconductor Science and Technology, 2004, 17, S196-201