Simple route to grow high-quality MgB2 thin films using decaborane as a boron source

Abstract

We report the growth of high-quality MgB2 films by thermally decomposing decaborane (B10H14) in Mg vapor. B10H14 is solid at ambient temperatures and stable in air, and hence it is much more convenient to use in thin film growth than highly explosive diborane that has been commonly used in hybrid physical–chemical vapor deposition of MgB2 films. We grew MgB2 films on c-cut sapphire substrates held at 400–450°C by supplying vaporized B10H14 into a pocket heater with high Mg vapor pressure. The resultant films as thin as 100nm showed strong and sharp c-axis lattice peaks in X-ray diffraction, indicating nearly ideal epitaxial growth. The films showed a superconducting transition at around 39K.