Thermodynamic reactivity of the magnesium vapor with substrate materials during MgB2 deposition

Abstract

Abstract The MgB2 compound has a superconducting temperature of 39 K and its film has been successfully deposited by means of the hybrid physical chemical vapor deposition (HPCVD). In this paper, the CALPHAD technique was applied to study the reactivity of magnesium with several substrate materials during the HPCVD process. The calculated results showed that MgO, SiC, AlN and TaN are stable in the current HPCVD process. The Si, ZrO2, TiN, SiO2, Al2O3 and GaN substrates were also investigated. It was found that Mg reacts with these substrates under current HPCVD conditions. However, if the Mg vapor is low enough but still in the stability range of the MgB2 compound, the Si, ZrO2 and TiN substrates can be stable in the HPCVD process. The methodology used in the present work can be extended to other systems, and the current findings may be useful to guide other MgB2 thin film deposition processes.